:root {
    --primary-color: #001f3f;
    --secondary-color: #00ffcc;
    --accent-color: #ff851b;
    --bg-gradient-start: #e0e0ff;
    --bg-gradient-end: #f0e0ff;
    --card-bg: rgba(255, 255, 255, 0.9);
    --text-color: #333;
    --light-text: #f8f9fa;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

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

  body {
    background: linear-gradient(135deg, var(--bg-gradient-start), var(--bg-gradient-end));
    color: var(--text-color);
    font-family: 'Open Sans', sans-serif;
    line-height: 1.6;
    padding: 0;
    margin: 0;
    min-height: 100%;
    overflow-x: hidden;
  }

  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
  }

  .header {
    text-align: center;
    margin-bottom: 60px;
    position: relative;
  }

  .header::after {
    content: "";
    display: block;
    width: 100px;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
    margin: 20px auto;
    border-radius: 2px;
  }

  h1, h2, h3, h4 {
    font-family: 'Roboto', sans-serif;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 20px;
  }

  h1 {
    font-size: 2.5rem;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    display: inline-block;
  }

  h2 {
    font-size: 1.8rem;
    position: relative;
    padding-bottom: 10px;
    margin-top: 40px;
  }

  h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background: var(--secondary-color);
    border-radius: 3px;
  }

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

  .notice {
    background: rgba(255, 255, 255, 0.8);
    padding: 15px;
    border-radius: var(--border-radius);
    margin-bottom: 30px;
    text-align: center;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--accent-color);
    font-weight: 600;
  }

  .grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(500px, 1fr));
    gap: 30px;
    margin: 40px 0;
  }

  .card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
  }

  .card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.15);
  }

  .card-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 8px;
    margin-bottom: 20px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
  }

  .card-img:hover {
    transform: scale(1.02);
  }

  pre {
    background: #2d2d2d;
    color: #f8f8f2;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 25px 0;
    font-size: 0.9rem;
    line-height: 1.5;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    position: relative;
  }

  pre::before {
    content: "CSS";
    position: absolute;
    top: 0;
    left: 0;
    background: var(--secondary-color);
    color: #000;
    padding: 2px 10px;
    font-size: 0.8rem;
    border-bottom-right-radius: 5px;
    font-weight: bold;
  }

  code {
    font-family: 'Fira Code', monospace;
  }

  .highlight {
    color: var(--secondary-color);
    font-weight: 600;
  }

  .accent {
    color: var(--accent-color);
    font-weight: 600;
  }

  .nav-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
    margin: 40px 0;
  }

  .nav-link {
    padding: 10px 20px;
    background: rgba(255, 255, 255, 0.7);
    border-radius: 30px;
    text-decoration: none;
    color: var(--primary-color);
    font-weight: 600;
    transition: var(--transition);
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
  }

  .nav-link:hover {
    background: var(--secondary-color);
    color: white;
    transform: translateY(-3px);
  }

  .footer {
    text-align: center;
    margin-top: 60px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.7);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
  }

  @media (max-width: 768px) {
    .grid-container {
      grid-template-columns: 1fr;
    }
    
    h1 {
      font-size: 2rem;
    }
    
    h2 {
      font-size: 1.5rem;
    }
    
    .card {
      padding: 20px;
    }
  }

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

  .floating {
    animation: float 3s ease-in-out infinite;
  }