:root {
  --primary: #81C784;
  --secondary: #64B5F6;
  --accent: #FFD54F;
  --neutral: #F5F5F5;
  --dark: #424242;
  --light: #FFFFFF;
}

body {
  font-family: 'Open Sans', system-ui, sans-serif;
  line-height: 1.6;
  color: #333;
  background: var(--neutral);
  margin: 0;
  padding: 0;
  background-image: 
    radial-gradient(circle at 10% 20%, rgba(129, 199, 132, 0.05) 0%, transparent 20%),
    radial-gradient(circle at 90% 80%, rgba(100, 181, 246, 0.05) 0%, transparent 20%);
}

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

.header {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: var(--light);
  padding: 2rem 0;
  border-radius: 0 0 20px 20px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
}

.header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: 
    url('https://images.gptkong.com/demo/sample3.png') no-repeat -50px -50px,
    url('https://images.gptkong.com/demo/sample6.png') no-repeat calc(100% + 50px) calc(100% + 50px);
  opacity: 0.1;
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-links a {
  color: var(--light);
  text-decoration: none;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  transition: all 0.3s ease;
}

.nav-links a:hover {
  background: rgba(255,255,255,0.2);
  transform: translateY(-2px);
}

.banner {
  text-align: center;
  padding: 3rem 0;
}

.banner h1 {
  font-size: 3rem;
  margin: 0;
  animation: fadeIn 1.5s ease-in-out;
}

.banner p {
  font-size: 1.2rem;
  max-width: 700px;
  margin: 1rem auto 0;
  opacity: 0.9;
}

.notice {
  background: var(--light);
  color: var(--dark);
  padding: 1rem;
  border-radius: 8px;
  text-align: center;
  margin: 2rem auto;
  max-width: 800px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
  font-size: 0.9rem;
}

article {
  background: var(--light);
  border-radius: 20px;
  padding: 3rem;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  margin-bottom: 3rem;
}

article h2 {
  color: var(--primary);
  font-size: 2.2rem;
  margin-top: 0;
  position: relative;
  padding-bottom: 1rem;
}

article h2::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  border-radius: 2px;
}

article h3 {
  color: var(--secondary);
  font-size: 1.6rem;
  margin: 2rem 0 1rem;
}

article p {
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
}

.code-container {
  background: #2d2d2d;
  border-radius: 8px;
  padding: 1.5rem;
  margin: 2rem 0;
  overflow: auto;
  position: relative;
}

pre {
  margin: 0;
  font-family: 'Courier New', monospace;
  font-size: 0.95rem;
  line-height: 1.5;
  color: #f8f8f2;
}

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

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
  margin: 3rem 0;
}

.image-card {
  background: var(--light);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  transition: all 0.3s ease;
}

.image-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.image-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  display: block;
}

.image-card .caption {
  padding: 1rem;
  text-align: center;
  color: var(--dark);
}

.footer {
  background: var(--dark);
  color: var(--light);
  padding: 3rem 0;
  text-align: center;
  border-radius: 20px 20px 0 0;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 2rem;
}

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

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

.copyright {
  opacity: 0.7;
  font-size: 0.9rem;
}

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

@media (max-width: 768px) {
  .nav {
    flex-direction: column;
    gap: 1rem;
  }
  
  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .banner h1 {
    font-size: 2.2rem;
  }
  
  article {
    padding: 2rem;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}