:root {
  color-scheme: dark;
  --bg: #0a0e16;
  --bg-2: #0f1520;
  --card: #121a27;
  --card-2: #172132;
  --line: #223047;
  --line-2: #2c3d58;
  --ink: #eef2f8;
  --ink-2: #b4bfd0;
  --muted: #7d8aa0;
  --green: #22c55e;
  --amber: #f5a524;
  --red: #ef4444;
  --q: #4b93ea;       /* Q-learning (lifted from #2a78d6 for the dark surface) */
  --mc: #f07a4a;      /* Monte Carlo */
  --opt: #22c08a;     /* optimal */
  --accent: #5b9dff;
  --radius: 16px;
  --shadow: 0 20px 60px rgba(0, 0, 0, .45);
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 15px/1.6 Inter, system-ui, -apple-system, Segoe UI, sans-serif;
  -webkit-font-smoothing: antialiased;
  background-image:
    radial-gradient(1100px 520px at 80% -8%, rgba(91, 157, 255, .12), transparent 62%);
  background-repeat: no-repeat;
}
a { color: var(--accent); text-decoration: none; }
code, pre, .mono { font-family: var(--mono); }
code { font-size: .88em; background: rgba(91, 157, 255, .1); color: #cfe0ff; padding: .1em .4em; border-radius: 6px; }
.muted { color: var(--muted); }
.small { font-size: 13px; }
h1, h2, h3, h4 { line-height: 1.15; margin: 0 0 .5em; letter-spacing: -.02em; }

/* ------------------------------------------------------------------ nav */
.nav {
  position: sticky; top: 0; z-index: 50; display: flex; align-items: center; gap: 28px;
  padding: 14px clamp(16px, 4vw, 48px); background: rgba(10, 14, 22, .72);
  backdrop-filter: blur(14px) saturate(140%); border-bottom: 1px solid rgba(34, 48, 71, .6);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 700; font-size: 17px; }
.brand b { color: var(--green); }
.nav nav { display: flex; gap: 22px; margin-left: auto; }
.nav nav a { color: var(--ink-2); font-size: 14px; font-weight: 500; }
.nav nav a:hover { color: var(--ink); }

/* ------------------------------------------------------------------ buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px; cursor: pointer;
  font: 600 14px Inter, system-ui, sans-serif; padding: 11px 18px; border-radius: 11px; border: 1px solid transparent;
  transition: transform .15s ease, background .15s ease, border-color .15s ease; color: var(--ink);
}
.btn:active { transform: translateY(1px); }
.btn.primary { background: linear-gradient(180deg, #2fd46b, #18a64c); color: #04130a; box-shadow: 0 8px 24px rgba(34, 197, 94, .25); }
.btn.primary:hover { background: linear-gradient(180deg, #45dd7b, #1db455); }
.btn.ghost { background: rgba(255, 255, 255, .03); border-color: var(--line-2); }
.btn.ghost:hover { background: rgba(255, 255, 255, .07); border-color: #3b5074; }
.btn.small { padding: 7px 12px; font-size: 13px; }
.btn.icon { width: 42px; height: 42px; padding: 0; }
.btn:disabled { opacity: .5; cursor: progress; }
.btn:focus-visible, button:focus-visible, select:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ------------------------------------------------------------------ hero */
.hero {
  display: grid; grid-template-columns: 1.55fr 1fr; gap: clamp(24px, 5vw, 64px); align-items: end;
  padding: clamp(40px, 8vw, 88px) clamp(16px, 4vw, 48px) 36px; max-width: 1360px; margin: 0 auto;
}
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px; font-size: 12.5px; font-weight: 600; letter-spacing: .08em;
  text-transform: uppercase; color: var(--green);
}
.eyebrow .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--green); box-shadow: 0 0 12px var(--green); }
.hero h1 { font-size: clamp(36px, 4.9vw, 62px); font-weight: 800; margin: 18px 0 18px; }
.hero h1 em { font-style: normal; background: linear-gradient(90deg, #22c55e, #5b9dff); -webkit-background-clip: text; background-clip: text; color: transparent; }
.lead { font-size: 17.5px; color: var(--ink-2); max-width: 640px; margin: 0 0 28px; }
.lead strong { color: var(--ink); font-weight: 600; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; }
.kpis { display: grid; gap: 12px; }
.kpi {
  background: linear-gradient(180deg, var(--card-2), var(--card)); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 16px 20px; display: grid; grid-template-columns: 1fr auto; align-items: center;
}
.kpi-label { color: var(--ink-2); font-size: 13.5px; }
.kpi-value { grid-row: span 2; font: 700 30px/1 Inter, system-ui, sans-serif; letter-spacing: -.03em; color: var(--ink); }
.kpi-sub { color: var(--muted); font-size: 12.5px; }

