/* ── Themes ── */
:root {
  --text: #c8c8c8;
  --muted: #808080;
  --bg: #323232;
  --border: #444;
  --expansion-bg: #2a2a2a;
  --max-width: 680px;
}

[data-theme="light"] {
  --text: #1a1a1a;
  --muted: #777;
  --bg: #fafafa;
  --border: #e0e0e0;
  --expansion-bg: #f4f4f4;
}

[data-theme="dark"] {
  --text: #e0e0e0;
  --muted: #555;
  --bg: #111;
  --border: #222;
  --expansion-bg: #1a1a1a;
}

*, *::before, *::after {
  box-sizing: border-box;
}

html {
  font-size: 18px;
}

@media (max-width: 480px) {
  html {
    font-size: 16px;
  }

  header {
    padding: 1.5rem 1rem 0.75rem;
  }

  main {
    padding: 0 1rem 3rem;
  }

  .article-title {
    font-size: 1.2rem;
  }

  .article-item-meta {
    flex-wrap: wrap;
    gap: 0.4rem;
  }

  .article-meta {
    line-height: 1.6;
  }
}

body {
  font-family: Georgia, 'Times New Roman', serif;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  margin: 0;
  padding: 0;
}

/* Layout */
body > header {
  padding: 2.5rem 1.5rem 1rem;
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
}

/* Site title */
.site-title {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text);
  text-decoration: none;
}

/* Theme switcher */
.theme-switcher {
  display: flex;
  gap: 0.3rem;
}

.theme-btn {
  font-size: 0.85rem;
  width: 1.6rem;
  height: 1.6rem;
  border: 1px solid var(--border);
  background: none;
  cursor: pointer;
  color: var(--muted);
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
  padding: 0;
  line-height: 1;
}

.theme-btn:hover {
  color: var(--text);
  border-color: var(--text);
}

.theme-btn.active {
  background: var(--text);
  color: var(--bg);
  border-color: var(--text);
}

/* Tag filters */
.tag-filters {
  margin-bottom: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.tag-filter {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 0.75rem;
  padding: 0.2rem 0.65rem;
  border: 1px solid var(--border);
  background: none;
  cursor: pointer;
  color: var(--muted);
  border-radius: 2px;
  transition: all 0.1s;
}

.tag-filter:hover {
  border-color: var(--text);
  color: var(--text);
}

.tag-filter.active {
  background: var(--text);
  color: var(--bg);
  border-color: var(--text);
}

/* Article list */
.article-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.article-item {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border);
}

.article-item:last-child {
  border-bottom: none;
}

.article-item.hidden {
  display: none;
}

.article-item-title {
  font-size: 1rem;
  font-family: system-ui, -apple-system, sans-serif;
  font-weight: 500;
  margin: 0 0 0.3rem;
}

.article-item-title a {
  color: var(--text);
  text-decoration: none;
}

.article-item-title a:hover {
  text-decoration: underline;
  text-underline-offset: 2px;
}

.article-item-summary {
  font-size: 0.9rem;
  color: var(--muted);
  margin: 0 0 0.5rem;
}

.article-item-meta {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 0.75rem;
  color: var(--muted);
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

/* Single article */
.back-link {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 0.85rem;
  margin-bottom: 2rem;
  display: inline-block;
  color: var(--muted);
  text-decoration: none;
}

.back-link:hover {
  color: var(--text);
}

.article-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

.article-title {
  font-size: 1.4rem;
  font-family: system-ui, -apple-system, sans-serif;
  font-weight: 500;
  margin: 0 0 0.5rem;
}

.article-meta {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 0.8rem;
  color: var(--muted);
}

.article-body {
  line-height: 1.85;
}

.article-body p {
  margin: 0 0 1.2em;
}

.article-body a {
  color: var(--text);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.article-body a:hover {
  color: var(--muted);
}

/* Inline expansion */
.inline-expansion {
  border-left: 2px solid var(--border);
  margin: 1rem 0;
  padding: 0.75rem 1rem;
  background: var(--expansion-bg);
  font-size: 0.9em;
}

.inline-expansion-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.6rem;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 0.75rem;
}

.inline-expansion-title {
  font-weight: 500;
  color: var(--text);
}

.inline-expansion-close {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.1rem;
  color: var(--muted);
  padding: 0;
  line-height: 1;
}

.inline-expansion-close:hover {
  color: var(--text);
}

.inline-expansion-content p {
  margin: 0 0 0.8em;
}

.inline-expansion-content p:last-child {
  margin-bottom: 0;
}