body {
      background-color: #f8f9fa;
    }
    .phone-container {
      max-width: 380px;
      margin: 50px auto;
      padding: 30px;
      background-color: white;
      border-radius: 16px;
      box-shadow: 0 0 10px rgba(0,0,0,0.1);
      text-align: center;
    }
    .status {
      font-size: 1.1rem;
      color: green;
    }
    .keypad button {
      width: 80px;
      height: 80px;
      font-size: 24px;
      margin: 5px;
    }
    .action-btns button {
      width: 100px;
    }
    #timer {
      font-family: monospace;
      font-size: 1.2rem;
      padding: 5px;
      background: #c2f7c2;
      margin: 15px 0;
    }