:root {
  color-scheme: light dark;
  --bg: #EEF1F4;
  --panel: #FBFCFD;
  --panel-2: #F1F4F7;
  --ink: #161B22;
  --muted: #5A6675;
  --line: #D6DCE3;
  --line-2: #C2CAD4;
  --accent: #0A7A87;
  --accent-ink: #0A6B75;
  --accent-soft: #0E8C9915;
  --on-accent: #fff;
  /* category colors, semantic, shared across themes */
  --cat-script: #E4A93A;
  --cat-script-ink: #7A5410;
  --cat-render: #9377D6;
  --cat-render-ink: #574089;
  --cat-paint: #46A877;
  --cat-paint-ink: #276048;
  --cat-load: #5B8DEF;
  --cat-load-ink: #2E579E;
  --cat-system: #97A1B0;
  --cat-system-ink: #55606F;
  /* theme-aware text-safe variants (AA on this theme's background) */
  --cat-script-text: #7A5410;
  --cat-render-text: #574089;
  --cat-paint-text: #276048;
  --danger-text: #B23A28;
  --net-ttfb: #C9D6EA;
  --net-download: #5B8DEF;
  --danger: #D6533F;
  --shadow: 0 1px 2px rgba(20,27,34,.06), 0 10px 30px -14px rgba(20,27,34,.25);
  --mono: ui-monospace, "SF Mono", "SFMono-Regular", Menlo, "Cascadia Code", Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0C1016;
    --panel: #141A22;
    --panel-2: #1B222C;
    --ink: #E6EBF1;
    --muted: #93A0AF;
    --line: #253040;
    --line-2: #33404F;
    --accent: #2EC2CF;
    --accent-ink: #57D2DD;
    --accent-soft: #2EC2CF1E;
    --on-accent: #06232A;
    --cat-script: #E9B356;
    --cat-render: #A488E4;
    --cat-paint: #5DBC8B;
    --cat-load: #6E9BF5;
    --cat-system: #8592A2;
    --cat-script-text: #E9B356;
    --cat-render-text: #A488E4;
    --cat-paint-text: #5DBC8B;
    --danger-text: #F0897A;
    --net-ttfb: #2C3A4E;
    --net-download: #6E9BF5;
    --danger: #E56A57;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 14px 40px -16px rgba(0,0,0,.7);
  }
}
:root[data-theme="light"]{ color-scheme: light;
  --bg:#EEF1F4;--panel:#FBFCFD;--panel-2:#F1F4F7;--ink:#161B22;--muted:#5A6675;--line:#D6DCE3;--line-2:#C2CAD4;
  --accent:#0A7A87;--accent-ink:#0A6B75;--accent-soft:#0E8C9915;--on-accent:#fff;
  --cat-script:#E4A93A;--cat-render:#9377D6;--cat-paint:#46A877;--cat-load:#5B8DEF;--cat-system:#97A1B0;
  --cat-script-text:#7A5410;--cat-render-text:#574089;--cat-paint-text:#276048;--danger-text:#B23A28;
  --net-ttfb:#C9D6EA;--net-download:#5B8DEF;--danger:#D6533F;
  --shadow:0 1px 2px rgba(20,27,34,.06),0 10px 30px -14px rgba(20,27,34,.25);
}
:root[data-theme="dark"]{ color-scheme: dark;
  --bg:#0C1016;--panel:#141A22;--panel-2:#1B222C;--ink:#E6EBF1;--muted:#93A0AF;--line:#253040;--line-2:#33404F;
  --accent:#2EC2CF;--accent-ink:#57D2DD;--accent-soft:#2EC2CF1E;--on-accent:#06232A;
  --cat-script:#E9B356;--cat-render:#A488E4;--cat-paint:#5DBC8B;--cat-load:#6E9BF5;--cat-system:#8592A2;
  --cat-script-text:#E9B356;--cat-render-text:#A488E4;--cat-paint-text:#5DBC8B;--danger-text:#F0897A;
  --net-ttfb:#2C3A4E;--net-download:#6E9BF5;--danger:#E56A57;
  --shadow:0 1px 2px rgba(0,0,0,.4),0 14px 40px -16px rgba(0,0,0,.7);
}

