feat(hosts): add hosts list page with filters, pagination and delete

Implements task #7. The Hosts page provides:
- Name/network/port/application filters (sentinel values instead of
  Option<T> to avoid server function serialization issues)
- Configurable page size (15 default, 25/50/100/All)
- Prev/next navigation with total host count
- Add host form with network selector
- Delete action per row

Sub-components (AddHostForm, FilterBar, PaginationBar, HostTable) each
call .into_any() to erase their concrete view types. This breaks the
deeply-nested generic type that caused "queries overflow the depth
limit!" without requiring an unbounded recursion_limit increase.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,18 @@
+# .env.example — Copier ce fichier en .env et adapter les valeurs
+#
+# Ce fichier est versionné dans git pour servir de référence.
+# Le fichier .env réel contient des secrets et ne doit JAMAIS être commité.
+
+# --- Base de données ---
+# Choisir UNE des deux options ci-dessous :
+
+# Option 1 : SQLite (recommandé pour le développement — aucun serveur requis)
+# Le fichier sera créé automatiquement s'il n'existe pas.
+DATABASE_URL=sqlite://data/ipam.db
+
+# Option 2 : PostgreSQL (recommandé pour la production)
+# DATABASE_URL=postgresql://utilisateur:motdepasse@localhost:5432/ipam
+
+# --- Logs ---
+# Niveau de log : error | warn | info | debug | trace
+RUST_LOG=info

.gitignore

@@ -1 +1,4 @@
 /target
+.env
+data/
+.DS_Store

CLAUDE.md

@@ -26,6 +26,7 @@
 - Ne jamais utiliser `unwrap()` en production — toujours `?` ou `.expect("message clair")`
 - Toujours expliquer les lifetimes si elles apparaissent
 - Préférer les types idiomatiques Rust (`Option`, `Result`)
+- Le code généré devra suivre le conventions standard, le code et les commentaires sont rédigés en anglais.
 
 ## Git & Commits
 - Committer chaque changement fonctionnel terminé (ne pas accumuler)
@@ -37,4 +38,14 @@
   - `chore(deps): update axum to 0.8`
 - Ne jamais committer du code qui ne compile pas (`cargo check` avant)
 - Une fonctionnalité = une branche = une PR
-- Branches : `feature/<nom>`, `fix/<nom>`, `chore/<nom>`
+- Branches : `feature/<nom>`, `fix/<nom>`, `chore/<nom>`
+
+## Architecture
+- Deux databases possible, postgresql ou sqlite. Le choix dois se faire par la configuration de l'application.
+- Un hote possede un nom, une IP, des ports ouverts
+- Les ports peuvent avoir une description pour indiquer quel est le protocole le plus probable d'être utiliser sur ce port (ex: 22 - SSH, 53 - DNS, 80 - HTTP, 443 - HTTPS)
+- Un port peut être associé à une application, l'association n'est pas strict car un port peut être utilisé par plusieurs applications.
+- Une application possede un nom, un ou plusieurs ports.
+- Un réseaux et définit par son CIDR (ex: 192.168.1.0/24)
+- L'application peut gérer plusieurs réseaux distinct.
+- Chaques hôtes doit appartenir au réseaux dans lequel il est définit.

Cargo.toml

@@ -1,6 +1,102 @@
 [package]
 name = "rust-ipam"
 version = "0.1.0"
-edition = "2024"
+edition = "2021"
+
+# Leptos nécessite deux formats de compilation :
+# - rlib   : bibliothèque normale, utilisée par le serveur Axum
+# - cdylib : bibliothèque dynamique compilée en WebAssembly pour le navigateur
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+# Les "features" permettent d'activer du code conditionnellement selon le contexte.
+# On compile deux fois le même code : une fois en mode "ssr" (serveur), une fois "hydrate" (WASM).
+[features]
+# Mode serveur : active Axum, Tokio, et le rendu HTML côté serveur
+ssr = [
+    "dep:axum",
+    "dep:tokio",
+    "dep:tower-http",
+    "dep:leptos_axum",
+    "dep:tracing-subscriber",
+    "dep:dotenvy",
+    "dep:ipnetwork",
+    "dep:sqlx",
+    "leptos/ssr",
+    "leptos_meta/ssr",
+    "leptos_router/ssr",
+]
+# Mode client : compile l'application en WebAssembly pour le navigateur
+# Note : seul `leptos` expose une feature "hydrate" ; leptos_meta et leptos_router
+# n'en ont pas besoin — ils s'adaptent automatiquement au mode de compilation.
+hydrate = [
+    "dep:console_error_panic_hook",
+    "dep:wasm-bindgen",
+    "dep:web-sys",
+    "leptos/hydrate",
+]
 
 [dependencies]
+# --- Dépendances partagées (compilées côté serveur ET client) ---
+
+# Framework UI réactif full-stack : le cœur du projet
+leptos = { version = "0.7", features = [] }
+# Gestion des balises HTML <head> (title, meta tags, liens CSS...)
+leptos_meta = { version = "0.7", features = [] }
+# Routeur : associe des URLs à des composants, côté serveur et client
+leptos_router = { version = "0.7", features = [] }
+
+# Dérive automatiquement des types d'erreurs idiomatiques Rust
+thiserror = "1"
+# Macros pour les logs : tracing::info!(), tracing::error!()...
+tracing = "0.1"
+# Sérialisation/désérialisation — nécessaire pour les server functions Leptos
+# (les types de retour doivent traverser la frontière server ↔ client)
+serde = { version = "1", features = ["derive"] }
+
+# --- Dépendances serveur uniquement (activées par la feature "ssr") ---
+
+# Serveur HTTP asynchrone rapide et ergonomique
+axum = { version = "0.7", optional = true }
+# Runtime asynchrone Rust (nécessaire pour `async fn main()` et les Futures)
+tokio = { version = "1", features = ["full"], optional = true }
+# Pont entre Leptos et Axum : SSR, server functions, streaming...
+leptos_axum = { version = "0.7", optional = true }
+# Middleware HTTP : sert les fichiers statiques (CSS, WASM compilé, images...)
+tower-http = { version = "0.5", features = ["fs"], optional = true }
+# Formateur de logs pour le terminal (affiche les messages tracing::info!...)
+tracing-subscriber = { version = "0.3", features = ["env-filter"], optional = true }
+# Charge automatiquement le fichier .env au démarrage du serveur
+dotenvy = { version = "0.15", optional = true }
+# Parsing et calcul de plages d'adresses IP (CIDR) — ex: 192.168.1.0/24
+ipnetwork = { version = "0.20", optional = true }
+# Database access: connection pools, queries, migrations — SQLite + PostgreSQL
+# "any" = runtime-dispatched driver (same code works with both backends)
+sqlx = { version = "0.8", features = ["runtime-tokio", "tls-rustls", "sqlite", "postgres", "migrate", "any"], optional = true }
+
+# --- Dépendances client uniquement (activées par la feature "hydrate") ---
+
+# Affiche les panics Rust dans la console du navigateur (indispensable pour déboguer)
+console_error_panic_hook = { version = "0.1", optional = true }
+# Pont entre Rust/WASM et JavaScript : permet d'appeler du JS depuis Rust
+wasm-bindgen = { version = "0.2", optional = true }
+# Bindings aux APIs du navigateur : window, document, localStorage, Element...
+web-sys = { version = "0.3", features = ["Window", "Document", "Element", "Storage"], optional = true }
+
+# Configuration Leptos lue par get_configuration(Some("Cargo.toml"))
+# Définit les chemins des fichiers compilés et l'adresse du serveur.
+[package.metadata.leptos]
+output-name = "rust-ipam"     # Nom de base des fichiers .wasm et .js générés
+site-root = "target/site"     # Dossier racine des fichiers compilés par trunk
+site-pkg-dir = "pkg"          # Sous-dossier des assets WASM/JS dans site-root
+site-addr = "127.0.0.1:3000"  # Adresse d'écoute du serveur Axum
+reload-port = 3001             # Port WebSocket pour le hot-reload en développement
+
+# Profil de compilation WASM optimisé pour réduire la taille du fichier .wasm
+# Un fichier WASM plus petit = page qui charge plus vite
+[profile.wasm-release]
+inherits = "release"
+opt-level = "z"     # Optimise pour la taille (z) plutôt que la vitesse (3)
+lto = true           # Link-Time Optimization : élimine le code mort entre crates
+codegen-units = 1    # Un seul thread de codegen = meilleure optimisation globale
+panic = "abort"      # Pas de stack unwinding = binaire plus petit

Trunk.toml

@@ -0,0 +1,29 @@
+# Trunk.toml — Configuration de trunk
+# trunk est l'outil de build pour les applications Rust/WASM.
+#
+# Commandes principales :
+#   trunk build --features hydrate          → compilation dev
+#   trunk build --features hydrate --release → compilation prod optimisée
+#   trunk serve --features hydrate           → serveur de dev avec hot-reload
+
+[build]
+# Feature à activer lors de la compilation WASM
+features = ["hydrate"]
+
+# Dossier de sortie des fichiers WASM/JS.
+# Doit correspondre à site-pkg-dir dans [package.metadata.leptos] du Cargo.toml,
+# car Axum sert ce dossier sur le chemin "/pkg/".
+dist = "target/site/pkg"
+
+# Désactive les hashes dans les noms de fichiers (ex: rust-ipam-abc123.js → rust-ipam.js).
+# Sans ça, HydrationScripts (Leptos) ne peut pas trouver les bons fichiers WASM
+# car il génère des URLs sans hash (/pkg/rust-ipam.js).
+filehash = false
+
+[watch]
+# Ne pas surveiller ces dossiers pour éviter les boucles infinies
+ignore = ["./target"]
+
+[serve]
+port = 3000
+open = false

index.html

@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<html lang="fr">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <!--
+      trunk complète automatiquement ce fichier lors de `trunk build` ou `trunk serve` :
+      - Il injecte les balises <link> pour charger le CSS compilé
+      - Il injecte les balises <script> pour charger le bundle WebAssembly
+      Ne pas ajouter ces balises manuellement ici — trunk le fait pour vous.
+    -->
+    <!--
+      Indique à trunk de compiler le target "lib" (cdylib → WASM)
+      et non le binaire "rust-ipam" (qui lui est le serveur Axum).
+      data-target-name correspond au nom du crate avec underscores (convention Rust).
+    -->
+    <link data-trunk rel="rust" data-target-name="rust_ipam" />
+    <!--
+      Compile style/rust-ipam.css → target/site/pkg/rust-ipam.css
+      Served by Axum at /pkg/rust-ipam.css and loaded by the <Stylesheet>
+      component in app.rs.
+    -->
+    <link data-trunk rel="css" href="style/rust-ipam.css" />
+  </head>
+  <body>
+    <!--
+      Leptos monte l'application ici via mount_to_body() (défini dans lib.rs).
+
+      Flux SSR + Hydration :
+      1. Le navigateur demande la page au serveur Axum
+      2. Axum rend le composant App() en HTML (SSR) et l'envoie
+      3. Le navigateur affiche le HTML instantanément (pas d'écran blanc)
+      4. Le bundle WASM se charge en arrière-plan
+      5. Leptos "hydrate" le HTML : attache les event listeners pour le rendre interactif
+    -->
+  </body>
+</html>

migrations/postgres/0001_create_networks.sql

@@ -0,0 +1,6 @@
+-- networks: IP address ranges managed by the IPAM.
+-- BIGSERIAL: auto-incrementing 64-bit integer (PostgreSQL's equivalent of AUTOINCREMENT).
+CREATE TABLE IF NOT EXISTS networks (
+    id   BIGSERIAL PRIMARY KEY,
+    cidr TEXT      NOT NULL UNIQUE
+);

migrations/postgres/0002_create_hosts.sql

@@ -0,0 +1,7 @@
+-- hosts: physical or virtual machines belonging to a network.
+CREATE TABLE IF NOT EXISTS hosts (
+    id         BIGSERIAL PRIMARY KEY,
+    name       TEXT   NOT NULL,
+    ip         TEXT   NOT NULL,
+    network_id BIGINT NOT NULL REFERENCES networks(id) ON DELETE CASCADE
+);

migrations/postgres/0003_create_ports.sql

@@ -0,0 +1,5 @@
+-- ports: global catalog of TCP/UDP port numbers and their known protocol.
+CREATE TABLE IF NOT EXISTS ports (
+    number      INTEGER PRIMARY KEY,
+    description TEXT
+);

migrations/postgres/0004_create_applications.sql

@@ -0,0 +1,5 @@
+-- applications: software stacks that use one or more ports.
+CREATE TABLE IF NOT EXISTS applications (
+    id   BIGSERIAL PRIMARY KEY,
+    name TEXT      NOT NULL
+);

migrations/postgres/0005_create_host_ports.sql

@@ -0,0 +1,6 @@
+-- host_ports: which ports are open on which host (many-to-many).
+CREATE TABLE IF NOT EXISTS host_ports (
+    host_id     BIGINT  NOT NULL REFERENCES hosts(id) ON DELETE CASCADE,
+    port_number INTEGER NOT NULL REFERENCES ports(number) ON DELETE CASCADE,
+    PRIMARY KEY (host_id, port_number)
+);

migrations/postgres/0006_create_application_ports.sql

@@ -0,0 +1,6 @@
+-- application_ports: which ports an application typically uses (many-to-many).
+CREATE TABLE IF NOT EXISTS application_ports (
+    application_id BIGINT  NOT NULL REFERENCES applications(id) ON DELETE CASCADE,
+    port_number    INTEGER NOT NULL,
+    PRIMARY KEY (application_id, port_number)
+);

migrations/sqlite/0001_create_networks.sql

@@ -0,0 +1,6 @@
+-- networks: IP address ranges managed by the IPAM.
+-- Each network has a unique CIDR block (e.g. "192.168.1.0/24").
+CREATE TABLE IF NOT EXISTS networks (
+    id   INTEGER PRIMARY KEY AUTOINCREMENT,
+    cidr TEXT    NOT NULL UNIQUE
+);

migrations/sqlite/0002_create_hosts.sql

@@ -0,0 +1,9 @@
+-- hosts: physical or virtual machines belonging to a network.
+-- The ip field must fall within the CIDR of the parent network
+-- (enforced in application code, not at the DB level).
+CREATE TABLE IF NOT EXISTS hosts (
+    id         INTEGER PRIMARY KEY AUTOINCREMENT,
+    name       TEXT    NOT NULL,
+    ip         TEXT    NOT NULL,
+    network_id INTEGER NOT NULL REFERENCES networks(id) ON DELETE CASCADE
+);

migrations/sqlite/0003_create_ports.sql

@@ -0,0 +1,7 @@
+-- ports: global catalog of TCP/UDP port numbers and their known protocol.
+-- Ports are not tied to a specific host here — host_ports handles that link.
+-- Port numbers range from 0 to 65535 (fits in INTEGER).
+CREATE TABLE IF NOT EXISTS ports (
+    number      INTEGER PRIMARY KEY,
+    description TEXT
+);

migrations/sqlite/0004_create_applications.sql

@@ -0,0 +1,6 @@
+-- applications: software stacks that use one or more ports.
+-- Examples: "Nginx", "PostgreSQL", "Prometheus".
+CREATE TABLE IF NOT EXISTS applications (
+    id   INTEGER PRIMARY KEY AUTOINCREMENT,
+    name TEXT    NOT NULL
+);

migrations/sqlite/0005_create_host_ports.sql

@@ -0,0 +1,7 @@
+-- host_ports: which ports are open on which host (many-to-many).
+-- Composite primary key prevents duplicate (host, port) pairs.
+CREATE TABLE IF NOT EXISTS host_ports (
+    host_id     INTEGER NOT NULL REFERENCES hosts(id) ON DELETE CASCADE,
+    port_number INTEGER NOT NULL REFERENCES ports(number) ON DELETE CASCADE,
+    PRIMARY KEY (host_id, port_number)
+);

migrations/sqlite/0006_create_application_ports.sql

@@ -0,0 +1,8 @@
+-- application_ports: which ports an application typically uses (many-to-many).
+-- port_number is not a strict FK to ports to allow registering an application
+-- before its port entry exists in the catalog.
+CREATE TABLE IF NOT EXISTS application_ports (
+    application_id INTEGER NOT NULL REFERENCES applications(id) ON DELETE CASCADE,
+    port_number    INTEGER NOT NULL,
+    PRIMARY KEY (application_id, port_number)
+);

