Will it work?

src/page/background/background.html.ts

@@ -5,6 +5,7 @@ export const generate = (
   count: number,
   color?: () => string,
   height?: () => number,
+  isAnimated?: (index) => boolean,
   transform?: () => string
 ): html => `
     <section class="background">
@@ -13,8 +14,12 @@ export const generate = (
             ? new Array(count)
                 .fill(0, 0, count)
                 .map(
-                  _ =>
-                    `<div style="background-color: ${color()}; height: ${height()}px; transform: ${transform()}"></div>`
+                  (_, i) => `
+                    <div class="${
+                      isAnimated(i) ? "animated" : ""
+                    }" style="background-color: ${color()}; height: ${height()}px; transform: ${transform()}"
+                    ></div>
+                `
                 )
                 .join("")
             : ""