:root {
  color-scheme: dark;
  --bg: #0b0b0d;
  --surface: #141416;
  --surface-2: #1b1b1f;
  --ink: #f4f3ee;
  --ink-2: #c3c2b7;
  --muted: #8a8983;
  --grid: #25252a;
  --axis: #3a3a3f;
  --hair: rgba(255, 255, 255, 0.08);
  --rec: #3987e5;
  --img: #d95926;
  --ret: #199e70;
  --mid: #3a3a3d;
  --gold: #d9b26a;
  --serif: "Newsreader", "Iowan Old Style", Georgia, serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, Menlo, monospace;
  --prose: 680px;
  --wide: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: var(--ink); text-decoration-color: var(--muted); text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--ink); }
::selection { background: #3987e555; }

.rec { color: var(--rec); } .img { color: var(--img); } .ret { color: var(--ret); }
.sw { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 6px; vertical-align: 0; }
.sw.rec { background: var(--rec); } .sw.img { background: var(--img); } .sw.ret { background: var(--ret); }
b.rec, b.img, b.ret { font-weight: 600; }

/* ------------------------------------------------ nav */
.topbar {
  position: fixed; inset: 0 0 auto 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 24px; font-size: 13px; color: var(--ink-2);
  background: linear-gradient(var(--bg) 30%, transparent);
  pointer-events: none;
}
.topbar > * { pointer-events: auto; }
.topbar .brand { font-family: var(--serif); font-size: 17px; color: var(--ink); letter-spacing: .01em; }
.topbar nav { display: flex; gap: 18px; }
.topbar nav a { color: var(--muted); text-decoration: none; }
.topbar nav a:hover, .topbar nav a.on { color: var(--ink); }
.progress { position: fixed; top: 0; left: 0; height: 2px; background: var(--ink-2); z-index: 60; width: 0; }

/* ------------------------------------------------ hero */
.hero { position: relative; min-height: 100vh; display: grid; place-items: end start; padding: 0 24px 9vh; overflow: hidden; }
#heroCanvas { position: absolute; inset: 0; width: 100%; height: 100%; opacity: .9; }
.hero::after { content: ""; position: absolute; inset: 0; background: radial-gradient(ellipse at 20% 85%, var(--bg) 10%, transparent 60%), linear-gradient(transparent 55%, var(--bg)); pointer-events: none; }
.hero-inner { position: relative; z-index: 2; max-width: var(--wide); width: 100%; margin: 0 auto; }
.kicker { font: 500 12px/1 var(--sans); letter-spacing: .18em; text-transform: uppercase; color: var(--muted); }
.hero h1 { font: 400 clamp(56px, 11vw, 148px)/.92 var(--serif); letter-spacing: -.035em; margin: 18px 0 22px; }
.hero h1 em { font-style: italic; color: var(--ink-2); }
.hero .dek { font: 300 clamp(19px, 2.3vw, 26px)/1.4 var(--serif); color: var(--ink-2); max-width: 760px; margin: 0; }
.byline { margin-top: 28px; font-size: 13px; color: var(--muted); }
.byline b { color: var(--ink-2); font-weight: 500; }
.scrollcue { position: absolute; right: 24px; bottom: 9vh; z-index: 2; font-size: 12px; color: var(--muted); letter-spacing: .14em; text-transform: uppercase; writing-mode: vertical-rl; }

/* ------------------------------------------------ stats strip */
.strip { max-width: var(--wide); margin: 0 auto; padding: 36px 24px; display: grid; grid-template-columns: repeat(5, 1fr); gap: 1px; background: var(--hair); border-block: 1px solid var(--hair); }
.strip > div { background: var(--bg); padding: 18px 18px 14px; }
.strip .n { font: 300 clamp(28px, 3.6vw, 44px)/1 var(--serif); letter-spacing: -.02em; }
.strip .l { font-size: 12px; color: var(--muted); margin-top: 8px; line-height: 1.4; }