* { box-sizing: border-box; }
body { margin:0; background:var(--bg); color:var(--ink); font-family:var(--sans); font-size:16px; line-height:1.6; -webkit-font-smoothing:antialiased; }
.wrap { max-width: 1000px; margin:0 auto; padding: clamp(24px,4vw,56px) clamp(16px,3.5vw,36px) 100px; }
.mono { font-family: var(--mono); }
h1,h2,h3 { text-wrap: balance; letter-spacing:-.02em; }
a { color: var(--accent-ink); }

/* header */
.eyebrow { font-family:var(--mono); font-size:12px; letter-spacing:.16em; text-transform:uppercase; color:var(--accent-ink); font-weight:600; }
h1 { font-size: clamp(30px, 5vw, 46px); line-height:1.05; margin:14px 0 0; font-weight:700; }
.lede { color:var(--muted); font-size:18px; max-width:64ch; margin:16px 0 0; }
.tools-note { margin-top:20px; font-size:13.5px; color:var(--muted); display:flex; gap:8px; align-items:center; flex-wrap:wrap; }
.tools-note .pill { font-family:var(--mono); font-size:12px; border:1px solid var(--line-2); border-radius:999px; padding:2px 9px; color:var(--ink); }

section { margin-top: clamp(40px,6vw,68px); scroll-margin-top:20px; }
.sec-num { font-family:var(--mono); font-size:12px; color:var(--accent-ink); letter-spacing:.1em; }
h2 { font-size: clamp(22px,3vw,28px); margin:6px 0 6px; font-weight:660; }
.sec-intro { color:var(--muted); max-width:66ch; margin:0 0 22px; }
p { margin: 12px 0; }
em.k { font-style:normal; font-weight:640; color:var(--ink); }
code { font-family:var(--mono); font-size:.9em; background:var(--panel-2); border:1px solid var(--line); border-radius:4px; padding:.06em .36em; }

.card { background:var(--panel); border:1px solid var(--line); border-radius:14px; box-shadow:var(--shadow); overflow:hidden; }
.card-pad { padding: clamp(18px,3vw,26px); }
figure { margin:0; }
figcaption { font-size:13.5px; color:var(--muted); padding:10px 4px 0; }

/* interactive controls */
.controls { display:flex; flex-wrap:wrap; gap:8px; margin:16px 0 4px; }
button.toggle, .seg button {
  font-family:var(--mono); font-size:12.5px; font-weight:600; letter-spacing:.02em;
  color:var(--ink); background:var(--panel-2); border:1px solid var(--line-2); border-radius:8px;
  padding:8px 13px; cursor:pointer; transition: background .15s, border-color .15s, color .15s;
}
button.toggle:hover, .seg button:hover { border-color:var(--accent); }
.seg { display:inline-flex; border:1px solid var(--line-2); border-radius:9px; overflow:hidden; }
.seg button { border:none; border-radius:0; border-right:1px solid var(--line-2); }
.seg button:last-child { border-right:none; }
.seg button[aria-pressed="true"], button.toggle[aria-pressed="true"] { background:var(--accent); color:var(--on-accent); border-color:var(--accent); }
:root[data-theme="dark"] .seg button[aria-pressed="true"], :root[data-theme="dark"] button.toggle[aria-pressed="true"], @media (prefers-color-scheme:dark){}
button:focus-visible, [tabindex]:focus-visible, .hit:focus-visible { outline:2px solid var(--accent); outline-offset:2px; border-radius:4px; }

/* readout panel */
.readout { margin-top:14px; background:var(--panel-2); border:1px solid var(--line); border-radius:10px; padding:14px 16px; min-height:76px; font-size:14.5px; }
.readout .tag { font-family:var(--mono); font-size:12px; letter-spacing:.06em; text-transform:uppercase; color:var(--accent-ink); font-weight:600; }
.readout h4 { margin:4px 0 4px; font-size:15px; }
.readout p { margin:2px 0; color:var(--muted); font-size:13.5px; }

