/* Base reset and typography */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --color-bg: #ffffff;
  --color-text: #222;
  --color-text-muted: #666;
  --color-link: #222;
  --color-link-hover: #000;
  --color-border: #e0e0e0;
  --color-bg-subtle: #f7f7f7;
  --color-accent: #2563eb;
  --color-tag-bg: #eef2ff;
  --color-tag-border: #c7d2fe;
  --color-tag-text: #4338ca;
  --max-width: 48rem;
  --max-width-wide: 64rem;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 4rem;
}

html {
  font-size: 100%;
  line-height: 1.6;
  -webkit-text-size-adjust: 100%;
  height: 100%;
}

body {
  font-family:
    -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100%;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-color: #ccc;
  text-underline-offset: 2px;
}

a:hover {
  color: var(--color-link-hover);
  text-decoration-color: var(--color-link-hover);
}

img {
  max-width: 100%;
  height: auto;
}

/* Site header */
.site-header {
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-md) 0;
}

.site-nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}

.site-logo:hover {
  color: var(--color-text);
  text-decoration: none;
}

.site-nav ul {
  list-style: none;
  display: flex;
  gap: var(--space-md);
}

.site-nav ul a {
  text-decoration: none;
}

.site-nav ul a:hover {
  text-decoration: underline;
  text-decoration-color: var(--color-link-hover);
}

/* Main content */
main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md);
  width: 100%;
}

/* Widen main when blog post has a topic sidebar */
main:has(.topic-sidebar) {
  max-width: var(--max-width-wide);
}

/* Article header */
.article-header {
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 2px solid var(--color-border);
}

.article-header .category {
  display: inline-block;
  margin-bottom: var(--space-sm);
}

.article-header .category a {
  font-size: 0.8125rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  padding: 0.125rem 0.5rem;
  background: var(--color-tag-bg);
  border-radius: 0.25rem;
  text-decoration: none;
}

.article-header .category a:hover {
  text-decoration: none;
  background: var(--color-tag-border);
}

.article-header .date {
  display: block;
  color: var(--color-text-muted);
  font-size: 0.875rem;
  margin-bottom: var(--space-sm);
}

.article-header h1 {
  font-size: 2.25rem;
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: -0.02em;
}

@media (min-width: 640px) {
  .article-header h1 {
    font-size: 2.5rem;
  }
}

/* Top image */
.top-image {
  margin-bottom: var(--space-lg);
}

.top-image img {
  width: 100%;
  border-radius: 0.375rem;
}

/* Lead paragraph */
.lead {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
  line-height: 1.7;
}

/* Blog post content layout (main + sidebar) */
.blog-post-content {
  display: block;
}

@media (min-width: 768px) {
  .blog-post-content:has(.topic-sidebar) {
    display: grid;
    grid-template-columns: 1fr 15rem;
    gap: var(--space-xl);
    align-items: start;
  }
}

@media (min-width: 1024px) {
  .blog-post-content:has(.topic-sidebar) {
    grid-template-columns: 1fr 18rem;
  }
}

/* Main body content */
.main-body {
  margin-bottom: var(--space-xl);
}

.main-body h2 {
  font-size: 1.5rem;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.main-body h3 {
  font-size: 1.25rem;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-md);
}

.main-body p {
  margin-bottom: var(--space-md);
}

.main-body ul,
.main-body ol {
  margin-bottom: var(--space-md);
  padding-left: var(--space-lg);
}

.main-body li {
  margin-bottom: var(--space-xs);
}

.main-body pre {
  border: 1px solid var(--color-border);
  border-radius: 0.25rem;
  padding: var(--space-md);
  overflow-x: auto;
  margin-bottom: var(--space-md);
  font-size: 0.875rem;
  line-height: 1.5;
}

.main-body code {
  font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;
  font-size: 0.875em;
}

.main-body :not(pre) > code {
  background: var(--color-bg-subtle);
  padding: 0.125rem 0.375rem;
  border-radius: 0.25rem;
}

