/* ============================================================================
   footprintjs.github.io — the home page, v4.
   One static page, no build step, no CDN, no webfonts. The film is drawn in
   film.js; this file owns the theme tokens it reads, and everything around it.
   ============================================================================ */

/* ── theme tokens ─────────────────────────────────────────────────────────── */
:root {
  --bg: #fbfaf8;
  --bg-elev: #ffffff;
  --chip: #f4f3ee;
  --fg: #18181b;
  --fg-muted: #55585f;
  --fg-faint: #898c93;
  --border: #e7e5df;
  --border-strong: #d6d5d0;
  --yellow: #ffc700;
  --yellow-on: #18181b;
  --yellow-ink: #7a5d00;
  --yellow-bg: #fff6d6;

  /* the film's colour language, taken from the logo: nodes are yellow, the run
     going forward is blue, the walk back is green. A gap is coral. */
  --f-note: #ffffff;
  --f-note-line: #dcdad3;
  --f-faux: #e0ded7;
  --f-shadow: rgba(40, 36, 20, 0.08);
  --f-edge: #bfbdb4;
  --f-run: #0a7cff;
  --f-walk: #2c9a1c;
  --f-walk-bg: #e9f8e1;
  --f-gap: #e04e28;
  --f-gap-bg: #fff0ea;
  --f-own: #0c8577;
  --f-bind: #6d5ae0;
  --f-bind-bg: #efecfd;
  --f-hybrid: #b7791f;
  --f-lens: #0a7cff;
  --f-dot: rgba(24, 24, 27, 0.075);

  --g-foundations: #d9a400;
  --g-own: var(--f-own);
  --g-bind: var(--f-bind);
  --g-lenses: var(--f-lens);
  --g-more: var(--fg-faint);

  --shadow: 0 1px 3px rgb(0 0 0 / 0.04), 0 18px 44px -22px rgb(0 0 0 / 0.16);
  --content: 1180px;
  --pad: clamp(18px, 4vw, 28px);
  --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
  --beat: 24vh;
}
html.dark {
  color-scheme: dark;
  --bg: #0a0a0b;
  --bg-elev: #141416;
  --chip: #1c1f26;
  --fg: #fafafa;
  --fg-muted: #a7a8ad;
  --fg-faint: #75777f;
  --border: #262628;
  --border-strong: #3a3a3d;
  --yellow-ink: #ffd84d;
  --yellow-bg: #2a2308;

  --f-note: #17181b;
  --f-note-line: #303136;
  --f-faux: #34353a;
  --f-shadow: rgba(0, 0, 0, 0.4);
  --f-edge: #4b4c53;
  --f-run: #39b7ff;
  --f-walk: #8be23a;
  --f-walk-bg: #1b2c11;
  --f-gap: #ff7a52;
  --f-gap-bg: #2e1a13;
  --f-own: #3ad0ba;
  --f-bind: #a79aff;
  --f-bind-bg: #221d3d;
  --f-hybrid: #e8b04e;
  --f-lens: #39b7ff;
  --f-dot: rgba(255, 255, 255, 0.06);
  --g-foundations: var(--yellow);
  --shadow: 0 1px 3px rgb(0 0 0 / 0.4), 0 20px 48px -22px rgb(0 0 0 / 0.6);
}

/* ── base ─────────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 96px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: inherit; text-decoration: none; }
a:hover { color: var(--yellow-ink); }
img { max-width: 100%; }
::selection { background: var(--yellow); color: #17181a; }
:focus-visible { outline: 2px solid var(--yellow); outline-offset: 2px; border-radius: 4px; }
.wrap { max-width: var(--content); margin: 0 auto; padding-inline: var(--pad); }
.mono { font-family: var(--mono); }
.skip {
  position: fixed; left: 12px; top: -60px; z-index: 60;
  background: var(--fg); color: var(--bg); padding: 8px 14px; border-radius: 8px;
  transition: top 0.15s;
}
.skip:focus { top: 10px; color: var(--bg); }
.section-title {
  margin: 0;
  font-size: clamp(30px, 4vw, 46px);
  font-weight: 650;
  letter-spacing: -0.035em;
  line-height: 1.06;
  text-wrap: balance;
}

