Issue #3381043: Table heads show on top of flyouts

css/base/base.css

@@ -59,7 +59,7 @@ body {
   width: 4rem;
   position: fixed;
   height: 100vh;
-  z-index: 102; /* Appear above Olivero's expand menu button. */
+  z-index: 501;
   padding-left: var(--space-xs);
   padding-right: var(--space-xs);
   padding-top: var(--space-xs);

css/base/base.pcss.css

@@ -53,7 +53,7 @@ body {
   inline-size: 64px;
   position: fixed;
   height: 100vh;
-  z-index: 102; /* Appear above Olivero's expand menu button. */
+  z-index: 501;
   padding-inline: var(--space-xs);
   padding-block-start: var(--space-xs);