/* ------------------------------------------------ prose */
section { padding: 12vh 24px 4vh; }
.prose { max-width: var(--prose); margin: 0 auto; }
.prose p { margin: 0 0 1.15em; color: var(--ink-2); }
.prose p strong { color: var(--ink); font-weight: 500; }
.prose .lede::first-letter { font: 400 4.2em/.8 var(--serif); float: left; margin: .08em .08em 0 0; color: var(--ink); }
.chapter { font: 500 12px/1 var(--mono); color: var(--muted); letter-spacing: .1em; margin-bottom: 18px; display: flex; gap: 12px; align-items: center; }
.chapter::after { content: ""; flex: 1; height: 1px; background: var(--hair); }
h2 { font: 400 clamp(36px, 5.2vw, 60px)/1.02 var(--serif); letter-spacing: -.025em; margin: 0 0 28px; }
h2 em { color: var(--ink-2); }
h3 { font: 500 20px/1.3 var(--serif); margin: 2.2em 0 .6em; letter-spacing: -.005em; }
.pull { font: 300 italic clamp(24px, 3vw, 34px)/1.3 var(--serif); color: var(--ink); border-left: 2px solid var(--axis); padding-left: 22px; margin: 1.6em 0; }
.cite { font-size: 13px; color: var(--muted); }
sup a { text-decoration: none; color: var(--muted); font-size: 11px; }

/* ------------------------------------------------ figures */
figure { margin: 48px auto; max-width: var(--wide); }
figure.mid { max-width: 880px; }
.fig-head { display: flex; justify-content: space-between; align-items: flex-end; gap: 16px; flex-wrap: wrap; margin-bottom: 14px; }
.fig-title { font: 500 15px/1.35 var(--sans); color: var(--ink); max-width: 640px; }
.fig-sub { font-size: 13px; color: var(--muted); margin-top: 4px; max-width: 640px; line-height: 1.5; }
.card { background: var(--surface); border: 1px solid var(--hair); border-radius: 14px; padding: 22px 22px 14px; }
figcaption { font-size: 12.5px; color: var(--muted); margin-top: 12px; line-height: 1.55; max-width: 760px; }
figcaption b { color: var(--ink-2); font-weight: 500; }
.chart { width: 100%; position: relative; }
.chart svg { display: block; width: 100%; height: auto; overflow: visible; }
.legend { display: flex; gap: 16px; flex-wrap: wrap; font-size: 12.5px; color: var(--ink-2); }
.legend span { display: inline-flex; align-items: center; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.grid4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.panel-title { font-size: 13px; color: var(--ink-2); margin: 0 0 6px; font-weight: 500; }
.panel-note { font-size: 11.5px; color: var(--muted); margin-top: 2px; }

/* svg chrome */
.axis text, .tick text { fill: var(--muted); font: 11px var(--sans); }
.axis path, .axis line, .tick line { stroke: var(--axis); }
.gridline line { stroke: var(--grid); }
.gridline path { display: none; }
.lbl { fill: var(--ink-2); font: 12px var(--sans); }
.lbl-m { fill: var(--muted); font: 11px var(--sans); }
.lbl-b { fill: var(--ink); font: 500 12px var(--sans); }
.zero { stroke: var(--axis); }

/* controls */
.seg { display: inline-flex; background: var(--surface-2); border: 1px solid var(--hair); border-radius: 999px; padding: 3px; gap: 2px; flex-wrap: wrap; }
.seg button { all: unset; cursor: pointer; font-size: 12.5px; color: var(--muted); padding: 6px 12px; border-radius: 999px; transition: background .2s, color .2s; }
.seg button:hover { color: var(--ink); }
.seg button.on { background: #2c2c31; color: var(--ink); }
.seg button:focus-visible { outline: 2px solid var(--ink-2); outline-offset: 1px; }
select { background: var(--surface-2); color: var(--ink); border: 1px solid var(--hair); border-radius: 8px; padding: 6px 10px; font: 13px var(--sans); }

/* tooltip */
.tip { position: fixed; z-index: 100; pointer-events: none; background: #1f1f23ee; backdrop-filter: blur(8px); border: 1px solid var(--hair); border-radius: 10px; padding: 10px 12px; font-size: 12.5px; color: var(--ink-2); max-width: 300px; line-height: 1.45; opacity: 0; transition: opacity .12s; box-shadow: 0 10px 30px #0008; }
.tip b { color: var(--ink); font-weight: 500; }
.tip .row { display: flex; justify-content: space-between; gap: 14px; font-variant-numeric: tabular-nums; }

