feat: add blink keyframe animation

app/globals.css

@@ -130,3 +130,13 @@ body {
 .prose :not(pre) > code::after {
   content: none !important;
 }
+
+/* ── Corner ribbon animation ── */
+@keyframes blink {
+  0%, 100% { opacity: 1; }
+  50% { opacity: 0.4; }
+}
+
+.animate-blink {
+  animation: blink 0.8s ease-in-out infinite;
+}