src/api/applications.rs

@@ -0,0 +1,107 @@
+// api/applications.rs — Server functions for applications and their port associations
+
+use leptos::prelude::*;
+
+use crate::models::Application;
+
+// ─── Queries ──────────────────────────────────────────────────────────────────
+
+/// Returns all applications ordered by name.
+#[server]
+pub async fn get_applications() -> Result<Vec<Application>, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::list_applications(&pool)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Returns the port numbers associated with an application.
+#[server]
+pub async fn get_ports_for_application(
+    application_id: i64,
+) -> Result<Vec<u16>, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::list_ports_for_application(&pool, application_id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+// ─── Mutations ────────────────────────────────────────────────────────────────
+
+/// Creates a new application and returns the created record.
+#[server]
+pub async fn create_application(name: String) -> Result<Application, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::create_application(&pool, &name)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Deletes an application and all its port associations.
+///
+/// Returns `true` if the application existed and was deleted.
+#[server]
+pub async fn delete_application(id: i64) -> Result<bool, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::delete_application(&pool, id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Associates a port number with an application.
+///
+/// If the association already exists, this is a no-op.
+#[server]
+pub async fn add_port_to_application(
+    application_id: i64,
+    port_number: u16,
+) -> Result<(), ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::add_port_to_application(&pool, application_id, port_number)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Removes a port association from an application.
+///
+/// If the association does not exist, this is a no-op.
+#[server]
+pub async fn remove_port_from_application(
+    application_id: i64,
+    port_number: u16,
+) -> Result<(), ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::remove_port_from_application(&pool, application_id, port_number)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}

src/api/hosts.rs

@@ -0,0 +1,222 @@
+// api/hosts.rs — Server functions for hosts
+
+use leptos::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use crate::models::Host;
+
+// ─── Presentation types ───────────────────────────────────────────────────────
+
+// A host row enriched with its network CIDR and pre-computed counts.
+// Used by the paginated hosts list (get_hosts_page).
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct HostRow {
+    pub id: i64,
+    pub name: String,
+    pub ip: String,
+    pub network_id: i64,
+    pub network_cidr: String,
+    pub port_count: i64,
+    pub application_count: i64,
+}
+
+// Result of a paginated, filtered host query.
+#[derive(Clone, Debug, Serialize, Deserialize, Default)]
+pub struct HostsPage {
+    pub rows: Vec<HostRow>,
+    pub total: i64,       // total rows matching the filters (ignoring pagination)
+    pub page: i64,        // current page (1-indexed)
+    pub per_page: i64,    // items per page; 0 = all
+    pub total_pages: i64, // ceil(total / per_page); always ≥ 1
+}
+
+// ─── Queries ──────────────────────────────────────────────────────────────────
+
+/// Returns all hosts belonging to a given network.
+#[server]
+pub async fn get_hosts_by_network(network_id: i64) -> Result<Vec<Host>, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::hosts as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::list_hosts_by_network(&pool, network_id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Returns a filtered and paginated list of hosts across all networks.
+///
+/// Filter parameters use sentinel values (0 / empty string) to mean "no filter":
+///   - `name_filter`            : substring match on host name (case-insensitive); "" = all
+///   - `network_id_filter`      : exact network id; 0 = all
+///   - `port_filter`            : hosts with this port open; 0 = all
+///   - `application_id_filter`  : hosts linked to this application; 0 = all
+///   - `per_page`               : items per page; 0 = return everything
+///   - `page`                   : 1-indexed page number
+///
+/// The SQL uses each bind parameter twice in the WHERE clause
+/// (once for the IS NULL guard, once for the actual comparison).
+/// Each $N placeholder refers to the N-th bound argument by index.
+#[server]
+pub async fn get_hosts_page(
+    name_filter: String,
+    network_id_filter: i64,
+    port_filter: i64,
+    application_id_filter: i64,
+    page: i64,
+    per_page: i64,
+) -> Result<HostsPage, ServerFnError> {
+    use sqlx::{AnyPool, Row};
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    // Convert sentinel values to Option for SQL NULL binding.
+    // None → binds as SQL NULL → "$N IS NULL" evaluates to TRUE → filter skipped.
+    let name_like: Option<String> = if name_filter.is_empty() {
+        None
+    } else {
+        Some(format!("%{}%", name_filter))
+    };
+    let network_id: Option<i64> = if network_id_filter == 0 { None } else { Some(network_id_filter) };
+    let port: Option<i64>       = if port_filter == 0        { None } else { Some(port_filter) };
+    let app_id: Option<i64>     = if application_id_filter == 0 { None } else { Some(application_id_filter) };
+
+    // Each filter param is bound twice so the same $N can appear in both
+    // the IS NULL guard and the comparison without re-declaring parameters.
+    const WHERE: &str = "
+        JOIN networks n ON n.id = h.network_id
+        LEFT JOIN host_ports hp  ON hp.host_id = h.id
+        LEFT JOIN application_ports ap ON ap.port_number = hp.port_number
+        WHERE ($1 IS NULL OR LOWER(h.name) LIKE LOWER($1))
+          AND ($2 IS NULL OR h.network_id = $2)
+          AND ($3 IS NULL OR EXISTS (
+                  SELECT 1 FROM host_ports
+                  WHERE host_id = h.id AND port_number = $3
+              ))
+          AND ($4 IS NULL OR EXISTS (
+                  SELECT 1 FROM host_ports hp2
+                  JOIN application_ports ap2 ON ap2.port_number = hp2.port_number
+                  WHERE hp2.host_id = h.id AND ap2.application_id = $4
+              ))";
+
+    // Count matching hosts (ignoring pagination).
+    let count_sql = format!("SELECT COUNT(DISTINCT h.id) FROM hosts h {WHERE}");
+    let total: i64 = sqlx::query_scalar(&count_sql)
+        .bind(name_like.as_deref())
+        .bind(network_id)
+        .bind(port)
+        .bind(app_id)
+        .fetch_one(&pool)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    // Compute pagination bounds.
+    let safe_page = page.max(1);
+    let (limit, offset, total_pages) = if per_page <= 0 {
+        (1_000_000_000i64, 0i64, 1i64)
+    } else {
+        let tp = ((total + per_page - 1) / per_page).max(1);
+        (per_page, (safe_page - 1) * per_page, tp)
+    };
+
+    // Fetch the page of hosts with enriched columns.
+    let data_sql = format!(
+        "SELECT h.id, h.name, h.ip, h.network_id,
+                n.cidr AS network_cidr,
+                COUNT(DISTINCT hp.port_number)      AS port_count,
+                COUNT(DISTINCT ap.application_id)   AS application_count
+         FROM hosts h
+         {WHERE}
+         GROUP BY h.id, h.name, h.ip, h.network_id, n.cidr
+         ORDER BY h.name, h.id
+         LIMIT $5 OFFSET $6"
+    );
+
+    let rows = sqlx::query(&data_sql)
+        .bind(name_like.as_deref())
+        .bind(network_id)
+        .bind(port)
+        .bind(app_id)
+        .bind(limit)
+        .bind(offset)
+        .fetch_all(&pool)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let host_rows = rows
+        .into_iter()
+        .map(|row| HostRow {
+            id:                row.get("id"),
+            name:              row.get("name"),
+            ip:                row.get("ip"),
+            network_id:        row.get("network_id"),
+            network_cidr:      row.get("network_cidr"),
+            port_count:        row.get("port_count"),
+            application_count: row.get("application_count"),
+        })
+        .collect();
+
+    Ok(HostsPage {
+        rows: host_rows,
+        total,
+        page: safe_page,
+        per_page,
+        total_pages,
+    })
+}
+
+// ─── Mutations ────────────────────────────────────────────────────────────────
+
+/// Creates a new host inside the specified network.
+///
+/// Validates that `ip` falls within the CIDR of `network_id`.
+/// Returns an error if the network does not exist or the IP is out of range.
+#[server]
+pub async fn create_host(
+    name: String,
+    ip: String,
+    network_id: i64,
+) -> Result<Host, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::{
+        repository::{hosts, networks},
+        validation::validate_ip_in_network,
+    };
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    let network = networks::find_network(&pool, network_id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?
+        .ok_or_else(|| {
+            ServerFnError::new(format!("Network {network_id} not found"))
+        })?;
+
+    validate_ip_in_network(&ip, &network.cidr)
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    hosts::create_host(&pool, &name, &ip, network_id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Deletes a host by id.
+///
+/// Also removes all its port associations (via `ON DELETE CASCADE`).
+/// Returns `true` if the host existed and was deleted.
+#[server]
+pub async fn delete_host(id: i64) -> Result<bool, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::hosts as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::delete_host(&pool, id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}

src/api/mod.rs

@@ -0,0 +1,20 @@
+// api/ — Leptos server functions (the bridge between client and server)
+//
+// Server functions are annotated with `#[server]`.
+// Leptos compiles them differently depending on the active feature:
+//
+//   ssr     → the function body runs on the server (normal async Rust code)
+//   hydrate → the body is replaced by an HTTP POST call to /api/<fn-name>
+//
+// This means:
+//   - Function signatures (arguments + return types) must compile for BOTH targets.
+//     All types used here must also be in `models.rs` (shared code).
+//   - Imports inside the function body are only compiled for `ssr`,
+//     so ssr-only modules (server::repository, sqlx) can be used freely there.
+//   - The pool is retrieved via `use_context::<AnyPool>()` — it is injected
+//     into the Leptos context by `main.rs` for every request.
+
+pub mod applications;
+pub mod hosts;
+pub mod networks;
+pub mod summary;

src/api/networks.rs

@@ -0,0 +1,125 @@
+// api/networks.rs — Server functions for networks
+
+use leptos::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use crate::models::Network;
+
+// Network row augmented with pre-computed counts.
+// Defined here (not in models.rs) because it is a presentation model
+// specific to the Networks page, not a pure domain entity.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct NetworkWithCounts {
+    pub id: i64,
+    pub cidr: String,
+    /// Number of hosts whose IP falls within this network's CIDR range.
+    pub host_count: i64,
+    /// Number of distinct applications linked via ports open on hosts in this network.
+    pub application_count: i64,
+}
+
+// ─── Queries ──────────────────────────────────────────────────────────────────
+
+/// Returns all networks from the database.
+///
+/// Called by the Networks page to populate the list.
+#[server]
+pub async fn get_networks() -> Result<Vec<Network>, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::networks as repo;
+
+    // `use_context` retrieves a value previously registered with `provide_context`.
+    // The pool was injected in main.rs before every request.
+    // `ok_or_else` converts `None` into an error (defensive: should never happen).
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    // Propagate any DB error as a ServerFnError so the client sees a clean message.
+    repo::list_networks(&pool)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Returns all networks enriched with host and application counts.
+///
+/// A single SQL query fetches everything at once using correlated subqueries,
+/// avoiding N+1 round-trips regardless of the number of networks.
+///
+/// `application_count` = distinct applications whose registered ports appear
+/// among the ports open on hosts in each network (via host_ports → application_ports).
+#[server]
+pub async fn get_networks_with_counts() -> Result<Vec<NetworkWithCounts>, ServerFnError> {
+    use sqlx::{AnyPool, Row};
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    let rows = sqlx::query(
+        "SELECT
+            n.id,
+            n.cidr,
+            (SELECT COUNT(*) FROM hosts WHERE network_id = n.id) AS host_count,
+            (SELECT COUNT(DISTINCT ap.application_id)
+               FROM hosts h
+               JOIN host_ports hp ON hp.host_id = h.id
+               JOIN application_ports ap ON ap.port_number = hp.port_number
+              WHERE h.network_id = n.id) AS application_count
+         FROM networks n
+         ORDER BY n.id",
+    )
+    .fetch_all(&pool)
+    .await
+    .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let networks = rows
+        .into_iter()
+        .map(|row| NetworkWithCounts {
+            id:                row.get("id"),
+            cidr:              row.get("cidr"),
+            host_count:        row.get("host_count"),
+            application_count: row.get("application_count"),
+        })
+        .collect();
+
+    Ok(networks)
+}
+
+// ─── Mutations ────────────────────────────────────────────────────────────────
+
+/// Creates a new network with the given CIDR block.
+///
+/// Returns the created record (with its auto-generated id).
+/// Returns an error if the CIDR is malformed or already exists.
+#[server]
+pub async fn create_network(cidr: String) -> Result<Network, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::{repository::networks as repo, validation::validate_cidr};
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    // Validate the CIDR before touching the database.
+    // Example of a valid CIDR: "192.168.1.0/24"
+    validate_cidr(&cidr).map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    repo::create_network(&pool, &cidr)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
+/// Deletes a network by id.
+///
+/// Also deletes all hosts in that network (via `ON DELETE CASCADE`).
+/// Returns `true` if the network existed and was deleted.
+#[server]
+pub async fn delete_network(id: i64) -> Result<bool, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::networks as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    repo::delete_network(&pool, id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}

src/api/summary.rs

@@ -0,0 +1,45 @@
+// api/summary.rs — Dashboard summary server function
+//
+// Returns the count of each main entity in a single server round-trip.
+// The home page uses this to display a quick-glance dashboard without
+// loading the full list of each entity.
+
+use leptos::prelude::*;
+use serde::{Deserialize, Serialize};
+
+// Counts for every top-level entity shown on the dashboard.
+// Add a field here when a new entity type is introduced.
+#[derive(Clone, Debug, Serialize, Deserialize, Default)]
+pub struct Summary {
+    pub network_count: i64,
+    pub host_count: i64,
+    pub application_count: i64,
+}
+
+#[server]
+pub async fn get_summary() -> Result<Summary, ServerFnError> {
+    use sqlx::AnyPool;
+    use leptos::prelude::use_context;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    // Three lightweight COUNT queries — no full table scans on the payload side.
+    // sqlx returns COUNT(*) as i64 for both SQLite and PostgreSQL.
+    let network_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM networks")
+        .fetch_one(&pool)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let host_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM hosts")
+        .fetch_one(&pool)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let application_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM applications")
+        .fetch_one(&pool)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    Ok(Summary { network_count, host_count, application_count })
+}

