fix: fix layout spacing and make topbar fixed position

- Removed duplicate main-wrapper div that caused large gap
- Changed topbar from sticky to fixed position
- Topbar now stays at top across all section loads
- Added margin-top to page-content to account for fixed topbar
- Updated sidebar toggle to also move topbar position
- Layout: sidebar (fixed) | topbar (fixed) | content (scrollable)

public/admin.html

@@ -233,8 +233,10 @@
 
         /* ============ TOPBAR ============ */
         .topbar {
-            position: sticky;
+            position: fixed;
             top: 0;
+            left: var(--sidebar-width);
+            right: 0;
             height: var(--topbar-height);
             background: var(--card-bg);
             border-bottom: 1px solid var(--card-border);
@@ -243,6 +245,19 @@
             justify-content: space-between;
             padding: 0 32px;
             z-index: 100;
+            transition: left 0.3s ease;
+        }
+
+        .page-content {
+            padding: 32px;
+            overflow-x: hidden;
+            margin-top: var(--topbar-height);
+        }
+
+        .page-content {
+            padding: 32px;
+            overflow-x: hidden;
+            margin-top: var(--topbar-height);
         }
 
         .topbar-left {
@@ -1245,8 +1260,6 @@
     </aside>
 
     <!-- ============ MAIN CONTENT ============ -->
-
-    <div class="main-wrapper">
     <div class="main-wrapper">
         <!-- Topbar -->
         <header class="topbar">
@@ -1537,6 +1550,7 @@
             if (isCollapsed) {
                 sidebar.css('width', '280px');
                 $('.main-wrapper').css('margin-left', '280px');
+                $('.topbar').css('left', '280px');
                 $('.sidebar-logo-text, .sidebar-section-title, .sidebar-link span, .sidebar-link .badge, .sidebar-user-info, .sidebar-footer').show();
                 $('.sidebar-link i').css('margin-right', '14px');
                 $('.sidebar-logo').css('justify-content', 'flex-start');
@@ -1544,6 +1558,7 @@
             } else {
                 sidebar.css('width', '80px');
                 $('.main-wrapper').css('margin-left', '80px');
+                $('.topbar').css('left', '80px');
                 $('.sidebar-logo-text, .sidebar-section-title, .sidebar-link span, .sidebar-link .badge, .sidebar-user-info, .sidebar-footer').hide();
                 $('.sidebar-link i').css('margin-right', '0');
                 $('.sidebar-logo').css('justify-content', 'center');