:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface2: #21262d;
  --surface3: #2d333b;
  --border: #30363d;
  --border2: #444c56;
  --accent: #7ee787;
  --accent2: #58a6ff;
  --accent3: #f78166;
  --warn: #d29922;
  --danger: #f85149;
  --text: #c9d1d9;
  --muted: #8b949e;
  --code-bg: #1c2128;
  --lua: #79c0ff;
  --cpp: #7ee787;
  --tag-done: #0d2210;
  --tag-wip: #271c00;
  --tag-plan: #1c1c1c;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 15px;
}
a { color: var(--accent2); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ─── Header ─────────────────────────────────────────── */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  height: 56px;
  gap: 2rem;
}
.site-header .logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent);
  white-space: nowrap;
  font-family: "Courier New", monospace;
  letter-spacing: -0.02em;
}
.site-header nav { display: flex; gap: 1.2rem; flex-wrap: wrap; }
.site-header nav a { color: var(--muted); font-size: 0.88rem; transition: color .15s; }
.site-header nav a:hover { color: var(--text); text-decoration: none; }
.site-header nav a.active { color: var(--accent); text-decoration: none; }

/* ─── Layout ──────────────────────────────────────────── */
.layout { display: flex; min-height: calc(100vh - 56px); }

.sidebar {
  width: 240px;
  flex-shrink: 0;
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 1.5rem 1rem;
  position: sticky;
  top: 56px;
  height: calc(100vh - 56px);
  overflow-y: auto;
}
.sidebar h3 {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--muted);
  margin: 1.2rem 0 0.4rem;
}
.sidebar h3:first-child { margin-top: 0; }
.sidebar ul { list-style: none; }
.sidebar ul li a {
  display: block;
  padding: 0.28rem 0.6rem;
  border-radius: 4px;
  color: var(--muted);
  font-size: 0.855rem;
  transition: background .1s, color .1s;
}
.sidebar ul li a:hover,
.sidebar ul li a.active {
  background: var(--surface2);
  color: var(--text);
  text-decoration: none;
}
.sidebar ul li a.active { color: var(--accent); }

.content {
  flex: 1;
  padding: 2rem 3rem 4rem;
  max-width: 980px;
  min-width: 0;
}

/* ─── Hero ────────────────────────────────────────────── */
.hero {
  background: linear-gradient(135deg, #0d1f0e 0%, #0d1117 55%, #0d1520 100%);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 2.5rem 2.2rem;
  margin-bottom: 2rem;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  top: -60px; right: -60px;
  width: 220px; height: 220px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(126,231,135,.06) 0%, transparent 70%);
  pointer-events: none;
}
.hero h1 {
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--accent);
  font-family: "Courier New", monospace;
  margin-bottom: 0.5rem;
  letter-spacing: -0.03em;
}
.hero .subtitle {
  font-size: 1.1rem;
  color: var(--text);
  max-width: 620px;
  margin-bottom: 0.5rem;
}
.hero .tagline {
  color: var(--muted);
  font-size: 0.92rem;
  max-width: 620px;
  margin-bottom: 1.2rem;
}

/* ─── Typography ──────────────────────────────────────── */
h1 { font-size: 1.8rem; font-weight: 700; margin-bottom: 0.6rem; }
h2 {
  font-size: 1.22rem;
  font-weight: 700;
  margin: 2.2rem 0 0.7rem;
  color: var(--text);
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.35rem;
}
h3 { font-size: 1rem; font-weight: 600; margin: 1.6rem 0 0.5rem; color: var(--accent2); }
h4 { font-size: 0.92rem; font-weight: 600; margin: 1.2rem 0 0.3rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.06em; }
p { margin-bottom: 0.85rem; }
p:last-child { margin-bottom: 0; }
ul, ol { margin-left: 1.5rem; margin-bottom: 0.9rem; }
li { margin-bottom: 0.25rem; }
strong { color: var(--text); }
em { color: var(--muted); font-style: italic; }
hr { border: none; border-top: 1px solid var(--border); margin: 2rem 0; }

