:root {
  --primary-dark: #0f2027;
  --primary-mid: #203a43;
  --primary-light: #2c5364;
  --accent-purple: #6a11cb;
  --accent-blue: #2575fc;
  --highlight-orange: #ff7e5f;
  --highlight-green: #4CAF50;
  --text-light: #ffffff;
  --text-muted: rgba(255,255,255,0.7);
}

body {
  font-family: 'Open Sans', sans-serif;
  line-height: 1.6;
  color: var(--text-light);
  background: var(--primary-dark);
  margin: 0;
  padding: 0;
  overflow-x: hidden;
}

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

.header {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-mid));
  padding: 30px 0;
  text-align: center;
  border-radius: 0 0 20px 20px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.3);
  margin-bottom: 40px;
  position: relative;
  overflow: hidden;
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('https://images.gptkong.com/demo/sample3.png') center/cover no-repeat;
  opacity: 0.1;
  z-index: 0;
}

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

.notice {
  background: rgba(255,255,255,0.1);
  padding: 15px;
  border-radius: 10px;
  margin: 20px 0;
  text-align: center;
  font-size: 0.9rem;
  border-left: 4px solid var(--highlight-orange);
}

.article-container {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 30px;
}

article {
  background: rgba(32, 58, 67, 0.7);
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  backdrop-filter: blur(5px);
}

article h2 {
  font-size: 1.8rem;
  color: var(--text-light);
  margin-top: 0;
  border-bottom: 2px solid var(--accent-blue);
  padding-bottom: 10px;
}

article h3 {
  font-size: 1.4rem;
  color: var(--text-light);
  margin-top: 30px;
  position: relative;
  padding-left: 15px;
}

article h3::before {
  content: '';
  position: absolute;
  left: 0;
  top: 5px;
  height: 80%;
  width: 5px;
  background: linear-gradient(to bottom, var(--accent-purple), var(--accent-blue));
  border-radius: 5px;
}

article p {
  font-size: 1.1rem;
  margin-bottom: 20px;
}

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

.nav-card {
  background: rgba(32, 58, 67, 0.7);
  padding: 20px;
  border-radius: 15px;
  margin-bottom: 20px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  backdrop-filter: blur(5px);
}

.nav-card h3 {
  margin-top: 0;
  color: var(--text-light);
  font-size: 1.2rem;
}

.nav-links {
  list-style: none;
  padding: 0;
  margin: 0;
}

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

.nav-links a {
  display: block;
  padding: 10px 15px;
  color: var(--text-muted);
  text-decoration: none;
  border-radius: 8px;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.nav-links a::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 3px;
  height: 100%;
  background: var(--accent-blue);
  transform: translateX(-10px);
  transition: transform 0.3s ease;
}

.nav-links a:hover {
  color: var(--text-light);
  background: rgba(255,255,255,0.1);
}

.nav-links a:hover::before {
  transform: translateX(0);
}

.image-gallery {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 15px;
  margin-top: 20px;
}

.gallery-item {
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  transition: transform 0.3s ease;
}

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

.gallery-item img {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.5s ease;
}

.gallery-item:hover img {
  transform: scale(1.1);
}

pre {
  background: rgba(15, 32, 39, 0.8);
  padding: 20px;
  border-radius: 10px;
  overflow-x: auto;
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
  margin: 20px 0;
  border-left: 4px solid var(--highlight-orange);
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  right: 0;
  background: var(--highlight-orange);
  color: white;
  padding: 2px 10px;
  font-size: 0.8rem;
  border-radius: 0 0 0 5px;
}

code {
  font-family: 'Courier New', monospace;
  color: #f8f8f2;
}

.tech-decoration {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: -1;
  opacity: 0.1;
}

.tech-decoration::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 200%;
  height: 100%;
  background: repeating-linear-gradient(
    0deg,
    rgba(255,255,255,0.1),
    rgba(255,255,255,0.1) 1px,
    transparent 1px,
    transparent 10px
  );
  animation: moveBackground 60s linear infinite;
}

@keyframes moveBackground {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

.footer {
  text-align: center;
  padding: 30px 0;
  margin-top: 50px;
  background: rgba(32, 58, 67, 0.7);
  border-radius: 20px 20px 0 0;
  box-shadow: 0 -5px 15px rgba(0,0,0,0.2);
}

@media (max-width: 900px) {
  .article-container {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    position: static;
  }
}

@media (max-width: 600px) {
  .header h1 {
    font-size: 2rem;
  }
  
  article {
    padding: 20px;
  }
  
  .image-gallery {
    grid-template-columns: 1fr;
  }
}