/* ── header ───────────────────────────────────────────────────────────────── */
.hd {
  position: fixed; inset: 0 0 auto 0; z-index: 40;
  padding-top: env(safe-area-inset-top, 0px);
  background: color-mix(in srgb, var(--bg) 76%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s;
}
.hd.is-past { border-bottom-color: var(--border); }
.hd-in {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 12px;
  min-height: 56px;
  padding-inline: clamp(14px, 3.4vw, 40px);
}
.hd-brand { display: inline-flex; align-items: center; gap: 8px; justify-self: start; }
.hd-brand:hover { color: inherit; }
.hd-mark { display: block; flex: none; }
.logo-run { animation: logoRun 1.5s linear infinite; }
@keyframes logoRun { to { stroke-dashoffset: -7.4; } }
.hd-brand:hover .logo-toes circle { animation: logoToe 0.6s var(--ease) both; }
.hd-brand:hover .logo-toes circle:nth-child(2) { animation-delay: 0.06s; }
.hd-brand:hover .logo-toes circle:nth-child(3) { animation-delay: 0.12s; }
.hd-brand:hover .logo-toes circle:nth-child(4) { animation-delay: 0.18s; }
.hd-brand:hover .logo-toes circle:nth-child(5) { animation-delay: 0.24s; }
@keyframes logoToe { 40% { transform: translateY(-1.6px); } }
.hd-word { font-weight: 680; letter-spacing: -0.03em; font-size: 17px; }
.hd-word em { font-style: normal; color: var(--f-walk); }
.hd-right { display: flex; align-items: center; justify-content: flex-end; gap: clamp(10px, 1.6vw, 20px); }
.hd-nav { font-size: 14px; color: var(--fg-muted); white-space: nowrap; }
.hd-nav:hover { color: var(--fg); }
.hd-icon {
  display: inline-grid; place-items: center; width: 32px; height: 32px;
  border: 1px solid var(--border); border-radius: 8px; background: transparent; color: var(--fg-muted);
  cursor: pointer;
}
.hd-icon:hover { color: var(--fg); border-color: var(--border-strong); }
.ic-moon { display: none; }
html.dark .ic-moon { display: block; }
html.dark .ic-sun { display: none; }

/* the switch: the accent yellow is reserved for it */
.lens-toggle {
  position: relative;
  display: inline-flex; align-items: center; gap: 2px;
  padding: 3px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  background: var(--bg-elev);
  box-shadow: 0 1px 2px rgb(0 0 0 / 0.04);
}
.lens-toggle-label {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: 0.02em; color: var(--fg-faint);
  padding: 0 8px 0 10px; white-space: nowrap;
}
.lens-option {
  border: 0; background: transparent; color: var(--fg-muted);
  font: inherit; font-size: 13px; font-weight: 550;
  padding: 5px 12px; border-radius: 999px; cursor: pointer;
  transition: background 0.2s, color 0.2s, transform 0.2s;
}
.lens-option:hover { color: var(--fg); }
.lens-option.active { background: var(--yellow); color: var(--yellow-on); }
.lens-option:active { transform: scale(0.96); }
body.lens-nudge .lens-toggle { animation: lensNudge 1.6s ease-in-out infinite; }
@keyframes lensNudge {
  0%, 100% { box-shadow: 0 0 0 0 rgb(255 199 0 / 0); }
  50% { box-shadow: 0 0 0 6px rgb(255 199 0 / 0.38); }
}
@media (max-width: 760px) {
  .hd-in { grid-template-columns: 1fr auto; row-gap: 4px; min-height: 0; padding-block: 8px 8px; }
  .lens-toggle { grid-column: 1 / -1; grid-row: 2; justify-self: center; }
  .lens-toggle-label { padding: 0 6px 0 8px; }
  .hd-nav-opt { display: none; }
  html { scroll-padding-top: 110px; }
}
@media (max-width: 1040px) and (min-width: 761px) { .hd-nav-opt { display: none; } }

/* ── buttons ──────────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  height: 46px; padding: 0 20px;
  border-radius: 12px; border: 1px solid transparent;
  font: inherit; font-size: 15px; font-weight: 600; cursor: pointer; white-space: nowrap;
  transition: transform 0.2s var(--ease), box-shadow 0.2s, background 0.2s, border-color 0.2s, color 0.2s;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0) scale(0.985); }
.btn-primary { background: var(--fg); color: var(--bg); box-shadow: var(--shadow); }
.btn-primary:hover { color: var(--bg); }
.btn-ghost { background: var(--bg-elev); color: var(--fg); border-color: var(--border-strong); }
.btn-ghost:hover { color: var(--fg); border-color: var(--fg-faint); }
.ic-pp { display: none; }
.is-playing .ic-p { display: none; }
.is-playing .ic-pp { display: inline; }

/* until the data arrives, hold the stage back rather than flash the reading-order text */
html.js:not(.ready) .film { height: 100vh; overflow: hidden; }
html.js:not(.ready) .film-stage { visibility: hidden; }

