/* === RESET & BASE === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #0f0f18;
  --bg-tertiary: #161622;
  --bg-card: #12121e;
  --border: #1e1e30;
  --border-hover: #2a2a44;
  --text-primary: #c9d1d9;
  --text-secondary: #8b949e;
  --text-muted: #484f58;
  --accent: #00d4ff;
  --accent-dim: #0099bb;
  --accent-glow: rgba(0, 212, 255, 0.15);
  --accent-secondary: #7b61ff;
  --tag-bg: rgba(0, 212, 255, 0.08);
  --tag-border: rgba(0, 212, 255, 0.25);
  --code-bg: #0d1117;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'SF Mono', Consolas, monospace;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --sidebar-width: 280px;
  --header-height: 56px;
}

html { font-size: 15px; scroll-behavior: smooth; }
body {
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; transition: color 0.15s; }
a:hover { color: #fff; }

::selection { background: var(--accent); color: var(--bg-primary); }
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-hover); }

/* === LAYOUT === */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  z-index: 100;
  backdrop-filter: blur(12px);
}

.site-logo {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}
.site-logo span { color: var(--accent); }
.site-logo .subtitle {
  color: var(--text-muted);
  font-weight: 400;
  font-size: 0.8rem;
  margin-left: 8px;
}

.header-actions { display: flex; align-items: center; gap: 12px; }

.search-toggle {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 6px 14px;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s;
  display: flex;
  align-items: center;
  gap: 8px;
}
.search-toggle:hover { border-color: var(--accent); color: var(--accent); }
.search-toggle kbd {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 0.7rem;
}

.sidebar-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1.1rem;
}

/* === SIDEBAR === */
.sidebar {
  position: fixed;
  top: var(--header-height);
  left: 0;
  bottom: 0;
  width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 20px 0;
  z-index: 50;
  transition: transform 0.25s ease;
}

.sidebar-section { padding: 0 16px; margin-bottom: 24px; }
.sidebar-section-title {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  padding: 0 8px;
  margin-bottom: 8px;
}

.sidebar-item {
  display: block;
  padding: 6px 8px;
  border-radius: 4px;
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: all 0.1s;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.sidebar-item:hover { background: var(--bg-tertiary); color: var(--text-primary); }
.sidebar-item.active { background: var(--accent-glow); color: var(--accent); }

.sidebar-tag {
  display: inline-block;
  padding: 3px 10px;
  margin: 2px 4px 2px 0;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background: var(--tag-bg);
  border: 1px solid var(--tag-border);
  color: var(--accent);
  transition: all 0.15s;
}
.sidebar-tag:hover { background: var(--accent); color: var(--bg-primary); }
.sidebar-tag .count {
  color: var(--text-muted);
  margin-left: 4px;
  font-size: 0.65rem;
}

/* === MAIN CONTENT === */
.main-content {
  margin-left: var(--sidebar-width);
  margin-top: var(--header-height);
  padding: 40px 48px;
  max-width: 900px;
}

/* === HOME PAGE === */
.featured-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.featured-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 32px;
  transition: all 0.2s;
  cursor: pointer;
}
.article-card:hover {
  border-color: var(--accent-dim);
  box-shadow: 0 0 24px var(--accent-glow);
}
.card-title { color: inherit; }
.card-title:hover { color: inherit; }
.article-card h2 {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text-primary);
}
.article-card .meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}
.article-card .summary {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}
.article-card .tags { margin-top: 16px; }

/* === ARTICLE VIEW === */
.article-header { margin-bottom: 40px; }
.article-header h1 {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 12px;
}
.article-header .meta {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.article-body { font-size: 1rem; line-height: 1.8; }
.article-body h1, .article-body h2, .article-body h3,
.article-body h4, .article-body h5, .article-body h6 {
  font-family: var(--font-mono);
  font-weight: 600;
  margin-top: 2em;
  margin-bottom: 0.8em;
  color: var(--text-primary);
}
.article-body h2 { font-size: 1.5rem; border-bottom: 1px solid var(--border); padding-bottom: 8px; }
.article-body h3 { font-size: 1.2rem; }

.article-body p { margin-bottom: 1.2em; }
.article-body ul, .article-body ol { margin-bottom: 1.2em; padding-left: 24px; }
.article-body li { margin-bottom: 0.4em; }
.article-body blockquote {
  border-left: 3px solid var(--accent);
  padding: 12px 20px;
  margin: 1.5em 0;
  background: var(--bg-secondary);
  border-radius: 0 4px 4px 0;
  color: var(--text-secondary);
}
.article-body img {
  max-width: 100%;
  border-radius: 8px;
  border: 1px solid var(--border);
  margin: 1.5em 0;
}

/* Code blocks */
.article-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 3px;
  border: 1px solid var(--border);
}
.article-body pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 20px;
  overflow-x: auto;
  margin: 1.5em 0;
  position: relative;
}
.article-body pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.6;
}
.article-body pre .lang-label {
  position: absolute;
  top: 8px;
  right: 12px;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5em 0;
}
.article-body th, .article-body td {
  border: 1px solid var(--border);
  padding: 10px 14px;
  text-align: left;
  font-size: 0.9rem;
}
.article-body th {
  background: var(--bg-secondary);
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.8rem;
}
.article-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2em 0;
}

