:root {
  --primary-color: #ffffff;
  --secondary-color: #f5f5f5;
  --accent-color-blue: #4A90E2;
  --accent-color-green: #50E3C2;
  --highlight-color: #333333;
  --shadow-color: rgba(0,0,0,0.1);
  --border-radius: 12px;
  --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

body {
  font-family: 'Roboto', sans-serif;
  line-height: 1.6;
  color: var(--highlight-color);
  background-color: var(--secondary-color);
  padding-top: 80px;
}

.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(135deg, var(--accent-color-blue), var(--accent-color-green));
  color: white;
  padding: 20px;
  box-shadow: 0 4px 12px var(--shadow-color);
  z-index: 1000;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header h1 {
  font-size: 1.8rem;
  font-weight: 500;
}

.notice {
  background-color: var(--primary-color);
  padding: 10px 20px;
  border-radius: var(--border-radius);
  font-size: 0.9rem;
  box-shadow: 0 2px 8px var(--shadow-color);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
  margin-bottom: 60px;
}

.card {
  background: var(--primary-color);
  border-radius: var(--border-radius);
  box-shadow: 0 4px 12px var(--shadow-color);
  overflow: hidden;
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

.card-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: var(--border-radius) var(--border-radius) 0 0;
}

.card-content {
  padding: 25px;
}

.card h3 {
  font-size: 1.3rem;
  margin-bottom: 15px;
  color: var(--accent-color-blue);
}

.card p {
  margin-bottom: 15px;
  color: #666;
}

.tag {
  display: inline-block;
  background: var(--secondary-color);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  margin-right: 8px;
  margin-bottom: 8px;
  color: var(--highlight-color);
}

.article-container {
  background: var(--primary-color);
  border-radius: var(--border-radius);
  box-shadow: 0 4px 12px var(--shadow-color);
  padding: 40px;
  margin-bottom: 60px;
}

.article-container h2 {
  font-size: 2rem;
  margin-bottom: 30px;
  color: var(--accent-color-blue);
  position: relative;
  padding-bottom: 15px;
}

.article-container h2:after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(to right, var(--accent-color-blue), var(--accent-color-green));
}

.article-container h3 {
  font-size: 1.5rem;
  margin: 30px 0 20px;
  color: var(--highlight-color);
}

.article-container p {
  margin-bottom: 20px;
  font-size: 1.1rem;
  line-height: 1.8;
}

pre {
  background: #f8f8f8;
  border-radius: var(--border-radius);
  padding: 20px;
  margin: 25px 0;
  overflow-x: auto;
  box-shadow: inset 0 0 8px rgba(0,0,0,0.05);
}

code {
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  color: #333;
}

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

.image-grid img {
  width: 100%;
  height: auto;
  border-radius: var(--border-radius);
  box-shadow: 0 4px 12px var(--shadow-color);
  transition: var(--transition);
}

.image-grid img:hover {
  transform: scale(1.03);
}

.nav-links {
  position: sticky;
  top: 100px;
  align-self: start;
  background: var(--primary-color);
  border-radius: var(--border-radius);
  box-shadow: 0 4px 12px var(--shadow-color);
  padding: 20px;
}

.nav-links h4 {
  font-size: 1.2rem;
  margin-bottom: 15px;
  color: var(--accent-color-blue);
}

.nav-links ul {
  list-style: none;
}

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

.nav-links a {
  text-decoration: none;
  color: var(--highlight-color);
  transition: var(--transition);
  display: block;
  padding: 8px 0;
  border-bottom: 1px solid var(--secondary-color);
}

.nav-links a:hover {
  color: var(--accent-color-blue);
  padding-left: 10px;
}

.footer {
  background: linear-gradient(135deg, var(--accent-color-blue), var(--accent-color-green));
  color: white;
  padding: 30px;
  text-align: center;
  border-radius: var(--border-radius);
  margin-top: 60px;
}

@media (max-width: 768px) {
  .container {
    padding: 20px;
  }
  
  .article-container {
    padding: 25px;
  }
  
  .grid {
    grid-template-columns: 1fr;
  }
  
  .header h1 {
    font-size: 1.4rem;
  }
}

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

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