:root {
  --primary: #0D47A1;
  --primary-light: #1976D2;
  --secondary: #FF9800;
  --accent: #43A047;
  --text: #212121;
  --light: #f5f5f5;
  --dark: #1A237E;
  --gradient: linear-gradient(135deg, var(--primary), var(--primary-light));
}

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

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

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

.header {
  background: var(--gradient);
  color: white;
  padding: 60px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
  border-radius: 0 0 20px 20px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
  margin-bottom: 60px;
}

.header::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/contain;
  opacity: 0.1;
}

.header h1 {
  font-size: 2.8rem;
  margin-bottom: 20px;
  position: relative;
  z-index: 2;
  text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.header p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto 30px;
  position: relative;
  z-index: 2;
}

.note {
  background: rgba(255,255,255,0.2);
  padding: 15px;
  border-radius: 8px;
  display: inline-block;
  margin-top: 20px;
  font-size: 0.9rem;
  backdrop-filter: blur(5px);
}

article {
  background: white;
  border-radius: 20px;
  padding: 40px;
  margin-bottom: 60px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
}

article h2 {
  color: var(--primary);
  font-size: 2rem;
  margin-bottom: 30px;
  position: relative;
  padding-bottom: 15px;
}

article h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 80px;
  height: 4px;
  background: var(--secondary);
  border-radius: 2px;
}

article h3 {
  color: var(--primary-light);
  font-size: 1.5rem;
  margin: 40px 0 20px;
}

article p {
  margin-bottom: 20px;
  font-size: 1.1rem;
  line-height: 1.8;
}

pre {
  background: #263238;
  color: #ECEFF1;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 30px 0;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  left: 0;
  background: var(--secondary);
  color: white;
  padding: 3px 10px;
  border-radius: 0 0 5px 0;
  font-size: 0.8rem;
}

code {
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 40px 0;
}

.image-card {
  background: white;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 5px 15px 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: 200px;
  object-fit: cover;
  display: block;
}

.image-caption {
  padding: 15px;
  background: white;
}

.footer {
  background: var(--gradient);
  color: white;
  padding: 40px 0;
  text-align: center;
  border-radius: 20px 20px 0 0;
}

.footer p {
  margin-bottom: 20px;
}

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

.nav-links a {
  color: white;
  text-decoration: none;
  padding: 8px 15px;
  border-radius: 20px;
  transition: background 0.3s ease;
}

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

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  article {
    padding: 30px 20px;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.floating {
  animation: float 3s ease-in-out infinite;
}