:root {
    --primary-dark: #1e1e1e;
    --secondary-dark: #2c2c2c;
    --accent-blue: #00BFFF;
    --accent-green: #00FF7F;
    --accent-orange: #FF4500;
    --text-light: #E0E0E0;
    --text-muted: #A0A0A0;
    --transition-base: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }

  body {
    font-family: 'Roboto', sans-serif;
    background: linear-gradient(135deg, var(--primary-dark), var(--secondary-dark);
    color: var(--text-light);
    line-height: 1.6;
    min-height: 100%;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
  }

  .header {
    text-align: center;
    padding: 40px 0;
    position: relative;
    overflow: hidden;
  }

  .header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 50% 50%, rgba(0,191,255,0.1) 0%, transparent 70%);
    z-index: -1;
  }

  h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-green));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
  }

  .design-notice {
    display: inline-block;
    padding: 8px 16px;
    background: rgba(0,191,255,0.2);
    border: 1px solid var(--accent-blue);
    border-radius: 20px;
    font-size: 0.9rem;
    margin-bottom: 30px;
    animation: pulse 2s infinite;
  }

  @keyframes pulse {
    0% { box-shadow: 0 0 0 0 rgba(0,191,255,0.4); }
    70% { box-shadow: 0 0 0 10px rgba(0,191,255,0); }
    100% { box-shadow: 0 0 0 0 rgba(0,191,255,0); }
  }

  .grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin: 40px 0;
  }

  .card {
    background: var(--secondary-dark);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.3);
    transition: var(--transition-base);
    position: relative;
    overflow: hidden;
  }

  .card::after {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, transparent, rgba(255,255,255,0.03), transparent);
    transform: rotate(45deg);
    transition: var(--transition-base);
  }

  .card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.4);
  }

  .card:hover::after {
    left: 100%;
  }

  h2 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--accent-blue);
    position: relative;
    display: inline-block;
  }

  h2::after {
    content: "";
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 50px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-blue), transparent);
    border-radius: 3px;
  }

  h3 {
    font-size: 1.4rem;
    margin: 25px 0 15px;
    color: var(--accent-green);
  }

  p {
    margin-bottom: 20px;
    font-size: 1.1rem;
  }

  .image-container {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin: 30px 0;
    justify-content: center;
  }

  .decorative-image {
    width: 150px;
    height: 150px;
    border-radius: 12px;
    object-fit: cover;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    transition: var(--transition-base);
    filter: grayscale(30%);
  }

  .decorative-image:hover {
    transform: scale(1.05);
    filter: grayscale(0%);
    box-shadow: 0 8px 25px rgba(0,191,255,0.3);
  }

  pre {
    background: rgba(0,0,0,0.3);
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
    overflow-x: auto;
    border-left: 4px solid var(--accent-orange);
    font-family: 'Courier New', monospace;
    position: relative;
  }

  pre::before {
    content: "CSS";
    position: absolute;
    top: 0;
    right: 0;
    background: var(--accent-orange);
    color: white;
    padding: 2px 8px;
    font-size: 0.8rem;
    border-bottom-left-radius: 4px;
  }

  code {
    color: var(--accent-green);
    font-family: 'Courier New', monospace;
    font-size: 0.95rem;
  }

  .nav-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    flex-wrap: wrap;
  }

  .nav-tab {
    padding: 8px 16px;
    background: rgba(0,191,255,0.1);
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--accent-blue);
    transition: var(--transition-base);
    cursor: pointer;
    border: 1px solid transparent;
  }

  .nav-tab:hover {
    background: rgba(0,191,255,0.2);
    border-color: var(--accent-blue);
  }

  .footer {
    text-align: center;
    padding: 40px 0;
    margin-top: 60px;
    border-top: 1px solid rgba(255,255,255,0.1);
  }

  @media (max-width: 768px) {
    h1 {
      font-size: 2rem;
    }
    .grid {
      grid-template-columns: 1fr;
    }
    .card {
      padding: 20px;
    }
  }