/* ── the film: ordinary reading order until film.js takes the stage ───────── */
.film { position: relative; padding-top: 96px; }
.film-stage { position: relative; }
#film-canvas, .film-readout, .film-tag, .orbit-tip, .film-rail, .film-line { display: none; }
.film-hero, .film-caps { max-width: 760px; margin-inline: auto; padding-inline: var(--pad); }
.film-hero { max-width: none; text-align: center; }
.film-hero { padding-block: 30px 18px; }
.film-hero h1 {
  margin: 0;
  font-size: min(8.4vw, 13svh, 92px);
  font-weight: 660;
  letter-spacing: -0.042em;
  line-height: 1;
  text-wrap: balance;
}
.hero-kicker { margin: 0 0 12px; font-family: var(--mono); font-size: 12.5px; line-height: 1.4; color: var(--fg-muted); text-wrap: balance; }
.hero-tagline { max-width: 58ch; margin: 18px auto 0; font-size: clamp(16px, 1.4vw, 20px); line-height: 1.45; color: var(--fg-muted); text-wrap: pretty; }
.hero-cta { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin-top: 24px; }
.film:not(.is-live) [data-film-play] { display: none; }
.hero-hint { display: none; }
.film-caps { list-style: none; margin-block: 0; }
.cap { padding-block: 22px; }
.cap-num { font-family: var(--mono); font-size: 12px; color: var(--fg-faint); }
.cap h2 {
  margin: 4px 0 0;
  font-size: clamp(25px, 3vw, 42px);
  font-weight: 650;
  letter-spacing: -0.035em;
  line-height: 1.08;
  text-wrap: balance;
}
.cap > p { margin: 10px 0 0; font-size: clamp(16px, 1.3vw, 18px); color: var(--fg-muted); text-wrap: pretty; }
.cap-hint { display: none; }
.cap-still { display: block; width: 100%; height: auto; margin-top: 12px; border-radius: 14px; }

.answers { display: grid; gap: 8px; margin-top: 14px; }
.answer {
  margin: 0; padding: 10px 14px;
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  box-shadow: var(--shadow);
}
.answer-label { font-family: var(--mono); font-size: 10.5px; color: var(--fg-faint); }
.answer-text { margin: 2px 0 0; font-size: 14.5px; line-height: 1.38; font-weight: 520; white-space: pre-line; }
.answer-guess { position: relative; }
.answer-guess .answer-text { position: relative; width: fit-content; color: var(--fg-muted); }
.answer-guess .answer-text::after {
  content: ''; position: absolute; left: -2px; right: -2px; top: 54%; height: 2px;
  background: var(--f-gap); transform-origin: left; transform: scaleX(var(--strike, 1));
}
.answer-honest { border-color: var(--f-walk); background: color-mix(in srgb, var(--f-walk-bg) 62%, var(--bg-elev)); }
.is-mono .answer-text { font-family: var(--mono); font-size: 12.5px; font-weight: 500; }

/* ── the film, live: pinned, scrubbed by scroll ───────────────────────────── */
.film.is-live {
  /* The opening, in film time. The sentence and links leave first (rest), the title rises and fades (open, gone), and only then do the film and its header arrive (in), so the two lines never overlap. */
  --rest: clamp(0, 1 - var(--film-t, 0) / 0.22, 1);
  --open: clamp(0, (var(--film-t, 0) - 0.04) / 0.6, 1);
  --gone: clamp(0, (var(--film-t, 0) - 0.3) / 0.22, 1);
  --in: clamp(0, (var(--film-t, 0) - 0.5) / 0.2, 1);
  padding-top: 0; height: calc(var(--film-beats, 34.6) * var(--beat) + 35svh); min-height: 400vh;
}
.film.is-live .film-stage {
  position: sticky; top: 0;
  height: 100vh; height: 100svh;
  overflow: hidden;
  background: var(--bg);
}
.film-grid { display: none; }
.film.is-live .film-grid {
  display: block; position: absolute; inset: -24px 0;
  background-image: radial-gradient(var(--f-dot) 1px, transparent 1.2px);
  background-size: 24px 24px;
  background-position: center top;
  will-change: transform;
}
.film.is-live #film-canvas { display: block; position: absolute; inset: 0; width: 100%; height: 100%; opacity: clamp(0, (var(--film-t, 0) - 0.44) / 0.32, 1); }
.film.is-live .film-hero,
.film.is-live .film-caps { max-width: none; margin: 0; padding: 0; }
.film-stage { --rail: 60px; }
.film-stage.is-portrait { --rail: 52px; }