src/app.rs

@@ -0,0 +1,110 @@
+// app.rs — Root Leptos components
+//
+// This file contains two components:
+//   - `Shell` : full HTML document (head + body) — SSR only
+//   - `App`   : page content and router — shared between SSR and WASM
+
+use leptos::prelude::*;
+use leptos_meta::*;
+use leptos_router::{
+    components::{Route, Router, Routes},
+    path,
+};
+
+use crate::client::{home::HomePage, hosts::HostsPage, networks::NetworksPage, theme::ThemeToggle};
+
+// Shell — full HTML document rendered by the Axum server.
+//
+// This component only exists in SSR mode (`#[cfg(feature = "ssr")]`).
+// It provides the HTML skeleton that leptos_meta requires:
+// a valid <head> and <body>. Without it, <Title> and <Stylesheet>
+// components have nowhere to inject their output.
+//
+// SSR rendering flow:
+//   1. Axum calls Shell() for each incoming request
+//   2. Shell renders <head> with MetaTags (a placeholder filled by App)
+//   3. Shell renders <body> containing App()
+//   4. App() calls provide_meta_context() and registers metadata
+//   5. Leptos retroactively injects that metadata into MetaTags
+//   6. HydrationScripts generates <script> tags to load the WASM bundle
+#[cfg(feature = "ssr")]
+#[component]
+pub fn Shell(
+    // LeptosOptions holds project configuration (paths, file names, ports...).
+    // Used by HydrationScripts to build the WASM bundle URLs.
+    options: leptos::config::LeptosOptions,
+) -> impl IntoView {
+    view! {
+        <!DOCTYPE html>
+        <html lang="en">
+            <head>
+                <meta charset="utf-8"/>
+                <meta name="viewport" content="width=device-width, initial-scale=1"/>
+                // MetaTags: placeholder where leptos_meta injects tags collected
+                // from <Title>, <Stylesheet>, <Meta>... defined inside App().
+                <MetaTags/>
+                // HydrationScripts: generates <link> and <script> tags that load
+                // the trunk-compiled WASM bundle and call hydrate() from lib.rs.
+                <HydrationScripts options=options.clone()/>
+                // AutoReload: hot-reload during development (no-op in production).
+                // Only activates when the LEPTOS_WATCH environment variable is set.
+                <AutoReload options/>
+            </head>
+            <body>
+                // App() runs here, provides the meta context, and renders page content.
+                <App/>
+            </body>
+        </html>
+    }
+}
+
+// App — root component shared between the server (SSR) and the browser (WASM).
+//
+// This component is rendered:
+//   - server-side : inside the Shell <body>, to generate HTML
+//   - client-side : via hydrate() in lib.rs, to attach reactivity
+//
+// `-> impl IntoView` : returns "something displayable". The concrete type is
+// opaque because Leptos's `view!` macro generates a complex internal type.
+#[component]
+pub fn App() -> impl IntoView {
+    // Initialize the Leptos metadata context.
+    // Without this call, <Title>, <Stylesheet>, and <Meta> in child components
+    // would have no context to store their metadata in.
+    provide_meta_context();
+
+    view! {
+        <Title text="Rust IPAM — IP Address Manager"/>
+
+        // Load the global CSS from /pkg/rust-ipam.css.
+        // This file is generated by trunk from style.css (to be added later).
+        <Stylesheet id="main" href="/pkg/rust-ipam.css"/>
+
+        // Router handles client-side navigation without full page reloads.
+        // On the server, it determines which component to render for the requested URL.
+        <Router>
+                <nav>
+                <a href="/">"Rust IPAM"</a>
+                <a href="/networks">"Networks"</a>
+                <a href="/hosts">"Hosts"</a>
+                <span class="nav-spacer"/>
+                <ThemeToggle/>
+            </nav>
+
+            <main>
+                // <Routes> is the container for all route definitions.
+                // `fallback` is displayed when no route matches the current URL.
+                <Routes fallback=|| view! {
+                    <div class="not-found">
+                        <h1>"404 — Page not found"</h1>
+                        <a href="/">"← Back to home"</a>
+                    </div>
+                }>
+                    <Route path=path!("/") view=HomePage/>
+                    <Route path=path!("/networks") view=NetworksPage/>
+                    <Route path=path!("/hosts") view=HostsPage/>
+                </Routes>
+            </main>
+        </Router>
+    }
+}

src/client/home.rs

@@ -0,0 +1,72 @@
+// client/home.rs — Dashboard home page
+//
+// Shows a quick-glance summary card for each main entity (Networks, Hosts,
+// Applications). Each card displays the total count and navigates to the
+// corresponding page on click.
+//
+// The counts are fetched via a single `get_summary()` server function call
+// so the page only makes one round-trip to the server.
+
+use leptos::prelude::*;
+use crate::api::summary::get_summary;
+
+// A single summary card — count + label + link.
+//
+// `href`  : navigation target when the card is clicked
+// `label` : entity name displayed on the card
+// `count` : the number to show, or None while loading
+#[component]
+fn SummaryCard(href: &'static str, label: &'static str, count: Signal<Option<i64>>) -> impl IntoView {
+    view! {
+        <a href=href class="summary-card">
+            <span class="summary-card__count">
+                {move || match count.get() {
+                    Some(n) => n.to_string(),
+                    None    => "—".to_string(),
+                }}
+            </span>
+            <span class="summary-card__label">{label}</span>
+        </a>
+    }
+}
+
+#[component]
+pub fn HomePage() -> impl IntoView {
+    // Fetch all counts in a single server call.
+    // Source `|| ()` is constant — the fetcher runs exactly once on mount.
+    let summary = Resource::new(|| (), |_| get_summary());
+
+    view! {
+        <div class="home-page">
+            <header class="home-header">
+                <h1>"Rust IPAM"</h1>
+                <p>"IP Address Manager"</p>
+            </header>
+
+            // `<Suspense>` lets the SSR server wait for the resource before sending
+            // HTML, so the counts are already filled in on first page load.
+            // The fallback is only shown in the browser while the WASM loads
+            // (for users with slow connections).
+            <Suspense fallback=|| view! {
+                <div class="summary-grid">
+                    <div class="summary-card"><span class="summary-card__count">"—"</span><span class="summary-card__label">"Networks"</span></div>
+                    <div class="summary-card"><span class="summary-card__count">"—"</span><span class="summary-card__label">"Hosts"</span></div>
+                    <div class="summary-card"><span class="summary-card__count">"—"</span><span class="summary-card__label">"Applications"</span></div>
+                </div>
+            }>
+                {move || summary.get().map(|result| match result {
+                    Err(e) => view! {
+                        <p class="error">"Could not load summary: " {e.to_string()}</p>
+                    }.into_any(),
+                    Ok(s) => view! {
+                        <div class="summary-grid">
+                            <SummaryCard href="/networks"     label="Networks"     count=Signal::derive(move || Some(s.network_count))/>
+                            <SummaryCard href="/hosts"        label="Hosts"        count=Signal::derive(move || Some(s.host_count))/>
+                            <SummaryCard href="/applications" label="Applications" count=Signal::derive(move || Some(s.application_count))/>
+                        </div>
+                    }.into_any(),
+                })}
+            </Suspense>
+        </div>
+    }
+}

src/client/hosts.rs

@@ -0,0 +1,352 @@
+// client/hosts.rs — Hosts list page
+//
+// Displays all hosts across every network with:
+//   - Add form    : create a host inside a chosen network
+//   - Filter bar  : name (substring), network, open port, application
+//   - Table       : name, IP, network, port count, application count, delete
+//   - Pagination  : configurable page size (15 / 25 / 50 / 100 / All)
+//
+// Each sub-component calls `.into_any()` on its view to return `AnyView`
+// (a type-erased wrapper). This prevents Rust from composing all the nested
+// generic types into a single enormous type in the parent's monomorphization,
+// which would otherwise overflow the compiler's query depth limit.
+
+use leptos::prelude::*;
+use leptos::form::ActionForm;
+
+use crate::api::{
+    applications::get_applications,
+    hosts::{CreateHost, DeleteHost, get_hosts_page, HostsPage as HostsPageData},
+    networks::get_networks,
+};
+
+const PER_PAGE_OPTIONS: &[(i64, &str)] = &[
+    (15,  "15"),
+    (25,  "25"),
+    (50,  "50"),
+    (100, "100"),
+    (0,   "All"),
+];
+
+// ─── Add host form ────────────────────────────────────────────────────────────
+
+#[component]
+fn AddHostForm(
+    create_action: ServerAction<CreateHost>,
+    networks_res: Resource<Result<Vec<crate::models::Network>, ServerFnError>>,
+) -> impl IntoView {
+    view! {
+        <section class="add-form">
+            <h2>"Add a host"</h2>
+            <ActionForm action=create_action>
+                <div class="add-form__fields">
+                    <label>
+                        "Name"
+                        <input type="text" name="name" placeholder="e.g. web-server-01" required/>
+                    </label>
+                    <label>
+                        "IP address"
+                        <input type="text" name="ip" placeholder="e.g. 192.168.1.10" required/>
+                    </label>
+                    <label>
+                        "Network"
+                        <select name="network_id" required>
+                            <option value="">"— choose —"</option>
+                            {move || networks_res.get()
+                                .and_then(|r| r.ok())
+                                .map(|nets| nets.into_iter().map(|n| {
+                                    view! { <option value=n.id.to_string()>{n.cidr}</option> }
+                                }).collect_view())
+                            }
+                        </select>
+                    </label>
+                    <button type="submit">"Add"</button>
+                </div>
+            </ActionForm>
+            {move || create_action.value().get()
+                .and_then(|r| r.err())
+                .map(|e| view! { <p class="error">{e.to_string()}</p> })
+            }
+        </section>
+    }.into_any()
+}
+
+// ─── Filter bar ───────────────────────────────────────────────────────────────
+
+#[component]
+fn FilterBar(
+    networks_res: Resource<Result<Vec<crate::models::Network>, ServerFnError>>,
+    applications_res: Resource<Result<Vec<crate::models::Application>, ServerFnError>>,
+    name_filter: RwSignal<String>,
+    network_id_filter: RwSignal<i64>,
+    port_filter: RwSignal<i64>,
+    app_id_filter: RwSignal<i64>,
+    page: RwSignal<i64>,
+) -> impl IntoView {
+    view! {
+        <section class="filter-bar">
+            <div class="filter-bar__fields">
+                <label class="filter-field">
+                    "Name"
+                    <input
+                        type="text"
+                        placeholder="Search…"
+                        on:change=move |e| {
+                            name_filter.set(event_target_value(&e));
+                            page.set(1);
+                        }
+                    />
+                </label>
+
+                <label class="filter-field">
+                    "Network"
+                    <select on:change=move |e| {
+                        network_id_filter.set(event_target_value(&e).parse().unwrap_or(0));
+                        page.set(1);
+                    }>
+                        <option value="0">"All networks"</option>
+                        {move || networks_res.get()
+                            .and_then(|r| r.ok())
+                            .map(|nets| nets.into_iter().map(|n| {
+                                view! { <option value=n.id.to_string()>{n.cidr}</option> }
+                            }).collect_view())
+                        }
+                    </select>
+                </label>
+
+                <label class="filter-field">
+                    "Open port"
+                    <input
+                        type="number"
+                        min="1"
+                        max="65535"
+                        placeholder="e.g. 443"
+                        on:change=move |e| {
+                            port_filter.set(event_target_value(&e).parse().unwrap_or(0));
+                            page.set(1);
+                        }
+                    />
+                </label>
+
+                <label class="filter-field">
+                    "Application"
+                    <select on:change=move |e| {
+                        app_id_filter.set(event_target_value(&e).parse().unwrap_or(0));
+                        page.set(1);
+                    }>
+                        <option value="0">"All applications"</option>
+                        {move || applications_res.get()
+                            .and_then(|r| r.ok())
+                            .map(|apps| apps.into_iter().map(|a| {
+                                view! { <option value=a.id.to_string()>{a.name}</option> }
+                            }).collect_view())
+                        }
+                    </select>
+                </label>
+            </div>
+        </section>
+    }.into_any()
+}
+
+// ─── Pagination bar ───────────────────────────────────────────────────────────
+
+#[component]
+fn PaginationBar(
+    total: Signal<i64>,
+    page: RwSignal<i64>,
+    per_page: RwSignal<i64>,
+    total_pages: Signal<i64>,
+) -> impl IntoView {
+    view! {
+        <div class="pagination-bar">
+            <div class="pagination-bar__info">
+                {move || {
+                    let t = total.get();
+                    if t == 0 { "No hosts found".to_string() }
+                    else { format!("{} host{}", t, if t == 1 { "" } else { "s" }) }
+                }}
+            </div>
+            <div class="pagination-bar__controls">
+                <label class="pagination-per-page">
+                    "Per page "
+                    <select on:change=move |e| {
+                        per_page.set(event_target_value(&e).parse().unwrap_or(15));
+                        page.set(1);
+                    }>
+                        {PER_PAGE_OPTIONS.iter().map(|(value, label)| {
+                            view! {
+                                <option value=value.to_string() selected=*value == 15>
+                                    {*label}
+                                </option>
+                            }
+                        }).collect_view()}
+                    </select>
+                </label>
+
+                // Page navigation — hidden when showing all results (per_page == 0)
+                {move || (per_page.get() > 0).then(|| view! {
+                    <div class="pagination-nav">
+                        <button
+                            disabled=move || page.get() <= 1
+                            on:click=move |_| page.update(|p| *p = (*p - 1).max(1))
+                        >"‹"</button>
+                        <span class="pagination-nav__label">
+                            {move || format!("Page {} of {}", page.get(), total_pages.get().max(1))}
+                        </span>
+                        <button
+                            disabled=move || page.get() >= total_pages.get()
+                            on:click=move |_| {
+                                let max = total_pages.get_untracked();
+                                page.update(|p| *p = (*p + 1).min(max));
+                            }
+                        >"›"</button>
+                    </div>
+                })}
+            </div>
+        </div>
+    }.into_any()
+}
+
+// ─── Host table ───────────────────────────────────────────────────────────────
+
+// Separate component for the table body to further reduce type depth in HostsPage.
+#[component]
+fn HostTable(
+    hosts: Resource<Result<HostsPageData, ServerFnError>>,
+    delete_action: ServerAction<DeleteHost>,
+) -> impl IntoView {
+    view! {
+        <Suspense fallback=|| view! { <p class="empty">"Loading hosts…"</p> }>
+            {move || hosts.get().map(|result| match result {
+                Err(e) => view! {
+                    <p class="error">"Could not load hosts: " {e.to_string()}</p>
+                }.into_any(),
+
+                Ok(HostsPageData { rows, .. }) if rows.is_empty() => view! {
+                    <p class="empty">"No hosts match the current filters."</p>
+                }.into_any(),
+
+                Ok(HostsPageData { rows, .. }) => view! {
+                    <div class="table-container">
+                        <table>
+                            <thead>
+                                <tr>
+                                    <th>"Name"</th>
+                                    <th>"IP"</th>
+                                    <th>"Network"</th>
+                                    <th class="col-count">"Ports"</th>
+                                    <th class="col-count">"Applications"</th>
+                                    <th class="col-actions">"Actions"</th>
+                                </tr>
+                            </thead>
+                            <tbody>
+                                {rows.into_iter().map(|host| {
+                                    let id = host.id;
+                                    view! {
+                                        <tr>
+                                            <td>
+                                                <a class="table-link" href=format!("/hosts/{id}")>
+                                                    {host.name}
+                                                </a>
+                                            </td>
+                                            <td class="cell-mono">{host.ip}</td>
+                                            <td>
+                                                <a class="table-link" href=format!("/networks/{}", host.network_id)>
+                                                    {host.network_cidr}
+                                                </a>
+                                            </td>
+                                            <td class="col-count">{host.port_count}</td>
+                                            <td class="col-count">{host.application_count}</td>
+                                            <td class="col-actions">
+                                                <button on:click=move |_| {
+                                                    delete_action.dispatch(DeleteHost { id });
+                                                }>
+                                                    "Delete"
+                                                </button>
+                                            </td>
+                                        </tr>
+                                    }
+                                }).collect_view()}
+                            </tbody>
+                        </table>
+                    </div>
+                }.into_any(),
+            })}
+        </Suspense>
+    }.into_any()
+}
+
+// ─── Main page component ──────────────────────────────────────────────────────
+
+#[component]
+pub fn HostsPage() -> impl IntoView {
+    // Actions
+    let create_action = ServerAction::<CreateHost>::new();
+    let delete_action = ServerAction::<DeleteHost>::new();
+
+    // Filter signals (0 / "" = no filter)
+    let name_filter       = RwSignal::new(String::new());
+    let network_id_filter = RwSignal::new(0i64);
+    let port_filter       = RwSignal::new(0i64);
+    let app_id_filter     = RwSignal::new(0i64);
+
+    // Pagination signals
+    let page     = RwSignal::new(1i64);
+    let per_page = RwSignal::new(15i64);
+
+    // Hosts resource — refetches whenever any filter/pagination/action changes
+    let hosts = Resource::new(
+        move || (
+            name_filter.get(),
+            network_id_filter.get(),
+            port_filter.get(),
+            app_id_filter.get(),
+            page.get(),
+            per_page.get(),
+            create_action.version().get(),
+            delete_action.version().get(),
+        ),
+        |(name, net, port, app, p, pp, _, _)| get_hosts_page(name, net, port, app, p, pp),
+    );
+
+    // Dropdown resources (fetched once on mount)
+    let networks_res     = Resource::new(|| (), |_| get_networks());
+    let applications_res = Resource::new(|| (), |_| get_applications());
+
+    // Derived pagination signals
+    let total_pages = Signal::derive(move || {
+        hosts.get().and_then(|r| r.ok()).map(|p| p.total_pages).unwrap_or(1)
+    });
+    let total = Signal::derive(move || {
+        hosts.get().and_then(|r| r.ok()).map(|p| p.total).unwrap_or(0)
+    });
+
+    view! {
+        <div class="hosts-page">
+            <h1>"Hosts"</h1>
+
+            <AddHostForm create_action=create_action networks_res=networks_res/>
+
+            <FilterBar
+                networks_res=networks_res
+                applications_res=applications_res
+                name_filter=name_filter
+                network_id_filter=network_id_filter
+                port_filter=port_filter
+                app_id_filter=app_id_filter
+                page=page
+            />
+
+            <section class="list">
+                {move || delete_action.value().get()
+                    .and_then(|r| r.err())
+                    .map(|e| view! { <p class="error">"Delete failed: " {e.to_string()}</p> })
+                }
+
+                <PaginationBar total=total page=page per_page=per_page total_pages=total_pages/>
+
+                <HostTable hosts=hosts delete_action=delete_action/>
+            </section>
+        </div>
+    }.into_any()
+}

