html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    font-family: 'Cairo', sans-serif;
    background: #f5f7fa;
    color: #333;
    overflow-x: hidden;
    scroll-behavior: smooth;
    direction: rtl;
    display: flex;
    flex-direction: column;
  }
  
  header {
    background: linear-gradient(135deg, #1a2a44, #00b7eb);
    padding: 15px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    position: relative;
    z-index: 10;
  }
  
  header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: #fff;
    margin: 0;
  }
  
  .btn-back {
    background: rgba(255, 255, 255, 0.2);
    color: #fff;
    padding: 8px 18px;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.3s ease;
  }
  
  .btn-back:hover {
    background: #fff;
    color: #007bff;
    transform: translateY(-2px);
  }
  
  main {
    flex: 1;
    padding: 30px 15px;
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
    width: 100%;
  }
  
  .subject {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 15px;
    list-style: none;
    padding: 0;
  }
  
  .subject li a {
    display: block;
    background: linear-gradient(135deg, #4682b4 0%, #87cefa 100%);
    border-radius: 12px;
    padding: 70px;
    color: #fff;
    font-size: 2rem;
    font-weight: 700;
    text-decoration: none;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }
  
  .subject li a:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
  }
  
  footer {
    background: linear-gradient(135deg, #1a2a44, #00b7eb);
    padding: 10px;
    text-align: center;
    color: #fff;
    font-size: 0.8rem;
    font-weight: 500;
    box-shadow: 0 -5px 15px rgba(0, 183, 235, 0.3);
    margin-top: auto;
  }
  
  @media (max-width: 1024px) {
    .subject {
      grid-template-columns: repeat(2, 1fr);
    }
  }
  
  @media (max-width: 768px) {
    header {
      padding: 10px 20px;
    }
  
    header h1 {
      font-size: 1.5rem;
    }
  
    .btn-back {
      padding: 6px 15px;
      font-size: 0.9rem;
    }
  
    .subject {
      grid-template-columns: repeat(2, 1fr);
      gap: 10px;
    }
  
    .subject li a {
      padding: 50px;
      font-size: 1.5rem;
    }
  
    footer {
      padding: 8px;
      font-size: 0.7rem;
    }
  }
  
  @media (max-width: 480px) {
    .subject {
      grid-template-columns: repeat(1, 1fr);
    }
  }