:root {
  --ink: #17343a;
  --ink-soft: #49666a;
  --paper: #f1eee4;
  --paper-deep: #e5e1d4;
  --water: #b6ded2;
  --water-deep: #5ca99b;
  --coral: #df725f;
  --yellow: #f0cf6f;
  --line: rgba(23, 52, 58, 0.18);
  --shadow: 0 20px 60px rgba(21, 54, 58, 0.12);
  --serif: Iowan Old Style, Palatino Linotype, Book Antiqua, Palatino, Georgia, serif;
  --sans: Avenir Next, Avenir, Helvetica Neue, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--sans);
  line-height: 1.55;
  overflow-x: hidden;
}
a { color: inherit; }
button, input { font: inherit; }
button { cursor: pointer; }
:focus-visible { outline: 3px solid var(--coral); outline-offset: 4px; }

.shell { width: min(1180px, calc(100% - 72px)); margin-inline: auto; }
.site-header {
  border-bottom: 1px solid var(--line);
  background: rgba(241, 238, 228, 0.92);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(12px);
}
.header-inner {
  width: min(1180px, calc(100% - 72px));
  min-height: 68px;
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: -0.02em; text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 28px; height: 28px; border: 1px solid var(--ink); border-radius: 50%; color: var(--water-deep); font-size: 21px; line-height: 1; }
.language-nav { display: flex; gap: 8px; }
.language-link { min-width: 44px; min-height: 40px; display: grid; place-items: center; border-bottom: 2px solid transparent; text-decoration: none; font-family: var(--mono); font-size: 12px; letter-spacing: 0.1em; }
.language-link.active { border-bottom-color: var(--coral); color: var(--coral); }

.hero { display: grid; grid-template-columns: minmax(0, 0.94fr) minmax(400px, 1.06fr); gap: 54px; align-items: center; padding-block: 80px 74px; }
.hero-copy { max-width: 580px; }
.eyebrow, .section-kicker { margin: 0 0 18px; color: var(--water-deep); font-family: var(--mono); font-size: 11px; font-weight: 700; letter-spacing: 0.15em; text-transform: uppercase; }
h1, h2 { font-family: var(--serif); font-weight: 500; letter-spacing: -0.045em; }
h1 { margin: 0; font-size: clamp(3.5rem, 6.2vw, 6.1rem); line-height: 0.92; }
h2 { margin: 0 0 22px; font-size: clamp(2.2rem, 4vw, 4rem); line-height: 0.98; }
.hero-deck { margin: 28px 0 30px; max-width: 56ch; color: var(--ink-soft); font-size: clamp(1.05rem, 1.4vw, 1.23rem); }
.hero-deck strong { color: var(--ink); }
.hero-proof { display: flex; gap: 25px; flex-wrap: wrap; padding-block: 18px 22px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.proof-item { display: grid; gap: 2px; max-width: 180px; }
.proof-value { font-family: var(--serif); font-size: 2.2rem; line-height: 1; color: var(--coral); }
.proof-label { color: var(--ink-soft); font-size: 0.76rem; line-height: 1.25; }
.text-link { display: inline-flex; align-items: center; gap: 12px; margin-top: 26px; color: var(--ink); font-size: 0.88rem; font-weight: 700; text-decoration-thickness: 1px; text-underline-offset: 4px; }
.text-link span { color: var(--coral); font-size: 1.4rem; }

.topo-figure { position: relative; margin: 0; padding: 22px; background: var(--ink); color: var(--paper); box-shadow: var(--shadow); border-radius: 26px 26px 26px 6px; }
.topo-figure::after { position: absolute; right: -18px; bottom: 30px; width: 86px; height: 86px; content: ""; border: 1px solid var(--coral); border-radius: 50%; opacity: 0.7; }
.figure-label, .range-label, .range-ends { display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.figure-label { color: var(--water); font-family: var(--mono); font-size: 10px; letter-spacing: 0.12em; text-transform: uppercase; }
.figure-label span:last-child { color: var(--yellow); }
#wrinkleCanvas { display: block; width: 100%; height: auto; min-height: 280px; margin: 10px 0 8px; }
figcaption { color: var(--ink-soft); font-size: 0.76rem; line-height: 1.4; }
.topo-figure figcaption { color: rgba(241, 238, 228, 0.72); }
.range-label { margin-top: 18px; font-size: 0.82rem; font-weight: 700; }
.range-label output { color: var(--coral); font-family: var(--mono); font-size: 0.74rem; }
.range { width: 100%; height: 28px; margin: 5px 0 0; accent-color: var(--coral); cursor: pointer; }
.range-ends { color: var(--ink-soft); font-family: var(--mono); font-size: 10px; }
.topo-figure .range-ends { color: rgba(241, 238, 228, 0.58); }

