:root {
  --primary: #001f3f;
  --secondary: #003366;
  --accent: #00aaff;
  --text: #ffffff;
  --bg: #000a1a;
  --card-bg: rgba(255, 255, 255, 0.1);
}

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

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

.header {
  text-align: center;
  padding: 2rem;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  margin-bottom: 3rem;
  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: 0.15;
  z-index: 0;
}

.header h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  position: relative;
  z-index: 1;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
}

.header p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.notice {
  background: rgba(0, 170, 255, 0.2);
  padding: 1rem;
  border-left: 4px solid var(--accent);
  margin: 2rem auto;
  max-width: 800px;
  border-radius: 0 8px 8px 0;
  backdrop-filter: blur(5px);
}

.nav-container {
  position: sticky;
  top: 0;
  z-index: 1000;
}

.navbar {
  display: flex;
  justify-content: center;
  background: rgba(0, 31, 63, 0.9);
  backdrop-filter: blur(10px);
  padding: 1rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.nav-link {
  color: var(--text);
  text-decoration: none;
  margin: 0 1.5rem;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  transition: all 0.3s ease;
  font-weight: 500;
  position: relative;
}

.nav-link:hover {
  color: var(--accent);
  background: rgba(0, 170, 255, 0.1);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s ease;
}

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

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

article {
  background: rgba(0, 10, 26, 0.7);
  padding: 3rem;
  border-radius: 15px;
  margin: 3rem 0;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(5px);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

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

article h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), transparent);
}

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

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

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

.image-card {
  background: var(--card-bg);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 30px rgba(0, 170, 255, 0.3);
}

.image-card img {
  width: 100%;
  height: 300px;
  object-fit: cover;
  display: block;
  border-radius: 10px 10px 0 0;
}

.image-caption {
  padding: 1.5rem;
}

pre {
  background: rgba(0, 0, 0, 0.3);
  border-radius: 8px;
  padding: 1.5rem;
  margin: 2rem 0;
  overflow-x: auto;
  border-left: 4px solid var(--accent);
  font-family: 'Courier New', monospace;
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  right: 0;
  background: var(--accent);
  color: white;
  padding: 0.2rem 0.8rem;
  font-size: 0.8rem;
  border-radius: 0 0 0 8px;
}

code {
  font-family: 'Courier New', monospace;
  background: rgba(0, 170, 255, 0.1);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9rem;
}

.footer {
  text-align: center;
  padding: 3rem;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  margin-top: 3rem;
  position: relative;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('https://images.gptkong.com/demo/sample12.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: 0;
}

.footer p {
  position: relative;
  z-index: 1;
}

@media (max-width: 768px) {
  .navbar {
    flex-direction: column;
    align-items: center;
  }
  
  .nav-link {
    margin: 0.5rem 0;
  }
  
  article {
    padding: 2rem 1.5rem;
  }
  
  .header h1 {
    font-size: 2rem;
  }
  
  .image-grid {
    grid-template-columns: 1fr;
  }
}

@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-20px);
  }
}

.floating {
  animation: float 6s ease-in-out infinite;
}

.glow {
  text-shadow: 0 0 10px rgba(0, 170, 255, 0.7);
}