mobile: off-canvas sidebar, responsive grids/charts/top-bar

- Sidebar becomes slide-in overlay under 768px with backdrop
- Hamburger button in top-bar for mobile nav toggle
- Grids stack single-column, charts shrink to 280px
- Tables scroll horizontally with touch momentum
- Status text hidden on mobile (dot stays visible)
- Card headers/actions stack vertically
- Period selectors scroll horizontally

also: image size validation clamp in handleImageGenerations

internal/server/server.go

@@ -850,6 +850,31 @@ func (s *Server) handleImageGenerations(c *gin.Context) {
 		}
 	}
 
+	// ponytail: per-model valid size sets. Add new models here.
+	if req.Size != nil {
+		validSizes := map[string][]string{
+			"gpt-image": {"1024x1024", "1024x1536", "1536x1024", "auto"},
+			"dall-e-3":  {"1024x1024", "1024x1792", "1792x1024", "auto"},
+			"dall-e-2":  {"256x256", "512x512", "1024x1024", "auto"},
+		}
+		for prefix, sizes := range validSizes {
+			if strings.HasPrefix(req.Model, prefix) {
+				valid := false
+				for _, s := range sizes {
+					if *req.Size == s {
+						valid = true
+						break
+					}
+				}
+				if !valid {
+					*req.Size = "1024x1024"
+					log.Printf("[WARN] Unsupported size for %s, clamped to 1024x1024", req.Model)
+				}
+				break
+			}
+		}
+	}
+
 	provider, ok := s.providers[providerName]
 	if !ok {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("Provider %s not enabled or supported", providerName)})

static/css/dashboard.css

@@ -1395,8 +1395,150 @@ body {
     border: 1px solid var(--bg2);
 }
 
-/* Settings: Warning Card */
+/* Warning Card */
 .warning-card {
     border: 1px dashed var(--warning);
     background: rgba(215, 153, 33, 0.08);
 }
+
+/* ==================== MOBILE BAREBONES ==================== */
+@media (max-width: 767px) {
+    .sidebar {
+        transform: translateX(-100%);
+        width: 280px;
+        z-index: 2000;
+    }
+    .sidebar.mobile-visible {
+        transform: translateX(0);
+    }
+    .sidebar.collapsed {
+        width: 280px;
+    }
+    .sidebar.collapsed .menu-item span,
+    .sidebar.collapsed .menu-title,
+    .sidebar.collapsed .user-details {
+        display: block;
+    }
+    .sidebar.collapsed .menu-item {
+        justify-content: flex-start;
+        padding: 0.75rem var(--spacing-lg);
+    }
+    .sidebar.collapsed .menu-item i {
+        font-size: inherit;
+    }
+    .sidebar.collapsed .sidebar-footer {
+        justify-content: space-between;
+        padding: var(--spacing-lg);
+    }
+
+    .sidebar-backdrop {
+        position: fixed;
+        inset: 0;
+        background: rgba(0,0,0,0.6);
+        z-index: 1999;
+        opacity: 0;
+        pointer-events: none;
+        transition: opacity 0.3s;
+    }
+    .sidebar-backdrop.visible {
+        opacity: 1;
+        pointer-events: auto;
+    }
+
+    .main-content {
+        padding-left: 0 !important;
+    }
+
+    .mobile-menu-btn {
+        display: inline-flex;
+        align-items: center;
+        justify-content: center;
+        background: var(--bg1);
+        border: 1px solid var(--bg3);
+        color: var(--fg1);
+        width: 36px;
+        height: 36px;
+        border-radius: 6px;
+        cursor: pointer;
+        font-size: 1rem;
+        flex-shrink: 0;
+    }
+    .mobile-menu-btn:active {
+        background: var(--bg2);
+    }
+
+    .stats-grid {
+        grid-template-columns: 1fr;
+    }
+    .grid-2 {
+        grid-template-columns: 1fr;
+    }
+    .grid-3 {
+        grid-template-columns: 1fr;
+    }
+
+    .chart-container {
+        height: 280px;
+    }
+
+    .table-container {
+        overflow-x: auto;
+        -webkit-overflow-scrolling: touch;
+    }
+
+    .content-body {
+        padding: var(--spacing-md);
+    }
+    .top-bar {
+        padding: 0 var(--spacing-md);
+        gap: 0.5rem;
+    }
+    .top-bar .page-title h2 {
+        font-size: 1rem;
+    }
+    .top-bar-actions {
+        gap: var(--spacing-sm);
+    }
+
+    .status-indicator .status-text {
+        display: none;
+    }
+
+    .monitoring-layout {
+        grid-template-columns: 1fr;
+    }
+
+    .card-header {
+        flex-direction: column;
+        align-items: flex-start;
+    }
+    .card-actions {
+        width: 100%;
+    }
+
+    .login-card {
+        padding: 2rem 1.25rem;
+    }
+
+    .period-selector {
+        overflow-x: auto;
+        flex-wrap: nowrap;
+        -webkit-overflow-scrolling: touch;
+    }
+
+    .modal-content {
+        width: 95%;
+        margin: 1rem;
+    }
+}
+
+@media (max-width: 767px) {
+    .mobile-menu-btn { display: inline-flex; }
+}
+@media (min-width: 768px) {
+    .mobile-menu-btn { display: none; }
+    .sidebar-backdrop { display: none; }
+}
+
+/* ponytail: single-breakpoint responsive layer, no card-based table fallback
+   add table→card reflow when tables get too wide to scroll horizontally */

