:root {
  --bg: #050509;
  --bg-elevated: #11121a;
  --border: #21222e;
  --text: #e7e8ec;
  --text-dim: #9a9ca8;
  --text-secondary: #cfd0d8;
  --accent: #c41e1e;
  --accent-soft: rgba(196, 30, 30, 0.12);
  --code-bg: #14141d;
  --inline-code-color: #ffb86c;
  --pre-code-color: #d6deeb;
  --header-bg: rgba(5, 5, 9, 0.85);
  --callout-warning-border: #5a3a1f;
  --callout-warning-bg: rgba(255, 159, 67, 0.08);
  --particle-rgb: 255, 255, 255;
  --max-content: 760px;
  --sidebar-w: 264px;
  --toc-w: 232px;
  --header-h: 64px;
}

html[data-theme="light"] {
  --bg: #ffffff;
  --bg-elevated: #f4f4f7;
  --border: #e3e3ea;
  --text: #15151f;
  --text-dim: #6b6d7a;
  --text-secondary: #3c3e4a;
  --accent: #a31515;
  --accent-soft: rgba(163, 21, 21, 0.08);
  --code-bg: #f1f1f5;
  --inline-code-color: #a3460f;
  --pre-code-color: #2b2d36;
  --header-bg: rgba(255, 255, 255, 0.85);
  --callout-warning-border: #e0a45c;
  --callout-warning-bg: rgba(224, 142, 51, 0.1);
  --particle-rgb: 20, 20, 30;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
}

#particles-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
}

.site-header, .shell, .site-footer { position: relative; z-index: 1; }

/* Scrollbar styling */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dim); }
* { scrollbar-width: thin; scrollbar-color: var(--border) transparent; }

body, .site-header, .sidebar, .card, .callout, pre, code, .toc, .site-footer, .page-nav a, th, td {
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Header */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
  z-index: 100;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-dim);
  cursor: pointer;
  padding: 0;
  transition: color 0.2s, border-color 0.2s;
}

.theme-toggle:hover { color: var(--text); border-color: var(--accent); }
.theme-toggle svg { width: 16px; height: 16px; }
.theme-toggle .icon-sun { display: none; }
html[data-theme="light"] .theme-toggle .icon-moon { display: none; }
html[data-theme="light"] .theme-toggle .icon-sun { display: block; }

.site-header .brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 16px;
  color: var(--text);
}

.site-header .brand .logo-dot {
  width: 20px; height: 20px;
  border-radius: 6px;
  background: linear-gradient(135deg, var(--accent), #ff5cb3);
  display: inline-block;
}

.site-header nav {
  display: flex;
  gap: 24px;
  font-size: 14px;
}

.site-header nav a { color: var(--text-dim); }
.site-header nav a.active, .site-header nav a:hover { color: var(--text); }

.site-header .header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.header-actions a.icon-link { color: var(--text-dim); }
.header-actions a.icon-link:hover { color: var(--text); }

/* Layout shell */
.shell {
  display: flex;
  max-width: 1400px;
  margin: 0 auto;
  padding-top: var(--header-h);
}

/* Sidebar */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  position: fixed;
  top: var(--header-h);
  bottom: 0;
  left: 0;
  overflow-y: auto;
  padding: 28px 18px 60px;
  border-right: 1px solid var(--border);
}

@media (max-width: 1000px) {
  .sidebar { display: none; }
  .shell { padding-left: 0; }
}

.sidebar .group { margin-bottom: 22px; }
.sidebar .group-title {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  margin: 0 0 8px 10px;
  font-weight: 600;
}

.sidebar a {
  display: block;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 14px;
  color: var(--text-dim);
}

.sidebar a:hover { background: var(--bg-elevated); color: var(--text); text-decoration: none; }
.sidebar a.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }

.sidebar .sub-list { margin-left: 8px; border-left: 1px solid var(--border); padding-left: 4px; }
.sidebar .sub-list a { font-size: 13px; }

/* Main content */
.content-wrap {
  flex: 1;
  display: flex;
  justify-content: center;
  margin-left: var(--sidebar-w);
  min-width: 0;
}

