:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --text: #1f2937;
  --text-light: #6b7280;
  --bg: #ffffff;
  --bg-alt: #f9fafb;
  --border: #e5e7eb;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: var(--bg);
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
header {
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 100;
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-weight: 700;
  font-size: 18px;
  color: var(--text);
  text-decoration: none;
}

header nav a {
  margin-left: 24px;
  color: var(--text-light);
  text-decoration: none;
  font-size: 14px;
}

header nav a:hover {
  color: var(--primary);
}

/* Hero */
.hero {
  text-align: center;
  padding: 60px 0 40px;
}

.hero h1 {
  font-size: 42px;
  font-weight: 700;
  margin-bottom: 16px;
}

.tagline {
  font-size: 20px;
  color: var(--text-light);
}

/* Featured */
.featured {
  margin-bottom: 48px;
}

.featured h2 {
  font-size: 24px;
  margin-bottom: 20px;
}

.featured-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.featured-card {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  text-decoration: none;
  color: var(--text);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.featured-card:hover {
  border-color: var(--primary);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.1);
}

.featured-card h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.featured-card p {
  font-size: 14px;
  color: var(--text-light);
}

/* Categories */
.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 32px;
}

.category h2 {
  font-size: 16px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-light);
  margin-bottom: 12px;
}

.category ul {
  list-style: none;
}

.category li {
  margin-bottom: 8px;
}

.category a {
  color: var(--text);
  text-decoration: none;
  font-size: 15px;
}

.category a:hover {
  color: var(--primary);
}

/* Article */
article {
  padding: 40px 0 60px;
}

.breadcrumb {
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 24px;
}

.breadcrumb a {
  color: var(--primary);
  text-decoration: none;
}

article h1 {
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.2;
}

article h2 {
  font-size: 24px;
  font-weight: 600;
  margin-top: 48px;
  margin-bottom: 16px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

article h3 {
  font-size: 20px;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 12px;
}

article p {
  margin-bottom: 16px;
}

article ul, article ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

article li {
  margin-bottom: 8px;
}

article blockquote {
  background: var(--bg-alt);
  border-left: 4px solid var(--primary);
  padding: 16px 20px;
  margin: 24px 0;
  border-radius: 0 8px 8px 0;
}

article code {
  background: var(--bg-alt);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 14px;
}

article pre {
  background: #1f2937;
  color: #f9fafb;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 24px 0;
}

article pre code {
  background: none;
  padding: 0;
}

article table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
}

article th, article td {
  border: 1px solid var(--border);
  padding: 12px;
  text-align: left;
}

article th {
  background: var(--bg-alt);
  font-weight: 600;
}

article strong {
  font-weight: 600;
}

article a {
  color: var(--primary);
}

article hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 48px 0;
}

.article-footer {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

.article-footer ul {
  list-style: none;
  padding-left: 0;
}

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  margin-top: 60px;
  text-align: center;
  color: var(--text-light);
  font-size: 14px;
}

.footer-links {
  margin-top: 12px;
}

.footer-links a {
  color: var(--text-light);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--primary);
}

/* Responsive */
@media (max-width: 640px) {
  .hero h1 {
    font-size: 32px;
  }
  
  article h1 {
    font-size: 28px;
  }
  
  .featured-grid {
    grid-template-columns: 1fr;
  }
}