/* svg figure host */
.svg-scroll { overflow-x:auto; }
svg { display:block; width:100%; height:auto; font-family:var(--mono); }
svg text { fill: var(--ink); }
svg .tlabel { fill: var(--muted); font-size:9px; }
.hit { cursor:pointer; }
.hit:hover { filter: brightness(1.08); }

/* legend chips */
.legend { display:grid; grid-template-columns:repeat(auto-fit,minmax(150px,1fr)); gap:10px; }
.chip { display:flex; gap:10px; align-items:flex-start; padding:12px 13px; border:1px solid var(--line); border-radius:10px; background:var(--panel); cursor:default; }
.chip .sw { width:16px; height:16px; border-radius:4px; flex:0 0 auto; margin-top:2px; }
.chip b { font-size:13.5px; }
.chip span { display:block; font-size:12.5px; color:var(--muted); }

ol.steps { counter-reset:s; list-style:none; padding:0; margin:0; }
ol.steps li { counter-increment:s; position:relative; padding:2px 0 16px 44px; border-left:1px solid var(--line); margin-left:14px; }
ol.steps li:last-child { border-left-color:transparent; padding-bottom:0; }
ol.steps li::before { content:counter(s); position:absolute; left:-14px; top:-2px; width:28px; height:28px; display:grid; place-items:center; background:var(--panel); color:var(--accent-ink); border:1px solid var(--line-2); border-radius:50%; font-family:var(--mono); font-size:12px; font-weight:600; }
ol.steps b { font-size:15px; }
ol.steps p { margin:3px 0 0; font-size:14px; color:var(--muted); }
ul.habits { list-style:none; padding:0; margin:0; display:grid; gap:9px; }
ul.habits li { font-size:14px; color:var(--muted); padding-left:14px; border-left:2px solid var(--line-2); }

table.sig { width:100%; border-collapse:collapse; font-size:13.5px; }
table.sig th, table.sig td { text-align:left; padding:9px 12px; border-bottom:1px solid var(--line); vertical-align:top; }
table.sig thead th { font-family:var(--mono); font-size:12px; letter-spacing:.06em; text-transform:uppercase; color:var(--muted); }
table.sig td.mono { font-family:var(--mono); font-size:12.5px; color:var(--cat-render-ink); }
:root[data-theme="dark"] table.sig td.mono { color: var(--cat-render); }
  table.sig tr.sig-h th { font-family:var(--mono); font-size:12px; letter-spacing:.06em; text-transform:uppercase; color:var(--accent-ink); background:var(--panel-2); padding-top:13px; }

/* quiz */

.foot { margin-top:70px; padding-top:20px; border-top:1px solid var(--line); font-size:13px; color:var(--muted); }
/* frames + CLS */
.cls-stage{ display:flex; gap:22px; flex-wrap:wrap; align-items:flex-start; margin-top:6px; }
.cls-vp{ width:280px; border:1px solid var(--line-2); border-radius:14px; overflow:hidden; background:var(--panel); box-shadow:var(--shadow); }
.cls-bar{ font-family:var(--mono); font-size:12px; padding:7px 12px; background:var(--panel-2); color:var(--muted); border-bottom:1px solid var(--line); display:flex; justify-content:space-between; }
.cls-slot{ height:0; overflow:hidden; transition:height .5s ease; }
.cls-slot.reserved{ height:90px; }
.cls-slot.placeholder{ border-bottom:1px dashed var(--line-2); background:repeating-linear-gradient(45deg,transparent,transparent 6px,var(--panel-2) 6px,var(--panel-2) 12px); }
.cls-slot .img{ height:90px; background:linear-gradient(135deg,var(--cat-load),var(--cat-render)); display:grid; place-items:center; color:#fff; font-family:var(--mono); font-size:12px; }
.cls-flow{ padding:16px 16px 20px; }
.cls-h{ font-weight:640; margin-bottom:12px; }
.cls-line{ height:9px; background:var(--line); border-radius:4px; margin:8px 0; }
.cls-line.short{ width:55%; }
.cls-cta{ margin-top:16px; background:var(--accent); color:var(--on-accent); border:none; border-radius:8px; padding:10px 18px; font-family:var(--mono); font-size:12.5px; cursor:default; }
.cls-side{ flex:1; min-width:240px; }

