:root {
  --primary: #1e3c72;
  --secondary: #2a5298;
  --accent: #00ffcc;
  --dark: #0a0a1a;
  --light: #f8f9fa;
  --highlight: #00ffcc;
  --text: #e0e0e0;
  --card-bg: linear-gradient(135deg, var(--primary), var(--secondary));
  --nav-bg: rgba(10, 10, 26, 0.9);
}

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

body {
  background: var(--dark);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

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

header {
  background: var(--nav-bg);
  position: fixed;
  width: 100%;
  z-index: 1000;
  padding: 15px 0;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}

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

.logo {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 1px;
}

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

.nav-links a {
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
  position: relative;
}

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

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s;
}

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

.hero {
  padding: 150px 0 80px;
  text-align: center;
  background: radial-gradient(circle at center, rgba(30, 60, 114, 0.3), transparent 70%);
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 20px;
  background: linear-gradient(90deg, var(--accent), #ffffff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: gradientShift 5s ease infinite;
  background-size: 200% 200%;
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.hero p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto 40px;
  color: rgba(224, 224, 224, 0.8);
}

.notice {
  background: rgba(0, 255, 204, 0.1);
  border-left: 4px solid var(--accent);
  padding: 15px;
  margin: 30px 0;
  border-radius: 0 8px 8px 0;
}

.notice p {
  color: var(--accent);
  font-weight: 500;
}

.content-section {
  padding: 80px 0;
}

.section-title {
  font-size: 2.2rem;
  margin-bottom: 40px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--accent);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 30px;
  margin: 40px 0;
}

.card {
  background: var(--card-bg);
  border-radius: 15px;
  overflow: hidden;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
  transition: transform 0.3s, box-shadow 0.3s;
  position: relative;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.3);
}

.card-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 15px 15px 0 0;
}

.card-content {
  padding: 25px;
}

.card h3 {
  font-size: 1.5rem;
  margin-bottom: 15px;
  color: var(--accent);
}

.card p {
  margin-bottom: 20px;
  color: rgba(224, 224, 224, 0.8);
}

.code-block {
  background: rgba(0, 0, 0, 0.3);
  border-radius: 8px;
  padding: 20px;
  margin: 25px 0;
  overflow-x: auto;
  border-left: 4px solid var(--accent);
}

code {
  font-family: 'Courier New', monospace;
  color: var(--accent);
  background: transparent;
  padding: 2px 5px;
  border-radius: 3px;
}

pre {
  margin: 0;
  white-space: pre-wrap;
}

article {
  max-width: 900px;
  margin: 0 auto;
  padding: 20px;
}

article h2 {
  font-size: 2rem;
  margin: 40px 0 20px;
  color: var(--accent);
}

article h3 {
  font-size: 1.5rem;
  margin: 30px 0 15px;
  color: var(--accent);
}

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

article img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 20px 0;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

footer {
  background: var(--nav-bg);
  padding: 40px 0;
  text-align: center;
  margin-top: 80px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 30px;
  margin-bottom: 30px;
}

.footer-links a {
  color: var(--text);
  text-decoration: none;
  transition: color 0.3s;
}

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

.copyright {
  color: rgba(224, 224, 224, 0.6);
  font-size: 0.9rem;
}

@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.2rem;
  }
  
  .hero p {
    font-size: 1rem;
  }
  
  .nav-links {
    gap: 15px;
  }
  
  .card-grid {
    grid-template-columns: 1fr;
  }
  
  article h2 {
    font-size: 1.8rem;
  }
  
  article h3 {
    font-size: 1.3rem;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 120px 0 60px;
  }
  
  .hero h1 {
    font-size: 1.8rem;
  }
  
  .nav-container {
    flex-direction: column;
    gap: 15px;
  }
  
  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .section-title {
    font-size: 1.8rem;
  }
}

.particle-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  opacity: 0.1;
  background: url('https://images.gptkong.com/demo/sample1.png') repeat;
  animation: particlesMove 60s linear infinite;
}

@keyframes particlesMove {
  from { background-position: 0 0; }
  to { background-position: 1000px 1000px; }
}

.geometric-shape {
  position: absolute;
  width: 200px;
  height: 200px;
  background: radial-gradient(circle at 30% 30%, var(--accent), var(--primary));
  clip-path: polygon(50% 0%, 100% 100%, 0% 100%);
  animation: rotate 20s linear infinite;
  opacity: 0.2;
  z-index: -1;
}

.shape-1 {
  top: 10%;
  left: 5%;
}

.shape-2 {
  bottom: 10%;
  right: 5%;
  clip-path: circle(50% at 50% 50%);
  animation: rotateReverse 25s linear infinite;
}

@keyframes rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@keyframes rotateReverse {
  from { transform: rotate(360deg); }
  to { transform: rotate(0deg); }
}

.highlight {
  color: var(--accent);
  font-weight: 500;
}

.color-text {
  color: var(--accent);
  font-weight: 500;
}

.expandable {
  margin: 20px 0;
}

.expandable-header {
  background: rgba(0, 255, 204, 0.1);
  padding: 12px 20px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.3s;
}

.expandable-header:hover {
  background: rgba(0, 255, 204, 0.2);
}

.expandable-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.5s ease;
  padding: 0 20px;
  background: rgba(30, 60, 114, 0.2);
  border-radius: 0 0 8px 8px;
}

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

.toc {
  position: fixed;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(10, 10, 26, 0.8);
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
  z-index: 100;
  max-width: 250px;
}

.toc h3 {
  color: var(--accent);
  margin-bottom: 15px;
  font-size: 1.2rem;
}

.toc ul {
  list-style: none;
}

.toc li {
  margin-bottom: 10px;
}

.toc a {
  color: var(--text);
  text-decoration: none;
  transition: color 0.3s;
  font-size: 0.9rem;
}

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

@media (max-width: 1200px) {
  .toc {
    display: none;
  }
}