:root {
  --paper: #e8edf0;
  --paper-deep: #dbe3e7;
  --ink: #172d46;
  --ink-soft: #4b6072;
  --line: #9eafba;
  --orange: #e8623c;
  --orange-dark: #b44328;
  --green: #b9dd9b;
  --white: #f7f8f7;
  --mono: "Courier New", Courier, monospace;
  --sans: "Helvetica Neue", Helvetica, Arial, sans-serif;
  --measure: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.62;
  overflow-x: hidden;
}

a { color: inherit; }
a:focus-visible, input:focus-visible, summary:focus-visible {
  outline: 3px solid var(--orange);
  outline-offset: 4px;
}

.site-header, .site-footer {
  width: min(calc(100% - 48px), var(--measure));
  margin: 0 auto;
}
.site-header {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.brand { font-weight: 700; text-decoration: none; }
.site-nav { display: flex; align-items: center; gap: 24px; }
.site-nav a { text-decoration: none; }
.site-nav a:first-child { color: var(--ink-soft); }
.language-link {
  border-bottom: 2px solid transparent;
  padding: 5px 0;
}
.language-link.is-current { border-color: var(--orange); }

main { width: 100%; }
.hero {
  width: min(calc(100% - 48px), var(--measure));
  min-height: 680px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 0.88fr) minmax(0, 1.12fr);
  align-items: center;
  gap: clamp(32px, 6vw, 90px);
  padding: 88px 0 84px;
}
.hero-copy { max-width: 510px; }
.kicker, .section-tag, .demo-heading, .range-ends, .result-label {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  line-height: 1.4;
  text-transform: uppercase;
}
.kicker { margin: 0 0 24px; color: var(--orange-dark); }
h1, h2, p { text-wrap: balance; }
h1 {
  margin: 0;
  max-width: 9ch;
  font-size: clamp(3.5rem, 7vw, 7.2rem);
  font-weight: 700;
  letter-spacing: -0.075em;
  line-height: 0.9;
}
.dek {
  max-width: 50ch;
  margin: 34px 0 0;
  font-size: clamp(1.05rem, 1.55vw, 1.28rem);
  line-height: 1.42;
}
.lede { max-width: 49ch; margin: 18px 0 0; color: var(--ink-soft); }
.jump-link {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  margin-top: 34px;
  padding: 11px 0;
  border-bottom: 2px solid var(--orange);
  font-family: var(--mono);
  font-size: 0.76rem;
  text-decoration: none;
  text-transform: uppercase;
}
.jump-link span { color: var(--orange); font-size: 1.2rem; }

.hero-demo {
  position: relative;
  min-width: 0;
  padding: 22px 0 18px;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
}
.demo-heading { display: flex; justify-content: space-between; gap: 16px; color: var(--ink-soft); }
.demo-heading output { color: var(--orange-dark); font-size: 1rem; font-weight: 700; }
#spring-canvas { display: block; width: 100%; height: auto; margin: 30px 0 16px; background: linear-gradient(to bottom, transparent 82%, rgba(23,45,70,0.06) 82%, rgba(23,45,70,0.06) 82.5%, transparent 82.5%); }
.speed-row label { display: flex; justify-content: space-between; gap: 16px; font-size: 0.9rem; font-weight: 700; }
.speed-row label output { color: var(--orange-dark); font-family: var(--mono); font-size: 0.8rem; }
input[type="range"] { width: 100%; margin: 16px 0 4px; accent-color: var(--orange); cursor: ew-resize; }
.range-ends { display: flex; justify-content: space-between; color: var(--ink-soft); font-size: 0.63rem; letter-spacing: 0.04em; }
.demo-note { min-height: 26px; margin: 20px 0 0; color: var(--ink-soft); font-size: 0.82rem; }

.fact-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  width: 100%;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.fact-strip > div { min-height: 130px; padding: 26px max(24px, calc((100vw - var(--measure)) / 2 + 24px)); border-right: 1px solid var(--line); }
.fact-strip > div + div { padding-left: 28px; }
.fact-strip > div:last-child { border-right: 0; }
.fact-strip strong { display: block; font-family: var(--mono); font-size: clamp(1.5rem, 3vw, 2.2rem); letter-spacing: -0.08em; line-height: 1; }
.fact-strip span { display: block; max-width: 18ch; margin-top: 12px; color: var(--ink-soft); font-size: 0.8rem; line-height: 1.35; }