/* ------------------------------------------------ study design diagram */
.design { display: grid; grid-template-columns: 1fr 60px 1fr; gap: 0; align-items: center; }
.design .box { border: 1px solid var(--hair); border-radius: 12px; padding: 18px; background: var(--surface); }
.design .box h4 { margin: 0 0 6px; font: 500 15px var(--sans); }
.design .box p { margin: 0; font-size: 13.5px; color: var(--ink-2); line-height: 1.5; }
.design .box .big { font: 300 32px/1 var(--serif); margin: 6px 0 10px; }
.design .arrow { display: grid; place-items: center; color: var(--muted); font-size: 22px; }
.design .col { display: grid; gap: 14px; }

/* ------------------------------------------------ game */
.game { max-width: 880px; margin: 40px auto; }
.game .card { padding: 30px; }
.game-meta { display: flex; justify-content: space-between; font-size: 12.5px; color: var(--muted); margin-bottom: 18px; font-variant-numeric: tabular-nums; }
.game-text { font: 400 20px/1.6 var(--serif); color: var(--ink); min-height: 220px; }
.game-btns { display: flex; gap: 12px; margin-top: 24px; flex-wrap: wrap; }
.gbtn { all: unset; cursor: pointer; padding: 12px 22px; border-radius: 999px; border: 1px solid var(--axis); font-size: 14px; display: inline-flex; align-items: center; gap: 8px; transition: all .2s; }
.gbtn:hover { border-color: var(--ink-2); background: var(--surface-2); }
.gbtn:focus-visible { outline: 2px solid var(--ink-2); }
.gbtn.next { margin-left: auto; background: var(--ink); color: var(--bg); border-color: var(--ink); }
.gbtn.next:hover { background: var(--ink-2); }
.reveal { margin-top: 22px; padding-top: 20px; border-top: 1px solid var(--hair); display: none; }
.reveal.on { display: block; animation: fade .4s ease; }
.verdict { font: 400 22px/1.3 var(--serif); margin-bottom: 14px; }
.reveal-grid { display: grid; grid-template-columns: 1.1fr 1fr; gap: 24px; }
.meter { height: 8px; border-radius: 4px; background: linear-gradient(90deg, var(--img), var(--mid) 50%, var(--rec)); position: relative; margin: 10px 0 6px; }
.meter i { position: absolute; top: -5px; width: 3px; height: 18px; background: var(--ink); border-radius: 2px; transform: translateX(-50%); }
.meter-l { display: flex; justify-content: space-between; font-size: 11px; color: var(--muted); }
.fbar { display: grid; grid-template-columns: 110px 1fr; align-items: center; gap: 10px; font-size: 12px; color: var(--ink-2); margin: 5px 0; }
.fbar .track { height: 6px; background: var(--surface-2); border-radius: 3px; position: relative; }
.fbar .track i { position: absolute; left: 0; top: 0; bottom: 0; border-radius: 3px; background: var(--ink-2); }
.fbar .track u { position: absolute; left: 50%; top: -3px; bottom: -3px; width: 1px; background: var(--axis); }
.score { display: grid; grid-template-columns: repeat(2, auto); gap: 4px 18px; font-size: 13px; color: var(--ink-2); justify-content: start; }
.score b { font: 300 28px/1 var(--serif); color: var(--ink); }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ------------------------------------------------ scrolly map */
.scrolly { position: relative; max-width: 1280px; margin: 0 auto; display: grid; grid-template-columns: 380px 1fr; gap: 40px; padding: 0 24px; }
.scrolly .steps { padding: 30vh 0 40vh; }
.scrolly .step { min-height: 80vh; display: flex; align-items: center; }
.scrolly .step > div { background: var(--surface); border: 1px solid var(--hair); border-radius: 14px; padding: 22px; font-size: 15.5px; color: var(--ink-2); opacity: .35; transition: opacity .4s; }
.scrolly .step.on > div { opacity: 1; }
.scrolly .step h4 { margin: 0 0 8px; font: 500 19px/1.3 var(--serif); color: var(--ink); }
.scrolly .sticky { position: sticky; top: 8vh; height: 84vh; }
#mapCanvas { width: 100%; height: 100%; display: block; cursor: crosshair; }
.map-legend { position: absolute; left: 0; bottom: 0; font-size: 12px; color: var(--ink-2); display: flex; gap: 14px; flex-wrap: wrap; align-items: center; }
.map-legend .grad { width: 160px; height: 8px; border-radius: 4px; background: linear-gradient(90deg, var(--img), var(--mid), var(--rec)); display: inline-block; margin: 0 8px; }