src/client/mod.rs

@@ -0,0 +1,15 @@
+// client/mod.rs — Client UI module
+//
+// Contains Leptos pages and components.
+//
+// Despite the name "client", this code runs on BOTH sides:
+//   - Server-side : to generate the initial HTML (SSR)
+//   - Browser     : compiled to WASM to make the interface interactive
+//
+// Do not place code here that requires browser-only APIs (window, document...)
+// without guarding it with `#[cfg(target_arch = "wasm32")]`.
+
+pub mod home;     // Home page
+pub mod hosts;    // Hosts list with filters and pagination
+pub mod networks; // Networks list and creation
+pub mod theme;    // Theme toggle component (light / dark / system)

src/client/networks.rs

@@ -0,0 +1,155 @@
+// client/networks.rs — Networks page
+//
+// Displays all CIDR networks managed by the IPAM and lets the user add or
+// delete them. All data operations go through Leptos server functions
+// (api/networks.rs), which run on the server and are called via HTTP
+// from the browser after hydration.
+//
+// Key Leptos 0.7 concepts used here:
+//   - `ServerAction<F>` : wraps a `#[server]` function for use with forms / buttons
+//   - `Resource::new`   : async data that re-fetches when its source signal changes
+//   - `action.version() : a Signal<usize> that increments after each dispatch,
+//                          used here as a dependency to trigger list re-fetches
+//   - `<ActionForm>`    : a form that submits to a ServerAction (no JS needed)
+//   - `<Suspense>`      : shows a fallback while the Resource is loading
+
+use leptos::prelude::*;
+use leptos::form::ActionForm;
+
+use crate::api::networks::{CreateNetwork, DeleteNetwork, get_networks_with_counts};
+
+#[component]
+pub fn NetworksPage() -> impl IntoView {
+    // ── Actions ───────────────────────────────────────────────────────────────
+    //
+    // `ServerAction<F>` binds a `#[server]` function to a reactive action.
+    // Under the hood it posts to `/api/<fn-name>` and updates its signals
+    // (.pending(), .value(), .version()) when the call completes.
+    let create_action = ServerAction::<CreateNetwork>::new();
+    let delete_action = ServerAction::<DeleteNetwork>::new();
+
+    // ── Data resource ─────────────────────────────────────────────────────────
+    //
+    // `Resource::new(source, fetcher)`:
+    //   - source   : a closure whose return value Leptos tracks reactively
+    //   - fetcher  : an async closure called whenever the source changes
+    //
+    // By reading `.version()` from both actions, the list automatically
+    // re-fetches after any create or delete, keeping the view in sync.
+    let networks = Resource::new(
+        move || (create_action.version().get(), delete_action.version().get()),
+        |_| get_networks_with_counts(),
+    );
+
+    view! {
+        <div class="networks-page">
+            <h1>"Networks"</h1>
+
+            // ── Add form ──────────────────────────────────────────────────────
+            //
+            // `<ActionForm action=create_action>` submits the form to the server
+            // function registered in `create_action`. The `name` attribute on
+            // each input must match the parameter name in `create_network(cidr: String)`.
+            // After submission the form clears itself automatically.
+            <section class="add-form">
+                <h2>"Add a network"</h2>
+                <ActionForm action=create_action>
+                    <label>
+                        "CIDR block"
+                        <input
+                            type="text"
+                            name="cidr"
+                            placeholder="e.g. 192.168.1.0/24"
+                            required
+                        />
+                    </label>
+                    <button type="submit">"Add"</button>
+                </ActionForm>
+
+                // Show the error from the last create attempt, if any.
+                // `action.value().get()` → Option<Result<Network, ServerFnError>>
+                // `.and_then(|r| r.err())` extracts the error when present.
+                {move || {
+                    create_action
+                        .value()
+                        .get()
+                        .and_then(|r| r.err())
+                        .map(|e| view! { <p class="error">{e.to_string()}</p> })
+                }}
+            </section>
+
+            // ── Network list ──────────────────────────────────────────────────
+            <section class="list">
+                <h2>"All networks"</h2>
+
+                // Show delete errors above the list.
+                {move || {
+                    delete_action
+                        .value()
+                        .get()
+                        .and_then(|r| r.err())
+                        .map(|e| view! { <p class="error">"Delete failed: " {e.to_string()}</p> })
+                }}
+
+                // `<Suspense>` shows `fallback` while the Resource is loading,
+                // then switches to the children once data is available.
+                <Suspense fallback=|| view! { <p>"Loading networks…"</p> }>
+                    {move || {
+                        // `networks.get()` → None while loading, Some(result) once done.
+                        // Returning None here keeps <Suspense> in its fallback state.
+                        networks.get().map(|result| match result {
+                            Err(e) => view! {
+                                <p class="error">"Could not load networks: " {e.to_string()}</p>
+                            }
+                            .into_any(),
+
+                            Ok(list) if list.is_empty() => view! {
+                                <p class="empty">"No networks yet. Add one above."</p>
+                            }
+                            .into_any(),
+
+                            Ok(list) => view! {
+                                <div class="table-container">
+                                    <table>
+                                        <thead>
+                                            <tr>
+                                                <th>"CIDR"</th>
+                                                <th class="col-count">"Hosts"</th>
+                                                <th class="col-count">"Applications"</th>
+                                                <th class="col-actions">"Actions"</th>
+                                            </tr>
+                                        </thead>
+                                        <tbody>
+                                            {list
+                                                .into_iter()
+                                                .map(|network| {
+                                                    let id = network.id;
+                                                    view! {
+                                                        <tr>
+                                                            <td>{network.cidr}</td>
+                                                            <td class="col-count">{network.host_count}</td>
+                                                            <td class="col-count">{network.application_count}</td>
+                                                            <td class="col-actions">
+                                                                <button on:click=move |_| {
+                                                                    delete_action
+                                                                        .dispatch(DeleteNetwork { id });
+                                                                }>
+                                                                    "Delete"
+                                                                </button>
+                                                            </td>
+                                                        </tr>
+                                                    }
+                                                })
+                                                .collect_view()}
+                                        </tbody>
+                                    </table>
+                                </div>
+                            }
+                            .into_any(),
+                        })
+                    }}
+                </Suspense>
+            </section>
+        </div>
+    }
+}

src/client/theme.rs

@@ -0,0 +1,136 @@
+// client/theme.rs — Theme toggle component
+//
+// Architecture for multi-theme support:
+//   - ThemeChoice enum: each variant maps to a `data-theme` attribute value
+//     (None for "System" = follow OS preference via CSS media query)
+//   - Adding a future theme: add a variant here + a CSS [data-theme="..."] block
+//   - The active theme is persisted in localStorage under "ipam-theme"
+//   - When no value is stored, the CSS media query `prefers-color-scheme` decides
+//
+// SSR vs WASM:
+//   - SSR renders the button with no data-theme on <html> (system default applies)
+//   - On hydration, the WASM Effect reads localStorage and applies the stored choice
+//   - The `#[cfg(target_arch = "wasm32")]` guards prevent DOM/localStorage calls
+//     from being compiled into the server binary
+
+use leptos::prelude::*;
+
+// Used only in WASM builds — suppress false-positive dead_code warnings from SSR
+#[allow(dead_code)]
+const STORAGE_KEY: &str = "ipam-theme";
+
+// Each variant corresponds to a CSS `[data-theme]` value (None = follow OS).
+// To add a theme: add a variant, implement the methods, add CSS variables.
+#[allow(dead_code)]
+#[derive(Clone, PartialEq, Debug, Default)]
+pub enum ThemeChoice {
+    #[default]
+    System, // No data-theme attribute; CSS prefers-color-scheme decides
+    Light,
+    Dark,
+}
+
+#[allow(dead_code)]
+impl ThemeChoice {
+    // The attribute value written to <html data-theme="...">, or None to remove it.
+    fn attr_value(&self) -> Option<&'static str> {
+        match self {
+            Self::System => None,
+            Self::Light => Some("light"),
+            Self::Dark => Some("dark"),
+        }
+    }
+
+    // Label shown in the toggle button.
+    fn label(&self) -> &'static str {
+        match self {
+            Self::System => "Auto",
+            Self::Light => "Light",
+            Self::Dark => "Dark",
+        }
+    }
+
+    // Cycles to the next theme. Extend this as new variants are added.
+    fn next(&self) -> Self {
+        match self {
+            Self::System => Self::Light,
+            Self::Light => Self::Dark,
+            Self::Dark => Self::System,
+        }
+    }
+
+    fn from_stored(s: &str) -> Self {
+        match s {
+            "light" => Self::Light,
+            "dark" => Self::Dark,
+            _ => Self::System,
+        }
+    }
+}
+
+// ─── DOM helpers (WASM only) ─────────────────────────────────────────────────
+
+// Reads the stored theme name from localStorage.
+#[cfg(target_arch = "wasm32")]
+fn load_stored_theme() -> Option<ThemeChoice> {
+    let storage = web_sys::window()?.local_storage().ok()??;
+    let value = storage.get_item(STORAGE_KEY).ok()??;
+    Some(ThemeChoice::from_stored(&value))
+}
+
+// Applies `data-theme` attribute to <html> and persists to localStorage.
+#[cfg(target_arch = "wasm32")]
+fn apply_and_persist(choice: &ThemeChoice) {
+    let Some(window) = web_sys::window() else { return };
+    let Some(document) = window.document() else { return };
+    let Some(root) = document.document_element() else { return };
+
+    match choice.attr_value() {
+        Some(v) => { let _ = root.set_attribute("data-theme", v); }
+        None    => { let _ = root.remove_attribute("data-theme"); }
+    }
+
+    if let Ok(Some(storage)) = window.local_storage() {
+        match choice.attr_value() {
+            Some(v) => { let _ = storage.set_item(STORAGE_KEY, v); }
+            None    => { let _ = storage.remove_item(STORAGE_KEY); }
+        }
+    }
+}
+
+// ─── Component ───────────────────────────────────────────────────────────────
+
+#[component]
+pub fn ThemeToggle() -> impl IntoView {
+    let theme = RwSignal::new(ThemeChoice::System);
+
+    // Effect 1: runs once on mount — reads localStorage and initializes the signal.
+    // Does NOT track `theme`, so it never re-runs after the initial mount.
+    // Setting the signal here triggers Effect 2 below.
+    Effect::new(move |_| {
+        #[cfg(target_arch = "wasm32")]
+        if let Some(stored) = load_stored_theme() {
+            theme.set(stored);
+        }
+    });
+
+    // Effect 2: tracks `theme` — applies the choice to the DOM and localStorage
+    // whenever the signal changes (both on init and after user clicks).
+    Effect::new(move |_| {
+        let current = theme.get(); // tracked — re-runs when theme changes
+        #[cfg(target_arch = "wasm32")]
+        apply_and_persist(&current);
+        // Suppress unused variable warning when compiling for SSR
+        let _ = current;
+    });
+
+    view! {
+        <button
+            class="theme-toggle"
+            title="Toggle color theme"
+            on:click=move |_| theme.update(|t| *t = t.next())
+        >
+            {move || theme.get().label()}
+        </button>
+    }
+}

src/lib.rs

@@ -0,0 +1,46 @@
+// Leptos view! macros generate deeply-nested generic types; the default
+// limit of 128 is not enough for pages with many components.
+#![recursion_limit = "512"]
+
+// lib.rs — Shared library root
+//
+// This file is compiled in BOTH modes:
+//   "ssr"     → used by the Axum server to render HTML
+//   "hydrate" → compiled by trunk into WebAssembly for the browser
+//
+// This code sharing is what makes Leptos "full-stack":
+// components are written once and run on both sides.
+
+// Declare the sub-modules of this library.
+// `pub` makes them accessible from main.rs and other crates.
+pub mod api;    // Leptos server functions — the HTTP API between client and server
+pub mod app;    // Root App() component and router configuration
+pub mod client; // UI pages and Leptos components
+pub mod models; // Shared data structs: Network, Host, Port, Application
+pub mod server; // HTTP handlers and server-side business logic
+
+// WebAssembly entry point — called by the browser when the .wasm bundle loads.
+//
+// `#[cfg(feature = "hydrate")]` : this code only exists in the WASM bundle.
+// `#[wasm_bindgen(start)]`      : instructs wasm-bindgen to call this function
+//                                  automatically, without any JavaScript glue.
+#[cfg(feature = "hydrate")]
+#[wasm_bindgen::prelude::wasm_bindgen(start)]
+pub fn hydrate() {
+    use crate::app::App;
+
+    // Enable Rust panic messages in the browser console.
+    // Without this, a Rust panic in WASM only shows "unreachable executed" — useless.
+    // `set_once()` ensures the hook is registered at most once.
+    console_error_panic_hook::set_once();
+
+    // Mount the Leptos application into the <body> of the HTML page.
+    //
+    // In "hydration" mode (SSR + WASM), Leptos does not rebuild the DOM from scratch.
+    // It finds the HTML already rendered by the server and attaches event listeners
+    // to make the interface interactive. This is faster than a classic SPA
+    // that builds the entire DOM on the client side.
+    //
+    // `hydrate_body` (Leptos 0.7) = SSR + hydration mode (≠ `mount_to_body` which starts fresh)
+    leptos::mount::hydrate_body(App);
+}