/* Inline tag in articles */
.tag {
  display: inline-block;
  padding: 3px 10px;
  margin: 2px 4px 2px 0;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background: var(--tag-bg);
  border: 1px solid var(--tag-border);
  color: var(--accent);
  transition: all 0.15s;
}
.tag:hover { background: var(--accent); color: var(--bg-primary); }

/* === TAG SPLASH PAGE === */
.tag-splash { margin-bottom: 40px; }
.tag-splash h1 {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 12px;
}
.tag-splash .description {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.7;
  margin-bottom: 16px;
  max-width: 640px;
}
.tag-splash .entry-point {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: var(--accent-glow);
  border: 1px solid var(--tag-border);
  border-radius: 6px;
  color: var(--accent);
}
.tag-splash .entry-point:hover { background: var(--accent); color: var(--bg-primary); }
.tag-splash .article-count {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 24px;
  margin-bottom: 16px;
}

/* Article list (tag page, search results) */
.article-list { list-style: none; }
.article-list-item {
  padding: 20px 24px;
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-bottom: 8px;
  transition: all 0.15s;
  cursor: pointer;
}
.article-list-item:hover {
  border-color: var(--border-hover);
  background: var(--bg-card);
}
.article-list-item h3 {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 4px;
}
.article-list-item .meta {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-bottom: 6px;
}
.article-list-item .summary {
  color: var(--text-secondary);
  font-size: 0.88rem;
}

/* === SEARCH OVERLAY === */
.search-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(4px);
  z-index: 200;
  justify-content: center;
  padding-top: 15vh;
}
.search-overlay.active { display: flex; }

.search-box {
  width: 600px;
  max-width: 90vw;
  max-height: 70vh;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: 0 0 60px rgba(0, 0, 0, 0.5);
}

.search-input-wrap {
  display: flex;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  gap: 12px;
}
.search-input-wrap svg { color: var(--text-muted); flex-shrink: 0; }
.search-input {
  flex: 1;
  background: none;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 1rem;
  outline: none;
}
.search-input::placeholder { color: var(--text-muted); }

.search-mode-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 20px 16px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  margin-bottom: 4px;
}
.search-mode-toggle label { cursor: pointer; display: flex; align-items: center; gap: 6px; line-height: 1; }
.search-mode-toggle input[type="checkbox"] { accent-color: var(--accent); margin: 0; width: 14px; height: 14px; }
.semantic-status {
  font-size: 0.65rem;
  padding: 2px 6px;
  border-radius: 3px;
  background: var(--bg-tertiary);
}
.semantic-status.loading { color: #e8a735; }
.semantic-status.ready { color: #3fb950; }

.search-results {
  overflow-y: auto;
  padding: 12px;
  flex: 1;
}
.search-result-item {
  display: block;
  padding: 12px 16px;
  border-radius: 6px;
  color: inherit;
  transition: background 0.1s;
}
.search-result-item:hover { background: var(--bg-tertiary); color: inherit; }
.search-result-item .title { font-family: var(--font-mono); font-weight: 600; font-size: 0.9rem; }
.search-result-item .snippet { font-size: 0.8rem; color: var(--text-secondary); margin-top: 4px; }
.search-result-item .snippet mark { background: var(--accent-glow); color: var(--accent); border-radius: 2px; padding: 0 2px; }

.search-empty {
  text-align: center;
  padding: 40px;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

/* === RESPONSIVE === */
@media (max-width: 768px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); box-shadow: 4px 0 24px rgba(0,0,0,0.5); }
  .sidebar-toggle { display: block; }
  .main-content { margin-left: 0; padding: 24px 16px; }
  .article-header h1 { font-size: 1.5rem; }
}

/* === SYNTAX HIGHLIGHTING (dark) === */
.highlight .hll { background-color: #1e1e30; }
.highlight .c, .highlight .cm, .highlight .c1, .highlight .cs { color: #6a737d; font-style: italic; }
.highlight .k, .highlight .kc, .highlight .kd, .highlight .kn,
.highlight .kp, .highlight .kr, .highlight .kt { color: #ff7b72; }
.highlight .s, .highlight .sa, .highlight .sb, .highlight .sc,
.highlight .dl, .highlight .sd, .highlight .s2, .highlight .se,
.highlight .sh, .highlight .si, .highlight .sx, .highlight .sr,
.highlight .s1, .highlight .ss { color: #a5d6ff; }
.highlight .n, .highlight .na, .highlight .nb, .highlight .nc,
.highlight .no, .highlight .nd, .highlight .ni, .highlight .ne,
.highlight .nf, .highlight .nl, .highlight .nn, .highlight .nt,
.highlight .nv { color: #d2a8ff; }
.highlight .m, .highlight .mb, .highlight .mf, .highlight .mh,
.highlight .mi, .highlight .mo { color: #79c0ff; }
.highlight .o, .highlight .ow { color: #ff7b72; }
.highlight .p { color: var(--text-primary); }