:root {
    --primary: #0D47A1;
    --primary-light: #42A5F5;
    --secondary: #6A1B9A;
    --secondary-light: #AB47BC;
    --white: #ffffff;
    --gray-light: #f0f4f8;
    --gray: #555555;
    --black: #1a1a1a;
    --transition: all 0.3s ease;
  }

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

  body {
    background: var(--gray-light);
    color: var(--black);
    line-height: 1.6;
    overflow-x: hidden;
  }

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

  /* Header & Navigation */
  .header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 80px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 40px;
  }

  .logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--white);
    text-decoration: none;
    display: flex;
    align-items: center;
  }

  .logo img {
    width: 40px;
    height: 40px;
    margin-right: 10px;
    border-radius: 50%;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
  }

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

  .nav-link {
    color: var(--white);
    text-decoration: none;
    font-weight: 500;
    position: relative;
    padding: 5px 0;
    transition: var(--transition);
  }

  .nav-link:hover {
    color: var(--primary-light);
  }

  .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-light);
    transition: var(--transition);
  }

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

  /* Hero Section */
  .hero {
    min-height: 600px;
    padding-top: 120px;
    padding-bottom: 80px;
    background: linear-gradient(135deg, rgba(13, 71, 161, 0.1), rgba(106, 27, 154, 0.1));
    position: relative;
    overflow: hidden;
  }

  .hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat center right;
    background-size: contain;
    opacity: 0.1;
    z-index: -1;
  }

  .hero-content {
    max-width: 800px;
  }

  .hero-title {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 20px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
  }

  .hero-subtitle {
    font-size: 20px;
    color: var(--gray);
    margin-bottom: 40px;
    max-width: 600px;
  }

  .hero-image {
    position: absolute;
    right: 50px;
    top: 120px;
    width: 400px;
    height: 400px;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    transition: var(--transition);
  }

  .hero-image:hover {
    transform: translateY(-10px);
    box-shadow: 0 30px 50px rgba(0, 0, 0, 0.15);
  }

  .hero-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }

  /* Main Content */
  .main {
    padding: 80px 0;
  }

  .section {
    margin-bottom: 80px;
    background: var(--white);
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    position: relative;
    overflow: hidden;
  }

  .section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: linear-gradient(to bottom, var(--primary), var(--secondary));
  }

  .section-title {
    font-size: 32px;
    margin-bottom: 30px;
    color: var(--primary);
    position: relative;
    padding-left: 20px;
  }

  .section-title::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 8px;
    height: 40px;
    background: linear-gradient(to bottom, var(--primary), var(--secondary));
    border-radius: 4px;
  }

  .section-subtitle {
    font-size: 20px;
    color: var(--secondary);
    margin-bottom: 20px;
  }

  .section-content {
    margin-bottom: 30px;
  }

  .section-content p {
    margin-bottom: 20px;
    font-size: 17px;
    line-height: 1.7;
  }

  .section-image {
    width: 100%;
    max-width: 500px;
    margin: 30px auto;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
  }

  .section-image:hover {
    transform: scale(1.02);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
  }

  .section-image img {
    width: 100%;
    height: auto;
    display: block;
  }

  /* Code Blocks */
  pre {
    background: #1e1e1e;
    border-radius: 8px;
    padding: 20px;
    margin: 30px 0;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
    position: relative;
  }

  pre::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 30px;
    background: #333;
    border-radius: 8px 8px 0 0;
  }

  code {
    font-family: 'Courier New', monospace;
    color: #d4d4d4;
    font-size: 15px;
    line-height: 1.5;
  }

  .language-css {
    color: #9cdcfe;
  }

  .token.property {
    color: #9cdcfe;
  }

  .token.selector {
    color: #d7ba7d;
  }

  .token.punctuation {
    color: #d4d4d4;
  }

  .token.function {
    color: #dcdcaa;
  }

  /* Buttons */
  .btn {
    display: inline-block;
    padding: 12px 24px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--white);
    border: none;
    border-radius: 30px;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(13, 71, 161, 0.3);
  }

  .btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(13, 71, 161, 0.4);
    background: linear-gradient(135deg, var(--primary-light), var(--secondary-light));
  }

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

  .card {
    background: var(--white);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.05);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
  }

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

  .card::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(to right, var(--primary), var(--secondary));
  }

  .card-title {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--primary);
  }

  .card-content {
    margin-bottom: 20px;
  }

  .card-image {
    width: 100%;
    height: 200px;
    border-radius: 8px;
    overflow: hidden;
    margin-bottom: 20px;
  }

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

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

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

  .footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 10px;
    background: linear-gradient(to right, var(--primary-light), var(--secondary-light));
  }

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

  .footer-column h3 {
    font-size: 20px;
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 10px;
  }

  .footer-column h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 2px;
    background: var(--white);
  }

  .footer-links {
    list-style: none;
  }

  .footer-link {
    margin-bottom: 10px;
  }

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

  .footer-link a:hover {
    color: var(--white);
    padding-left: 5px;
  }

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

  /* Responsive */
  @media (max-width: 992px) {
    .hero-title {
      font-size: 36px;
    }
    
    .hero-image {
      width: 300px;
      height: 300px;
    }
  }

  @media (max-width: 768px) {
    .header {
      padding: 0 20px;
    }
    
    .nav {
      gap: 15px;
    }
    
    .hero {
      padding-top: 100px;
      text-align: center;
    }
    
    .hero-image {
      position: relative;
      right: auto;
      top: auto;
      margin: 40px auto 0;
    }
    
    .section {
      padding: 30px;
    }
  }

  @media (max-width: 576px) {
    .hero-title {
      font-size: 28px;
    }
    
    .hero-subtitle {
      font-size: 18px;
    }
    
    .section-title {
      font-size: 24px;
    }
    
    .nav {
      display: none;
    }
  }

  /* Animation */
  @keyframes float {
    0% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
    100% { transform: translateY(0px); }
  }

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

  /* Notice */
  .notice {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--white);
    color: var(--black);
    padding: 15px 20px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    font-size: 14px;
    max-width: 300px;
    transform: translateX(120%);
    transition: transform 0.5s ease;
  }

  .notice.show {
    transform: translateX(0);
  }

  .notice-close {
    position: absolute;
    top: 5px;
    right: 5px;
    background: none;
    border: none;
    color: var(--gray);
    cursor: pointer;
    font-size: 16px;
  }