/* Dreamcast audio & Manatee sound driver explainer - shared styles.
   Component colours are a validated categorical set (dataviz palette, light + dark):
   SH-4 blue, ARM/driver orange, AICA aqua, DSP violet, memory yellow. */

:root {
  color-scheme: dark;
  --bg: #121212;
  --surface-1: #1a1a19;
  --surface-2: #222220;
  --surface-3: #2c2c29;
  --border: #383835;
  --text-primary: #f4f3ee;
  --text-secondary: #c3c2b7;
  --text-muted: #8f8e86;
  --link: #6da7ec;
  --c-host: #3987e5;
  --c-arm: #d95926;
  --c-aica: #199e70;
  --c-dsp: #9085e9;
  --c-mem: #c98500;
  --c-host-soft: rgba(57, 135, 229, .16);
  --c-arm-soft: rgba(217, 89, 38, .16);
  --c-aica-soft: rgba(25, 158, 112, .16);
  --c-dsp-soft: rgba(144, 133, 233, .16);
  --c-mem-soft: rgba(201, 133, 0, .16);
  --critical: #d03b3b;
  --good: #0ca30c;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.25);
  --radius: 10px;
  --font: "Inter", ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sidebar: 272px;
  --toc: 220px;
}
:root[data-theme="light"] {
  color-scheme: light;
  --bg: #f4f3ef;
  --surface-1: #fcfcfb;
  --surface-2: #f3f2ee;
  --surface-3: #e8e7e2;
  --border: #d9d8d2;
  --text-primary: #0b0b0b;
  --text-secondary: #52514e;
  --text-muted: #77766f;
  --link: #1c5cab;
  --c-host: #2a78d6;
  --c-arm: #eb6834;
  --c-aica: #1baf7a;
  --c-dsp: #4a3aa7;
  --c-mem: #eda100;
  --c-host-soft: rgba(42, 120, 214, .10);
  --c-arm-soft: rgba(235, 104, 52, .11);
  --c-aica-soft: rgba(27, 175, 122, .11);
  --c-dsp-soft: rgba(74, 58, 167, .09);
  --c-mem-soft: rgba(237, 161, 0, .13);
  --shadow: 0 1px 2px rgba(0,0,0,.06), 0 6px 20px rgba(0,0,0,.06);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
body {
  margin: 0; background: var(--bg); color: var(--text-primary);
  font: 16px/1.65 var(--font); -webkit-font-smoothing: antialiased;
}
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
code, .mono { font-family: var(--mono); font-size: .88em; }
code { background: var(--surface-3); padding: .1em .35em; border-radius: 4px; }

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 20; height: 60px;
  display: flex; align-items: center; gap: 16px; padding: 0 20px;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px); border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 650; color: var(--text-primary); }
.brand:hover { text-decoration: none; }
.brand .logo { width: 30px; height: 30px; }
.brand small { font-weight: 450; color: var(--text-muted); }
.topbar .spacer { flex: 1; }
.icon-btn {
  border: 1px solid var(--border); background: var(--surface-1); color: var(--text-secondary);
  height: 34px; min-width: 34px; border-radius: 8px; cursor: pointer; font: inherit; font-size: 14px;
  display: inline-flex; align-items: center; justify-content: center; gap: 6px; padding: 0 10px;
}
.icon-btn:hover { color: var(--text-primary); border-color: var(--text-muted); }
#nav-toggle { display: none; }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: var(--sidebar) minmax(0, 1fr) var(--toc); }
.sidebar {
  position: sticky; top: 60px; height: calc(100vh - 60px); overflow-y: auto;
  padding: 22px 14px 40px 20px; border-right: 1px solid var(--border);
}
.sidebar h4 {
  margin: 18px 10px 6px; font-size: 11px; letter-spacing: .08em; text-transform: uppercase;
  color: var(--text-muted);
}
.sidebar a {
  display: flex; align-items: center; gap: 10px; padding: 7px 10px; border-radius: 8px;
  color: var(--text-secondary); font-size: 14.5px; line-height: 1.35;
}
.sidebar a:hover { background: var(--surface-2); color: var(--text-primary); text-decoration: none; }
.sidebar a.active { background: var(--surface-3); color: var(--text-primary); font-weight: 600; }
.sidebar .dot { width: 8px; height: 8px; border-radius: 50%; flex: none; background: var(--text-muted); }
.sidebar .num { color: var(--text-muted); font-variant-numeric: tabular-nums; width: 1.4em; font-size: 12.5px; }

main { padding: 36px 48px 80px; min-width: 0; }
.content { max-width: 860px; margin: 0 auto; }

.toc { position: sticky; top: 60px; height: calc(100vh - 60px); overflow-y: auto; padding: 30px 16px; }
.toc h5 { margin: 0 0 8px; font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--text-muted); }
.toc a { display: block; padding: 4px 10px; font-size: 13px; color: var(--text-muted); border-left: 2px solid var(--border); }
.toc a.h3 { padding-left: 22px; }
.toc a.active { color: var(--text-primary); border-left-color: var(--c-aica); }
.toc a:hover { color: var(--text-primary); text-decoration: none; }

