:root {
    --primary: #1A237E;
    --primary-gradient: linear-gradient(135deg, #6200EA, #3F51B5);
    --accent: #4CAF50;
    --accent-hover: linear-gradient(45deg, #4CAF50, #FF9800);
    --text: #f8f9fa;
    --text-secondary: #adb5bd;
    --card-bg: #212529;
    --shadow: 0 10px 20px rgba(0,0,0,0.2);
  }

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

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

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

  header {
    text-align: center;
    padding: 3rem 0;
    position: relative;
    overflow: hidden;
  }

  header::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(98,0,234,0.1) 0%, rgba(26,35,126,0) 70%);
    z-index: -1;
    animation: pulse 15s infinite alternate;
  }

  @keyframes pulse {
    0% { transform: scale(1); opacity: 0.5; }
    100% { transform: scale(1.2); opacity: 0.8; }
  }

  h1, h2, h3, h4 {
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
  }

  h1 {
    font-size: 3rem;
    background: linear-gradient(90deg, #fff, #4CAF50);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: 0 2px 10px rgba(0,0,0,0.2);
  }

  h2 {
    font-size: 2.2rem;
    color: #fff;
    position: relative;
    padding-bottom: 1rem;
  }

  h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100px;
    height: 4px;
    background: var(--accent);
    border-radius: 2px;
  }

  h3 {
    font-size: 1.8rem;
    color: var(--accent);
    margin-top: 3rem;
  }

  p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
  }

  .notice {
    background: rgba(255,255,255,0.1);
    border-left: 4px solid var(--accent);
    padding: 1rem;
    margin: 2rem 0;
    border-radius: 0 4px 4px 0;
    font-size: 0.9rem;
  }

  .grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
  }

  .card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
    overflow: hidden;
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.3);
  }

  .card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--accent-hover);
  }

  .img-container {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin: 2rem 0;
    justify-content: center;
  }

  .img-wrapper {
    width: 150px;
    height: 150px;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    transition: transform 0.3s ease;
  }

  .img-wrapper:hover {
    transform: scale(1.05);
  }

  .img-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: grayscale(30%);
    transition: filter 0.3s ease;
  }

  .img-wrapper:hover img {
    filter: grayscale(0%);
  }

  pre {
    background: rgba(0,0,0,0.3);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 2rem 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    position: relative;
    border-left: 4px solid var(--accent);
  }

  pre::before {
    content: "CSS";
    position: absolute;
    top: 0;
    right: 0;
    background: var(--accent);
    color: white;
    padding: 0.2rem 0.8rem;
    font-size: 0.8rem;
    border-radius: 0 0 0 4px;
  }

  code {
    color: #f8f9fa;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
  }

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

  .nav-tabs a {
    color: var(--text);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    background: rgba(255,255,255,0.1);
    transition: background 0.3s ease;
  }

  .nav-tabs a:hover {
    background: rgba(255,255,255,0.2);
  }

  .divider {
    height: 1px;
    background: rgba(255,255,255,0.1);
    margin: 3rem 0;
    position: relative;
  }

  .divider::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100px;
    height: 2px;
    background: var(--accent);
  }

  footer {
    text-align: center;
    padding: 2rem;
    margin-top: 4rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
  }

  @media (max-width: 768px) {
    h1 {
      font-size: 2.2rem;
    }
    h2 {
      font-size: 1.8rem;
    }
    .container {
      padding: 1rem;
    }
    .grid {
      grid-template-columns: 1fr;
    }
  }