body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: #004d40;
    background-color: #e0f7fa;
    background-image:
      linear-gradient(to right, #d0d0d0 1px, transparent 1px),
      linear-gradient(to bottom, #d0d0d0 1px, transparent 1px);
    background-size: 40px 40px;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
  }

  .container {
    text-align: center;
    background: rgba(255, 255, 255, 0.85);
    border: 2px solid #b2dfdb;
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
  }

  .container img {
    width: 200px;
    height: 200px;
    object-fit: cover;
    border-radius: 15px;
    margin-bottom: 20px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
  }

  h1 {
    font-size: 1.8rem;
    margin: 10px 0 30px;
    color: #00695c;
  }

  .mode-btn {
    display: block;
    margin: 10px auto;
    padding: 14px 28px;
    font-size: 1rem;
    font-weight: bold;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    width: 240px;
    transition: background 0.3s ease, transform 0.2s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  }

  .mode-btn:hover {
    transform: scale(1.05);
  }

  .easy {
    background-color: #81c784;
    color: white;
  }

  .normal {
    background-color: #64b5f6;
    color: white;
  }

  .hard {
    background-color: #e57373;
    color: white;
  }