body {
      font-family: 'Segoe UI', sans-serif;
      background: #1e1e2f;
      margin: 0;
      padding: 0;
      color: white;
    }

    .tabs {
      display: flex;
      justify-content: center;
      background: #292949;
    }

    .tab {
      padding: 15px 30px;
      cursor: pointer;
      border-bottom: 3px solid transparent;
      transition: background 0.3s, border-bottom 0.3s;
    }

    .tab.active {
      border-bottom: 3px solid #00b894;
      background: #1e1e2f;
    }

    .container {
      display: none;
      padding: 20px;
      max-width: 600px;
      margin: 0 auto;
    }

    .container.active {
      display: block;
    }

    .board {
      display: grid;
      grid-template-columns: repeat(3, 100px);
      gap: 10px;
      justify-content: center;
      margin-top: 20px;
    }

    .cell {
      width: 100px;
      height: 100px;
      font-size: 2.5rem;
      background: #39396b;
      display: flex;
      justify-content: center;
      align-items: center;
      border-radius: 10px;
      cursor: pointer;
      user-select: none;
      transition: background 0.3s;
    }

    .cell:hover {
      background: #4f4f8f;
    }

    #status {
      margin-top: 20px;
      text-align: center;
      font-size: 1.2rem;
    }

    button {
      margin-top: 15px;
      padding: 10px 20px;
      background: #00b894;
      border: none;
      color: #fff;
      font-size: 1rem;
      border-radius: 8px;
      cursor: pointer;
      display: block;
      margin-left: auto;
      margin-right: auto;
    }

    button:hover {
      background: #019875;
    }

    .rules {
      line-height: 1.6;
    }