:root {
  --primary: #1e3c72;
  --primary-light: #2a5298;
  --secondary: #4a6fa5;
  --accent: #ff6600;
  --text: #333;
  --light: #f9f9f9;
  --dark: #1a1a1a;
  --gradient: linear-gradient(135deg, var(--primary), var(--primary-light));
}

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

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

.header {
  background: var(--gradient);
  color: white;
  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;
}

.notice {
  background: rgba(255,255,255,0.2);
  padding: 1rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  backdrop-filter: blur(5px);
  border: 1px solid rgba(255,255,255,0.3);
}

.navbar {
  position: sticky;
  top: 0;
  background: var(--primary);
  z-index: 100;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-links a {
  color: white;
  text-decoration: none;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  transition: all 0.3s ease;
  position: relative;
}

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

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

.main-content {
  max-width: 1200px;
  margin: 3rem auto;
  padding: 0 2rem;
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
}

.article-container {
  background: white;
  border-radius: 12px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.05);
  padding: 3rem;
  position: relative;
  overflow: hidden;
}

.article-container::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 200px;
  height: 200px;
  background: url('https://images.gptkong.com/demo/sample2.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: 0;
}

article {
  position: relative;
  z-index: 1;
}

article h2 {
  color: var(--primary);
  margin-bottom: 1.5rem;
  font-size: 2rem;
  position: relative;
  padding-bottom: 0.5rem;
}

article h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--accent);
}

article h3 {
  color: var(--secondary);
  margin: 2rem 0 1rem;
  font-size: 1.5rem;
}

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

pre {
  background: var(--dark);
  color: #f8f8f2;
  padding: 1.5rem;
  border-radius: 8px;
  margin: 1.5rem 0;
  overflow-x: auto;
  font-family: 'Courier New', monospace;
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  left: 0;
  background: var(--accent);
  color: white;
  padding: 0.2rem 0.8rem;
  font-size: 0.8rem;
  border-radius: 0 0 4px 0;
}

code {
  font-family: 'Courier New', monospace;
  background: rgba(0,0,0,0.05);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9rem;
}

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

.image-card {
  background: white;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 12px 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 24px rgba(0,0,0,0.15);
}

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

.footer {
  background: var(--primary);
  color: white;
  padding: 3rem 2rem;
  text-align: center;
  margin-top: 3rem;
}

@media (max-width: 768px) {
  .nav-container {
    flex-direction: column;
    padding: 1rem;
  }
  
  .nav-links {
    margin-top: 1rem;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .article-container {
    padding: 2rem 1.5rem;
  }
  
  .main-content {
    padding: 0 1rem;
  }
}

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

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