.intro-band { padding: 42px 0 94px; border-top: 1px solid var(--line); }
.intro-grid { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 80px; align-items: start; }
.intro-statement { margin: 0; font-family: var(--serif); font-size: clamp(1.65rem, 3vw, 2.65rem); line-height: 1.08; }
.intro-note { margin: 0; max-width: 34ch; color: var(--ink-soft); font-size: 0.93rem; }

.observation { padding: 0 0 110px; }
.section-heading { max-width: 700px; }
.section-heading p:not(.section-kicker) { margin: 0; max-width: 62ch; color: var(--ink-soft); }
.timer-layout { display: grid; grid-template-columns: minmax(250px, 0.8fr) 1.2fr; gap: 36px; align-items: center; margin-top: 38px; padding: 32px; background: var(--water); border-radius: 6px 26px 26px 26px; }
.timer-readout { display: grid; gap: 4px; }
.timer-caption { color: var(--ink-soft); font-family: var(--mono); font-size: 10px; letter-spacing: 0.13em; text-transform: uppercase; }
#timerOutput { font-family: var(--mono); font-size: clamp(3.3rem, 7vw, 5.5rem); line-height: 0.95; letter-spacing: -0.09em; }
.timer-state { min-height: 1.5em; color: var(--ink-soft); font-size: 0.82rem; }
.timer-controls { display: flex; flex-wrap: wrap; gap: 10px; }
.button { min-height: 46px; padding: 10px 16px; border: 1px solid var(--ink); border-radius: 999px; color: var(--ink); background: transparent; font-weight: 700; font-size: 0.82rem; }
.button:hover:not(:disabled) { background: rgba(255,255,255,0.38); }
.button-primary { background: var(--coral); border-color: var(--coral); color: #fffaf0; }
.button-primary:hover:not(:disabled) { background: #c95d4c; }
.button-quiet { border-color: transparent; }
.button:disabled { opacity: 0.45; cursor: not-allowed; }
.small-note { margin: 15px 0 0; color: var(--ink-soft); font-size: 0.75rem; }

.force-section { padding: 0 0 120px; }
.force-lab { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(260px, 0.65fr); gap: 28px; align-items: start; margin-top: 38px; }
.force-figure { margin: 0; padding: 18px; background: var(--paper-deep); border: 1px solid var(--line); border-radius: 26px 6px 26px 26px; }
#forceCanvas { display: block; width: 100%; height: auto; }
.force-controls { padding: 14px 0; }
.force-results { display: grid; gap: 13px; margin-top: 28px; }
.force-result { display: grid; grid-template-columns: 12px 1fr auto; gap: 9px; align-items: center; border-bottom: 1px solid var(--line); padding-bottom: 10px; font-size: 0.8rem; }
.force-result strong { font-family: var(--mono); font-size: 0.75rem; }
.dot { display: inline-block; width: 10px; height: 10px; border-radius: 50%; }
.dot-dry { background: var(--ink-soft); }
.dot-wet { background: var(--coral); }
.dot-wrinkly { background: var(--water-deep); }
.formula { margin-top: 23px; color: var(--ink-soft); font-family: var(--mono); font-size: 0.72rem; }
.result-strip { display: grid; grid-template-columns: auto auto auto 1fr; gap: 22px; align-items: center; margin-top: 28px; padding: 22px; background: var(--ink); color: var(--paper); border-radius: 6px 6px 26px 26px; }
.result-strip > div:not(.result-operator):not(.result-interpretation) { display: grid; grid-template-columns: auto auto; gap: 4px 8px; align-items: baseline; }
.result-number { font-family: var(--serif); font-size: 2.7rem; line-height: 1; color: var(--yellow); }
.result-unit { color: var(--water); font-family: var(--mono); font-size: 0.75rem; }
.result-label { grid-column: 1 / -1; color: rgba(241,238,228,0.68); font-size: 0.72rem; }
.result-operator { color: var(--coral); font-size: 1.8rem; }
.result-interpretation { padding-left: 22px; border-left: 1px solid rgba(241,238,228,0.25); color: rgba(241,238,228,0.78); font-size: 0.78rem; }
.result-interpretation strong { color: var(--coral); font-family: var(--serif); font-size: 1.3rem; }