/* annotated real screenshots */
.realshot .realshot-eyebrow{ font-family:var(--mono); font-size:12px; letter-spacing:.14em; text-transform:uppercase; color:var(--accent-ink); font-weight:600; margin:0; }
.realshot .realshot-h{ font-size:19px; margin:6px 0 14px; font-weight:640; }
.shot{ position:relative; border:1px solid var(--line-2); border-radius:12px; overflow:hidden; background:var(--panel); box-shadow:var(--shadow); line-height:0; }
.shot picture{ display:block; }
  .shot img{ display:block; width:100%; height:auto; }
.shot svg.ov{ position:absolute; inset:0; width:100%; height:100%; overflow:visible; }
.ov .box{ fill:transparent; stroke:var(--accent); stroke-width:2.5; stroke-dasharray:6 5; opacity:.5; transition:opacity .15s, fill .15s, stroke-dasharray .15s; pointer-events:none; }
.ov g.cal.active .box{ opacity:1; fill:color-mix(in srgb, var(--accent) 18%, transparent); stroke-dasharray:none; }
.ov .badge{ fill:var(--panel); stroke:var(--accent); stroke-width:2; }
.ov g.cal.active .badge{ fill:var(--accent); }
.ov .badge-t{ fill:var(--accent-ink); font-family:var(--mono); font-size:16px; font-weight:700; }
.ov g.cal.active .badge-t{ fill:#fff; }
.shot-note{ font-size:12.5px; color:var(--muted); margin:8px 2px 0; font-style:italic; line-height:1.5; }
.legend-list{ list-style:none; padding:0; margin:14px 0 0; display:grid; gap:6px; }
.legend-list li{ display:flex; gap:12px; align-items:flex-start; padding:10px 13px; border:1px solid var(--line); border-radius:9px; background:var(--panel); cursor:pointer; transition:border-color .15s, background .15s; }
.legend-list li.active{ border-color:var(--accent); background:var(--accent-soft); }
.legend-list .lk{ font-family:var(--mono); font-weight:700; color:var(--accent-ink); flex:0 0 auto; width:18px; text-align:center; }
.legend-list p{ margin:0; font-size:13.5px; color:var(--muted); }
.legend-list li.active p{ color:var(--ink); }

/* INP */
.inp-stage{ display:flex; gap:22px; flex-wrap:wrap; align-items:center; margin-top:6px; }
.inp-btn{ font-family:var(--sans); font-size:15px; font-weight:600; color:var(--on-accent); background:var(--accent); border:none; border-radius:12px; padding:14px 24px; cursor:pointer; box-shadow:var(--shadow); }
.inp-btn:active{ transform:translateY(1px); }
.inp-live{ flex:1; min-width:250px; }
.mini-eyebrow{ font-family:var(--mono); font-size:12px; letter-spacing:.06em; text-transform:uppercase; color:var(--muted); margin:0 0 12px; }

  /* animations & compositing */
  .anim-stage{ display:flex; gap:26px; flex-wrap:wrap; align-items:flex-start; margin-top:6px; }
  .anim-demo{ flex:0 0 auto; width:150px; }
  .anim-box{ width:56px; height:56px; border-radius:14px; background:var(--accent); box-shadow:var(--shadow); }
  .anim-box.run-composited{ animation:animComposited 1.6s ease-in-out infinite alternate; }
  .anim-box.run-layout{ animation:animLayout 1.6s ease-in-out infinite alternate; }
  .anim-box.run-paint{ animation:animPaint 1.6s ease-in-out infinite alternate; }
  @keyframes animComposited{ to{ transform:translateX(66px) scale(1.15); opacity:.6; } }
  @keyframes animLayout{ to{ margin-left:60px; width:78px; } }
  @keyframes animPaint{ to{ background:var(--cat-render); box-shadow:0 12px 30px -6px var(--cat-render); } }
  .anim-track{ flex:1; min-width:290px; }

