:root {
  --primary: #283593;
  --secondary: #5c6bc0;
  --accent: #ff9800;
  --bg-light: #f5f7fa;
  --text-dark: #2d3748;
  --text-light: #f8f9fa;
  --card-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

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

body {
  background: linear-gradient(135deg, #f5f7fa 0%, #e4e8f0 100%);
  color: var(--text-dark);
  line-height: 1.6;
  padding-top: 80px;
}

.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(to right, var(--primary), var(--secondary));
  color: white;
  padding: 1rem 2rem;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  z-index: 1000;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header h1 {
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: 1px;
}

.note {
  background: rgba(255,255,255,0.2);
  padding: 0.5rem 1rem;
  border-radius: 20px;
  font-size: 0.9rem;
}

.main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

.hero {
  background: linear-gradient(135deg, rgba(40,53,147,0.9) 0%, rgba(92,107,192,0.9) 100%);
  color: white;
  padding: 3rem 2rem;
  border-radius: 16px;
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
  box-shadow: var(--card-shadow);
}

.hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: -1;
}

.hero h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.hero p {
  font-size: 1.1rem;
  max-width: 800px;
  margin-bottom: 2rem;
}

.content-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.section {
  background: white;
  border-radius: 16px;
  padding: 2rem;
  box-shadow: var(--card-shadow);
  transition: transform 0.3s ease;
}

.section:hover {
  transform: translateY(-5px);
}

.section h2, .section h3 {
  color: var(--primary);
  margin-bottom: 1.5rem;
  position: relative;
  padding-bottom: 0.5rem;
}

.section h2::after, .section h3::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(to right, var(--accent), var(--secondary));
}

.section p {
  margin-bottom: 1.5rem;
  font-size: 1.05rem;
}

.code-container {
  background: #2d3748;
  border-radius: 8px;
  padding: 1.5rem;
  margin: 1.5rem 0;
  overflow-x: auto;
}

pre {
  color: #f8f9fa;
  font-family: 'Courier New', monospace;
  font-size: 0.95rem;
  line-height: 1.5;
  tab-size: 2;
}

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

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.image-card {
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
  transition: all 0.3s ease;
}

.image-card:hover {
  transform: scale(1.03);
  box-shadow: 0 8px 16px rgba(0,0,0,0.15);
}

.image-card img {
  width: 100%;
  height: auto;
  display: block;
}

.footer {
  background: linear-gradient(to right, var(--primary), var(--secondary));
  color: white;
  padding: 2rem;
  text-align: center;
  margin-top: 3rem;
  border-radius: 16px;
}

@media (max-width: 768px) {
  .header {
    flex-direction: column;
    text-align: center;
    padding: 1rem;
  }
  
  .hero h2 {
    font-size: 2rem;
  }
  
  .main {
    padding: 1rem;
  }
  
  .section {
    padding: 1.5rem;
  }
}

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

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