body {
      font-family: 'Segoe UI', sans-serif;
      text-align: center;
      margin: 0;
      padding: 20px;
      transition: 0.3s;
  }

  body.dark {
      background: #111;
      color: #fff;
  }

  body.light {
      background: #f4f4f4;
      color: #111;
  }

  h1 {
      margin: 10px 0;
  }

  .container {
      display: grid;
      gap: 20px;
      justify-content: center;
  }

  .card {
      padding: 20px;
      border-radius: 20px;
      box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
      width: 320px;
  }

  .dark .card {
      background: #222;
  }

  .light .card {
      background: #fff;
  }

  .time {
      font-size: 2.5rem;
      margin: 15px 0;
      letter-spacing: 2px;
  }

  button {
      padding: 10px 15px;
      margin: 5px;
      border: none;
      border-radius: 10px;
      cursor: pointer;
      font-weight: bold;
  }

  .start {
      background: #28a745;
      color: white;
  }

  .stop {
      background: #dc3545;
      color: white;
  }

  .reset {
      background: #ffc107;
  }

  .lap {
      background: #17a2b8;
      color: white;
  }

  .toggle {
      background: #6f42c1;
      color: white;
  }

  ul {
      list-style: none;
      padding: 0;
      max-height: 150px;
      overflow-y: auto;
      text-align: left;
  }

  li {
      padding: 5px;
      border-bottom: 1px solid #ccc;
  }