src/main.rs

@@ -1,3 +1,151 @@
-fn main() {
-    println!("Hello, world!");
+// main.rs — Axum server entry point
+//
+// This file is compiled ONLY when the "ssr" feature is enabled.
+// `#[cfg(feature = "ssr")]` works like `#ifdef` in C:
+// the guarded code does not exist in the WASM bundle.
+//
+// Run the server:
+//   cargo run --features ssr
+//
+// Run with verbose logs:
+//   RUST_LOG=debug cargo run --features ssr
+
+#[cfg(feature = "ssr")]
+#[tokio::main]
+// `#[tokio::main]` turns the synchronous `fn main()` into an async function
+// managed by the Tokio runtime. Without it, Rust cannot execute `async` code.
+async fn main() {
+    use axum::Router;
+    use leptos::config::get_configuration;
+    use leptos::prelude::provide_context;
+    use leptos::view;
+    use leptos_axum::{
+        generate_route_list, handle_server_fns_with_context, LeptosRoutes,
+    };
+    use rust_ipam::{
+        app::{App, Shell},
+        server::{
+            config::AppConfig,
+            db::{create_pool, run_migrations},
+            routes::not_found_handler,
+            state::AppState,
+        },
+    };
+    use tower_http::services::ServeDir;
+
+    // Initialize structured logging.
+    // tracing::info!(), tracing::warn!(), etc. produce no output without this.
+    // RUST_LOG=debug cargo run --features ssr → enables debug-level logs
+    tracing_subscriber::fmt()
+        .with_env_filter(
+            std::env::var("RUST_LOG").unwrap_or_else(|_| "info".to_string()),
+        )
+        .init();
+
+    tracing::info!("Starting Rust IPAM server...");
+
+    // Load configuration from environment variables / .env file.
+    // The server cannot start without knowing which database to connect to,
+    // so we abort immediately on any configuration error.
+    let app_config = AppConfig::from_env()
+        .expect("Configuration error — check your .env file");
+
+    tracing::info!("Database: {} ({})", app_config.backend, app_config.database_url);
+
+    // Connect to the database and apply any pending migrations.
+    // The server cannot serve data without a working database, so we abort on error.
+    let pool = create_pool(&app_config)
+        .await
+        .expect("Failed to connect to database");
+
+    run_migrations(&pool, &app_config.backend)
+        .await
+        .expect("Database migration failed");
+
+    tracing::info!("Database ready.");
+
+    // `Some("Cargo.toml")` tells Leptos to read the [package.metadata.leptos]
+    // section from Cargo.toml (file paths, output names, server address...).
+    let conf = get_configuration(Some("Cargo.toml"))
+        .expect("Failed to load Leptos configuration from Cargo.toml");
+    let leptos_options = conf.leptos_options;
+    let addr = leptos_options.site_addr;
+
+    // Combine Leptos options and the database pool into a single shared state.
+    // `AppState` implements `FromRef<AppState> for LeptosOptions` so Leptos
+    // can still extract just what it needs from the full state.
+    let state = AppState { leptos_options: leptos_options.clone(), db: pool };
+
+    // Walk all `<Route>` components inside `App` to build the list of URLs
+    // that Leptos SSR must handle.
+    let routes = generate_route_list(App);
+
+    // Clone the pool so we can inject it into two different contexts:
+    //   1. `leptos_routes_with_context` — SSR rendering + server functions called during SSR
+    //   2. `handle_server_fns_with_context` — server functions called from the WASM client
+    let pool_for_routes = state.db.clone();
+    let pool_for_fns = state.db.clone();
+
+    // Build the Axum router using the builder pattern (method chaining).
+    //
+    // `Router::<AppState>::new()` explicitly tells Rust the state type is `AppState`.
+    // Without this annotation, type inference would default to `LeptosOptions`
+    // (inferred from `leptos_routes`) and then reject `.with_state(state: AppState)`.
+    let app = Router::<AppState>::new()
+        // Serve static files compiled by trunk (WASM, JS...).
+        // Trunk places them in target/site/pkg/ as configured in [package.metadata.leptos].
+        .nest_service("/pkg", ServeDir::new("target/site/pkg"))
+        // Handle server function HTTP calls from the WASM client.
+        //
+        // `#[server]` functions register themselves at "/api/<fn-name>".
+        // `handle_server_fns_with_context` runs the server function body and injects
+        // `additional_context` into the Leptos context before execution,
+        // so server functions can call `use_context::<AnyPool>()` to get the pool.
+        .route(
+            "/api/*fn_name",
+            axum::routing::post({
+                let pool = pool_for_fns;
+                move |req| {
+                    let pool = pool.clone();
+                    handle_server_fns_with_context(
+                        move || provide_context(pool.clone()),
+                        req,
+                    )
+                }
+            }),
+        )
+        // Mount all Leptos routes into Axum.
+        // `leptos_routes_with_context` injects the pool into the Leptos context
+        // for every SSR render — needed for server functions called during SSR
+        // (e.g. when a `Resource` pre-fetches data on the server).
+        .leptos_routes_with_context(
+            &state,
+            routes,
+            {
+                move || provide_context(pool_for_routes.clone())
+            },
+            {
+                let leptos_options = state.leptos_options.clone();
+                move || view! { <Shell options=leptos_options.clone()/> }
+            },
+        )
+        .fallback(not_found_handler)
+        // Share AppState (Leptos options + DB pool) with all handlers.
+        .with_state(state);
+
+    let listener = tokio::net::TcpListener::bind(&addr)
+        .await
+        .expect(&format!("Failed to bind to address {}", addr));
+
+    tracing::info!("Server listening on http://{}", addr);
+
+    axum::serve(listener, app)
+        .await
+        .expect("Fatal server error");
 }
+
+// This empty block is required so the compiler finds a `fn main()`
+// when building in WASM mode (where the "ssr" feature is not enabled).
+// In WASM, the real entry point is `hydrate()` in lib.rs.
+#[cfg(not(feature = "ssr"))]
+fn main() {}

src/models.rs

@@ -0,0 +1,141 @@
+// models.rs — Shared data models (server + client)
+//
+// This module defines the structs that represent the IPAM domain entities.
+// They are compiled for both the server and WASM, because Leptos needs them
+// on both sides:
+//   - Server : to read/write the database and render HTML
+//   - Client : to display data inside Leptos components
+//
+// Each struct derives `Serialize` and `Deserialize` from serde.
+// This is required for Leptos to transfer data between the server and the
+// browser through server functions (#[server]).
+
+use serde::{Deserialize, Serialize};
+
+// ─── Network ──────────────────────────────────────────────────────────────────
+
+/// An IP network defined by its CIDR range.
+///
+/// Example: { id: 1, cidr: "192.168.1.0/24" }
+///   → covers 192.168.1.0 to 192.168.1.255 (254 usable hosts)
+///
+/// CIDR (Classless Inter-Domain Routing) combines the network address and
+/// the subnet mask into a single field: <address>/<prefix length>.
+/// /24 = 24-bit mask = 255.255.255.0
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Network {
+    /// Unique identifier, auto-incremented by the database.
+    /// `i64` is a signed 64-bit integer — maps to `BIGINT` in SQL.
+    pub id: i64,
+
+    /// Address range in CIDR notation.
+    /// Examples: "10.0.0.0/8", "172.16.0.0/12", "192.168.1.0/24"
+    pub cidr: String,
+}
+
+// ─── Host ─────────────────────────────────────────────────────────────────────
+
+/// A host (server, workstation, network device) belonging to a network.
+///
+/// Constraint: the IP address must fall within the CIDR range of the network
+/// referenced by `network_id`. This is enforced on creation and update.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Host {
+    pub id: i64,
+
+    /// Human-readable name. Examples: "web-server-01", "main-router"
+    pub name: String,
+
+    /// IPv4 address stored as text. Example: "192.168.1.10"
+    /// We use String instead of IpAddr to simplify serialization
+    /// and database storage.
+    pub ip: String,
+
+    /// Foreign key referencing the network this host belongs to.
+    pub network_id: i64,
+}
+
+// ─── Port ─────────────────────────────────────────────────────────────────────
+
+/// A network port entry in the global port catalog.
+///
+/// Ports are defined once here; host_ports and application_ports link them
+/// to hosts and applications through separate join tables.
+/// Well-known ports (0–1023) have standardized protocol assignments.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Port {
+    /// TCP/UDP port number (0–65535).
+    /// `u16` is an unsigned 16-bit integer — the exact range for port numbers.
+    pub number: u16,
+
+    /// Description of the protocol typically running on this port.
+    /// `Option<String>`: absent (None) when the protocol is unknown.
+    /// Examples: Some("SSH"), Some("HTTPS"), None
+    pub description: Option<String>,
+}
+
+// ─── HostPort ─────────────────────────────────────────────────────────────────
+
+/// Join record representing a port open on a specific host.
+///
+/// Maps to the `host_ports` table (many-to-many between hosts and ports).
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct HostPort {
+    pub host_id: i64,
+    pub port_number: u16,
+}
+
+impl Port {
+    /// Returns the standard description for common well-known ports.
+    /// Used to pre-fill the description field when adding a port.
+    ///
+    /// `match` is Rust's exhaustive pattern-matching construct (like switch/case,
+    /// but the compiler enforces that all cases are handled).
+    pub fn known_protocol(number: u16) -> Option<&'static str> {
+        // `&'static str`: a reference to a string that lives for the entire
+        // program lifetime (string literals are stored in the compiled binary).
+        match number {
+            21   => Some("FTP"),
+            22   => Some("SSH"),
+            23   => Some("Telnet"),
+            25   => Some("SMTP"),
+            53   => Some("DNS"),
+            80   => Some("HTTP"),
+            110  => Some("POP3"),
+            143  => Some("IMAP"),
+            443  => Some("HTTPS"),
+            3306 => Some("MySQL"),
+            5432 => Some("PostgreSQL"),
+            6379 => Some("Redis"),
+            8080 => Some("HTTP (alternate)"),
+            _    => None, // `_` is the wildcard pattern — matches everything else
+        }
+    }
+}
+
+// ─── Application ──────────────────────────────────────────────────────────────
+
+/// An application that uses one or more ports.
+///
+/// The association between an application and a port is non-strict:
+/// the same port can be shared by multiple applications.
+/// Example: port 80 might be used by both Nginx and an application proxy.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Application {
+    pub id: i64,
+
+    /// Application name. Examples: "Nginx", "PostgreSQL", "Prometheus"
+    pub name: String,
+}
+
+// ─── ApplicationPort ──────────────────────────────────────────────────────────
+
+/// Join record linking an application to a port (many-to-many relationship).
+///
+/// A dedicated struct is used instead of Vec<Port> inside Application
+/// so it maps directly to the join table in the database.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ApplicationPort {
+    pub application_id: i64,
+    pub port_number: u16,
+}

src/server/config.rs

@@ -0,0 +1,100 @@
+// server/config.rs — Application configuration
+//
+// This module loads and validates configuration at server startup.
+// All configuration is read from environment variables,
+// which can be populated from a `.env` file via dotenvy.
+//
+// A single variable is enough to select the database backend:
+//   DATABASE_URL=sqlite://data/ipam.db        → SQLite (dev, no server needed)
+//   DATABASE_URL=postgresql://user:pw@host/db → PostgreSQL (production)
+
+use thiserror::Error;
+
+// ─── Configuration errors ─────────────────────────────────────────────────────
+
+// `#[derive(Error)]` from thiserror automatically generates the impl for the
+// standard `std::error::Error` trait — no need to write it by hand.
+//
+// `#[error("...")]` defines the message shown by Display / println!("{}", err).
+#[derive(Debug, Error)]
+pub enum ConfigError {
+    // `#[from]` auto-converts a VarError into ConfigError via the `?` operator.
+    // Example: std::env::var("X")? in a fn -> Result<_, ConfigError>
+    #[error("Missing environment variable: {0}")]
+    MissingVar(#[from] std::env::VarError),
+
+    #[error("Unknown database URL '{0}' — must start with sqlite:// or postgresql://")]
+    UnknownBackend(String),
+}
+
+// ─── Database backend ─────────────────────────────────────────────────────────
+
+// `#[derive(Debug, Clone)]` automatically generates:
+//   - Debug : allows printing the value with {:?} in logs
+//   - Clone : allows copying the value (required for Axum state)
+#[derive(Debug, Clone, PartialEq)]
+pub enum DatabaseBackend {
+    Postgres,
+    Sqlite,
+}
+
+// Display impl allows writing: tracing::info!("Backend: {}", backend)
+impl std::fmt::Display for DatabaseBackend {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            DatabaseBackend::Postgres => write!(f, "PostgreSQL"),
+            DatabaseBackend::Sqlite => write!(f, "SQLite"),
+        }
+    }
+}
+
+// ─── Application configuration ────────────────────────────────────────────────
+
+#[derive(Debug, Clone)]
+pub struct AppConfig {
+    /// Full database connection URL.
+    /// Examples: "sqlite://data/ipam.db" or "postgresql://user:pw@localhost/ipam"
+    pub database_url: String,
+
+    /// Backend detected automatically from the DATABASE_URL prefix.
+    pub backend: DatabaseBackend,
+}
+
+impl AppConfig {
+    /// Loads configuration from environment variables.
+    ///
+    /// Variable priority order:
+    ///   1. Variables already set in the shell (e.g. export DATABASE_URL=...)
+    ///   2. `.env` file at the project root
+    ///
+    /// Returns `ConfigError` if DATABASE_URL is missing or unrecognized.
+    pub fn from_env() -> Result<Self, ConfigError> {
+        // Load the .env file if it exists.
+        // `let _ =` silently ignores the error when .env is absent —
+        // this is intentional: in production, variables are injected directly.
+        let _ = dotenvy::dotenv();
+
+        // `std::env::var` returns Result<String, VarError>.
+        // The `?` propagates VarError, converted to ConfigError::MissingVar
+        // thanks to the `#[from]` attribute above.
+        let database_url = std::env::var("DATABASE_URL")?;
+
+        let backend = Self::detect_backend(&database_url)?;
+
+        Ok(Self { database_url, backend })
+    }
+
+    /// Infers the database backend from the URL prefix.
+    ///
+    /// `&str`: a borrowed string reference — no copy, just a borrow.
+    fn detect_backend(url: &str) -> Result<DatabaseBackend, ConfigError> {
+        if url.starts_with("postgresql://") || url.starts_with("postgres://") {
+            Ok(DatabaseBackend::Postgres)
+        } else if url.starts_with("sqlite://") {
+            Ok(DatabaseBackend::Sqlite)
+        } else {
+            // `to_string()` creates an owned String from a &str
+            Err(ConfigError::UnknownBackend(url.to_string()))
+        }
+    }
+}

src/server/db.rs

@@ -0,0 +1,110 @@
+// server/db.rs — Database connection pool and migrations
+//
+// This module provides two functions called once at server startup:
+//   - `create_pool`    : opens a connection pool to the database
+//   - `run_migrations` : applies all pending SQL migrations
+//
+// `AnyPool` lets the same Rust code target both SQLite (dev) and
+// PostgreSQL (production) — only DATABASE_URL changes.
+
+use sqlx::AnyPool;
+use thiserror::Error;
+
+use crate::server::config::{AppConfig, DatabaseBackend};
+
+// ─── Errors ───────────────────────────────────────────────────────────────────
+
+#[derive(Debug, Error)]
+pub enum DbError {
+    #[error("Database connection failed: {0}")]
+    Connection(#[from] sqlx::Error),
+
+    #[error("Migration failed: {0}")]
+    Migration(#[from] sqlx::migrate::MigrateError),
+
+    #[error("Record not found: {0}")]
+    NotFound(String),
+}
+
+// ─── Pool creation ────────────────────────────────────────────────────────────
+
+/// Opens a connection pool to the database specified in `config.database_url`.
+///
+/// A pool maintains multiple open connections so concurrent requests
+/// do not block each other waiting for a single connection.
+///
+/// `install_default_drivers()` must be called before `AnyPool::connect`
+/// to register both the SQLite and PostgreSQL drivers in the `Any` registry.
+///
+/// For SQLite, this function also creates the database file and its parent
+/// directory if they do not exist yet. The `AnyPool` driver cannot create
+/// a new SQLite file by itself — unlike the `SqlitePool` which has an
+/// explicit `create_if_missing` option.
+pub async fn create_pool(config: &AppConfig) -> Result<AnyPool, DbError> {
+    // Register SQLite and PostgreSQL drivers so `AnyPool` can dispatch
+    // to the correct one based on the URL scheme (sqlite:// vs postgres://).
+    sqlx::any::install_default_drivers();
+
+    // SQLite-specific setup: ensure the file exists before connecting.
+    //
+    // `AnyPool` does not expose `create_if_missing` like `SqlitePool` does,
+    // so we must touch the file ourselves.
+    //
+    // The URL is parsed the same way SQLx does it internally:
+    //   sqlite://data/ipam.db → strip sqlite:// → path = data/ipam.db
+    if let DatabaseBackend::Sqlite = &config.backend {
+        // Strip both possible prefixes (SQLx accepts both forms)
+        let path_str = config
+            .database_url
+            .trim_start_matches("sqlite://")
+            .trim_start_matches("sqlite:");
+
+        // Skip special filenames (in-memory, shared cache)
+        if path_str != ":memory:" && !path_str.is_empty() {
+            let path = std::path::Path::new(path_str);
+
+            // Create the parent directory if it does not exist
+            if let Some(parent) = path.parent() {
+                if !parent.as_os_str().is_empty() {
+                    std::fs::create_dir_all(parent)
+                        .map_err(|e| sqlx::Error::Io(e))?;
+                }
+            }
+
+            // Create an empty file so SQLite can open it
+            if !path.exists() {
+                std::fs::File::create(path)
+                    .map_err(|e| sqlx::Error::Io(e))?;
+            }
+        }
+    }
+
+    let pool = AnyPool::connect(&config.database_url).await?;
+    Ok(pool)
+}
+
+// ─── Migrations ───────────────────────────────────────────────────────────────
+
+/// Applies all pending migrations from the directory matching the active backend.
+///
+/// Two separate directories handle SQL syntax differences:
+///   - `migrations/sqlite/`   : uses `INTEGER PRIMARY KEY AUTOINCREMENT`
+///   - `migrations/postgres/` : uses `BIGSERIAL PRIMARY KEY`
+///
+/// SQLx tracks applied migrations in a `_sqlx_migrations` table, so running
+/// this function on an already-migrated database is always safe (idempotent).
+///
+/// `sqlx::migrate!("path")` is a compile-time macro: it embeds all `.sql`
+/// files from the given path directly into the binary. The path is relative
+/// to the project root (where Cargo.toml lives).
+pub async fn run_migrations(pool: &AnyPool, backend: &DatabaseBackend) -> Result<(), DbError> {
+    match backend {
+        DatabaseBackend::Sqlite => {
+            sqlx::migrate!("migrations/sqlite").run(pool).await?;
+        }
+        DatabaseBackend::Postgres => {
+            sqlx::migrate!("migrations/postgres").run(pool).await?;
+        }
+    }
+    Ok(())
+}