.article-flow { width: min(calc(100% - 48px), 760px); margin: 0 auto; }
.story-section { padding: 118px 0 0; scroll-margin-top: 24px; }
.section-tag { margin: 0 0 18px; color: var(--orange-dark); }
h2 { max-width: 18ch; margin: 0 0 26px; font-size: clamp(2rem, 4.4vw, 4.2rem); letter-spacing: -0.07em; line-height: 0.98; }
.story-section > p:not(.section-tag) { max-width: 63ch; margin: 0 0 20px; }
.formula { display: inline-block; padding: 0 5px; background: var(--green); font-family: var(--mono); font-size: 0.94em; line-height: 1.35; }
.mechanism-figure { margin: 54px 0 0; padding: 0 0 0 30px; border-left: 2px solid var(--orange); }
.figure-rail { position: relative; height: 20px; margin: 0 0 34px; border-top: 2px solid var(--ink); }
.rail-mark { position: absolute; top: -7px; width: 12px; height: 12px; border: 2px solid var(--ink); border-radius: 50%; background: var(--paper); }
.mark-a { left: 0; }.mark-b { left: 48%; }.mark-c { right: 0; }
.figure-copy { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
.phase { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 14px; }
.phase-label { grid-column: 1 / -1; color: var(--ink-soft); font-family: var(--mono); font-size: 0.72rem; text-transform: uppercase; }
.phase-line { height: 34px; border-bottom: 8px solid var(--orange); border-radius: 50% 12% 12% 50%; transform: skewX(-18deg); }
.phase-line--release { border-color: var(--green); border-radius: 12% 50% 50% 12%; transform: skewX(18deg); }
.phase strong { font-family: var(--mono); font-size: 0.75rem; text-transform: uppercase; }
figcaption { max-width: 55ch; margin-top: 26px; color: var(--ink-soft); font-size: 0.84rem; }

.evidence-table-wrap { overflow-x: auto; margin: 38px 0 28px; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--ink); }
.evidence-table { width: 100%; min-width: 420px; border-collapse: collapse; font-size: 0.95rem; }
.evidence-table caption { padding: 16px 0 12px; text-align: left; color: var(--ink-soft); font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.07em; text-transform: uppercase; }
.evidence-table th, .evidence-table td { padding: 14px 12px 14px 0; border-top: 1px solid var(--line); text-align: left; }
.evidence-table thead th { color: var(--ink-soft); font-family: var(--mono); font-size: 0.68rem; font-weight: 400; text-transform: uppercase; }
.evidence-table tbody th { font-weight: 700; }
.evidence-table td:last-child { font-family: var(--mono); font-weight: 700; }
.evidence-table .is-highlight { background: rgba(185, 221, 155, 0.45); }
.evidence-table .is-highlight th, .evidence-table .is-highlight td { padding-left: 12px; }
.callout { margin: 44px 0 0; padding: 22px 0 20px 22px; border-left: 8px solid var(--orange); background: var(--paper-deep); }
.callout strong { font-family: var(--mono); font-size: 0.75rem; letter-spacing: 0.06em; text-transform: uppercase; }
.callout p { margin: 8px 20px 0 0; }