static/index.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>GopherGate - Admin Dashboard</title>
-    <link rel="stylesheet" href="/css/dashboard.css?v=11">
+    <link rel="stylesheet" href="/css/dashboard.css?v=12">
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
     <link rel="preconnect" href="https://fonts.googleapis.com">
     <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
@@ -51,7 +51,7 @@
                     <span>GopherGate</span>
                 </div>
                 <button class="sidebar-toggle" id="sidebar-toggle">
-                    <i class="fas fa-bars"></i>
+                    <i class="fas fa-times"></i>
                 </button>
             </div>
             
@@ -135,11 +135,17 @@
             </div>
         </nav>
 
+        <!-- Mobile sidebar backdrop -->
+        <div class="sidebar-backdrop" id="sidebar-backdrop"></div>
+
         <!-- Main Content -->
         <main class="main-content">
             <header class="top-bar">
+                <button class="mobile-menu-btn" id="mobile-menu-btn">
+                    <i class="fas fa-bars"></i>
+                </button>
                 <div class="page-title">
-                    <h2 id="current-page-title">Overview</h2>
+                    <h2 id="page-title">Overview</h2>
                 </div>
                 <div class="top-bar-actions">
                     <div id="connection-status" class="status-indicator">

static/js/dashboard.js

@@ -60,23 +60,75 @@ class Dashboard {
         const toggleBtn = document.getElementById('sidebar-toggle');
         const sidebar = document.querySelector('.sidebar');
         const logoutBtn = document.getElementById('logout-btn');
-        
+        const backdrop = document.getElementById('sidebar-backdrop');
+        const mobileBtn = document.getElementById('mobile-menu-btn');
+
+        const isMobile = () => window.innerWidth < 768;
+
+        const closeMobileNav = () => {
+            if (sidebar) sidebar.classList.remove('mobile-visible');
+            if (backdrop) backdrop.classList.remove('visible');
+        };
+
+        const toggleMobileNav = () => {
+            if (!sidebar || !backdrop) return;
+            const opening = !sidebar.classList.contains('mobile-visible');
+            sidebar.classList.toggle('mobile-visible', opening);
+            backdrop.classList.toggle('visible', opening);
+            document.body.style.overflow = opening && isMobile() ? 'hidden' : '';
+        };
+
         if (toggleBtn && sidebar) {
             toggleBtn.onclick = () => {
-                sidebar.classList.toggle('collapsed');
+                if (isMobile()) {
-                localStorage.setItem('sidebar_collapsed', sidebar.classList.contains('collapsed'));
+                    toggleMobileNav();
+                } else {
+                    sidebar.classList.toggle('collapsed');
+                    localStorage.setItem('sidebar_collapsed', sidebar.classList.contains('collapsed'));
+                }
             };
-            
+
-            if (localStorage.getItem('sidebar_collapsed') === 'true') {
+            if (!isMobile() && localStorage.getItem('sidebar_collapsed') === 'true') {
                 sidebar.classList.add('collapsed');
             }
         }
 
+        if (mobileBtn) {
+            mobileBtn.onclick = toggleMobileNav;
+        }
+
+        if (backdrop) {
+            backdrop.onclick = closeMobileNav;
+        }
+
+        // Close sidebar on page navigation (mobile)
+        const menuItems = document.querySelectorAll('.menu-item');
+        menuItems.forEach(item => {
+            const origClick = item.onclick;
+            item.onclick = (e) => {
+                if (isMobile()) closeMobileNav();
+                if (origClick) origClick(e);
+            };
+        });
+
         if (logoutBtn) {
             logoutBtn.onclick = () => {
+                if (isMobile()) closeMobileNav();
                 window.authManager.logout();
             };
         }
+
+        // Handle resize
+        let resizeTimer;
+        window.addEventListener('resize', () => {
+            clearTimeout(resizeTimer);
+            resizeTimer = setTimeout(() => {
+                if (!isMobile()) {
+                    closeMobileNav();
+                    document.body.style.overflow = '';
+                }
+            }, 200);
+        });
     }
 
     setupRefresh() {