src/server/mod.rs

@@ -0,0 +1,24 @@
+// server/mod.rs — Server-side module
+//
+// Contains all code that runs on the server only.
+//
+// Some sub-modules depend on SSR-only crates (dotenvy, ipnetwork...)
+// and are therefore gated with `#[cfg(feature = "ssr")]` to prevent
+// them from being compiled into the WASM bundle.
+
+pub mod routes;
+
+#[cfg(feature = "ssr")]
+pub mod config;
+
+#[cfg(feature = "ssr")]
+pub mod db;
+
+#[cfg(feature = "ssr")]
+pub mod repository;
+
+#[cfg(feature = "ssr")]
+pub mod state;
+
+#[cfg(feature = "ssr")]
+pub mod validation;

src/server/repository/applications.rs

@@ -0,0 +1,134 @@
+// repository/applications.rs — CRUD for applications and their port associations
+
+use sqlx::{AnyPool, Row};
+
+use crate::models::Application;
+use crate::server::db::DbError;
+
+// ─── Read ─────────────────────────────────────────────────────────────────────
+
+/// Returns every application ordered by name.
+pub async fn list_applications(pool: &AnyPool) -> Result<Vec<Application>, DbError> {
+    let rows = sqlx::query("SELECT id, name FROM applications ORDER BY name")
+        .fetch_all(pool)
+        .await?;
+
+    Ok(rows.iter().map(row_to_application).collect())
+}
+
+/// Returns a single application by id, or `None` if it does not exist.
+pub async fn find_application(
+    pool: &AnyPool,
+    id: i64,
+) -> Result<Option<Application>, DbError> {
+    let row = sqlx::query("SELECT id, name FROM applications WHERE id = $1")
+        .bind(id)
+        .fetch_optional(pool)
+        .await?;
+
+    Ok(row.as_ref().map(row_to_application))
+}
+
+// ─── Write ────────────────────────────────────────────────────────────────────
+
+/// Inserts a new application and returns the created record.
+pub async fn create_application(pool: &AnyPool, name: &str) -> Result<Application, DbError> {
+    let row =
+        sqlx::query("INSERT INTO applications (name) VALUES ($1) RETURNING id, name")
+            .bind(name)
+            .fetch_one(pool)
+            .await?;
+
+    Ok(row_to_application(&row))
+}
+
+/// Deletes an application and its port associations (via `ON DELETE CASCADE`).
+///
+/// Returns `true` if a row was deleted, `false` if the id did not exist.
+pub async fn delete_application(pool: &AnyPool, id: i64) -> Result<bool, DbError> {
+    let result = sqlx::query("DELETE FROM applications WHERE id = $1")
+        .bind(id)
+        .execute(pool)
+        .await?;
+
+    Ok(result.rows_affected() > 0)
+}
+
+// ─── Application-port associations ───────────────────────────────────────────
+
+/// Returns all port numbers associated with an application, sorted numerically.
+///
+/// Note: the `application_ports` table does NOT have a FK to `ports`,
+/// so an application can reference a port number that is not in the catalog.
+/// Returns plain `u16` numbers, not full `Port` structs.
+pub async fn list_ports_for_application(
+    pool: &AnyPool,
+    application_id: i64,
+) -> Result<Vec<u16>, DbError> {
+    let rows = sqlx::query(
+        "SELECT port_number FROM application_ports
+         WHERE application_id = $1
+         ORDER BY port_number",
+    )
+    .bind(application_id)
+    .fetch_all(pool)
+    .await?;
+
+    Ok(rows
+        .iter()
+        .map(|r| r.get::<i64, _>("port_number") as u16)
+        .collect())
+}
+
+/// Associates a port number with an application.
+///
+/// If the association already exists, the call is a no-op (not an error).
+/// The port does not need to be in the `ports` catalog.
+pub async fn add_port_to_application(
+    pool: &AnyPool,
+    application_id: i64,
+    port_number: u16,
+) -> Result<(), DbError> {
+    let result = sqlx::query(
+        "INSERT INTO application_ports (application_id, port_number) VALUES ($1, $2)",
+    )
+    .bind(application_id)
+    .bind(port_number as i64)
+    .execute(pool)
+    .await;
+
+    match result {
+        Ok(_) => Ok(()),
+        Err(sqlx::Error::Database(ref e)) if e.is_unique_violation() => Ok(()),
+        Err(e) => Err(DbError::Connection(e)),
+    }
+}
+
+/// Removes a port association from an application.
+///
+/// If the association did not exist, this is a no-op (not an error).
+pub async fn remove_port_from_application(
+    pool: &AnyPool,
+    application_id: i64,
+    port_number: u16,
+) -> Result<(), DbError> {
+    sqlx::query(
+        "DELETE FROM application_ports
+         WHERE application_id = $1 AND port_number = $2",
+    )
+    .bind(application_id)
+    .bind(port_number as i64)
+    .execute(pool)
+    .await?;
+
+    Ok(())
+}
+
+// ─── Row mapping ──────────────────────────────────────────────────────────────
+
+fn row_to_application(row: &sqlx::any::AnyRow) -> Application {
+    Application {
+        id: row.get("id"),
+        name: row.get("name"),
+    }
+}

src/server/repository/hosts.rs

@@ -0,0 +1,86 @@
+// repository/hosts.rs — CRUD for the `hosts` table
+
+use sqlx::{AnyPool, Row};
+
+use crate::models::Host;
+use crate::server::db::DbError;
+
+// ─── Read ─────────────────────────────────────────────────────────────────────
+
+/// Returns every host belonging to a network, sorted by name.
+pub async fn list_hosts_by_network(
+    pool: &AnyPool,
+    network_id: i64,
+) -> Result<Vec<Host>, DbError> {
+    let rows = sqlx::query(
+        "SELECT id, name, ip, network_id FROM hosts
+         WHERE network_id = $1
+         ORDER BY name",
+    )
+    .bind(network_id)
+    .fetch_all(pool)
+    .await?;
+
+    Ok(rows.iter().map(row_to_host).collect())
+}
+
+/// Returns a single host by id, or `None` if it does not exist.
+pub async fn find_host(pool: &AnyPool, id: i64) -> Result<Option<Host>, DbError> {
+    let row = sqlx::query(
+        "SELECT id, name, ip, network_id FROM hosts WHERE id = $1",
+    )
+    .bind(id)
+    .fetch_optional(pool)
+    .await?;
+
+    Ok(row.as_ref().map(row_to_host))
+}
+
+// ─── Write ────────────────────────────────────────────────────────────────────
+
+/// Inserts a new host into the given network and returns the created record.
+///
+/// The caller must validate that `ip` falls within the CIDR range of `network_id`
+/// before calling this function — use `server::validation::validate_ip_in_network`.
+pub async fn create_host(
+    pool: &AnyPool,
+    name: &str,
+    ip: &str,
+    network_id: i64,
+) -> Result<Host, DbError> {
+    let row = sqlx::query(
+        "INSERT INTO hosts (name, ip, network_id)
+         VALUES ($1, $2, $3)
+         RETURNING id, name, ip, network_id",
+    )
+    .bind(name)
+    .bind(ip)
+    .bind(network_id)
+    .fetch_one(pool)
+    .await?;
+
+    Ok(row_to_host(&row))
+}
+
+/// Deletes a host and all its port associations (via `ON DELETE CASCADE`).
+///
+/// Returns `true` if a row was deleted, `false` if the id did not exist.
+pub async fn delete_host(pool: &AnyPool, id: i64) -> Result<bool, DbError> {
+    let result = sqlx::query("DELETE FROM hosts WHERE id = $1")
+        .bind(id)
+        .execute(pool)
+        .await?;
+
+    Ok(result.rows_affected() > 0)
+}
+
+// ─── Row mapping ──────────────────────────────────────────────────────────────
+
+fn row_to_host(row: &sqlx::any::AnyRow) -> Host {
+    Host {
+        id: row.get("id"),
+        name: row.get("name"),
+        ip: row.get("ip"),
+        network_id: row.get("network_id"),
+    }
+}

src/server/repository/mod.rs

@@ -0,0 +1,19 @@
+// server/repository — Database access layer (CRUD)
+//
+// Each sub-module owns the queries for one domain entity.
+// All functions accept `&AnyPool` and return `Result<_, DbError>`,
+// so the caller never has to think about raw SQL or connection management.
+//
+// Design choices:
+//   - Free functions (not struct methods) keep the API simple.
+//   - `sqlx::query()` is used instead of `sqlx::query!()` because the
+//     compile-time macro requires a live database at build time.
+//   - All integer columns are read as `i64` (the AnyPool normalizes
+//     INTEGER/BIGINT to 64-bit integers internally).
+//   - Port numbers are stored as i64 in the DB and cast to u16 in Rust
+//     (safe because valid port numbers 0–65535 fit in u16).
+
+pub mod applications;
+pub mod hosts;
+pub mod networks;
+pub mod ports;

src/server/repository/networks.rs

@@ -0,0 +1,79 @@
+// repository/networks.rs — CRUD for the `networks` table
+
+use sqlx::{AnyPool, Row};
+
+use crate::models::Network;
+use crate::server::db::DbError;
+
+// ─── Read ─────────────────────────────────────────────────────────────────────
+
+/// Returns every network ordered by id.
+pub async fn list_networks(pool: &AnyPool) -> Result<Vec<Network>, DbError> {
+    // `fetch_all` runs the query and collects every row into a Vec.
+    // It returns an error if the query fails; an empty table returns Ok(vec![]).
+    let rows = sqlx::query("SELECT id, cidr FROM networks ORDER BY id")
+        .fetch_all(pool)
+        .await?;
+
+    // `.iter().map(...).collect()` transforms each raw DB row into a Network struct.
+    Ok(rows.iter().map(row_to_network).collect())
+}
+
+/// Returns a single network by id, or `None` if it does not exist.
+pub async fn find_network(pool: &AnyPool, id: i64) -> Result<Option<Network>, DbError> {
+    // `fetch_optional` returns `Ok(None)` when no row matches — unlike
+    // `fetch_one`, which returns an error when nothing is found.
+    let row = sqlx::query("SELECT id, cidr FROM networks WHERE id = $1")
+        .bind(id) // `$1` is replaced with the value of `id` at runtime
+        .fetch_optional(pool)
+        .await?;
+
+    // `Option::map` applies the conversion only if the row is Some.
+    Ok(row.as_ref().map(row_to_network))
+}
+
+// ─── Write ────────────────────────────────────────────────────────────────────
+
+/// Inserts a new network and returns the created record (with its auto-generated id).
+///
+/// Fails with `DbError::Connection` if the CIDR is already registered
+/// (the `cidr` column has a UNIQUE constraint).
+///
+/// `RETURNING id, cidr` reads back the inserted row in a single round-trip,
+/// avoiding a separate SELECT after the INSERT.
+/// Requires SQLite ≥ 3.35 (2021) and any PostgreSQL version.
+pub async fn create_network(pool: &AnyPool, cidr: &str) -> Result<Network, DbError> {
+    let row = sqlx::query("INSERT INTO networks (cidr) VALUES ($1) RETURNING id, cidr")
+        .bind(cidr)
+        .fetch_one(pool) // exactly one row is returned by RETURNING
+        .await?;
+
+    Ok(row_to_network(&row))
+}
+
+/// Deletes a network by id and all its hosts (via `ON DELETE CASCADE`).
+///
+/// Returns `true` if a row was deleted, `false` if the id did not exist.
+pub async fn delete_network(pool: &AnyPool, id: i64) -> Result<bool, DbError> {
+    // `execute` runs the query without fetching rows.
+    // `rows_affected()` tells us how many rows were actually deleted.
+    let result = sqlx::query("DELETE FROM networks WHERE id = $1")
+        .bind(id)
+        .execute(pool)
+        .await?;
+
+    Ok(result.rows_affected() > 0)
+}
+
+// ─── Row mapping ──────────────────────────────────────────────────────────────
+
+/// Converts a raw database row into a `Network` struct.
+///
+/// `row.get("col")` extracts a typed value by column name.
+/// The type must implement `sqlx::Decode` for the `Any` backend.
+fn row_to_network(row: &sqlx::any::AnyRow) -> Network {
+    Network {
+        id: row.get("id"),
+        cidr: row.get("cidr"),
+    }
+}

src/server/repository/ports.rs

@@ -0,0 +1,156 @@
+// repository/ports.rs — Port catalog and host-port associations
+//
+// The `ports` table is a global catalog: a port number (e.g. 22) is defined
+// once with an optional description, then linked to hosts via `host_ports`.
+//
+// Port numbers in Rust are `u16` (0–65535).
+// In the database they are stored as INTEGER (i64 in SQLx/AnyPool).
+// `as u16` casts are safe because values above 65535 cannot be inserted
+// (the schema and application code enforce this).
+
+use sqlx::{AnyPool, Row};
+
+use crate::models::Port;
+use crate::server::db::DbError;
+
+// ─── Port catalog ─────────────────────────────────────────────────────────────
+
+/// Inserts or updates a port in the global catalog.
+///
+/// If the port number already exists, its description is updated.
+/// If it does not exist, a new row is inserted.
+///
+/// We use a try-INSERT then UPDATE pattern instead of database-specific
+/// upsert syntax (`INSERT OR REPLACE` for SQLite, `ON CONFLICT` for PostgreSQL)
+/// so the same code works with `AnyPool` on both backends.
+pub async fn upsert_port(
+    pool: &AnyPool,
+    number: u16,
+    description: Option<&str>,
+) -> Result<Port, DbError> {
+    let insert_result = sqlx::query(
+        "INSERT INTO ports (number, description) VALUES ($1, $2)",
+    )
+    .bind(number as i64)
+    .bind(description)
+    .execute(pool)
+    .await;
+
+    match insert_result {
+        Ok(_) => {}
+        Err(sqlx::Error::Database(ref db_err)) if db_err.is_unique_violation() => {
+            // Port already exists: update the description instead.
+            // `is_unique_violation()` works for both SQLite and PostgreSQL.
+            sqlx::query("UPDATE ports SET description = $1 WHERE number = $2")
+                .bind(description)
+                .bind(number as i64)
+                .execute(pool)
+                .await?;
+        }
+        Err(e) => return Err(DbError::Connection(e)),
+    }
+
+    // Return the current state of the port row.
+    find_port(pool, number)
+        .await?
+        .ok_or_else(|| DbError::NotFound(format!("port {number}")))
+}
+
+/// Returns a port from the catalog, or `None` if the number is not registered.
+pub async fn find_port(pool: &AnyPool, number: u16) -> Result<Option<Port>, DbError> {
+    let row = sqlx::query(
+        "SELECT number, description FROM ports WHERE number = $1",
+    )
+    .bind(number as i64)
+    .fetch_optional(pool)
+    .await?;
+
+    Ok(row.as_ref().map(row_to_port))
+}
+
+// ─── Host-port associations ───────────────────────────────────────────────────
+
+/// Returns all ports currently associated with a host, sorted by port number.
+///
+/// Uses a JOIN so callers get full `Port` structs (with descriptions), not just numbers.
+pub async fn list_ports_for_host(
+    pool: &AnyPool,
+    host_id: i64,
+) -> Result<Vec<Port>, DbError> {
+    let rows = sqlx::query(
+        "SELECT p.number, p.description
+         FROM ports p
+         JOIN host_ports hp ON hp.port_number = p.number
+         WHERE hp.host_id = $1
+         ORDER BY p.number",
+    )
+    .bind(host_id)
+    .fetch_all(pool)
+    .await?;
+
+    Ok(rows.iter().map(row_to_port).collect())
+}
+
+/// Adds a port to a host.
+///
+/// If the port is not yet in the global catalog, it is automatically registered
+/// with a description from `Port::known_protocol` (e.g. port 22 → "SSH").
+/// If the host already has this port, the call is a no-op (not an error).
+pub async fn add_port_to_host(
+    pool: &AnyPool,
+    host_id: i64,
+    port_number: u16,
+) -> Result<(), DbError> {
+    // Auto-register the port in the catalog if it is not already there.
+    // The `host_ports` table has a FK to `ports`, so the port must exist first.
+    let description = crate::models::Port::known_protocol(port_number);
+    upsert_port(pool, port_number, description).await?;
+
+    // Insert the host-port association.
+    // If it already exists, treat it as a no-op (unique violation is expected).
+    let result = sqlx::query(
+        "INSERT INTO host_ports (host_id, port_number) VALUES ($1, $2)",
+    )
+    .bind(host_id)
+    .bind(port_number as i64)
+    .execute(pool)
+    .await;
+
+    match result {
+        Ok(_) => Ok(()),
+        Err(sqlx::Error::Database(ref e)) if e.is_unique_violation() => Ok(()),
+        Err(e) => Err(DbError::Connection(e)),
+    }
+}
+
+/// Removes a port from a host.
+///
+/// If the association did not exist, this is a no-op (not an error).
+/// The port entry in the global catalog is NOT deleted.
+pub async fn remove_port_from_host(
+    pool: &AnyPool,
+    host_id: i64,
+    port_number: u16,
+) -> Result<(), DbError> {
+    sqlx::query(
+        "DELETE FROM host_ports WHERE host_id = $1 AND port_number = $2",
+    )
+    .bind(host_id)
+    .bind(port_number as i64)
+    .execute(pool)
+    .await?;
+
+    Ok(())
+}
+
+// ─── Row mapping ──────────────────────────────────────────────────────────────
+
+fn row_to_port(row: &sqlx::any::AnyRow) -> Port {
+    Port {
+        // Port numbers are stored as INTEGER in the DB.
+        // SQLx/AnyPool decodes all integers to i64; `as u16` is safe
+        // because values above 65535 cannot reach the DB.
+        number: row.get::<i64, _>("number") as u16,
+        description: row.get("description"),
+    }
+}

