Fix alarm card animation (#6096)

fixes #5074

src/common/style/icon_color_css.ts

@@ -57,9 +57,12 @@ export const iconColorCSS = css`
     0% {
       opacity: 1;
     }
-    100% {
+    50% {
       opacity: 0;
     }
+    100% {
+      opacity: 1;
+    }
   }
 
   ha-icon[data-domain="plant"][data-state="problem"],

src/panels/lovelace/cards/hui-alarm-panel-card.ts

@@ -309,10 +309,13 @@ class HuiAlarmPanelCard extends LitElement implements LovelaceCard {
 
       @keyframes pulse {
         0% {
-          --ha-label-badge-color: var(--alarm-state-color);
+          opacity: 1;
+        }
+        50% {
+          opacity: 0;
         }
         100% {
-          --ha-label-badge-color: rgba(255, 153, 0, 0.3);
+          opacity: 1;
         }
       }