/* ---------- typography ---------- */
.eyebrow { font-size: 12.5px; letter-spacing: .1em; text-transform: uppercase; color: var(--text-muted); font-weight: 600; }
h1 { font-size: 40px; line-height: 1.15; margin: 8px 0 14px; letter-spacing: -.02em; }
h2 { font-size: 26px; margin: 56px 0 14px; letter-spacing: -.01em; padding-top: 8px; border-top: 1px solid var(--border); }
h2:first-of-type { border-top: 0; }
h3 { font-size: 19px; margin: 34px 0 8px; }
p, li { color: var(--text-secondary); }
strong { color: var(--text-primary); font-weight: 620; }
.lead { font-size: 19px; color: var(--text-secondary); max-width: 720px; }
ul, ol { padding-left: 1.3em; }
li { margin: .3em 0; }
hr { border: 0; border-top: 1px solid var(--border); margin: 40px 0; }

/* ---------- components ---------- */
.card {
  background: var(--surface-1); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px; box-shadow: var(--shadow);
}
.grid { display: grid; gap: 14px; }
.grid.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid.four { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.tile { padding: 16px 18px; }
.tile .val { font-size: 30px; font-weight: 700; letter-spacing: -.02em; color: var(--text-primary); line-height: 1.1; }
.tile .lbl { font-size: 13.5px; color: var(--text-muted); margin-top: 4px; }

.pagecard { display: block; color: inherit; transition: transform .12s ease, border-color .12s ease; }
.pagecard:hover { transform: translateY(-2px); border-color: var(--text-muted); text-decoration: none; }
.pagecard h4 { margin: 6px 0 4px; font-size: 16.5px; color: var(--text-primary); }
.pagecard p { margin: 0; font-size: 14.5px; }
.pagecard .tag { font-size: 12px; color: var(--text-muted); }

.callout {
  border: 1px solid var(--border); border-left: 4px solid var(--c-aica); border-radius: 8px;
  background: var(--surface-1); padding: 12px 16px; margin: 20px 0;
}
.callout p { margin: .4em 0; }
.callout .title { font-weight: 650; color: var(--text-primary); display: flex; gap: 8px; align-items: center; }
.callout.driver { border-left-color: var(--c-arm); }
.callout.hw { border-left-color: var(--c-aica); }
.callout.host { border-left-color: var(--c-host); }
.callout.dsp { border-left-color: var(--c-dsp); }
.callout.warn { border-left-color: var(--critical); }
.callout.note { border-left-color: var(--text-muted); }

.chip {
  display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; font-weight: 600;
  padding: 2px 9px; border-radius: 999px; border: 1px solid var(--border); background: var(--surface-2);
  color: var(--text-secondary); white-space: nowrap;
}
.chip i { width: 8px; height: 8px; border-radius: 50%; display: inline-block; }
.chip.host i { background: var(--c-host); } .chip.arm i { background: var(--c-arm); }
.chip.aica i { background: var(--c-aica); } .chip.dsp i { background: var(--c-dsp); }
.chip.mem i { background: var(--c-mem); }
.legend { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0 0; }

figure { margin: 26px 0; }
figure .frame {
  background: var(--surface-1); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px; box-shadow: var(--shadow); overflow-x: auto;
}
figure svg { display: block; width: 100%; height: auto; }
figcaption { font-size: 13.5px; color: var(--text-muted); margin-top: 8px; padding: 0 4px; }
figcaption b { color: var(--text-secondary); }

table { width: 100%; border-collapse: collapse; margin: 18px 0; font-size: 14.5px; }
th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--border); vertical-align: top; }
th { font-size: 12px; letter-spacing: .06em; text-transform: uppercase; color: var(--text-muted); font-weight: 650; }
td { color: var(--text-secondary); }
td:first-child { color: var(--text-primary); }
.tablewrap { background: var(--surface-1); border: 1px solid var(--border); border-radius: var(--radius); padding: 4px 8px; overflow-x: auto; }
.tablewrap table { margin: 0; }
.tablewrap tr:last-child td { border-bottom: 0; }

.steps { counter-reset: step; list-style: none; padding: 0; }
.steps > li { counter-increment: step; position: relative; padding: 2px 0 12px 44px; margin: 0; }
.steps > li::before {
  content: counter(step); position: absolute; left: 0; top: 0; width: 28px; height: 28px; border-radius: 50%;
  display: grid; place-items: center; font-size: 13px; font-weight: 700;
  background: var(--surface-3); color: var(--text-primary); border: 1px solid var(--border);
}
.steps > li::after { content: ""; position: absolute; left: 13.5px; top: 30px; bottom: 0; width: 1px; background: var(--border); }
.steps > li:last-child::after { display: none; }
.steps > li > strong:first-child { display: block; }

details { background: var(--surface-1); border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; margin: 12px 0; }
details summary { cursor: pointer; font-weight: 600; color: var(--text-primary); }