src/server/routes.rs

@@ -0,0 +1,26 @@
+// server/routes.rs — Additional Axum HTTP handlers
+//
+// These handlers complement the routes managed by Leptos.
+// Intended for future use:
+//   - REST API endpoints (/api/...)
+//   - File exports (CSV, PDF...)
+//   - Incoming webhooks
+//   - Health check endpoint (/health)
+//
+// The entire file is guarded by `#[cfg(feature = "ssr")]`:
+// Axum does not exist in the WASM bundle, so this code is server-only.
+
+#[cfg(feature = "ssr")]
+use axum::{http::StatusCode, response::IntoResponse};
+
+// Fallback 404 handler — used in main.rs for any URL not matched by Leptos or Axum.
+//
+// `impl IntoResponse`: Axum accepts any type that implements this trait.
+// A `(StatusCode, &str)` tuple implements it automatically:
+// Axum turns it into an HTTP 404 response with the given body.
+//
+// `async fn` is required for Axum handlers, even without any async operations.
+#[cfg(feature = "ssr")]
+pub async fn not_found_handler() -> impl IntoResponse {
+    (StatusCode::NOT_FOUND, "Not found")
+}

src/server/state.rs

@@ -0,0 +1,42 @@
+// server/state.rs — Shared Axum application state
+//
+// Axum uses a typed state system: any handler can extract a specific type
+// from the shared state using the `State<T>` extractor.
+//
+// We store two pieces of state:
+//   - `leptos_options` : required by Leptos SSR routes
+//   - `db`             : database pool shared across all requests
+
+use axum::extract::FromRef;
+use leptos::config::LeptosOptions;
+use sqlx::AnyPool;
+
+// ─── AppState ─────────────────────────────────────────────────────────────────
+
+/// Shared state available to every Axum handler and Leptos server function.
+///
+/// `#[derive(Clone)]` is required by Axum: each request receives its own clone.
+/// Both fields are cheap to clone — they hold reference-counted pointers
+/// under the hood, so cloning just increments an atomic counter.
+#[derive(Clone)]
+pub struct AppState {
+    /// Leptos configuration (output paths, site address, reload port…).
+    pub leptos_options: LeptosOptions,
+
+    /// Shared connection pool to the database.
+    /// Using a pool (not a single connection) allows concurrent requests
+    /// to run their queries in parallel without contention.
+    pub db: AnyPool,
+}
+
+// ─── FromRef implementations ──────────────────────────────────────────────────
+
+/// Tells Axum how to extract just `LeptosOptions` from the full `AppState`.
+///
+/// `.leptos_routes()` in main.rs requires this impl because it stores
+/// only `LeptosOptions` internally, not the full application state.
+impl FromRef<AppState> for LeptosOptions {
+    fn from_ref(state: &AppState) -> Self {
+        state.leptos_options.clone()
+    }
+}

src/server/validation.rs

@@ -0,0 +1,108 @@
+// server/validation.rs — Business rule validation
+//
+// This module enforces rules that cannot be expressed through Rust's type system
+// alone. It runs server-side only because it uses `ipnetwork` for CIDR arithmetic.
+
+use ipnetwork::IpNetwork;
+use std::net::IpAddr;
+use thiserror::Error;
+
+// ─── Validation errors ────────────────────────────────────────────────────────
+
+#[derive(Debug, Error)]
+pub enum ValidationError {
+    /// The CIDR string is malformed (e.g. "192.168.1/24" instead of "192.168.1.0/24")
+    #[error("Invalid CIDR '{0}': {1}")]
+    InvalidCidr(String, ipnetwork::IpNetworkError),
+
+    /// The IP address string is malformed
+    #[error("Invalid IP address '{0}': {1}")]
+    InvalidIp(String, std::net::AddrParseError),
+
+    /// The host IP does not fall within the network's CIDR range
+    #[error("IP address {ip} does not belong to network {cidr}")]
+    IpOutsideNetwork { ip: String, cidr: String },
+}
+
+// ─── CIDR validation ──────────────────────────────────────────────────────────
+
+/// Validates that a string is a well-formed CIDR block.
+/// Returns the parsed network on success.
+///
+/// `&str`: borrowed string reference — no copy, just a borrow.
+/// `Result<T, E>`: either a value T (success) or an error E (failure).
+pub fn validate_cidr(cidr: &str) -> Result<IpNetwork, ValidationError> {
+    cidr.parse::<IpNetwork>()
+        // `.map_err` transforms the error if `parse` fails.
+        // `|e|` is a closure: an anonymous function that takes `e` as a parameter.
+        .map_err(|e| ValidationError::InvalidCidr(cidr.to_string(), e))
+}
+
+// ─── IP-in-network validation ─────────────────────────────────────────────────
+
+/// Verifies that an IP address belongs to a given CIDR network range.
+///
+/// Key business rule: a host must always reside within its assigned network.
+/// Example: 192.168.1.10 ✓ in 192.168.1.0/24
+///          10.0.0.1     ✗ in 192.168.1.0/24
+pub fn validate_ip_in_network(ip: &str, cidr: &str) -> Result<(), ValidationError> {
+    let network = validate_cidr(cidr)?;
+
+    let address: IpAddr = ip
+        .parse()
+        .map_err(|e| ValidationError::InvalidIp(ip.to_string(), e))?;
+
+    // `IpNetwork::contains` returns true if the address falls within the range.
+    if network.contains(address) {
+        Ok(())
+    } else {
+        Err(ValidationError::IpOutsideNetwork {
+            ip: ip.to_string(),
+            cidr: cidr.to_string(),
+        })
+    }
+}
+
+// ─── Tests ────────────────────────────────────────────────────────────────────
+
+// `#[cfg(test)]`: this block is only compiled when running `cargo test`.
+// Writing tests in the same file as the code being tested is idiomatic Rust.
+#[cfg(test)]
+mod tests {
+    // `super::*` imports everything from the parent module (this file).
+    use super::*;
+
+    #[test]
+    fn ip_within_valid_network() {
+        // `.unwrap()` is acceptable in tests — a failure here fails the test.
+        assert!(validate_ip_in_network("192.168.1.10", "192.168.1.0/24").is_ok());
+        assert!(validate_ip_in_network("10.0.0.1", "10.0.0.0/8").is_ok());
+        assert!(validate_ip_in_network("172.16.5.100", "172.16.0.0/12").is_ok());
+    }
+
+    #[test]
+    fn ip_outside_network() {
+        assert!(validate_ip_in_network("10.0.0.1", "192.168.1.0/24").is_err());
+        assert!(validate_ip_in_network("192.168.2.1", "192.168.1.0/24").is_err());
+    }
+
+    #[test]
+    fn invalid_cidr() {
+        assert!(validate_cidr("not-a-cidr").is_err());
+        assert!(validate_cidr("192.168.1/24").is_err()); // truncated address
+        assert!(validate_cidr("192.168.1.0/33").is_err()); // prefix > 32
+    }
+
+    #[test]
+    fn invalid_ip() {
+        assert!(validate_ip_in_network("999.0.0.1", "192.168.1.0/24").is_err());
+        assert!(validate_ip_in_network("not-an-ip", "192.168.1.0/24").is_err());
+    }
+
+    #[test]
+    fn known_protocol() {
+        assert_eq!(crate::models::Port::known_protocol(22), Some("SSH"));
+        assert_eq!(crate::models::Port::known_protocol(443), Some("HTTPS"));
+        assert_eq!(crate::models::Port::known_protocol(9999), None);
+    }
+}