.measure-section { width: 100vw; margin-left: calc((100% - 100vw) / 2); padding: 118px max(24px, calc((100vw - 1120px) / 2)) 0; background: var(--ink); color: var(--paper); }
.measure-section .section-tag { color: var(--green); }
.measure-section h2 { max-width: 14ch; }
.measure-section > p:not(.section-tag) { max-width: 58ch; color: #c6d1d7; }
.measure-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: start; margin: 42px 0 0; padding-bottom: 28px; }
.measure-form { display: grid; gap: 18px; }
.field { display: grid; grid-template-columns: 1fr 120px; align-items: center; gap: 16px; border-bottom: 1px solid #557086; padding-bottom: 12px; }
.field label { font-size: 0.94rem; }
.field label span { color: #9fb4c2; font-family: var(--mono); font-size: 0.7rem; text-transform: uppercase; }
.field input { width: 100%; border: 0; border-bottom: 2px solid var(--green); border-radius: 0; padding: 4px 0; background: transparent; color: var(--paper); font-family: var(--mono); font-size: 1.1rem; text-align: right; }
.form-hint { margin: 6px 0 0; color: #9fb4c2; font-size: 0.78rem; line-height: 1.45; }
.measure-result { min-height: 260px; padding: 24px; border: 1px solid #688194; background: #213d5a; }
.result-label { color: var(--green); font-size: 0.68rem; }
.measure-result output { display: block; margin: 18px 0 10px; color: var(--white); font-family: var(--mono); font-size: clamp(3rem, 8vw, 5.8rem); letter-spacing: -0.12em; line-height: 0.9; }
.measure-result p { max-width: 31ch; margin: 0; color: #d0dbe1; font-size: 0.9rem; }
.result-bar { height: 10px; margin: 28px 0 12px; background: #43627a; }
.result-bar span { display: block; width: 35%; height: 100%; background: var(--orange); transition: width 180ms ease-out; }
.result-scale { color: var(--green) !important; font-family: var(--mono); font-size: 0.72rem !important; }
.method-details { padding: 20px 0 110px; border-top: 1px solid #557086; }
.method-details summary { width: fit-content; cursor: pointer; font-family: var(--mono); font-size: 0.75rem; text-transform: uppercase; }
.method-details p { max-width: 68ch; margin: 18px 0 0; color: #c6d1d7; font-size: 0.85rem; }

.limits-section { padding-bottom: 22px; }
.limits-section p:last-child { padding-top: 16px; border-top: 1px solid var(--line); color: var(--ink-soft); font-size: 0.9rem; }
.sources-section { padding-bottom: 100px; }
.source-list { margin: 38px 0 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.source-list li { display: grid; grid-template-columns: minmax(0, 1fr) minmax(180px, 0.74fr); gap: 24px; padding: 18px 0; border-bottom: 1px solid var(--line); }
.source-list a { font-weight: 700; text-decoration-thickness: 1px; text-underline-offset: 3px; }
.source-list span { color: var(--ink-soft); font-size: 0.82rem; line-height: 1.42; }
.source-note { margin-top: 24px !important; color: var(--ink-soft); font-size: 0.78rem; }

.site-footer { display: flex; justify-content: space-between; gap: 18px; padding: 28px 0 42px; border-top: 1px solid var(--line); color: var(--ink-soft); font-family: var(--mono); font-size: 0.68rem; line-height: 1.5; }
.site-footer a { text-underline-offset: 3px; }

@media (max-width: 800px) {
  .hero { grid-template-columns: 1fr; min-height: auto; padding: 62px 0 64px; gap: 54px; }
  h1 { max-width: 10ch; font-size: clamp(3.4rem, 15vw, 5.4rem); }
  .fact-strip { grid-template-columns: 1fr; }
  .fact-strip > div, .fact-strip > div + div { min-height: auto; padding: 20px 24px; border-right: 0; border-bottom: 1px solid var(--line); }
  .fact-strip > div:last-child { border-bottom: 0; }
  .fact-strip span { max-width: none; }
  .article-flow { width: min(calc(100% - 48px), 680px); }
  .measure-section { padding-left: max(24px, calc((100vw - 680px) / 2)); padding-right: max(24px, calc((100vw - 680px) / 2)); }
}

@media (max-width: 600px) {
  .site-header, .site-footer { width: min(calc(100% - 32px), var(--measure)); }
  .site-header { min-height: 62px; gap: 18px; font-size: 0.62rem; }
  .site-nav { gap: 13px; }
  .site-nav a:first-child { max-width: 78px; line-height: 1.2; text-align: right; }
  .hero { width: min(calc(100% - 32px), var(--measure)); padding-top: 54px; }
  .hero-demo { padding-top: 18px; }
  .demo-heading { font-size: 0.63rem; }
  .range-ends { font-size: 0.56rem; }
  .article-flow { width: min(calc(100% - 32px), 680px); }
  .story-section { padding-top: 86px; }
  h2 { font-size: clamp(2.1rem, 11vw, 3.2rem); }
  .mechanism-figure { padding-left: 18px; }
  .figure-copy { grid-template-columns: 1fr; gap: 24px; }
  .measure-section { padding-left: 16px; padding-right: 16px; }
  .measure-grid { grid-template-columns: 1fr; gap: 38px; }
  .field { grid-template-columns: 1fr 92px; }
  .measure-result { padding: 20px; }
  .source-list li { grid-template-columns: 1fr; gap: 8px; }
  .site-footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}