:root {
  --primary-dark: #0f2027;
  --primary-mid: #203a43;
  --primary-light: #2c5364;
  --accent-blue: #00aaff;
  --accent-purple: #8e2de2;
  --neutral-dark: #1a1a1a;
  --neutral-mid: #4a4a4a;
  --neutral-light: #ffffff;
  --highlight: #ffcc00;
}

@font-face {
  font-family: 'Roboto';
  src: url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;500;700&display=swap');
}

@font-face {
  font-family: 'Open Sans';
  src: url('https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;600;700&display=swap');
}

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

body {
  font-family: 'Open Sans', sans-serif;
  line-height: 1.6;
  color: var(--neutral-light);
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-mid), var(--primary-light));
  min-height: 100%;
  overflow-x: hidden;
}

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

.header {
  position: relative;
  padding: 40px 0;
  text-align: center;
  background: rgba(26, 26, 26, 0.7);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  margin-bottom: 60px;
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
}

.header h1 {
  font-size: 2.5rem;
  margin-bottom: 15px;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.header p {
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.8);
  max-width: 800px;
  margin: 0 auto;
}

.notice {
  background: rgba(255, 204, 0, 0.1);
  border-left: 4px solid var(--highlight);
  padding: 15px;
  margin: 30px 0;
  border-radius: 0 5px 5px 0;
  font-size: 0.9rem;
}

.nav-tabs {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 15px;
  margin: 40px 0;
}

.tab {
  padding: 12px 25px;
  background: var(--neutral-dark);
  color: var(--neutral-light);
  border-radius: 30px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
  border: none;
  font-family: 'Roboto', sans-serif;
}

.tab:hover {
  background: linear-gradient(45deg, var(--accent-blue), var(--accent-purple));
  transform: translateY(-3px);
  box-shadow: 0 5px 15px rgba(0, 170, 255, 0.3);
}

.tab.active {
  background: linear-gradient(45deg, var(--accent-blue), var(--accent-purple));
}

.tab-icon {
  margin-right: 8px;
  font-size: 1.1rem;
}

.content-grid {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 30px;
  margin-bottom: 60px;
}

@media (max-width: 900px) {
  .content-grid {
    grid-template-columns: 1fr;
  }
}

.sidebar {
  background: rgba(26, 26, 26, 0.7);
  border-radius: 10px;
  padding: 20px;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  align-self: start;
  position: sticky;
  top: 20px;
}

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

.sidebar-nav li {
  margin-bottom: 15px;
}

.sidebar-nav a {
  display: block;
  padding: 10px 15px;
  color: var(--neutral-light);
  text-decoration: none;
  border-radius: 5px;
  transition: all 0.3s ease;
  font-family: 'Roboto', sans-serif;
}

.sidebar-nav a:hover {
  background: linear-gradient(90deg, rgba(0, 170, 255, 0.2), transparent);
  color: var(--accent-blue);
}

.sidebar-nav a.active {
  background: linear-gradient(90deg, rgba(0, 170, 255, 0.3), transparent);
  color: var(--accent-blue);
  border-left: 3px solid var(--accent-blue);
}

.main-content {
  background: rgba(26, 26, 26, 0.7);
  border-radius: 10px;
  padding: 30px;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

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

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

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

article h4 {
  font-size: 1.2rem;
  margin: 20px 0 10px;
  color: var(--neutral-light);
}

article p {
  margin-bottom: 15px;
  font-size: 1rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.8);
}

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 20px;
  margin: 30px 0;
}

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

.image-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 170, 255, 0.2);
}

.image-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.image-card .caption {
  padding: 15px;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.7);
}

pre {
  background: var(--neutral-dark);
  padding: 20px;
  border-radius: 5px;
  overflow-x: auto;
  margin: 20px 0;
  border-left: 4px solid var(--accent-blue);
  font-family: 'Roboto Mono', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
  color: var(--neutral-light);
}

code {
  font-family: 'Roboto Mono', monospace;
  background: rgba(0, 0, 0, 0.3);
  padding: 2px 5px;
  border-radius: 3px;
  font-size: 0.9rem;
}

.feature-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 25px;
  margin: 40px 0;
}

.feature-card {
  background: linear-gradient(135deg, rgba(44, 83, 100, 0.5), rgba(26, 26, 26, 0.8));
  border-radius: 10px;
  padding: 25px;
  transition: all 0.3s ease;
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(0, 170, 255, 0.1);
  border-color: rgba(0, 170, 255, 0.3);
}

.feature-card h4 {
  font-size: 1.2rem;
  margin-bottom: 15px;
  color: var(--accent-blue);
  display: flex;
  align-items: center;
}

.feature-card h4::before {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  background: var(--accent-blue);
  border-radius: 50%;
  margin-right: 10px;
}

.feature-card p {
  margin-bottom: 15px;
  font-size: 0.95rem;
}

.feature-list {
  list-style: none;
  margin-top: 15px;
}

.feature-list li {
  position: relative;
  padding-left: 20px;
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.feature-list li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--accent-blue);
}

.footer {
  text-align: center;
  padding: 30px 0;
  margin-top: 60px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.6);
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  .header p {
    font-size: 1rem;
  }
  
  .content-grid {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    position: static;
    margin-bottom: 30px;
  }
  
  article h2 {
    font-size: 1.6rem;
  }
  
  article h3 {
    font-size: 1.3rem;
  }
  
  .feature-cards {
    grid-template-columns: 1fr;
  }
}

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

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

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.6;
  }
}

.pulsing {
  animation: pulse 2s ease-in-out infinite;
}

/* Utility classes */
.text-gradient {
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.shadow-light {
  box-shadow: 0 5px 15px rgba(0, 170, 255, 0.1);
}

.shadow-dark {
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

.border-gradient {
  border: 1px solid transparent;
  border-image: linear-gradient(45deg, var(--accent-blue), var(--accent-purple)) 1;
}