/* ------------------------------------------------ tiles */
.tiles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.tile { background: var(--surface); border: 1px solid var(--hair); border-radius: 14px; padding: 20px; }
.tile .n { font: 300 46px/1 var(--serif); letter-spacing: -.02em; }
.tile .l { font-size: 13px; color: var(--ink-2); margin-top: 10px; line-height: 1.45; }
.tile .s { font-size: 11.5px; color: var(--muted); margin-top: 6px; }

/* ------------------------------------------------ proposals */
.props { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; max-width: var(--wide); margin: 40px auto; }
.prop { background: var(--surface); border: 1px solid var(--hair); border-radius: 14px; padding: 24px; }
.prop .tag { font: 500 11px var(--mono); letter-spacing: .1em; color: var(--muted); text-transform: uppercase; }
.prop h4 { font: 400 23px/1.25 var(--serif); margin: 10px 0 10px; }
.prop p { font-size: 14px; color: var(--ink-2); margin: 0 0 10px; line-height: 1.6; }
.prop .q { font-size: 13px; color: var(--muted); border-top: 1px solid var(--hair); padding-top: 10px; margin-top: 12px; }

/* ------------------------------------------------ methods */
.methods { font-size: 14px; }
.methods p, .methods li { color: var(--ink-2); }
.methods table { width: 100%; border-collapse: collapse; font-size: 12.5px; margin: 16px 0; }
.methods th, .methods td { text-align: left; padding: 7px 8px; border-bottom: 1px solid var(--hair); vertical-align: top; }
.methods th { color: var(--muted); font-weight: 500; }
.methods td:first-child { color: var(--ink); white-space: nowrap; }
.refs li { margin-bottom: 8px; font-size: 13px; }
footer { max-width: var(--prose); margin: 0 auto; padding: 60px 24px 100px; font-size: 13px; color: var(--muted); border-top: 1px solid var(--hair); }

/* ------------------------------------------------ motion */
.fade-in { opacity: 0; transform: translateY(18px); transition: opacity .9s ease, transform .9s ease; }
.fade-in.vis { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .fade-in { opacity: 1; transform: none; transition: none; } html { scroll-behavior: auto; } }

/* ------------------------------------------------ responsive */
@media (max-width: 900px) {
  .grid2, .grid3, .grid4, .props, .tiles { grid-template-columns: 1fr; }
  .grid4.keep2 { grid-template-columns: 1fr 1fr; }
  .strip { grid-template-columns: repeat(2, 1fr); }
  .strip > div:last-child { grid-column: span 2; }
  .design { grid-template-columns: 1fr; }
  .design .arrow { transform: rotate(90deg); height: 40px; }
  .reveal-grid { grid-template-columns: 1fr; }
  .topbar nav { display: none; }
  .scrolly { grid-template-columns: 1fr; padding: 0 16px; }
  .scrolly .sticky { grid-row: 1; grid-column: 1; height: 62vh; top: 56px; z-index: 1; }
  .scrolly .steps { grid-row: 1; grid-column: 1; position: relative; z-index: 2; padding-top: 60vh; }
  .scrolly .step { min-height: 100vh; align-items: flex-end; }
  .scrolly .step > div { background: #141416f5; opacity: 1; }
  .scrolly .step { padding-bottom: 4vh; }
  section { padding: 10vh 16px 4vh; }
  .hero { padding: 0 16px 9vh; }
  .card { padding: 16px 14px 10px; }
  .game .card { padding: 20px; }
  .game-text { font-size: 17px; }
  .scrollcue { display: none; }
}