:root {
  --primary-color: #2c3e50;
  --secondary-color: #95a5a6;
  --highlight-color: #e67e22;
  --accent-color: #3498db;
  --light-bg: rgba(255, 255, 255, 0.85);
  --dark-text: #333;
  --light-text: #ecf0f1;
}

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

body {
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  color: var(--dark-text);
  line-height: 1.6;
  min-height: 100%;
  padding: 0;
  margin: 0;
}

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

.header {
  position: relative;
  padding: 80px 0;
  text-align: center;
  background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
  color: var(--light-text);
  margin-bottom: 40px;
  border-radius: 0 0 20px 20px;
  overflow: hidden;
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
  opacity: 0.15;
  z-index: 0;
}

.header-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
}

.header h1 {
  font-size: 2.5rem;
  margin-bottom: 20px;
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.header p {
  font-size: 1.2rem;
  margin-bottom: 30px;
}

.notice {
  background: var(--light-bg);
  backdrop-filter: blur(10px);
  padding: 15px;
  border-radius: 8px;
  margin: 20px auto;
  max-width: 800px;
  text-align: center;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
  font-weight: bold;
  color: var(--primary-color);
}

.main-content {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 30px;
}

.sidebar {
  position: sticky;
  top: 20px;
  height: fit-content;
}

.nav-menu {
  background: var(--light-bg);
  backdrop-filter: blur(10px);
  border-radius: 10px;
  padding: 20px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

.nav-menu h3 {
  color: var(--primary-color);
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(0,0,0,0.1);
}

.nav-links {
  list-style: none;
}

.nav-links li {
  margin-bottom: 10px;
}

.nav-links a {
  display: block;
  padding: 8px 12px;
  color: var(--dark-text);
  text-decoration: none;
  border-radius: 5px;
  transition: all 0.3s ease;
}

.nav-links a:hover {
  background: rgba(0,0,0,0.05);
  color: var(--highlight-color);
}

.content {
  background: var(--light-bg);
  backdrop-filter: blur(10px);
  border-radius: 10px;
  padding: 30px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

article h2 {
  color: var(--primary-color);
  margin: 30px 0 20px;
  font-size: 1.8rem;
  position: relative;
  padding-bottom: 10px;
}

article h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--highlight-color), var(--accent-color));
}

article h3 {
  color: var(--primary-color);
  margin: 25px 0 15px;
  font-size: 1.4rem;
}

article p {
  margin-bottom: 20px;
  font-size: 1.05rem;
}

article ol, article ul {
  margin-left: 30px;
  margin-bottom: 20px;
}

article li {
  margin-bottom: 10px;
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 30px 0;
}

.image-card {
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

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

.image-caption {
  padding: 15px;
  text-align: center;
  font-size: 0.9rem;
  color: var(--secondary-color);
}

pre {
  background: rgba(44, 62, 80, 0.9);
  color: #f8f8f2;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 20px 0;
  font-size: 0.9rem;
  line-height: 1.5;
  tab-size: 2;
}

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

.footer {
  background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
  color: var(--light-text);
  padding: 40px 0;
  margin-top: 60px;
  text-align: center;
  border-radius: 20px 20px 0 0;
}

.footer-content {
  max-width: 800px;
  margin: 0 auto;
}

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

.frosted-glass {
  background: rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(10px);
  border-radius: 10px;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
  padding: 20px;
  margin: 20px 0;
}

.button {
  background: linear-gradient(45deg, var(--primary-color), var(--highlight-color));
  color: #fff;
  padding: 12px 24px;
  border: none;
  border-radius: 5px;
  transition: all 0.3s ease;
  display: inline-block;
  text-decoration: none;
  font-weight: bold;
  margin: 10px 0;
}

.button:hover {
  background: linear-gradient(45deg, var(--highlight-color), var(--primary-color));
  transform: scale(1.05);
  box-shadow: 0 8px 16px rgba(0,0,0,0.2);
}

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

.animated {
  animation: fadeIn 1s ease-out forwards;
}

@media (max-width: 768px) {
  .main-content {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    position: static;
    margin-bottom: 30px;
  }
  
  .header h1 {
    font-size: 2rem;
  }
  
  .header p {
    font-size: 1rem;
  }
  
  article h2 {
    font-size: 1.5rem;
  }
  
  article h3 {
    font-size: 1.2rem;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 15px;
  }
  
  .header {
    padding: 60px 0;
  }
  
  .content, .nav-menu {
    padding: 20px;
  }
  
  pre {
    padding: 15px;
    font-size: 0.8rem;
  }
}