:root {
    --primary: linear-gradient(135deg, #1a2a6c, #b21f1f, #fdbb2d);
    --secondary: rgba(255, 255, 255, 0.1);
    --accent: #f3ec78;
    --text: #ffffff;
    --text-secondary: #cccccc;
    --card-radius: 15px;
    --transition: all 0.3s ease;
  }

  @import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@400;700&display=swap');

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

  body {
    font-family: 'Montserrat', sans-serif;
    background: var(--primary);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
  }

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

  .header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 20px 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(10px);
    z-index: 1000;
    transition: var(--transition);
  }

  .header.scrolled {
    background: rgba(26, 42, 108, 0.9);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.2);
  }

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

  .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
  }

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

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

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

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

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

  .hero {
    height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
  }

  .hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle, rgba(0,0,0,0.1) 0%, rgba(0,0,0,0.7) 100%);
    z-index: -1;
  }

  .hero-content {
    max-width: 600px;
  }

  .hero-title {
    font-size: 3rem;
    margin-bottom: 20px;
    line-height: 1.2;
  }

  .hero-subtitle {
    font-size: 1.2rem;
    margin-bottom: 30px;
    color: var(--text-secondary);
  }

  .btn {
    display: inline-block;
    padding: 12px 30px;
    background: linear-gradient(45deg, #f3ec78, #af4261);
    color: var(--text);
    border-radius: 25px;
    text-decoration: none;
    font-weight: 700;
    transition: var(--transition);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
  }

  .btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
    background: linear-gradient(45deg, #af4261, #f3ec78);
  }

  .hero-image {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 50%;
    max-width: 600px;
    z-index: -1;
    opacity: 0.8;
  }

  .section {
    padding: 100px 0;
  }

  .section-title {
    font-size: 2.5rem;
    margin-bottom: 50px;
    text-align: center;
    position: relative;
  }

  .section-title::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 3px;
    background: var(--accent);
  }

  .card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 50px;
  }

  .card {
    background: var(--secondary);
    border-radius: var(--card-radius);
    padding: 30px;
    transition: var(--transition);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(5px);
  }

  .card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.4);
  }

  .card-img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: var(--card-radius);
    margin-bottom: 20px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    transition: var(--transition);
  }

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

  .card-title {
    font-size: 1.5rem;
    margin-bottom: 15px;
  }

  .card-text {
    color: var(--text-secondary);
    margin-bottom: 20px;
  }

  .code-block {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 10px;
    padding: 20px;
    margin: 30px 0;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
    border-left: 3px solid var(--accent);
  }

  code {
    color: #f8f8f2;
  }

  table {
    width: 100%;
    border-collapse: collapse;
    margin: 30px 0;
    background: var(--secondary);
    border-radius: var(--card-radius);
    overflow: hidden;
  }

  th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  }

  th {
    background: rgba(0, 0, 0, 0.2);
    font-weight: 700;
  }

  tr:hover {
    background: rgba(255, 255, 255, 0.05);
  }

  .footer {
    background: rgba(0, 0, 0, 0.5);
    padding: 50px 0;
    text-align: center;
  }

  .footer-text {
    color: var(--text-secondary);
    margin-bottom: 20px;
  }

  .social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 30px;
  }

  .social-link {
    color: var(--text);
    font-size: 1.5rem;
    transition: var(--transition);
  }

  .social-link:hover {
    color: var(--accent);
    transform: translateY(-3px);
  }

  .notice {
    background: rgba(255, 255, 255, 0.1);
    padding: 15px;
    border-radius: 5px;
    margin: 30px 0;
    text-align: center;
    font-size: 0.9rem;
    border-left: 3px solid var(--accent);
  }

  @media (max-width: 768px) {
    .hero {
      text-align: center;
    }

    .hero-content {
      max-width: 100%;
    }

    .hero-image {
      display: none;
    }

    .nav-links {
      display: none;
    }

    .section-title {
      font-size: 2rem;
    }

    .card-grid {
      grid-template-columns: 1fr;
    }
  }

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

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

  @keyframes pulse {
    0%, 100% {
      transform: scale(1);
    }
    50% {
      transform: scale(1.05);
    }
  }

  .pulse {
    animation: pulse 4s ease-in-out infinite;
  }

  /* 3D Effects */
  .model-container {
    perspective: 1000px;
    width: 100%;
    height: 500px;
    margin: 50px 0;
  }

  .model {
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample1.png') center center no-repeat;
    background-size: contain;
    transform-style: preserve-3d;
    transition: transform 1s;
  }

  .model:hover {
    transform: rotateY(180deg);
  }

  /* Accordion */
  .accordion {
    margin: 30px 0;
  }

  .accordion-item {
    margin-bottom: 10px;
    border-radius: var(--card-radius);
    overflow: hidden;
    background: var(--secondary);
  }

  .accordion-header {
    padding: 15px 20px;
    background: rgba(0, 0, 0, 0.2);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
  }

  .accordion-header:hover {
    background: rgba(0, 0, 0, 0.3);
  }

  .accordion-content {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
  }

  .accordion-item.active .accordion-content {
    padding: 20px;
    max-height: 500px;
  }

  .accordion-icon {
    transition: transform 0.3s;
  }

  .accordion-item.active .accordion-icon {
    transform: rotate(180deg);
  }