.film.is-live .film-hero {
  position: absolute;
  inset: calc(var(--head) - var(--line-h) + (100% - var(--head) + var(--line-h)) * 0.46) var(--gutter) auto;
  opacity: calc(1 - var(--gone));
  visibility: hidden;
  transform: translateY(calc(-50% - var(--open) * 38svh)) scale(calc(1 - var(--open) * 0.74));
  transition: visibility 0.3s;
  z-index: 3;
}
.film.is-live .film-hero.on { visibility: visible; }
.film.is-live .film-hero > :not(h1) { opacity: var(--rest); }
.film.is-live .hero-hint {
  display: flex; align-items: center; justify-content: center; gap: 10px;
  margin: 26px 0 0;
  font-family: var(--mono); font-size: 11.5px; color: var(--fg-faint);
}
.hero-steps { position: relative; flex: none; width: 26px; height: 36px; }
.hero-steps i {
  position: absolute; top: 0; left: 0; width: 11px; height: 17px;
  background: #e0a400;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 36 56'%3E%3Cg transform='translate(-5 -4)'%3E%3Ccircle cx='8.5' cy='17' r='2.6'/%3E%3Ccircle cx='13.5' cy='13' r='3'/%3E%3Ccircle cx='19.5' cy='10.5' r='3.2'/%3E%3Ccircle cx='26.5' cy='9' r='3.5'/%3E%3Ccircle cx='35' cy='9' r='4.6'/%3E%3Cpath d='M22 15.5C30 15 36 18 35.5 25 35 30 29 31 28 36 27.5 40 33 43 32.5 50 32 56 27 59 22 58.5 17 58 14 54 13 48 12 41 9 33 9 27 9 20 15 16 22 15.5Z'/%3E%3C/g%3E%3C/svg%3E") center / contain no-repeat;
  transform: rotate(180deg) scaleX(-1);
  animation: heroStep 1.7s var(--ease) infinite;
}
.hero-steps i + i { top: 18px; left: 14px; transform: rotate(180deg); animation-delay: 0.42s; }
@keyframes heroStep { 0%, 100% { opacity: 0.14; } 28%, 58% { opacity: 1; } }

/* the one line, heading the film. One part lights while the film expands it. */
.film.is-live .film-line {
  display: block;
  position: absolute;
  inset: calc(var(--head) - var(--line-h)) var(--gutter) auto;
  margin: 0;
  font-size: clamp(14px, 1.5vw, 21px); font-weight: 640; letter-spacing: -0.015em;
  line-height: var(--line-h);
  text-align: center; white-space: nowrap;
  color: var(--fg-muted);
  opacity: var(--in);
  pointer-events: none;
  transition: scale 0.4s var(--ease);
  z-index: 3;
}
.film-line span {
  background: linear-gradient(transparent 60%, color-mix(in oklab, var(--yellow) 70%, transparent) 60%) no-repeat 0 0 / 0 100%;
  transition: color 0.24s, background-size 0.36s var(--ease);
}
.film-line span.lit { color: var(--fg); background-size: 100% 100%; }
.film.is-live[data-chapter='payoff'] .film-line { scale: 1.14; }

.film.is-live .cap {
  position: absolute;
  left: var(--gutter); width: var(--cap-w);
  top: calc(var(--head) + (100% - var(--head) - var(--rail)) / 2);
  transform: translateY(-50%);
  padding: 0;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.22s;
  z-index: 2;
}
.film.is-live .cap.on { opacity: 1; }
.film.is-live .cap h2 { font-size: clamp(27px, 3vw, 46px); margin-top: 6px; }
.film.is-live .cap-num { display: inline-block; transition: color 0.3s; }
.film.is-live .cap.on .cap-num { color: var(--f-walk); }
.w { display: inline-block; overflow: hidden; vertical-align: top; padding: 0.06em 0.04em 0.16em 0; margin: -0.06em -0.04em -0.16em 0; }
.film-hero .w > span { display: inline-block; animation: wordRise 0.78s var(--ease) both; animation-delay: calc(var(--i) * 52ms + 0.12s); }
@keyframes wordRise { from { transform: translateY(112%); } }
html.js .film-hero .hero-tagline { animation: heroFade 0.7s var(--ease) 0.42s backwards; }
html.js .film-hero .hero-cta { animation: heroFade 0.7s var(--ease) 0.56s backwards; }
html.js .film-hero .hero-hint { animation: heroFade 0.7s var(--ease) 0.8s backwards; }
@keyframes heroFade { from { opacity: 0; transform: translateY(10px); } }
.cap .w > span { display: inline-block; transform: translateY(112%); transition: transform 0.16s; }
.cap.on .w > span { transform: none; transition: transform 0.62s var(--ease); transition-delay: calc(var(--i) * 42ms); }
.film.is-live .cap > p { opacity: 0; transform: translateY(8px); transition: opacity 0.15s, transform 0.15s; }
.film.is-live .cap.on > p { opacity: 1; transform: none; transition: opacity 0.5s 0.24s, transform 0.6s var(--ease) 0.24s; }
.film.is-live .cap-hint {
  display: inline-block; margin: 16px 0 0;
  font-size: 13.5px; font-weight: 600; color: var(--yellow-ink);
  background: var(--yellow-bg); padding: 5px 10px; border-radius: 8px;
}
.film.is-live .answers {
  position: absolute; margin: 0; z-index: 3; opacity: 0; visibility: hidden; transition: opacity 0.2s, visibility 0.2s;
}
.film.is-live .answers.on { opacity: 1; visibility: visible; }

