!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Click the Box Game</title>
  <style>
    body { margin: 0; display: flex; justify-content: center; align-items: center; height: 100vh; background-color: #f4f4f4; }
    .box { width: 100px; height: 100px; background-color: #3498db; position: absolute; animation: move 1s infinite; }
    @keyframes move {
      0% { top: 0; left: 0; }
      25% { top: 0; left: 90%; }
      50% { top: 90%; left: 90%; }
      75% { top: 90%; left: 0; }
      100% { top: 0; left: 0; }
    }
    .box:active { background-color: #e74c3c; }
  </style>
</head>
<body>
  <div class="box" onclick="alert('You clicked the box!')"></div>
</body>
</html>