Visibility polish: admin sidebar contrast/focus, table header readability, nav focus rings

src/app/globals.css

@@ -216,6 +216,10 @@ summary,
 		color: var(--color-primary-readable, var(--color-primary));
 		background-color: color-mix(in srgb, var(--color-primary) 10%, transparent);
 	}
+	.nav-item:focus-visible {
+		outline: 2px solid var(--color-primary-readable, var(--color-primary));
+		outline-offset: 2px;
+	}
 	.dropdown-item {
 		@apply block py-2.5 px-4 text-sm font-semibold rounded-lg mx-1;
 		color: var(--color-dropdown-text-readable, var(--color-text-readable));
@@ -225,6 +229,10 @@ summary,
 		background-color: color-mix(in srgb, var(--color-primary) 12%, transparent);
 		color: var(--color-primary-readable, var(--color-primary));
 	}
+	.dropdown-item:focus-visible {
+		outline: 2px solid var(--color-primary-readable, var(--color-primary));
+		outline-offset: -2px;
+	}
 	.dropdown-menu {
 		background-color: var(--color-dropdown);
 		border: 1px solid
@@ -550,7 +558,7 @@ tbody tr:hover {
 }
 .admin-page thead th {
 	background: color-mix(in srgb, var(--admin-accent) 8%, var(--admin-surface));
-	color: var(--admin-text-muted);
+	color: var(--admin-text);
 	border-bottom: 1px solid var(--admin-border);
 	white-space: nowrap;
 	font-size: 0.68rem;