:root {
  --primary-color: #0B4F6C;
  --secondary-color: #87CEEB;
  --accent-color: #FFA500;
  --highlight-color: #FFD700;
  --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  --card-shadow: 0 10px 30px rgba(0,0,0,0.1);
  --text-dark: #333;
  --text-light: #fff;
}

body {
  font-family: 'Roboto', sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  background: var(--bg-gradient);
  margin: 0;
  padding: 0;
}

header {
  background: var(--primary-color);
  color: var(--text-light);
  padding: 2rem 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

header::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: 0;
}

.header-content {
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

h1 {
  font-size: 3rem;
  margin: 0;
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.subtitle {
  font-size: 1.2rem;
  opacity: 0.9;
  margin-top: 1rem;
}

.reference-note {
  background: var(--highlight-color);
  color: var(--text-dark);
  padding: 0.5rem 1rem;
  border-radius: 20px;
  display: inline-block;
  margin-top: 1rem;
  font-weight: bold;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.main-container {
  max-width: 1200px;
  margin: 3rem auto;
  padding: 0 2rem;
}

article {
  background: white;
  border-radius: 12px;
  padding: 3rem;
  box-shadow: var(--card-shadow);
  margin-bottom: 3rem;
}

h2 {
  font-size: 2.2rem;
  color: var(--primary-color);
  margin-bottom: 1.5rem;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(to right, var(--accent-color), var(--highlight-color));
}

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

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

pre {
  background: #282c34;
  border-radius: 8px;
  padding: 1.5rem;
  overflow-x: auto;
  margin: 2rem 0;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

code {
  font-family: 'Fira Code', monospace;
  color: #abb2bf;
}

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

.feature-card {
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--card-shadow);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0,0,0,0.15);
}

.feature-img {
  height: 200px;
  background-size: cover;
  background-position: center;
}

.feature-content {
  padding: 1.5rem;
}

.feature-title {
  font-size: 1.3rem;
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

.feature-desc {
  color: #666;
  font-size: 0.95rem;
}

.nav-tabs {
  display: flex;
  flex-wrap: wrap;
  margin: 2rem 0;
  border-bottom: 1px solid #eee;
}

.nav-tab {
  padding: 0.8rem 1.5rem;
  margin-right: 0.5rem;
  background: #f5f5f5;
  border-radius: 5px 5px 0 0;
  cursor: pointer;
  transition: all 0.3s ease;
}

.nav-tab.active {
  background: var(--primary-color);
  color: white;
}

.nav-tab:hover:not(.active) {
  background: #e0e0e0;
}

.tab-content {
  display: none;
  padding: 2rem;
  background: white;
  border-radius: 0 0 8px 8px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
}

.tab-content.active {
  display: block;
}

@media (max-width: 768px) {
  h1 {
    font-size: 2.2rem;
  }
  
  .main-container {
    padding: 0 1rem;
  }
  
  article {
    padding: 2rem 1.5rem;
  }
  
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

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

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

.decorative-img {
  border-radius: 12px;
  box-shadow: 0 10px 20px rgba(0,0,0,0.1);
  transition: transform 0.3s ease;
  margin: 1rem 0;
}

.decorative-img:hover {
  transform: scale(1.02);
}