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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  line-height: 1.6;
  color: #333;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  background: #f8f9fa;
  padding: 1rem 0;
  border-bottom: 1px solid #e9ecef;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: #2563eb;
  text-decoration: none;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 2rem;
}

nav a {
  color: #495057;
  text-decoration: none;
}

nav a:hover {
  color: #2563eb;
}

main {
  padding: 3rem 0;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  color: #1a1a1a;
}

.subtitle {
  font-size: 1.25rem;
  color: #6c757d;
  margin-bottom: 2rem;
}

section {
  margin-bottom: 3rem;
}

h2 {
  font-size: 1.75rem;
  margin-bottom: 1rem;
  color: #1a1a1a;
}

.categories ul {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.categories a {
  display: block;
  padding: 1rem;
  background: #f8f9fa;
  border-radius: 8px;
  text-decoration: none;
  color: #2563eb;
  font-weight: 500;
}

.categories a:hover {
  background: #e9ecef;
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

article {
  padding: 1.5rem;
  background: #fff;
  border: 1px solid #e9ecef;
  border-radius: 8px;
}

article h3 {
  margin-bottom: 0.5rem;
}

article h3 a {
  color: #2563eb;
  text-decoration: none;
}

article h3 a:hover {
  text-decoration: underline;
}

article p {
  color: #6c757d;
  font-size: 0.9rem;
}

footer {
  background: #f8f9fa;
  padding: 2rem 0;
  margin-top: 3rem;
  border-top: 1px solid #e9ecef;
  text-align: center;
  color: #6c757d;
}

footer a {
  color: #495057;
  margin: 0 0.5rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
}

th, td {
  padding: 0.75rem;
  border: 1px solid #dee2e6;
  text-align: left;
}

th {
  background: #f8f9fa;
  font-weight: 600;
}

pre {
  background: #f8f9fa;
  padding: 1rem;
  border-radius: 4px;
  overflow-x: auto;
}

code {
  font-family: 'Fira Code', monospace;
  font-size: 0.9rem;
}

@media (max-width: 768px) {
  nav {
    flex-direction: column;
    gap: 1rem;
  }
  
  nav ul {
    gap: 1rem;
  }
  
  h1 {
    font-size: 2rem;
  }
}