:root {
  --primary-color: #1B2430;
  --secondary-color: #F5F7FA;
  --accent-color: #3D92FF;
  --highlight-color: #7ED321;
  --text-color: #333;
  --light-text: #fff;
  --transition: all 0.3s ease;
}

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

body {
  font-family: 'Roboto', sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background: linear-gradient(135deg, #f5f7fa 0%, #e4e8eb 100%);
  padding: 0;
  margin: 0;
}

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

.header {
  background: linear-gradient(135deg, var(--primary-color) 0%, #0a192f 100%);
  color: var(--light-text);
  padding: 2rem 0;
  text-align: center;
  border-radius: 0 0 20px 20px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  margin-bottom: 3rem;
}

.header h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  background: linear-gradient(90deg, var(--accent-color), var(--highlight-color));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.notice {
  background: rgba(255, 255, 255, 0.2);
  padding: 1rem;
  border-radius: 8px;
  margin: 1rem auto;
  max-width: 600px;
  backdrop-filter: blur(10px);
}

.article-container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
}

article {
  background: white;
  border-radius: 15px;
  padding: 2.5rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
  position: relative;
  overflow: hidden;
}

article::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 5px;
  height: 100%;
  background: linear-gradient(to bottom, var(--accent-color), var(--highlight-color));
}

article h2 {
  color: var(--primary-color);
  margin-bottom: 1.5rem;
  font-size: 1.8rem;
  position: relative;
  padding-bottom: 0.5rem;
}

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

article p {
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
  line-height: 1.8;
}

pre {
  background: var(--primary-color);
  color: white;
  padding: 1.5rem;
  border-radius: 10px;
  overflow-x: auto;
  margin: 1.5rem 0;
  box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.3);
  font-size: 0.95rem;
  position: relative;
}

pre::before {
  content: 'CSS';
  position: absolute;
  top: 0;
  right: 0;
  background: var(--highlight-color);
  color: var(--primary-color);
  padding: 0.2rem 0.8rem;
  font-size: 0.8rem;
  border-radius: 0 0 0 5px;
}

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

.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.image-card {
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  transition: var(--transition);
  position: relative;
}

.image-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

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

.image-card:hover img {
  transform: scale(1.05);
}

.nav-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 2rem 0;
}

.nav-link {
  padding: 0.8rem 1.5rem;
  background: linear-gradient(135deg, var(--accent-color), var(--highlight-color));
  color: white;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.nav-link:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.feature-section {
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(10px);
  border-radius: 15px;
  padding: 2rem;
  margin: 3rem 0;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.feature-card {
  background: white;
  border-radius: 10px;
  padding: 1.5rem;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.feature-card h3 {
  color: var(--primary-color);
  margin-bottom: 0.8rem;
  font-size: 1.2rem;
}

.feature-card p {
  font-size: 0.95rem;
  margin-bottom: 0.8rem;
}

.feature-list {
  list-style: none;
}

.feature-list li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
}

.feature-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.5rem;
  width: 8px;
  height: 8px;
  background: var(--highlight-color);
  border-radius: 50%;
}

.footer {
  text-align: center;
  padding: 2rem 0;
  margin-top: 3rem;
  color: var(--text-color);
  font-size: 0.9rem;
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  article {
    padding: 1.5rem;
  }
  
  .image-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  }
  
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .header {
    padding: 1.5rem 0;
  }
  
  article h2 {
    font-size: 1.5rem;
  }
  
  .nav-links {
    flex-direction: column;
    align-items: center;
  }
  
  .nav-link {
    width: 100%;
    text-align: center;
  }
}

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

article, .feature-section, .image-grid {
  animation: fadeIn 0.6s ease-out forwards;
}

.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }
.delay-3 { animation-delay: 0.6s; }