.main-body blockquote {
  border-left: 3px solid var(--color-accent);
  padding-left: var(--space-md);
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

.main-body img {
  border-radius: 0.375rem;
}

/* Tags box */
.tags {
  margin-bottom: var(--space-lg);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
}

.tags .legend {
  font-weight: 600;
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin-right: var(--space-xs);
}

.tags a {
  display: inline-block;
  background: var(--color-tag-bg);
  border: 1px solid var(--color-tag-border);
  border-radius: 2rem;
  padding: 0.1875rem 0.75rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-tag-text);
  text-decoration: none;
  transition:
    background-color 0.15s,
    border-color 0.15s;
}

.tags a:hover {
  text-decoration: none;
  background: var(--color-tag-border);
  border-color: var(--color-accent);
  color: var(--color-tag-text);
}

/* Topic sidebar */
.topic-sidebar {
  margin-top: var(--space-lg);
}

@media (min-width: 768px) {
  .topic-sidebar {
    margin-top: 0;
    position: sticky;
    top: var(--space-lg);
  }
}

.topic-list {
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: 0.5rem;
  padding: var(--space-md);
}

.topic-list .legend {
  display: block;
  font-weight: 700;
  font-size: 0.875rem;
  margin-bottom: var(--space-sm);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-accent);
  color: var(--color-text);
}

.topic-list ol {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: topic-counter;
}

.topic-list li {
  counter-increment: topic-counter;
  font-size: 0.8125rem;
  line-height: 1.4;
  border-bottom: 1px solid var(--color-border);
}

.topic-list li:last-child {
  border-bottom: none;
}

.topic-list li a {
  display: block;
  padding: var(--space-sm) var(--space-sm) var(--space-sm) 0;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.topic-list li a::before {
  content: counter(topic-counter) '. ';
  font-weight: 600;
  color: var(--color-text-muted);
}

.topic-list li a:hover {
  color: var(--color-link);
  text-decoration: none;
}

.topic-list li.current a {
  color: var(--color-text);
  font-weight: 600;
}

.topic-list li.current a::before {
  color: var(--color-accent);
}

/* Post list and teasers */
.post-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  margin-top: var(--space-lg);
}

.post-teaser {
  display: grid;
  gap: var(--space-md);
  padding-bottom: var(--space-lg);
  border-bottom: 1px dashed var(--color-border);
}

@media (min-width: 640px) {
  .post-teaser:has(.post-teaser-image) {
    grid-template-columns: 12rem 1fr;
  }
}

.post-teaser:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.post-teaser-image {
  display: block;
  overflow: hidden;
  border-radius: 0.375rem;
  text-decoration: none;
}

.post-teaser-image img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  border-radius: 0.375rem;
  transition: transform 0.2s;
}

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

.post-teaser-content .date {
  display: block;
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xs);
}

.post-teaser-content h2,
.post-teaser-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: var(--space-xs);
}

.post-teaser-content h2 a,
.post-teaser-content h3 a {
  color: var(--color-text);
  text-decoration: none;
}

.post-teaser-content h2 a:hover,
.post-teaser-content h3 a:hover {
  color: var(--color-text);
  text-decoration: underline;
  text-decoration-color: var(--color-text);
}

.post-teaser-content p {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* Pagination */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.pagination-prev,
.pagination-next {
  font-size: 0.875rem;
  font-weight: 500;
  padding: var(--space-xs) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: 0.375rem;
  text-decoration: none;
  transition:
    border-color 0.15s,
    background-color 0.15s;
}

.pagination-prev:hover,
.pagination-next:hover {
  text-decoration: none;
  border-color: var(--color-accent);
  background: var(--color-bg-subtle);
}

.pagination-info {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

/* Home page */
.hero {
  text-align: center;
  padding: var(--space-xl) 0;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-xs);
}

.hero p {
  font-size: 1.25rem;
  color: var(--color-text-muted);
}

.social-links {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

.social-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.social-links a:hover {
  color: var(--color-text);
}

/* Category page */
.category-description {
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  color: #999;
  font-size: 0.875rem;
}