/* ------------------------------------------------------------------ simulator */
.sim-section { max-width: 1360px; margin: 0 auto; padding: 12px clamp(16px, 4vw, 48px) 40px; }
.sim-shell {
  display: grid; grid-template-columns: minmax(0, 1fr) 340px; border: 1px solid var(--line);
  border-radius: 22px; overflow: hidden; background: var(--card); box-shadow: var(--shadow);
}
.stage { position: relative; min-height: 620px; background: #0b1322; overflow: hidden; }
#scene { position: absolute; inset: 0; width: 100%; height: 100%; display: block; cursor: grab; touch-action: none; }
#scene:active { cursor: grabbing; }
.stage-loading {
  position: absolute; inset: 0; display: grid; place-content: center; justify-items: center; gap: 14px;
  color: var(--ink-2); background: #0b1322; z-index: 5; transition: opacity .5s ease;
}
.stage-loading.done { opacity: 0; pointer-events: none; }
.spinner { width: 34px; height: 34px; border-radius: 50%; border: 3px solid var(--line-2); border-top-color: var(--green); animation: spin 0.9s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.stage-hud { position: absolute; top: 16px; display: flex; gap: 8px; z-index: 3; pointer-events: none; }
.stage-hud.top-left { left: 16px; }
.stage-hud.top-right { right: 16px; }
.hud-chip, .phase {
  display: inline-flex; align-items: center; gap: 8px; padding: 8px 12px; border-radius: 10px; font-size: 13px; font-weight: 600;
  background: rgba(9, 14, 24, .72); border: 1px solid rgba(60, 80, 110, .55); backdrop-filter: blur(8px); color: var(--ink);
}
.hud-chip b { color: var(--green); font-weight: 600; }
.live-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--green); box-shadow: 0 0 0 0 rgba(34, 197, 94, .6); animation: pulse 1.6s infinite; }
.paused .live-dot { background: var(--amber); animation: none; }
@keyframes pulse { 70% { box-shadow: 0 0 0 8px rgba(34, 197, 94, 0); } 100% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0); } }
.phase .lamp { width: 10px; height: 10px; border-radius: 50%; background: var(--green); box-shadow: 0 0 10px var(--green); }
.phase.amber .lamp { background: var(--amber); box-shadow: 0 0 10px var(--amber); }
.queue-label {
  position: absolute; z-index: 3; transform: translate(-50%, -100%); pointer-events: none; text-align: center;
  background: rgba(9, 14, 24, .8); border: 1px solid rgba(60, 80, 110, .6); border-radius: 10px; padding: 5px 10px;
  backdrop-filter: blur(6px); white-space: nowrap; transition: border-color .2s;
}
.queue-label small { display: block; font-size: 10.5px; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
.queue-label b { font: 700 16px var(--mono); }
.queue-label.green { border-color: rgba(34, 197, 94, .8); }
.queue-label.full b { color: var(--amber); }
.toast-layer { position: absolute; inset: 0; pointer-events: none; z-index: 4; }
.float-tag {
  position: absolute; transform: translate(-50%, -50%); font: 600 12px Inter, system-ui, sans-serif; padding: 3px 8px; border-radius: 999px;
  background: rgba(239, 68, 68, .9); color: white; animation: floatUp 1.6s ease-out forwards; white-space: nowrap;
}
@keyframes floatUp { from { opacity: 0; margin-top: 0; } 15% { opacity: 1; } to { opacity: 0; margin-top: -46px; } }
.stage-hint { position: absolute; bottom: 12px; left: 16px; font-size: 12px; color: rgba(180, 191, 208, .7); z-index: 3; pointer-events: none; }