@media (max-width: 1000px) {
  .content-wrap { margin-left: 0; }
}

main.content {
  width: 100%;
  max-width: var(--max-content);
  padding: 40px 32px 100px;
  min-width: 0;
}

main.content h1 {
  font-size: 32px;
  margin: 0 0 6px;
}

main.content .lede {
  color: var(--text-dim);
  font-size: 17px;
  margin-bottom: 32px;
}

main.content h2 {
  font-size: 22px;
  margin: 40px 0 12px;
  padding-top: 8px;
  border-top: 1px solid var(--border);
}

main.content h2:first-of-type { border-top: none; }

main.content h3 {
  font-size: 17px;
  margin: 28px 0 10px;
  color: var(--text);
}

main.content p { color: var(--text-secondary); }

main.content ul, main.content ol {
  color: var(--text-secondary);
  padding-left: 22px;
}

main.content li { margin-bottom: 6px; }

main.content code {
  background: var(--code-bg);
  border: 1px solid var(--border);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 13px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  color: var(--inline-code-color);
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 34px 18px 16px;
  overflow-x: auto;
  margin: 16px 0 24px;
  position: relative;
}

main.content pre code, pre code {
  display: block;
  background: none !important;
  border: none !important;
  padding: 0 !important;
  border-radius: 0 !important;
  color: var(--pre-code-color) !important;
  font-size: 13px;
  line-height: 1.6;
  text-decoration: none !important;
  box-shadow: none !important;
  background-image: none !important;
}

pre code *, pre span {
  text-decoration: none !important;
  border-bottom: none !important;
  box-shadow: none !important;
  background-image: none !important;
}

.code-lang {
  position: absolute;
  top: 8px;
  left: 12px;
  font-size: 11px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.copy-btn {
  position: absolute;
  top: 6px;
  right: 8px;
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 3px 8px;
  font-size: 11px;
  font-family: inherit;
  color: var(--text-dim);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 5px;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  user-select: none;
}
.copy-btn:hover {
  color: var(--text);
  background: var(--border);
}
.copy-btn.copied {
  color: #4ade80;
  border-color: #4ade80;
}
.copy-btn svg {
  width: 13px;
  height: 13px;
  flex-shrink: 0;
}

blockquote {
  border-left: 3px solid var(--accent);
  margin: 20px 0;
  padding: 4px 16px;
  color: var(--text-dim);
  background: var(--accent-soft);
  border-radius: 0 8px 8px 0;
}

.callout {
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  border-radius: 10px;
  padding: 14px 18px;
  margin: 20px 0;
  font-size: 14px;
}

.callout.warning { border-color: var(--callout-warning-border); background: var(--callout-warning-bg); }
.callout-title { font-weight: 700; margin-bottom: 4px; display: block; }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0 24px;
  font-size: 14px;
}

th, td {
  border: 1px solid var(--border);
  padding: 8px 12px;
  text-align: left;
}

th { background: var(--bg-elevated); color: var(--text-dim); }

.page-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  gap: 12px;
}

.page-nav a {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 16px;
  flex: 1;
  color: var(--text);
}

.page-nav a:hover { border-color: var(--accent); text-decoration: none; }
.page-nav .dir { display: block; font-size: 12px; color: var(--text-dim); margin-bottom: 4px; }
.page-nav .next { text-align: right; }

/* TOC */
.toc {
  width: var(--toc-w);
  flex-shrink: 0;
  position: sticky;
  top: calc(var(--header-h) + 32px);
  align-self: flex-start;
  padding: 40px 16px 0 0;
  height: fit-content;
}

@media (max-width: 1280px) {
  .toc { display: none; }
}

.toc .toc-title {
  font-size: 12px;
  text-transform: uppercase;
  color: var(--text-dim);
  letter-spacing: 0.06em;
  margin-bottom: 10px;
}

.toc a {
  display: block;
  font-size: 13px;
  color: var(--text-dim);
  padding: 4px 0;
}

.toc a:hover { color: var(--text); text-decoration: none; }
.toc a.sub { padding-left: 12px; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  margin-left: var(--sidebar-w);
  padding: 32px 32px 60px;
  color: var(--text-dim);
  font-size: 13px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

@media (max-width: 1000px) {
  .site-footer { margin-left: 0; }
}

.site-footer .footer-links { display: flex; gap: 18px; }
.site-footer a { color: var(--text-dim); }
.site-footer a:hover { color: var(--text); }

.cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 20px 0 30px;
}

@media (max-width: 600px) {
  .cards { grid-template-columns: 1fr; }
}

.card {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 18px;
  background: var(--bg-elevated);
  display: block;
  color: var(--text);
}

.card:hover { border-color: var(--accent); text-decoration: none; }
.card .card-title { font-weight: 700; margin-bottom: 4px; }
.card .card-desc { font-size: 13px; color: var(--text-dim); }