/* ─── Code ────────────────────────────────────────────── */
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem 1.5rem;
  overflow-x: auto;
  font-family: "Courier New", Consolas, "SFMono-Regular", monospace;
  font-size: 0.84rem;
  line-height: 1.55;
  margin-bottom: 1.1rem;
  tab-size: 4;
}
pre .line-num {
  display: inline-block;
  width: 2em;
  color: #444c56;
  user-select: none;
  margin-right: 0.5rem;
}
code {
  font-family: "Courier New", Consolas, "SFMono-Regular", monospace;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0.1em 0.38em;
  font-size: 0.875em;
  color: #a5d6ff;
}
pre code { background: none; border: none; padding: 0; font-size: inherit; color: inherit; }

/* ─── Syntax Highlighting ─────────────────────────────── */
/* C++ */
.kw  { color: #ff7b72; }        /* keywords */
.ty  { color: #79c0ff; }        /* types */
.fn  { color: #d2a8ff; }        /* function names */
.st  { color: #a5d6ff; }        /* strings */
.nm  { color: #f2cc60; }        /* numbers / special names */
.cm  { color: #6e7681; font-style: italic; }  /* comments */
.val { color: #79c0ff; }        /* literals */
.pp  { color: #ffa657; }        /* preprocessor */
/* Lua */
.lua-kw  { color: #ff7b72; }
.lua-fn  { color: #d2a8ff; }
.lua-str { color: #a5d6ff; }
.lua-cm  { color: #6e7681; font-style: italic; }
.lua-num { color: #79c0ff; }
.lua-op  { color: #ff7b72; }
/* Shell */
.sh-cm   { color: #6e7681; font-style: italic; }
.sh-kw   { color: #ff7b72; }
.sh-str  { color: #a5d6ff; }
.sh-flag { color: #ffa657; }
.sh-var  { color: #79c0ff; }

/* ─── Tables ──────────────────────────────────────────── */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.25rem;
  font-size: 0.875rem;
}
th {
  background: var(--surface2);
  text-align: left;
  padding: 0.55rem 0.9rem;
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
}
td {
  padding: 0.5rem 0.9rem;
  border: 1px solid var(--border);
  vertical-align: top;
  line-height: 1.5;
}
tr:nth-child(even) td { background: rgba(255,255,255,.02); }
tr:hover td { background: rgba(255,255,255,.04); }
td code { font-size: 0.82rem; }

/* ─── Badges ──────────────────────────────────────────── */
.badge {
  display: inline-block;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.15rem 0.7rem;
  font-size: 0.76rem;
  color: var(--muted);
  margin: 0.15rem 0.15rem 0.15rem 0;
}
.badge-green { border-color: #3fb950; color: #3fb950; background: var(--tag-done); }
.badge-blue  { border-color: var(--accent2); color: var(--accent2); background: #0d1f35; }
.badge-lua   { border-color: var(--lua);    color: var(--lua);    background: #101928; }
.badge-orange{ border-color: #ffa657;       color: #ffa657;       background: #1c1200; }
.badge-red   { border-color: var(--accent3); color: var(--accent3); background: #1c0000; }

/* ─── Cards ───────────────────────────────────────────── */
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-bottom: 1.5rem; }
.grid3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1rem; margin-bottom: 1.5rem; }
.grid4 { display: grid; grid-template-columns: 1fr 1fr 1fr 1fr; gap: 0.8rem; margin-bottom: 1.5rem; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem 1.3rem;
  transition: border-color .2s;
}
.card:hover { border-color: var(--border2); }
.card h3 { margin-top: 0; color: var(--accent); font-size: 0.9rem; margin-bottom: 0.4rem; }
.card p { font-size: 0.855rem; color: var(--muted); margin: 0; line-height: 1.5; }
.card code { font-size: 0.8rem; }

.card-blue   { border-left: 3px solid var(--accent2); }
.card-green  { border-left: 3px solid var(--accent); }
.card-orange { border-left: 3px solid #ffa657; }

/* ─── Status icons ────────────────────────────────────── */
.status-done { color: #3fb950; font-weight: 600; }
.status-wip  { color: var(--warn); font-weight: 600; }
.status-plan { color: var(--muted); }

