:root {
    --primary: #C5E1A5;
    --secondary: #03A9F4;
    --background: #FFFDE7;
    --accent: #FF9800;
    --neutral: #E0E0E0;
    --text: #333333;
    --shadow: 0 4px 20px rgba(0,0,0,0.08);
    --radius: 12px;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  }

  @font-face {
    font-family: 'ModernSans';
    src: local('Helvetica Neue'), local('Arial Nova'), sans-serif;
  }

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

  body {
    font-family: 'ModernSans', sans-serif;
    line-height: 1.8;
    color: var(--text);
    background: var(--background);
    overflow-x: hidden;
    font-size: 17px;
  }

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

  /* Header Styles */
  .hero {
    position: relative;
    height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    overflow: hidden;
    margin-bottom: 80px;
    border-radius: 0 0 var(--radius) var(--radius);
  }

  .hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample3.png') no-repeat center/cover;
    opacity: 0.15;
  }

  .hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    padding: 40px;
    max-width: 800px;
  }

  .hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.2);
  }

  .hero p {
    font-size: 1.3rem;
    margin-bottom: 30px;
    opacity: 0.9;
  }

  /* Navigation */
  .navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255, 253, 231, 0.95);
    box-shadow: var(--shadow);
    z-index: 1000;
    padding: 15px 0;
    transition: var(--transition);
  }

  .nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--secondary);
    text-decoration: none;
    display: flex;
    align-items: center;
  }

  .logo img {
    height: 40px;
    margin-right: 10px;
  }

  .nav-links {
    display: flex;
    gap: 30px;
  }

  .nav-links a {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    position: relative;
    transition: var(--transition);
  }

  .nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: var(--transition);
  }

  .nav-links a:hover {
    color: var(--accent);
  }

  .nav-links a:hover::after {
    width: 100%;
  }

  /* Main Content */
  .main-content {
    padding: 100px 0;
  }

  article {
    background: white;
    padding: 60px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 60px;
  }

  article h2 {
    font-size: 2.2rem;
    color: var(--secondary);
    margin-bottom: 30px;
    position: relative;
    padding-bottom: 15px;
  }

  article h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background: linear-gradient(to right, var(--primary), var(--accent));
    border-radius: 2px;
  }

  article h3 {
    font-size: 1.8rem;
    color: var(--secondary);
    margin: 40px 0 20px;
  }

  article p {
    margin-bottom: 20px;
    color: #555;
  }

  /* Code Blocks */
  pre {
    background: #2d2d2d;
    color: #f8f8f2;
    padding: 20px;
    border-radius: var(--radius);
    overflow-x: auto;
    margin: 30px 0;
    box-shadow: var(--shadow);
    position: relative;
  }

  pre::before {
    content: 'CSS';
    position: absolute;
    top: 10px;
    right: 15px;
    color: rgba(255,255,255,0.3);
    font-size: 0.8rem;
  }

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

  /* Tables */
  table {
    width: 100%;
    border-collapse: collapse;
    margin: 30px 0;
    box-shadow: var(--shadow);
    border-radius: var(--radius);
    overflow: hidden;
  }

  th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--neutral);
  }

  th {
    background: var(--primary);
    color: white;
    font-weight: 500;
  }

  tr:nth-child(even) {
    background: rgba(197, 225, 165, 0.1);
  }

  /* Image Gallery */
  .gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin: 40px 0;
  }

  .gallery-item {
    position: relative;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
  }

  .gallery-item:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.15);
  }

  .gallery-item img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    transition: var(--transition);
  }

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

  .gallery-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.7), transparent);
    color: white;
    padding: 20px;
    opacity: 0;
    transition: var(--transition);
  }

  .gallery-item:hover .gallery-caption {
    opacity: 1;
  }

  /* Cards */
  .card-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
    margin: 50px 0;
  }

  .card {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: var(--transition);
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.1);
  }

  .card-img {
    height: 200px;
    background: var(--neutral);
    position: relative;
    overflow: hidden;
  }

  .card-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
  }

  .card:hover .card-img img {
    transform: scale(1.1);
  }

  .card-content {
    padding: 25px;
  }

  .card h3 {
    color: var(--secondary);
    margin-bottom: 15px;
    font-size: 1.4rem;
  }

  .card p {
    color: #666;
    margin-bottom: 20px;
  }

  /* Footer */
  .footer {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 60px 0 30px;
    position: relative;
  }

  .footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample6.png') no-repeat center/cover;
    opacity: 0.1;
  }

  .footer-content {
    position: relative;
    z-index: 2;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
  }

  .footer-column h3 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    position: relative;
    display: inline-block;
  }

  .footer-column h3::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--accent);
  }

  .footer-column ul {
    list-style: none;
  }

  .footer-column ul li {
    margin-bottom: 10px;
  }

  .footer-column ul li a {
    color: rgba(255,255,255,0.8);
    text-decoration: none;
    transition: var(--transition);
  }

  .footer-column ul li a:hover {
    color: white;
    padding-left: 5px;
  }

  .footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255,255,255,0.1);
    font-size: 0.9rem;
    opacity: 0.8;
  }

  /* Animations */
  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
  }

  .animate {
    animation: fadeIn 0.8s ease-out forwards;
  }

  .delay-1 { animation-delay: 0.2s; }
  .delay-2 { animation-delay: 0.4s; }
  .delay-3 { animation-delay: 0.6s; }

  /* Responsive */
  @media (max-width: 992px) {
    .hero h1 {
      font-size: 2.8rem;
    }
    
    article {
      padding: 40px;
    }
  }

  @media (max-width: 768px) {
    .hero {
      height: 500px;
    }
    
    .hero h1 {
      font-size: 2.2rem;
    }
    
    .hero p {
      font-size: 1.1rem;
    }
    
    .nav-links {
      display: none;
    }
    
    article {
      padding: 30px;
    }
    
    .card-container {
      grid-template-columns: 1fr;
    }
  }

  @media (max-width: 576px) {
    .hero {
      height: 400px;
      margin-bottom: 50px;
    }
    
    .hero h1 {
      font-size: 1.8rem;
    }
    
    article {
      padding: 20px;
    }
    
    pre {
      padding: 15px;
      font-size: 0.8rem;
    }
  }

  /* Utility Classes */
  .btn {
    display: inline-block;
    background: var(--accent);
    color: white;
    padding: 12px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(255, 152, 0, 0.3);
  }

  .btn:hover {
    background: #e68900;
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(255, 152, 0, 0.4);
  }

  .text-center {
    text-align: center;
  }

  .mt-0 { margin-top: 0; }
  .mb-0 { margin-bottom: 0; }
  .mt-1 { margin-top: 10px; }
  .mb-1 { margin-bottom: 10px; }
  .mt-2 { margin-top: 20px; }
  .mb-2 { margin-bottom: 20px; }
  .mt-3 { margin-top: 30px; }
  .mb-3 { margin-bottom: 30px; }
  .mt-4 { margin-top: 40px; }
  .mb-4 { margin-bottom: 40px; }
  .mt-5 { margin-top: 50px; }
  .mb-5 { margin-bottom: 50px; }

  .notice {
    background: rgba(255, 152, 0, 0.1);
    border-left: 4px solid var(--accent);
    padding: 20px;
    margin: 30px 0;
    border-radius: 0 var(--radius) var(--radius) 0;
  }

  .notice p {
    margin-bottom: 0;
    color: #666;
  }