feat: add drop shadow filter to menu container for improved visual depth

Author: caperaven

components/menu/menu-container/menu-container.css

@@ -12,16 +12,19 @@
     background: var(--menu-bg);
     border-radius: var(--menu-border-radius);
     border: var(--border);
-    filter: var(--drop-shadow);
     user-select: none;
     min-width: var(--min-width);
 }
 
+::slotted(.shadow) {
+    filter: var(--drop-shadow);
+}
+
 ::slotted(.menu-item) {
     padding: 8px 16px;
     cursor: pointer;
 }
 
 ::slotted(.menu-item:hover) {
     background: var(--menu-item-hover-bg);
-}
+}