feat: Update Notification system and UI refinements (v1.0.7)

src/styles/layout.css

@@ -164,6 +164,70 @@
   color: var(--text-primary);
 }
 
+/* ─── Update Toast ─── */
+@keyframes update-toast-in {
+  from { opacity: 0; transform: translateY(6px); }
+  to   { opacity: 1; transform: translateY(0); }
+}
+
+.update-toast {
+  margin: 0 var(--space-1) var(--space-2);
+  padding: var(--space-3) var(--space-3);
+  border-radius: var(--radius-md);
+  background: var(--accent-dim);
+  border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
+  display: flex;
+  flex-direction: column;
+  gap: 3px;
+  animation: update-toast-in 0.35s ease both;
+}
+
+.update-toast-header {
+  display: flex;
+  align-items: center;
+  gap: var(--space-2);
+  color: var(--accent);
+}
+
+.update-toast-label {
+  font-size: 11px;
+  font-weight: 700;
+  letter-spacing: 0.04em;
+  text-transform: uppercase;
+  color: var(--accent);
+}
+
+.update-toast-version {
+  font-size: 12px;
+  color: var(--text-secondary);
+  padding-left: 22px;
+}
+
+.update-toast-link {
+  font-size: 11px;
+  font-weight: 600;
+  color: var(--accent);
+  text-decoration: none;
+  padding-left: 22px;
+  opacity: 0.8;
+  transition: opacity var(--transition-fast);
+}
+
+.update-toast-link:hover {
+  opacity: 1;
+  text-decoration: underline;
+}
+
+.update-toast-icon {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: var(--space-2) 0;
+  color: var(--accent);
+  animation: update-toast-in 0.35s ease both;
+  cursor: default;
+}
+
 /* ─── Main Content ─── */
 .main-content {
   grid-area: main;