:root {
  --primary: #1E272E;
  --secondary: #6C5CE7;
  --accent: #00B894;
  --text: #2D3436;
  --light: #F5F6FA;
  --white: #FFFFFF;
}

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

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

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

.header {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  height: 80px;
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 100;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 40px;
}

.logo {
  color: var(--white);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 1px;
}

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

.nav a {
  color: var(--white);
  text-decoration: none;
  font-weight: 600;
  position: relative;
  padding: 5px 0;
  transition: all 0.3s ease;
}

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

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

.main {
  margin-top: 100px;
  padding-bottom: 80px;
}

.hero {
  background: linear-gradient(135deg, rgba(30,39,46,0.9), rgba(108,92,231,0.9)), url('https://images.gptkong.com/demo/sample1.png');
  background-size: cover;
  background-position: center;
  height: 500px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  text-align: center;
  padding: 0 20px;
  margin-bottom: 60px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.hero h1 {
  color: var(--white);
  font-size: 48px;
  margin-bottom: 20px;
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.hero p {
  color: var(--white);
  font-size: 20px;
  max-width: 700px;
  opacity: 0.9;
}

.notice {
  background: var(--white);
  padding: 20px;
  border-radius: 8px;
  margin-bottom: 40px;
  text-align: center;
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
  border-left: 4px solid var(--accent);
}

.notice p {
  font-size: 16px;
  color: var(--text);
}

article {
  background: var(--white);
  padding: 40px;
  border-radius: 16px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.05);
  margin-bottom: 60px;
}

article h2 {
  color: var(--primary);
  font-size: 32px;
  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(90deg, var(--secondary), var(--accent));
  border-radius: 2px;
}

article h3 {
  color: var(--secondary);
  font-size: 24px;
  margin: 30px 0 20px;
}

article p {
  margin-bottom: 20px;
  font-size: 17px;
}

pre {
  background: #2D3436;
  padding: 20px;
  border-radius: 8px;
  margin: 25px 0;
  overflow-x: auto;
  box-shadow: inset 0 0 10px rgba(0,0,0,0.2);
}

code {
  font-family: 'Courier New', monospace;
  color: #F5F6FA;
  font-size: 15px;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 30px;
  margin: 40px 0;
}

.image-card {
  background: var(--white);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 8px 20px rgba(0,0,0,0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 30px rgba(0,0,0,0.15);
}

.image-card img {
  width: 100%;
  height: 240px;
  object-fit: cover;
  display: block;
}

.footer {
  background: var(--primary);
  color: var(--white);
  padding: 40px 0;
  text-align: center;
}

.footer p {
  opacity: 0.8;
  font-size: 14px;
}

.particle {
  position: absolute;
  width: 5px;
  height: 5px;
  background: var(--secondary);
  border-radius: 50%;
  animation: move 10s linear infinite;
  opacity: 0;
}

@keyframes move {
  0% { transform: translate(0, 0); opacity: 1; }
  100% { transform: translate(500px, 500px); opacity: 0; }
}

@media (max-width: 768px) {
  .header {
    padding: 0 20px;
    height: 70px;
  }
  
  .nav {
    gap: 15px;
  }
  
  .hero h1 {
    font-size: 36px;
  }
  
  .hero p {
    font-size: 18px;
  }
  
  article {
    padding: 30px;
  }
  
  article h2 {
    font-size: 28px;
  }
  
  article h3 {
    font-size: 22px;
  }
}

@media (max-width: 480px) {
  .header {
    flex-direction: column;
    height: auto;
    padding: 15px;
  }
  
  .nav {
    margin-top: 15px;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .hero {
    height: 400px;
  }
  
  .hero h1 {
    font-size: 28px;
  }
  
  article {
    padding: 20px;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}