/* ─── Callouts ────────────────────────────────────────── */
.callout {
  border-left: 3px solid var(--border2);
  background: var(--surface);
  border-radius: 0 6px 6px 0;
  padding: 0.9rem 1.2rem;
  margin-bottom: 1.1rem;
}
.callout > *:last-child { margin-bottom: 0; }
.callout p  { font-size: 0.9rem; margin-bottom: 0.4rem; }
.callout h4 { font-size: 0.78rem; margin: 0 0 0.4rem; color: inherit; opacity: 0.7; }
.callout.ok   { border-color: var(--accent); background: #0d1f10; }
.callout.warn { border-color: var(--warn);   background: #1c1400; }
.callout.info { border-color: var(--accent2); background: #0d1520; }
.callout.lua  { border-color: var(--lua);    background: #0e1822; }
.callout.danger { border-color: var(--danger); background: #1c0a0a; }
.callout.ok   h4 { color: var(--accent); }
.callout.warn h4 { color: var(--warn); }
.callout.info h4 { color: var(--accent2); }
.callout.lua  h4 { color: var(--lua); }
.callout.danger h4 { color: var(--danger); }

/* ─── Architecture diagram ────────────────────────────── */
.arch-diagram {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.5rem 1.8rem;
  font-family: "Courier New", monospace;
  font-size: 0.82rem;
  line-height: 1.65;
  color: var(--text);
  margin-bottom: 1.5rem;
  overflow-x: auto;
  white-space: pre;
}
.arch-layer-api   { color: var(--accent); }
.arch-layer-engine{ color: var(--accent2); }
.arch-layer-gpu   { color: #ffa657; }

/* ─── Method reference blocks ─────────────────────────── */
.method-group {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 1.5rem;
  overflow: hidden;
}
.method-group-header {
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
  padding: 0.6rem 1.1rem;
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--muted);
  font-weight: 700;
}

/* ─── Parameter doc tables ────────────────────────────── */
.param-table { margin-bottom: 0.8rem; }
.param-table th { font-size: 0.72rem; background: var(--surface3); }
.param-table td:first-child code { color: var(--accent2); }
.param-table td:nth-child(2) { color: var(--lua); font-family: monospace; font-size: 0.82rem; }
.param-table td:nth-child(3) { color: var(--muted); font-size: 0.85rem; }

/* ─── Inline signature ────────────────────────────────── */
.sig {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.65rem 1rem;
  font-family: "Courier New", monospace;
  font-size: 0.85rem;
  margin-bottom: 0.6rem;
  overflow-x: auto;
  white-space: nowrap;
}

/* ─── Comparison table ────────────────────────────────── */
.compare-yes { color: #3fb950; text-align: center; }
.compare-no  { color: var(--muted); text-align: center; }
.compare-wip { color: var(--warn); text-align: center; }

/* ─── Steps / numbered guide ──────────────────────────── */
.step {
  display: flex;
  gap: 1.1rem;
  margin-bottom: 1.5rem;
  align-items: flex-start;
}
.step-num {
  flex-shrink: 0;
  width: 2rem; height: 2rem;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
}
.step-body { flex: 1; min-width: 0; }
.step-body h3 { margin-top: 0; color: var(--text); }
.step-body p { font-size: 0.9rem; }

/* ─── Key combo ───────────────────────────────────────── */
kbd {
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 4px;
  padding: 0.1em 0.4em;
  font-size: 0.8em;
  font-family: "Courier New", monospace;
}

/* ─── Section divider ─────────────────────────────────── */
.section-intro {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1rem 1.2rem;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
  color: var(--muted);
}
.section-intro strong { color: var(--text); }

/* ─── Two-column content ──────────────────────────────── */
.col2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin-bottom: 1.5rem; align-items: start; }

/* ─── Footer ──────────────────────────────────────────── */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 1.2rem 2rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--muted);
}
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--text); }

/* ─── Responsive ──────────────────────────────────────── */
@media (max-width: 900px) {
  .sidebar { display: none; }
  .content { padding: 1.5rem; }
  .grid2, .grid3, .grid4, .col2 { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .site-header nav { display: none; }
  .content { padding: 1rem; }
}