Improve notifications, fix styles not being added

Based on https://petr.codes/blog/rails/modern-rails-flash-messages/part-3/

app/assets/stylesheets/components/notifications.css

@@ -0,0 +1,39 @@
+@layer components {
+  @keyframes notification-countdown {
+    from { width: 100%; }
+    to   { width: 0; }
+  }
+
+  .notification-enter {
+    @apply transform ease-out duration-300 transition;
+  }
+
+  .notification-enter-from {
+    @apply translate-y-2 opacity-0;
+  }
+
+  .notification-enter-to {
+    @apply translate-y-0 opacity-100;
+  }
+
+  @screen sm {
+    .notification-enter-from {
+      @apply translate-y-0 translate-x-2;
+    }
+    .notification-enter-to {
+      @apply translate-x-0;
+    }
+  }
+
+  .notification-leave {
+    @apply transition ease-in duration-100;
+  }
+
+  .notification-leave-from {
+    @apply opacity-100;
+  }
+
+  .notification-leave-to {
+    @apply opacity-0;
+  }
+}