1 files changed, 69 insertions, 14 deletions
diff --git a/frontend-vanilla/src/style.css b/frontend-vanilla/src/style.css
index a3a7978..f724916 100644
--- a/frontend-vanilla/src/style.css
+++ b/frontend-vanilla/src/style.css
@@ -77,7 +77,8 @@ html {
 /* Sidebar Header Removed */
 
 .sidebar-search {
-  margin-bottom: 2rem;
+  margin-top: 1rem;
+  margin-bottom: 1rem;
 }
 
 .sidebar-search input {
@@ -196,9 +197,9 @@ html {
   opacity: 1;
 }
 
-/* Main Content area */
+/* Main Content area - always fills full width (sidebar overlays) */
 .main-content {
-  flex: 1;
+  width: 100%;
   min-width: 0;
   overflow-y: auto;
   background-color: var(--bg-color);
@@ -282,24 +283,40 @@ html {
   }
 }
 
-/* Desktop Sidebar state */
+/* CONTENT CENTERING PARAMETER:
+ * The sidebar overlays content (position: fixed) and never shifts the main content area.
+ * Content is always centered in the full viewport width.
+ * To revert to sidebar-shifts-content: remove the @media (min-width: 1025px) fixed rules below
+ * and restore "flex: 1; min-width: 0" on .main-content only.
+ */
 @media (min-width: 1025px) {
-  /* Desktop Sidebar state - Removed to keep toggle fixed */
+  .sidebar {
+    position: fixed;
+    top: 0;
+    left: 0;
+    bottom: 0;
+    z-index: 1000;
+    transform: translateX(-100%);
+    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
+  }
+
+  .sidebar-visible .sidebar {
+    transform: translateX(0);
+    box-shadow: 10px 0 20px rgba(0, 0, 0, 0.1);
+  }
+
+  .sidebar-hidden .sidebar {
+    transform: translateX(-100%);
+  }
 }
 
 /* Layout State */
 .sidebar-hidden .sidebar {
-  display: none;
+  display: flex;
 }
 
-@media (min-width: 1025px) {
-  .sidebar-hidden .sidebar {
-    display: none;
-  }
-
-  .sidebar-visible .sidebar {
-    display: flex;
-  }
+.sidebar-visible .sidebar {
+  display: flex;
 }
 
 input[type="text"],
@@ -422,6 +439,11 @@ select:focus {
   word-break: break-word;
 }
 
+.item-description a {
+  text-decoration: none;
+  color: var(--link-color);
+}
+
 .item-description img,
 .item-description video,
 .item-description pre {
@@ -460,6 +482,39 @@ select:focus {
   --link-color: #5ac8fa;
   --border-color: #333333;
   --accent-color: #2188ff;
+  --sidebar-text-color: rgba(0, 0, 0, 0.87);
+}
+
+/* Dark mode: sidebar uses grey background with dark text */
+.theme-dark .sidebar {
+  background: rgba(180, 180, 180, 0.85);
+  border-right-color: rgba(0, 0, 0, 0.15);
+}
+
+.theme-dark .sidebar-section li a,
+.theme-dark .sidebar-section h3,
+.theme-dark .sidebar-footer a {
+  color: rgba(0, 0, 0, 0.87);
+}
+
+.theme-dark .sidebar-section li.active a {
+  background: rgba(0, 0, 0, 0.15);
+}
+
+.theme-dark .sidebar-section li a:hover {
+  background: rgba(0, 0, 0, 0.08);
+}
+
+/* Dark mode: sidebar-toggle button should have no background */
+.theme-dark .sidebar-toggle {
+  background: none;
+}
+
+/* Dark mode: sidebar search input should use light background */
+.theme-dark .sidebar-search input {
+  background: rgba(255, 255, 255, 0.7);
+  color: rgba(0, 0, 0, 0.87);
+  border-color: rgba(0, 0, 0, 0.2);
 }
 
 .font-serif {