added support for dark mode

src/baby_monitor/static/menu.css

@@ -5,18 +5,19 @@
   left: 1rem;
   cursor: pointer;
   z-index: 1000;
-  background: white;
+  background: var(--bg-secondary, #ffffff);
   padding: 0.5rem;
   border-radius: 4px;
-  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
+  box-shadow: var(--shadow-md, 0 2px 10px rgba(0, 0, 0, 0.1));
+  transition: background 0.3s, box-shadow 0.3s;
 }
 
 .burger-menu div {
   width: 25px;
   height: 3px;
-  background-color: #333;
+  background-color: var(--text-primary, #333333);
   margin: 5px 0;
-  transition: 0.3s;
+  transition: background-color 0.3s;
 }
 
 .menu-backdrop {
@@ -37,14 +38,15 @@
 .menu-overlay {
   position: fixed;
   top: 0;
-  left: -250px;
+  left: -100%;
   width: 250px;
   height: 100vh;
-  background: white;
-  box-shadow: 2px 0 10px rgba(0, 0, 0, 0.1);
-  transition: left 0.3s;
+  background: var(--bg-secondary, #ffffff);
+  box-shadow: var(--shadow-md, 2px 0 10px rgba(0, 0, 0, 0.1));
+  transition: left 0.3s, background 0.3s;
   z-index: 999;
   padding: 4rem 1rem 1rem 1rem;
+  overflow: hidden;
 }
 
 .menu-overlay.open {
@@ -53,13 +55,14 @@
 
 .menu-item {
   padding: 1rem;
-  border-bottom: 1px solid #eee;
+  border-bottom: 1px solid var(--border-color, #eeeeee);
   cursor: pointer;
-  transition: background 0.2s;
+  transition: background 0.2s, color 0.3s, border-color 0.3s;
+  color: var(--text-primary, #333333);
 }
 
 .menu-item:hover {
-  background: #f5f5f5;
+  background: var(--bg-tertiary, #f5f5f5);
 }
 
 .menu-item.admin {