.panel { border-left: 1px solid var(--line); background: var(--bg-2); display: flex; flex-direction: column; }
.panel-block { padding: 18px 20px; border-bottom: 1px solid var(--line); }
.panel-block:last-child { border-bottom: 0; }
.panel-title { display: block; font-size: 12px; font-weight: 600; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); margin-bottom: 10px; }
.select-wrap { position: relative; }
.select-wrap::after { content: ""; position: absolute; right: 14px; top: 50%; width: 8px; height: 8px; border-right: 2px solid var(--ink-2); border-bottom: 2px solid var(--ink-2); transform: translateY(-70%) rotate(45deg); pointer-events: none; }
select {
  width: 100%; appearance: none; background: var(--card-2); color: var(--ink); border: 1px solid var(--line-2);
  border-radius: 11px; padding: 11px 36px 11px 14px; font: 600 14px Inter, system-ui, sans-serif;
}
.policy-desc { font-size: 13px; color: var(--ink-2); margin: 10px 0 0; min-height: 3.2em; }
.controls { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.speed { margin-left: auto; display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--muted); }
.seg { display: flex; background: var(--card-2); border: 1px solid var(--line-2); border-radius: 10px; padding: 3px; }
.seg button { background: none; border: 0; color: var(--ink-2); font: 600 12px Inter, system-ui, sans-serif; padding: 6px 8px; border-radius: 7px; cursor: pointer; }
.seg button.on { background: #24344f; color: var(--ink); }
.stats { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 10px 12px; }
.stat span { display: block; font-size: 12px; color: var(--muted); }
.stat b { font: 700 20px var(--mono); letter-spacing: -.02em; }
.spark { width: 100%; height: 70px; margin-top: 12px; display: block; }
.spark-legend { display: flex; justify-content: space-between; font-size: 11.5px; color: var(--muted); }
.qbars { display: grid; gap: 8px; }
.qrow { display: grid; grid-template-columns: 70px 1fr 64px; align-items: center; gap: 10px; font-size: 13px; color: var(--ink-2); }
.qrow code { background: none; padding: 0; text-align: right; color: var(--ink); }
.qtrack { height: 10px; background: var(--card-2); border-radius: 6px; overflow: hidden; }
.qtrack i { display: block; height: 100%; width: 0; border-radius: 6px; background: #3a4a66; transition: width .4s ease, background .3s; }
.qtrack i.best { background: var(--green); }

/* ------------------------------------------------------------------ cards / grids */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 18px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 16px; }
.cards-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.card h3 { font-size: 18px; }
.card p { margin: 0 0 14px; }
.card.mini h4, .card.algo h4 { font-size: 16px; margin-bottom: 6px; }
.card.mini p, .card.algo p { color: var(--ink-2); font-size: 14px; margin: 0; }
.card.mini .ico { font: 700 20px var(--mono); color: var(--green); margin-bottom: 10px; }
.swatch { display: inline-block; width: 28px; height: 5px; border-radius: 3px; background: var(--c); margin-bottom: 12px; }
.ask { display: flex; gap: 14px; align-items: flex-end; flex-wrap: wrap; }
.stepper label { display: block; font-size: 12.5px; color: var(--ink-2); margin-bottom: 6px; font-weight: 600; }
.stepper label small { color: var(--muted); font-weight: 400; }
.stepper > div { display: flex; align-items: center; background: var(--card-2); border: 1px solid var(--line-2); border-radius: 11px; }
.stepper button { width: 38px; height: 40px; background: none; border: 0; color: var(--ink); font-size: 18px; cursor: pointer; }
.stepper button:hover { background: rgba(255, 255, 255, .06); }
.stepper output { width: 30px; text-align: center; font: 700 16px var(--mono); }
.answer { margin-top: 16px; }
.answer-head { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; font-size: 13.5px; color: var(--ink-2); }
.badge { font-weight: 700; font-size: 13px; padding: 4px 10px; border-radius: 999px; background: rgba(34, 197, 94, .15); color: #6ee7a0; border: 1px solid rgba(34, 197, 94, .4); }
pre { margin: 0; background: #0b111c; border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; font-size: 12.5px; color: #c9d6ea; overflow-x: auto; }
pre.code { font-size: 13px; line-height: 1.7; }
pre .c { color: var(--muted); }
.bench { display: grid; gap: 9px; margin-top: 16px; }
.brow { display: grid; grid-template-columns: 170px 1fr 52px; align-items: center; gap: 10px; font-size: 13px; color: var(--ink-2); }
.brow .bar { height: 12px; border-radius: 0 4px 4px 0; background: #475569; width: 0; transition: width .6s cubic-bezier(.2, .8, .2, 1); }
.brow code { background: none; padding: 0; color: var(--ink); text-align: right; }