style/rust-ipam.css

@@ -0,0 +1,908 @@
+/* ============================================================
+   DESIGN TOKENS
+   All visual properties live as CSS custom properties.
+   To add a new theme, define a [data-theme="my-theme"] block
+   with the same variable set below.
+   ============================================================ */
+
+:root {
+  /* --- Shared tokens (identical across all themes) --- */
+  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
+    Roboto, "Helvetica Neue", Arial, sans-serif;
+  --font-mono: "SF Mono", "Fira Code", "Cascadia Code", "Consolas", monospace;
+
+  --size-xs:  4px;
+  --size-sm:  8px;
+  --size-md: 16px;
+  --size-lg: 24px;
+  --size-xl: 40px;
+  --size-2xl: 64px;
+
+  --radius-sm: 6px;
+  --radius-md: 10px;
+  --radius-lg: 14px;
+  --radius-pill: 999px;
+
+  --font-xs:   12px;
+  --font-sm:   13px;
+  --font-base: 15px;
+  --font-lg:   17px;
+  --font-xl:   22px;
+  --font-2xl:  28px;
+  --font-3xl:  34px;
+
+  --transition-fast: 100ms ease;
+  --transition-base: 200ms ease;
+
+  --nav-height: 52px;
+  --content-width: 1000px;
+
+  /* --- Light theme (default) --- */
+  --bg:          #f5f5f7;
+  --bg-surface:  #ffffff;
+  --bg-surface2: #f9f9fb;
+  --bg-hover:    rgba(0, 0, 0, 0.04);
+  --bg-overlay:  rgba(255, 255, 255, 0.8);
+
+  --border:       rgba(0, 0, 0, 0.12);
+  --border-focus: #0071e3;
+
+  --text:          #1d1d1f;
+  --text-secondary: #6e6e73;
+  --text-tertiary:  #aeaeb2;
+  --text-on-accent: #ffffff;
+
+  --accent:       #0071e3;
+  --accent-hover: #0077ed;
+  --accent-light: rgba(0, 113, 227, 0.10);
+
+  --danger:       #ff3b30;
+  --danger-hover: #ff2d20;
+  --danger-light: rgba(255, 59, 48, 0.10);
+
+  --success:      #34c759;
+
+  --shadow-sm: 0 1px 2px rgba(0,0,0,.06), 0 1px 4px rgba(0,0,0,.04);
+  --shadow-md: 0 4px 12px rgba(0,0,0,.08), 0 2px 4px rgba(0,0,0,.04);
+  --shadow-lg: 0 8px 24px rgba(0,0,0,.12), 0 4px 8px rgba(0,0,0,.06);
+}
+
+/* System dark mode — only applies when no explicit data-theme is set */
+@media (prefers-color-scheme: dark) {
+  :root:not([data-theme]) {
+    --bg:          #000000;
+    --bg-surface:  #1c1c1e;
+    --bg-surface2: #2c2c2e;
+    --bg-hover:    rgba(255, 255, 255, 0.06);
+    --bg-overlay:  rgba(28, 28, 30, 0.85);
+
+    --border:       rgba(255, 255, 255, 0.12);
+    --border-focus: #0a84ff;
+
+    --text:           #f5f5f7;
+    --text-secondary: #aeaeb2;
+    --text-tertiary:  #636366;
+    --text-on-accent: #ffffff;
+
+    --accent:       #0a84ff;
+    --accent-hover: #409cff;
+    --accent-light: rgba(10, 132, 255, 0.15);
+
+    --danger:       #ff453a;
+    --danger-hover: #ff6961;
+    --danger-light: rgba(255, 69, 58, 0.15);
+
+    --success:      #32d74b;
+
+    --shadow-sm: 0 1px 2px rgba(0,0,0,.3), 0 1px 4px rgba(0,0,0,.2);
+    --shadow-md: 0 4px 12px rgba(0,0,0,.4), 0 2px 4px rgba(0,0,0,.2);
+    --shadow-lg: 0 8px 24px rgba(0,0,0,.5), 0 4px 8px rgba(0,0,0,.3);
+  }
+}
+
+/* Explicit light theme */
+[data-theme="light"] {
+  --bg:          #f5f5f7;
+  --bg-surface:  #ffffff;
+  --bg-surface2: #f9f9fb;
+  --bg-hover:    rgba(0, 0, 0, 0.04);
+  --bg-overlay:  rgba(255, 255, 255, 0.8);
+
+  --border:       rgba(0, 0, 0, 0.12);
+  --border-focus: #0071e3;
+
+  --text:           #1d1d1f;
+  --text-secondary: #6e6e73;
+  --text-tertiary:  #aeaeb2;
+  --text-on-accent: #ffffff;
+
+  --accent:       #0071e3;
+  --accent-hover: #0077ed;
+  --accent-light: rgba(0, 113, 227, 0.10);
+
+  --danger:       #ff3b30;
+  --danger-hover: #ff2d20;
+  --danger-light: rgba(255, 59, 48, 0.10);
+
+  --success:      #34c759;
+
+  --shadow-sm: 0 1px 2px rgba(0,0,0,.06), 0 1px 4px rgba(0,0,0,.04);
+  --shadow-md: 0 4px 12px rgba(0,0,0,.08), 0 2px 4px rgba(0,0,0,.04);
+  --shadow-lg: 0 8px 24px rgba(0,0,0,.12), 0 4px 8px rgba(0,0,0,.06);
+}
+
+/* Explicit dark theme */
+[data-theme="dark"] {
+  --bg:          #000000;
+  --bg-surface:  #1c1c1e;
+  --bg-surface2: #2c2c2e;
+  --bg-hover:    rgba(255, 255, 255, 0.06);
+  --bg-overlay:  rgba(28, 28, 30, 0.85);
+
+  --border:       rgba(255, 255, 255, 0.12);
+  --border-focus: #0a84ff;
+
+  --text:           #f5f5f7;
+  --text-secondary: #aeaeb2;
+  --text-tertiary:  #636366;
+  --text-on-accent: #ffffff;
+
+  --accent:       #0a84ff;
+  --accent-hover: #409cff;
+  --accent-light: rgba(10, 132, 255, 0.15);
+
+  --danger:       #ff453a;
+  --danger-hover: #ff6961;
+  --danger-light: rgba(255, 69, 58, 0.15);
+
+  --success:      #32d74b;
+
+  --shadow-sm: 0 1px 2px rgba(0,0,0,.3), 0 1px 4px rgba(0,0,0,.2);
+  --shadow-md: 0 4px 12px rgba(0,0,0,.4), 0 2px 4px rgba(0,0,0,.2);
+  --shadow-lg: 0 8px 24px rgba(0,0,0,.5), 0 4px 8px rgba(0,0,0,.3);
+}
+
+/* ============================================================
+   RESET & BASE
+   ============================================================ */
+
+*, *::before, *::after {
+  box-sizing: border-box;
+  margin: 0;
+  padding: 0;
+}
+
+html {
+  font-size: var(--font-base);
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  text-rendering: optimizeLegibility;
+}
+
+body {
+  font-family: var(--font-sans);
+  font-size: var(--font-base);
+  line-height: 1.6;
+  color: var(--text);
+  background: var(--bg);
+  min-height: 100vh;
+  transition: background var(--transition-base), color var(--transition-base);
+}
+
+/* ============================================================
+   NAVIGATION
+   ============================================================ */
+
+nav {
+  position: sticky;
+  top: 0;
+  z-index: 100;
+  height: var(--nav-height);
+  display: flex;
+  align-items: center;
+  gap: var(--size-sm);
+  padding: 0 var(--size-lg);
+  background: var(--bg-overlay);
+  border-bottom: 1px solid var(--border);
+  backdrop-filter: blur(20px) saturate(180%);
+  -webkit-backdrop-filter: blur(20px) saturate(180%);
+}
+
+nav a {
+  font-size: var(--font-sm);
+  font-weight: 500;
+  color: var(--text-secondary);
+  text-decoration: none;
+  padding: var(--size-xs) var(--size-sm);
+  border-radius: var(--radius-sm);
+  transition: color var(--transition-fast), background var(--transition-fast);
+}
+
+nav a:hover {
+  color: var(--text);
+  background: var(--bg-hover);
+}
+
+nav a.active {
+  color: var(--accent);
+}
+
+/* Spacer pushes theme toggle to the right */
+nav .nav-spacer {
+  flex: 1;
+}
+
+/* ============================================================
+   LAYOUT
+   ============================================================ */
+
+main {
+  max-width: var(--content-width);
+  margin: 0 auto;
+  padding: var(--size-xl) var(--size-lg);
+}
+
+/* ============================================================
+   TYPOGRAPHY
+   ============================================================ */
+
+h1 {
+  font-size: var(--font-3xl);
+  font-weight: 700;
+  letter-spacing: -0.5px;
+  color: var(--text);
+  margin-bottom: var(--size-sm);
+}
+
+h2 {
+  font-size: var(--font-xl);
+  font-weight: 600;
+  letter-spacing: -0.3px;
+  color: var(--text);
+  margin-bottom: var(--size-md);
+}
+
+h3 {
+  font-size: var(--font-lg);
+  font-weight: 600;
+  color: var(--text);
+  margin-bottom: var(--size-sm);
+}
+
+p {
+  color: var(--text-secondary);
+  line-height: 1.7;
+}
+
+code {
+  font-family: var(--font-mono);
+  font-size: 0.9em;
+  background: var(--bg-surface2);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-sm);
+  padding: 1px 6px;
+}
+
+/* ============================================================
+   BUTTONS
+   ============================================================ */
+
+button,
+.btn {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: var(--size-xs);
+  font-family: var(--font-sans);
+  font-size: var(--font-sm);
+  font-weight: 500;
+  line-height: 1;
+  padding: 8px 16px;
+  border-radius: var(--radius-sm);
+  border: 1px solid transparent;
+  cursor: pointer;
+  transition:
+    background var(--transition-fast),
+    color var(--transition-fast),
+    box-shadow var(--transition-fast),
+    transform var(--transition-fast);
+  text-decoration: none;
+  white-space: nowrap;
+  user-select: none;
+}
+
+button:active,
+.btn:active {
+  transform: scale(0.98);
+}
+
+/* Primary — filled accent */
+button[type="submit"],
+.btn-primary {
+  background: var(--accent);
+  color: var(--text-on-accent);
+  border-color: var(--accent);
+}
+
+button[type="submit"]:hover,
+.btn-primary:hover {
+  background: var(--accent-hover);
+  border-color: var(--accent-hover);
+  box-shadow: var(--shadow-sm);
+}
+
+/* Secondary — outlined */
+.btn-secondary {
+  background: transparent;
+  color: var(--text);
+  border-color: var(--border);
+}
+
+.btn-secondary:hover {
+  background: var(--bg-hover);
+}
+
+/* Danger — for delete actions */
+.btn-danger {
+  background: transparent;
+  color: var(--danger);
+  border-color: transparent;
+  font-size: var(--font-xs);
+  padding: 4px 10px;
+}
+
+.btn-danger:hover {
+  background: var(--danger-light);
+  border-color: var(--danger);
+}
+
+/* Theme toggle */
+.theme-toggle {
+  background: var(--bg-hover);
+  color: var(--text-secondary);
+  border: 1px solid var(--border);
+  font-size: var(--font-xs);
+  font-weight: 600;
+  padding: 4px 10px;
+  border-radius: var(--radius-pill);
+  letter-spacing: 0.3px;
+}
+
+.theme-toggle:hover {
+  color: var(--text);
+  background: var(--bg-surface2);
+  border-color: var(--border-focus);
+}
+
+/* ============================================================
+   FORMS & INPUTS
+   ============================================================ */
+
+.form-group {
+  display: flex;
+  flex-direction: column;
+  gap: var(--size-xs);
+  margin-bottom: var(--size-md);
+}
+
+label {
+  display: flex;
+  flex-direction: column;
+  gap: var(--size-xs);
+  font-size: var(--font-sm);
+  font-weight: 500;
+  color: var(--text-secondary);
+}
+
+input[type="text"],
+input[type="email"],
+input[type="number"],
+input[type="password"],
+input[type="search"],
+select,
+textarea {
+  font-family: var(--font-sans);
+  font-size: var(--font-base);
+  color: var(--text);
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-sm);
+  padding: 9px 12px;
+  width: 100%;
+  transition:
+    border-color var(--transition-fast),
+    box-shadow var(--transition-fast);
+  outline: none;
+  -webkit-appearance: none;
+}
+
+input::placeholder,
+textarea::placeholder {
+  color: var(--text-tertiary);
+}
+
+input:focus,
+select:focus,
+textarea:focus {
+  border-color: var(--border-focus);
+  box-shadow: 0 0 0 3px var(--accent-light);
+}
+
+/* Inline form layout (label + input + button on one line) */
+.form-inline {
+  display: flex;
+  align-items: flex-end;
+  gap: var(--size-sm);
+  flex-wrap: wrap;
+}
+
+.form-inline label {
+  flex: 1;
+  min-width: 200px;
+}
+
+/* ============================================================
+   CARDS & SECTIONS
+   ============================================================ */
+
+.card {
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-sm);
+  padding: var(--size-lg);
+  transition: box-shadow var(--transition-base);
+}
+
+.card:hover {
+  box-shadow: var(--shadow-md);
+}
+
+/* Section spacing between cards */
+section + section {
+  margin-top: var(--size-lg);
+}
+
+/* ============================================================
+   TABLES
+   ============================================================ */
+
+.table-container {
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-sm);
+  overflow: hidden;
+}
+
+table {
+  width: 100%;
+  border-collapse: collapse;
+  font-size: var(--font-sm);
+}
+
+thead {
+  background: var(--bg-surface2);
+  border-bottom: 1px solid var(--border);
+}
+
+thead th {
+  padding: 10px var(--size-md);
+  text-align: left;
+  font-size: var(--font-xs);
+  font-weight: 600;
+  letter-spacing: 0.5px;
+  text-transform: uppercase;
+  color: var(--text-tertiary);
+}
+
+tbody tr {
+  border-bottom: 1px solid var(--border);
+  transition: background var(--transition-fast);
+}
+
+tbody tr:last-child {
+  border-bottom: none;
+}
+
+tbody tr:hover {
+  background: var(--bg-hover);
+}
+
+tbody td {
+  padding: 12px var(--size-md);
+  color: var(--text);
+  vertical-align: middle;
+}
+
+/* Count columns (Hosts, Applications...) — right-aligned, muted color */
+th.col-count,
+td.col-count {
+  text-align: right;
+  color: var(--text-secondary);
+  font-variant-numeric: tabular-nums;
+  width: 120px;
+}
+
+th.col-count {
+  color: var(--text-tertiary);
+}
+
+/* Actions column — right-aligned to match the button position */
+th.col-actions,
+td.col-actions {
+  text-align: right;
+  width: 100px;
+}
+
+/* ============================================================
+   STATUS MESSAGES
+   ============================================================ */
+
+.error {
+  display: flex;
+  align-items: center;
+  gap: var(--size-sm);
+  font-size: var(--font-sm);
+  color: var(--danger);
+  background: var(--danger-light);
+  border: 1px solid var(--danger);
+  border-radius: var(--radius-sm);
+  padding: var(--size-sm) var(--size-md);
+  margin-bottom: var(--size-md);
+}
+
+.empty {
+  font-size: var(--font-sm);
+  color: var(--text-tertiary);
+  text-align: center;
+  padding: var(--size-xl);
+}
+
+/* ============================================================
+   HOME PAGE — Dashboard
+   ============================================================ */
+
+.home-page {
+  max-width: 860px;
+  margin: 0 auto;
+  padding-top: var(--size-2xl);
+}
+
+.home-header {
+  text-align: center;
+  margin-bottom: var(--size-2xl);
+}
+
+.home-header h1 {
+  font-size: var(--font-3xl);
+  margin-bottom: var(--size-xs);
+}
+
+.home-header p {
+  font-size: var(--font-lg);
+  color: var(--text-secondary);
+  margin-bottom: 0;
+}
+
+/* Summary grid — one card per entity */
+.summary-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
+  gap: var(--size-md);
+}
+
+/* Clickable summary card */
+.summary-card {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: var(--size-sm);
+  padding: var(--size-xl) var(--size-lg);
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-sm);
+  text-decoration: none;
+  cursor: pointer;
+  transition:
+    box-shadow var(--transition-base),
+    border-color var(--transition-base),
+    transform var(--transition-base),
+    background var(--transition-base);
+}
+
+.summary-card:hover {
+  box-shadow: var(--shadow-md);
+  border-color: var(--accent);
+  background: var(--accent-light);
+  transform: translateY(-2px);
+}
+
+.summary-card:active {
+  transform: translateY(0);
+  box-shadow: var(--shadow-sm);
+}
+
+.summary-card__count {
+  font-size: var(--font-3xl);
+  font-weight: 700;
+  letter-spacing: -1px;
+  color: var(--text);
+  line-height: 1;
+  /* Animate count changes gracefully */
+  transition: color var(--transition-base);
+}
+
+.summary-card:hover .summary-card__count {
+  color: var(--accent);
+}
+
+.summary-card__label {
+  font-size: var(--font-sm);
+  font-weight: 500;
+  color: var(--text-secondary);
+  letter-spacing: 0.3px;
+  text-transform: uppercase;
+}
+
+/* ============================================================
+   NETWORKS PAGE
+   ============================================================ */
+
+.networks-page h1 {
+  margin-bottom: var(--size-lg);
+}
+
+.networks-page .add-form {
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-sm);
+  padding: var(--size-lg);
+  margin-bottom: var(--size-lg);
+}
+
+.networks-page .add-form h2 {
+  margin-bottom: var(--size-md);
+}
+
+.networks-page .add-form form {
+  display: flex;
+  align-items: flex-end;
+  gap: var(--size-sm);
+  flex-wrap: wrap;
+}
+
+.networks-page .add-form label {
+  flex: 1;
+  min-width: 220px;
+}
+
+.networks-page .add-form input {
+  margin-top: var(--size-xs);
+}
+
+.networks-page .list h2 {
+  margin-bottom: var(--size-md);
+}
+
+.networks-page .list .table-container {
+  margin-top: 0;
+}
+
+/* Delete button inside table */
+.networks-page td button {
+  background: transparent;
+  color: var(--danger);
+  border: 1px solid transparent;
+  font-size: var(--font-xs);
+  padding: 3px 10px;
+  border-radius: var(--radius-sm);
+  cursor: pointer;
+  transition: background var(--transition-fast), border-color var(--transition-fast);
+}
+
+.networks-page td button:hover {
+  background: var(--danger-light);
+  border-color: var(--danger);
+}
+
+/* ============================================================
+   404 PAGE
+   ============================================================ */
+
+.not-found {
+  text-align: center;
+  padding-top: var(--size-2xl);
+}
+
+.not-found h1 {
+  font-size: var(--font-2xl);
+  margin-bottom: var(--size-md);
+}
+
+.not-found a {
+  color: var(--accent);
+  text-decoration: none;
+  font-weight: 500;
+}
+
+.not-found a:hover {
+  text-decoration: underline;
+}
+
+/* ============================================================
+   TABLE UTILITIES — shared across pages
+   ============================================================ */
+
+/* Clickable link inside a table cell */
+.table-link {
+  color: var(--accent);
+  text-decoration: none;
+  font-weight: 500;
+}
+
+.table-link:hover {
+  text-decoration: underline;
+}
+
+/* Monospace cell (IPs, CIDRs…) */
+.cell-mono {
+  font-family: var(--font-mono);
+  font-size: var(--font-sm);
+  color: var(--text-secondary);
+}
+
+/* ============================================================
+   FILTER BAR
+   ============================================================ */
+
+.filter-bar {
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-sm);
+  padding: var(--size-md) var(--size-lg);
+  margin-bottom: var(--size-md);
+}
+
+.filter-bar__fields {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
+  gap: var(--size-md);
+  align-items: end;
+}
+
+.filter-field {
+  display: flex;
+  flex-direction: column;
+  gap: var(--size-xs);
+  font-size: var(--font-sm);
+  font-weight: 500;
+  color: var(--text-secondary);
+}
+
+/* ============================================================
+   PAGINATION BAR
+   ============================================================ */
+
+.pagination-bar {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  flex-wrap: wrap;
+  gap: var(--size-sm);
+  padding: var(--size-sm) 0;
+  margin-bottom: var(--size-sm);
+}
+
+.pagination-bar__info {
+  font-size: var(--font-sm);
+  color: var(--text-secondary);
+}
+
+.pagination-bar__controls {
+  display: flex;
+  align-items: center;
+  gap: var(--size-md);
+}
+
+.pagination-per-page {
+  display: flex;
+  align-items: center;
+  gap: var(--size-xs);
+  font-size: var(--font-sm);
+  color: var(--text-secondary);
+  font-weight: 500;
+}
+
+.pagination-per-page select {
+  width: auto;
+  padding: 4px 8px;
+  font-size: var(--font-sm);
+}
+
+.pagination-nav {
+  display: flex;
+  align-items: center;
+  gap: var(--size-xs);
+}
+
+.pagination-nav button {
+  background: var(--bg-surface);
+  color: var(--text);
+  border: 1px solid var(--border);
+  padding: 4px 10px;
+  font-size: var(--font-base);
+  border-radius: var(--radius-sm);
+  min-width: 32px;
+}
+
+.pagination-nav button:hover:not(:disabled) {
+  background: var(--bg-hover);
+  border-color: var(--accent);
+  color: var(--accent);
+}
+
+.pagination-nav button:disabled {
+  opacity: 0.35;
+  cursor: not-allowed;
+}
+
+.pagination-nav__label {
+  font-size: var(--font-sm);
+  color: var(--text-secondary);
+  white-space: nowrap;
+  padding: 0 var(--size-xs);
+}
+
+/* ============================================================
+   HOSTS PAGE
+   ============================================================ */
+
+.hosts-page h1 {
+  margin-bottom: var(--size-lg);
+}
+
+.hosts-page .add-form {
+  background: var(--bg-surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-sm);
+  padding: var(--size-lg);
+  margin-bottom: var(--size-md);
+}
+
+.hosts-page .add-form h2 {
+  margin-bottom: var(--size-md);
+}
+
+.add-form__fields {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
+  gap: var(--size-md);
+  align-items: end;
+}
+
+.add-form__fields button[type="submit"] {
+  align-self: end;
+}
+
+/* Delete button inside hosts table */
+.hosts-page td button {
+  background: transparent;
+  color: var(--danger);
+  border: 1px solid transparent;
+  font-size: var(--font-xs);
+  padding: 3px 10px;
+  border-radius: var(--radius-sm);
+  cursor: pointer;
+  transition: background var(--transition-fast), border-color var(--transition-fast);
+}
+
+.hosts-page td button:hover {
+  background: var(--danger-light);
+  border-color: var(--danger);
+}