/* three views tables */
.view-host{ margin-top:10px; }
.tt{ width:100%; border-collapse:collapse; font-size:13.5px; min-width:520px; }
.tt th{ font-family:var(--mono); font-size:12px; letter-spacing:.06em; text-transform:uppercase; color:var(--muted); text-align:left; padding:7px 10px; border-bottom:1px solid var(--line-2); }
.tt th.num{ text-align:right; }
.tt td{ padding:5px 10px; border-bottom:1px solid var(--line); }
.tt td.num{ font-family:var(--mono); text-align:right; font-variant-numeric:tabular-nums; white-space:nowrap; width:58px; color:var(--ink); }
.tt td.fn{ white-space:nowrap; }
.tt .disc{ display:inline-block; width:14px; color:var(--muted); cursor:pointer; user-select:none; font-size:12px; }
.tt .disc-sp{ display:inline-block; width:14px; }
.tt .tw{ display:inline-block; width:11px; height:11px; border-radius:3px; vertical-align:middle; margin:0 6px 0 2px; }
.tt .name{ font-family:var(--mono); }
.tt .name.caller{ color:var(--muted); }
.tt .barcell{ width:34%; min-width:120px; }
.tt .bar{ display:block; height:11px; border-radius:3px; background:var(--accent); opacity:.55; }
.tt tbody tr:hover{ background:var(--panel-2); }

/* sticky table of contents */
.toc{ position:fixed; top:50%; transform:translateY(-50%); left:22px; display:none; flex-direction:column; gap:3px; z-index:60; }
@media (min-width:1340px){ .toc{ display:flex; } }
.toc-i{ display:flex; align-items:center; gap:10px; text-decoration:none; padding:2px 4px; border-radius:8px; }
.toc-i .n{ font-family:var(--mono); font-size:12px; width:24px; height:24px; border:1px solid var(--line-2); border-radius:50%; display:grid; place-items:center; color:var(--muted); background:var(--panel); transition:border-color .15s, color .15s, background .15s; flex:0 0 auto; }
.toc-i .t{ font-size:12.5px; color:var(--ink); max-width:0; overflow:hidden; white-space:nowrap; opacity:0; transition:max-width .2s, opacity .2s, padding .2s; background:var(--panel); border:1px solid var(--line); border-radius:7px; padding:4px 0; box-shadow:var(--shadow); }
.toc-i:hover .t, .toc-i.active .t{ max-width:280px; opacity:1; padding:4px 11px; }
.toc-i:hover .n, .toc-i.active .n{ border-color:var(--accent); color:var(--accent-ink); }
.toc-i.active .n{ background:var(--accent); color:var(--on-accent); border-color:var(--accent); }

/* theme toggle */
.theme-toggle{ position:fixed; top:16px; right:16px; z-index:100; width:40px; height:40px; border-radius:50%; border:1px solid var(--line-2); background:var(--panel); color:var(--ink); cursor:pointer; box-shadow:var(--shadow); display:grid; place-items:center; transition:border-color .15s, background .15s, color .15s; }
.theme-toggle:hover{ border-color:var(--accent); color:var(--accent-ink); }
.theme-toggle:focus-visible{ outline:2px solid var(--accent); outline-offset:2px; }
.theme-toggle svg{ width:19px; height:19px; }
.theme-toggle .sun{ display:none; }
.theme-toggle .moon{ display:block; }
:root[data-theme="dark"] .theme-toggle .sun{ display:block; }
:root[data-theme="dark"] .theme-toggle .moon{ display:none; }

@media (prefers-reduced-motion: reduce){ *{ transition:none !important; } .anim-box{ animation:none !important; } }