.pager { display: flex; justify-content: space-between; gap: 12px; margin-top: 64px; }
.pager a {
  flex: 1; border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 18px;
  background: var(--surface-1); color: var(--text-primary);
}
.pager a:hover { border-color: var(--text-muted); text-decoration: none; }
.pager a span { display: block; font-size: 12px; color: var(--text-muted); text-transform: uppercase; letter-spacing: .08em; }
.pager a.next { text-align: right; }

.footer { margin-top: 40px; font-size: 13px; color: var(--text-muted); }

.hero {
  border-radius: 16px; padding: 34px 34px 28px; margin-bottom: 28px;
  background:
    radial-gradient(900px 300px at 0% 0%, var(--c-host-soft), transparent 60%),
    radial-gradient(700px 300px at 100% 0%, var(--c-arm-soft), transparent 60%),
    radial-gradient(700px 320px at 60% 120%, var(--c-dsp-soft), transparent 60%),
    var(--surface-1);
  border: 1px solid var(--border);
}

/* ---------- SVG diagram classes (theme-aware) ---------- */
svg text { font-family: var(--font); fill: var(--text-primary); }
svg .t-muted { fill: var(--text-muted); }
svg .t-sec { fill: var(--text-secondary); }
svg .t-mono { font-family: var(--mono); }
svg .box { fill: var(--surface-2); stroke: var(--border); stroke-width: 1.2; }
svg .box-soft { fill: var(--surface-3); stroke: var(--border); stroke-width: 1; }
svg .host { fill: var(--c-host-soft); stroke: var(--c-host); stroke-width: 1.6; }
svg .arm { fill: var(--c-arm-soft); stroke: var(--c-arm); stroke-width: 1.6; }
svg .aica { fill: var(--c-aica-soft); stroke: var(--c-aica); stroke-width: 1.6; }
svg .dsp { fill: var(--c-dsp-soft); stroke: var(--c-dsp); stroke-width: 1.6; }
svg .mem { fill: var(--c-mem-soft); stroke: var(--c-mem); stroke-width: 1.6; }
svg .f-host { fill: var(--c-host); } svg .f-arm { fill: var(--c-arm); } svg .f-aica { fill: var(--c-aica); }
svg .f-dsp { fill: var(--c-dsp); } svg .f-mem { fill: var(--c-mem); }
svg .s-host { stroke: var(--c-host); } svg .s-arm { stroke: var(--c-arm); } svg .s-aica { stroke: var(--c-aica); }
svg .s-dsp { stroke: var(--c-dsp); } svg .s-mem { stroke: var(--c-mem); }
svg .wire { stroke: var(--text-muted); stroke-width: 1.6; fill: none; }
svg .wire-thick { stroke: var(--text-muted); stroke-width: 3; fill: none; }
svg .dash { stroke-dasharray: 5 4; }
svg .grid-line { stroke: var(--border); stroke-width: 1; }
svg .plot { fill: none; stroke-width: 2.2; stroke-linejoin: round; stroke-linecap: round; }
svg .hit { fill: transparent; }
svg .hit:hover + .hl, svg g.hover:hover .hl { opacity: 1; }
svg .hl { opacity: 0; transition: opacity .12s; }
svg g.hover { cursor: default; }
svg g.hover:hover rect.box, svg g.hover:hover rect.box-soft { stroke: var(--text-secondary); }

/* tooltip for diagrams */
.tip {
  position: fixed; z-index: 50; pointer-events: none; max-width: 300px;
  background: var(--surface-1); color: var(--text-primary); border: 1px solid var(--border);
  box-shadow: var(--shadow); border-radius: 8px; padding: 8px 11px; font-size: 13px; line-height: 1.45;
  opacity: 0; transition: opacity .1s;
}
.tip.show { opacity: 1; }
.tip b { display: block; margin-bottom: 2px; }

/* ---------- responsive ---------- */
@media (max-width: 1280px) {
  .layout { grid-template-columns: var(--sidebar) minmax(0, 1fr); }
  .toc { display: none; }
}
@media (max-width: 900px) {
  #nav-toggle { display: inline-flex; }
  .layout { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed; left: 0; top: 60px; z-index: 30; width: 290px; background: var(--bg);
    transform: translateX(-100%); transition: transform .2s ease; box-shadow: var(--shadow);
  }
  body.nav-open .sidebar { transform: none; }
  main { padding: 26px 18px 60px; }
  h1 { font-size: 31px; }
  .grid.three, .grid.four { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid.two { grid-template-columns: 1fr; }
}
@media print {
  .topbar, .sidebar, .toc, .pager { display: none; }
  .layout { display: block; }
}