:root {
    --primary: #0F172A;
    --secondary: #635BCC;
    --accent: #D4D4D4;
    --highlight: #3BEA9E;
    --text: #F8FAFC;
    --bg-gradient: linear-gradient(135deg, var(--primary), var(--secondary));
  }

  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;
  }

  body {
    background: var(--bg-gradient);
    color: var(--text);
    line-height: 1.6;
    min-height: 100%;
    position: relative;
    overflow-x: hidden;
  }

  body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample1.png') repeat;
    opacity: 0.05;
    z-index: -1;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
  }

  .header {
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
  }

  .header::after {
    content: '';
    display: block;
    width: 150px;
    height: 4px;
    background: var(--highlight);
    margin: 1.5rem auto;
    border-radius: 2px;
  }

  h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    background: linear-gradient(90deg, var(--accent), var(--highlight));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: 0 2px 10px rgba(0,0,0,0.2);
  }

  h2 {
    font-size: 1.8rem;
    margin: 2rem 0 1rem;
    color: var(--highlight);
    position: relative;
    padding-left: 1rem;
  }

  h2::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 4px;
    background: var(--highlight);
    border-radius: 2px;
  }

  h3 {
    font-size: 1.4rem;
    margin: 1.5rem 0 0.8rem;
    color: var(--accent);
  }

  p {
    margin-bottom: 1.2rem;
    font-size: 1.1rem;
  }

  .content-block {
    background: rgba(15, 23, 42, 0.7);
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 3rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
  }

  .content-block:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.4);
  }

  .image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
  }

  .image-card {
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    transition: transform 0.3s;
    position: relative;
  }

  .image-card:hover {
    transform: scale(1.03);
  }

  .image-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, transparent 60%, rgba(0,0,0,0.7)));
  }

  .image-card img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    display: block;
  }

  pre {
    background: rgba(0,0,0,0.3);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    overflow-x: auto;
    border-left: 4px solid var(--highlight);
    font-family: 'Courier New', monospace;
    font-size: 0.95rem;
    line-height: 1.5;
    position: relative;
  }

  pre::before {
    content: 'CSS';
    position: absolute;
    top: 0;
    right: 0;
    background: var(--highlight);
    color: var(--primary);
    padding: 0.2rem 0.8rem;
    font-size: 0.8rem;
    border-bottom-left-radius: 8px;
  }

  code {
    color: var(--highlight);
    font-family: 'Courier New', monospace;
  }

  .notice {
    background: rgba(59, 234, 158, 0.1);
    border-left: 4px solid var(--highlight);
    padding: 1rem;
    margin: 2rem 0;
    border-radius: 0 8px 8px 0;
  }

  .notice p {
    margin: 0;
    color: var(--highlight);
  }

  .nav-tabs {
    display: flex;
    justify-content: center;
    margin: 2rem 0;
    gap: 1rem;
  }

  .nav-tab {
    padding: 0.8rem 1.5rem;
    background: rgba(99, 91, 204, 0.2);
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
  }

  .nav-tab:hover {
    background: rgba(99, 91, 204, 0.4);
    transform: translateY(-2px);
  }

  .nav-tab.active {
    background: var(--secondary);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 91, 204, 0.4);
  }

  @media (max-width: 768px) {
    .container {
      padding: 1.5rem;
    }
    
    h1 {
      font-size: 2rem;
    }
    
    h2 {
      font-size: 1.5rem;
    }
    
    .content-block {
      padding: 1.5rem;
    }
    
    .image-grid {
      grid-template-columns: 1fr;
    }
  }

  @media (max-width: 480px) {
    .container {
      padding: 1rem;
    }
    
    h1 {
      font-size: 1.8rem;
    }
    
    .nav-tabs {
      flex-wrap: wrap;
    }
    
    .nav-tab {
      padding: 0.6rem 1rem;
      font-size: 0.9rem;
    }
  }

  /* Animation */
  @keyframes float {
    0%, 100% {
      transform: translateY(0);
    }
    50% {
      transform: translateY(-10px);
    }
  }

  .floating {
    animation: float 6s ease-in-out infinite;
  }