diff --git a/ucp/assets/ucp.js b/ucp/assets/ucp.js
index d8249f6..da3a99d 100644
--- a/ucp/assets/ucp.js
+++ b/ucp/assets/ucp.js
@@ -286,8 +286,8 @@ function renderExtensionsGrid() {
             : '';
 
         return `
-            <div class="ucp-card rounded-2xl p-5 space-y-4">
-                <div class="flex items-start justify-between gap-3">
+            <div class="ucp-card rounded-2xl p-4 sm:p-5 space-y-4 min-w-0 overflow-hidden">
+                <div class="flex items-start justify-between gap-3 min-w-0">
                     <div class="flex items-center gap-3 min-w-0">
                         ${avatarSrc
                             ? `<img src="${escapeHtml(avatarSrc)}" alt="" class="w-12 h-12 rounded-full object-cover border border-slate-200 shrink-0">`
@@ -301,7 +301,7 @@ function renderExtensionsGrid() {
                                 ${statusPill}
                                 ${vmPill}
                             </div>
-                            ${ext.ip ? `<div class="text-[11px] text-slate-400 font-mono mt-1">${escapeHtml(ext.ip)} ${ext.user_agent ? '• ' + escapeHtml(ext.user_agent) : ''}</div>` : ''}
+                            ${ext.ip ? `<div class="text-[11px] text-slate-400 font-mono mt-1 break-all">${escapeHtml(ext.ip)} ${ext.user_agent ? '• ' + escapeHtml(ext.user_agent) : ''}</div>` : ''}
                         </div>
                     </div>
                 </div>
diff --git a/ucp/index.php b/ucp/index.php
index 7a67c1b..eba53cd 100644
--- a/ucp/index.php
+++ b/ucp/index.php
@@ -24,7 +24,7 @@ $csrfToken   = UcpAuth::getCsrfToken();
 <html lang="fr" class="h-full bg-slate-50">
 <head>
     <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
     <title><?= htmlspecialchars($companyName ?: 'NexusPBX') ?> — Portail Utilisateur (UCP)</title>
     <link rel="icon" type="image/png" href="/assets/favicon.png?v=<?= file_exists(__DIR__ . '/assets/favicon.png') ? filemtime(__DIR__ . '/assets/favicon.png') : 1 ?>">
     <script src="https://cdn.tailwindcss.com"></script>
@@ -41,8 +41,18 @@ $csrfToken   = UcpAuth::getCsrfToken();
         };
     </script>
     <style>
+        html, body {
+            max-width: 100%;
+            overflow-x: hidden;
+            -webkit-text-size-adjust: 100%;
+        }
         body { background-color: #f8fafc; color: #0f172a; }
         .ucp-card { background: #ffffff; border: 1px solid #e2e8f0; box-shadow: 0 1px 3px rgba(15, 23, 42, 0.04); }
+        @media screen and (max-width: 639px) {
+            input, select, textarea {
+                font-size: 16px !important;
+            }
+        }
         ::-webkit-scrollbar { width: 7px; height: 7px; }
         ::-webkit-scrollbar-track { background: #f1f5f9; }
         ::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 4px; }
@@ -100,7 +110,7 @@ $csrfToken   = UcpAuth::getCsrfToken();
 <body class="min-h-full font-sans antialiased text-slate-800">
 
     <!-- Toast Container -->
-    <div id="ucp-toast-container" class="fixed top-4 right-4 z-50 flex flex-col gap-2 max-w-sm w-full pointer-events-none px-4 sm:px-0"></div>
+    <div id="ucp-toast-container" class="fixed top-4 inset-x-3 sm:inset-x-auto sm:right-4 z-50 flex flex-col gap-2 sm:max-w-sm sm:w-full pointer-events-none"></div>
 
 <?php if (!$ucpEnabled): ?>
     <div class="min-h-screen flex items-center justify-center p-6">
@@ -132,13 +142,13 @@ $csrfToken   = UcpAuth::getCsrfToken();
                     <label for="ucp-login-user" class="block text-xs font-semibold text-slate-700 mb-1.5">Identifiant utilisateur</label>
                     <input type="text" id="ucp-login-user" name="username" required autocomplete="username" autofocus
                         placeholder="ex: fred ou fred@entreprise.fr"
-                        class="w-full px-3.5 py-2.5 rounded-xl bg-slate-50 border border-slate-300 text-sm text-slate-900 focus:bg-white focus:ring-2 focus:ring-indigo-500/30 focus:border-indigo-500 focus:outline-none transition">
+                        class="w-full px-3.5 py-2.5 rounded-xl bg-slate-50 border border-slate-300 text-base sm:text-sm text-slate-900 focus:bg-white focus:ring-2 focus:ring-indigo-500/30 focus:border-indigo-500 focus:outline-none transition">
                 </div>
                 <div>
                     <label for="ucp-login-pass" class="block text-xs font-semibold text-slate-700 mb-1.5">Mot de passe</label>
                     <input type="password" id="ucp-login-pass" name="password" required autocomplete="current-password"
                         placeholder="••••••••"
-                        class="w-full px-3.5 py-2.5 rounded-xl bg-slate-50 border border-slate-300 text-sm text-slate-900 focus:bg-white focus:ring-2 focus:ring-indigo-500/30 focus:border-indigo-500 focus:outline-none transition">
+                        class="w-full px-3.5 py-2.5 rounded-xl bg-slate-50 border border-slate-300 text-base sm:text-sm text-slate-900 focus:bg-white focus:ring-2 focus:ring-indigo-500/30 focus:border-indigo-500 focus:outline-none transition">
                 </div>
                 <div id="ucp-login-error" class="hidden rounded-xl bg-rose-50 border border-rose-200 px-3.5 py-2.5 text-xs font-medium text-rose-700"></div>
                 <button type="submit" id="ucp-login-btn"
@@ -154,7 +164,7 @@ $csrfToken   = UcpAuth::getCsrfToken();
     </div>
 <?php else: ?>
     <!-- INTERFACE PRINCIPALE UCP -->
-    <div class="min-h-screen flex flex-col">
+    <div class="min-h-screen flex flex-col overflow-x-hidden">
         <!-- Top Navbar -->
         <header class="sticky top-0 z-30 bg-white/95 backdrop-blur border-b border-slate-200">
             <div class="max-w-6xl mx-auto px-4 sm:px-6 h-16 flex items-center justify-between gap-4">
diff --git a/version.json b/version.json
index 7cd9d14..a4dcf7a 100644
--- a/version.json
+++ b/version.json
@@ -1,9 +1,10 @@
 {
-  "version": "2.5.4",
+  "version": "2.5.5",
   "codename": "Pulsar UCP",
   "release_date": "2026-11-11",
   "min_php_version": "8.2",
   "changelog": [
+    "Correctif v2.5.5 : suppression du zoom automatique iOS/iPhone sur les champs (<16px) et blocage du débordement horizontal mobile dans l'UCP",
     "Correctif v2.5.4 : correction du journal personnel UCP « Mes Appels » (correspondance caller_number/callee_number/canaux PJSIP et filtres Répondus/Manqués)",
     "Nouveauté v2.5.3 : onglet UCP « Notice & Codes » avec mémo pas-à-pas, codes de fonction dynamiques et export PDF / impression A4 corporate (logo, encarts, poste utilisateur)",
     "Correctif v2.5.2 : purge systématique try/finally + auto-nettoyage des dossiers temporaires HA /tmp (élimine la saturation tmpfs 100% qui bloquait la réplication)",