/* ------------------------------------------------------------------ sections */
.section { max-width: 1360px; margin: 0 auto; padding: 64px clamp(16px, 4vw, 48px) 8px; }
.section-head { max-width: 760px; margin-bottom: 26px; }
.section-head h2 { font-size: clamp(28px, 3.4vw, 40px); font-weight: 800; margin-top: 10px; }
h3.sub { font-size: 20px; margin: 36px 0 14px; }
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--card); }
table.results { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 620px; }
table.results th .g { text-transform: none; }
table.results th { text-align: left; font-size: 12px; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); font-weight: 600; padding: 12px 16px; border-bottom: 1px solid var(--line); }
table.results td { padding: 11px 16px; border-bottom: 1px solid rgba(34, 48, 71, .6); color: var(--ink-2); }
table.results tr:last-child td { border-bottom: 0; }
table.results td:first-child { color: var(--ink); font-weight: 500; }
table.results .num { text-align: right; font-family: var(--mono); font-size: 13px; }
table.results .key { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 9px; background: #475569; vertical-align: -1px; }
.figs { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 18px; }
figure { margin: 0; background: #fcfcfb; border-radius: var(--radius); padding: 10px; border: 1px solid var(--line); }
figure.wide { grid-column: 1 / -1; }
figure img { width: 100%; display: block; border-radius: 8px; }
figcaption { color: #52514e; font-size: 12.5px; padding: 8px 6px 2px; }
.callout { margin-top: 18px; border: 1px solid rgba(245, 165, 36, .35); background: linear-gradient(180deg, rgba(245, 165, 36, .08), rgba(245, 165, 36, .03)); border-radius: var(--radius); padding: 20px 22px; }
.callout h4 { color: #fcd38a; font-size: 16px; }
.callout p { margin: 0; color: var(--ink-2); }
table.plain { width: 100%; border-collapse: collapse; font-size: 13.5px; margin-bottom: 10px; }
table.plain td { padding: 9px 4px; border-bottom: 1px solid var(--line); color: var(--ink-2); vertical-align: top; }
table.plain td:first-child { white-space: nowrap; padding-right: 14px; }
.team { display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; }
.person { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; font-weight: 600; font-size: 14px; display: grid; gap: 12px; }
.person span { width: 42px; height: 42px; border-radius: 12px; display: grid; place-items: center; font-size: 14px; background: linear-gradient(135deg, #1d3a2a, #1d2f4f); color: #9fe8bc; border: 1px solid var(--line-2); }
.footer { max-width: 1360px; margin: 64px auto 0; padding: 26px clamp(16px, 4vw, 48px) 40px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; color: var(--muted); font-size: 13px; }

/* ------------------------------------------------------------------ responsive */
@media (max-width: 1080px) {
  .sim-shell { grid-template-columns: 1fr; }
  .panel { border-left: 0; border-top: 1px solid var(--line); display: grid; grid-template-columns: 1fr 1fr; }
  .panel-block { border-right: 1px solid var(--line); }
  .cards-4 { grid-template-columns: 1fr 1fr; }
  .team { grid-template-columns: repeat(3, 1fr); }
}
@media (max-width: 820px) {
  .hero { grid-template-columns: 1fr; }
  .nav nav { display: none; }
  .nav .btn { margin-left: auto; }
  .grid-2, .grid-3, .figs { grid-template-columns: 1fr; }
  .panel { grid-template-columns: 1fr; }
  .panel-block { border-right: 0; }
  .stage { min-height: 460px; }
  .team { grid-template-columns: 1fr 1fr; }
  .brow { grid-template-columns: 130px 1fr 48px; }
}
@media (max-width: 520px) {
  .cards-4, .team { grid-template-columns: 1fr; }
  .stage-hud.top-right { top: auto; bottom: 12px; }
  .stage-hint { display: none; }
  .hud-chip, .phase { font-size: 12px; padding: 6px 10px; }
  .stage { min-height: 400px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .live-dot, .spinner { animation: none; }
}