.story { border-top: 1px solid var(--line); }
.story-section { display: grid; grid-template-columns: 88px minmax(0, 700px); gap: 34px; padding: 86px 0; }
.story-section + .story-section { border-top: 1px solid var(--line); }
.story-index { color: var(--coral); font-family: var(--mono); font-size: 0.8rem; letter-spacing: 0.1em; }
.story-copy p { color: var(--ink-soft); }
.story-copy p:first-of-type { margin-top: 0; }
.story-copy p:last-of-type { margin-bottom: 0; }
.mechanism-line { display: flex; flex-wrap: wrap; gap: 8px 12px; align-items: center; margin: 30px 0; padding: 16px 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); color: var(--ink); font-family: var(--mono); font-size: 0.72rem; }
.mechanism-line i { color: var(--coral); font-style: normal; font-size: 1.2rem; }
.margin-note { padding-left: 16px; border-left: 3px solid var(--yellow); font-size: 0.84rem; }

.method-section { padding: 26px 0 110px; }
.method-header { display: grid; grid-template-columns: 0.8fr 1.2fr; gap: 60px; align-items: end; }
.method-header h2 { font-size: clamp(2rem, 3.4vw, 3.2rem); }
.method-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; padding-top: 24px; border-top: 1px solid var(--line); }
.method-grid p { margin: 0; color: var(--ink-soft); font-size: 0.85rem; }
.method-grid strong { color: var(--ink); font-family: var(--mono); font-size: 0.82rem; }

.sources-section { display: grid; grid-template-columns: 0.95fr 1.05fr; gap: 80px; padding: 58px 0 118px; border-top: 1px solid var(--line); }
.sources-section h2 { font-size: clamp(2rem, 3.2vw, 3.4rem); }
.source-list { margin: 0; padding: 0; list-style: none; }
.source-list li { display: grid; gap: 3px; padding: 13px 0; border-bottom: 1px solid var(--line); }
.source-list a { font-weight: 700; text-underline-offset: 3px; }
.source-list span { color: var(--ink-soft); font-size: 0.78rem; }
.site-footer { padding: 24px 0; background: var(--ink); color: var(--paper); }
.footer-inner { width: min(1180px, calc(100% - 72px)); margin-inline: auto; display: flex; justify-content: space-between; gap: 20px; align-items: center; }
.footer-inner p { margin: 0; color: rgba(241,238,228,0.72); font-size: 0.74rem; }
.footer-inner div { display: flex; flex-wrap: wrap; gap: 18px; }
.footer-inner a { color: var(--water); font-size: 0.74rem; text-underline-offset: 3px; }
.not-found { min-height: 100vh; display: grid; place-items: center; padding: 30px; }
.not-found main { width: min(600px, 100%); }
.not-found h1 { font-size: clamp(3.5rem, 9vw, 6rem); }
.not-found p:not(.eyebrow) { color: var(--ink-soft); margin: 24px 0; }

@media (max-width: 820px) {
  .shell, .header-inner, .footer-inner { width: min(100% - 40px, 620px); }
  .hero { grid-template-columns: 1fr; gap: 42px; padding-block: 52px 62px; }
  h1 { font-size: clamp(3.15rem, 14vw, 5.4rem); }
  .topo-figure { margin-right: 12px; }
  .intro-grid, .timer-layout, .force-lab, .sources-section, .method-header { grid-template-columns: 1fr; gap: 28px; }
  .intro-band { padding-bottom: 75px; }
  .timer-layout { margin-top: 28px; padding: 24px; }
  .force-lab { margin-top: 25px; }
  .result-strip { grid-template-columns: auto auto auto; gap: 14px; }
  .result-interpretation { grid-column: 1 / -1; padding: 17px 0 0; border-left: 0; border-top: 1px solid rgba(241,238,228,0.25); }
  .story-section { grid-template-columns: 44px 1fr; gap: 16px; padding: 60px 0; }
  .method-grid { grid-template-columns: 1fr; gap: 16px; }
  .sources-section { padding-top: 42px; padding-bottom: 78px; }
  .footer-inner { align-items: flex-start; flex-direction: column; }
}

@media (max-width: 480px) {
  .shell, .header-inner, .footer-inner { width: calc(100% - 28px); }
  .header-inner { min-height: 60px; }
  .brand { font-size: 0.9rem; }
  .hero { padding-top: 42px; }
  .hero-proof { gap: 16px; }
  .proof-value { font-size: 1.9rem; }
  .topo-figure { padding: 15px; border-radius: 18px 18px 18px 5px; }
  #wrinkleCanvas { min-height: 220px; }
  .timer-controls { display: grid; grid-template-columns: 1fr; }
  .button { width: 100%; }
  .force-figure { padding: 10px; border-radius: 18px 5px 18px 18px; }
  .result-strip { padding: 16px; }
  .result-number { font-size: 2.1rem; }
  .result-strip > div:not(.result-operator):not(.result-interpretation) { gap: 2px 5px; }
  .result-label { font-size: 0.65rem; }
  h2 { font-size: 2.35rem; }
  .story-section { grid-template-columns: 1fr; gap: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
}