.film.is-live .film-readout {
  display: flex; align-items: baseline; gap: 10px;
  position: absolute; left: var(--gutter); bottom: 78px;
  opacity: 0; transform: translateY(6px);
  transition: opacity 0.25s, transform 0.4s var(--ease);
  z-index: 2;
}
.film.is-live .film-readout.on { opacity: 1; transform: none; }
.film-readout b {
  font-family: var(--mono); font-weight: 650; font-size: clamp(40px, 4.4vw, 64px);
  letter-spacing: -0.05em; line-height: 1; font-variant-numeric: tabular-nums;
  color: var(--f-run); transition: color 0.3s;
}
.film-readout.is-walk b { color: var(--f-walk); }
.film-readout span { font-family: var(--mono); font-size: 12px; color: var(--fg-muted); }

.film.is-live .film-tag {
  display: block; position: absolute; right: var(--gutter); bottom: 64px;
  font-family: var(--mono); font-size: 10.5px; color: var(--fg-faint);
  opacity: 0; transition: opacity 0.3s; z-index: 1;
}
.film.is-live .film-tag.on { opacity: 1; }

.film.is-live .orbit-tip {
  display: block; position: absolute; left: 0; top: 0; width: 220px; z-index: 4;
  padding: 8px 12px; border-radius: 10px;
  background: var(--fg); color: var(--bg);
  font-size: 12.5px; line-height: 1.32;
  opacity: 0; pointer-events: none; transition: opacity 0.14s;
  box-shadow: var(--shadow);
}
.film.is-live .orbit-tip.on { opacity: 1; }
.orbit-tip b { display: block; font-size: 13.5px; }
.orbit-tip span { opacity: 0.8; }
.film-stage.is-pointing { cursor: pointer; }

/* the scrubber: time travel, in the open. Two tracks that merge at the walk back,
   with one cursor running both. */
.film.is-live[data-chapter='hero'] .film-rail { pointer-events: none; }
.film.is-live .film-rail:focus-within { opacity: 1; }
.film.is-live .film-rail {
  opacity: var(--in);
  display: flex; align-items: center; gap: clamp(10px, 2vw, 22px);
  position: absolute; inset: auto 0 env(safe-area-inset-bottom, 0px) 0; height: 60px;
  padding-inline: var(--gutter);
  z-index: 5;
}
.rail-play {
  display: inline-flex; align-items: center; gap: 7px; flex: none;
  height: 30px; padding: 0 12px;
  border: 1px solid var(--border-strong); border-radius: 999px;
  background: var(--bg-elev); color: var(--fg);
  font: inherit; font-size: 12.5px; font-weight: 600; cursor: pointer;
}
.rail-play:hover { border-color: var(--fg-faint); }
.rail-play [data-play-label] { min-width: 2.9em; text-align: left; }
.rail-track { position: relative; flex: 1; height: 46px; cursor: ew-resize; touch-action: none; }
.rail-svg { position: absolute; inset: 0; width: 100%; height: 100%; overflow: visible; pointer-events: none; }
.rail-base { fill: none; stroke: var(--border-strong); stroke-width: 2; }
.rail-top, .rail-bot, .rail-mid { fill: none; stroke-width: 2.6; stroke-linecap: round; transition: opacity 0.25s; }
.rail-top { stroke: var(--f-own); }
.rail-bot { stroke: var(--f-bind); }
.rail-mid { stroke: var(--f-walk); }
.rail-svg[data-active='top'] .rail-bot, .rail-svg[data-active='bottom'] .rail-top { opacity: 0.38; }
.rail-head { stroke: var(--fg-faint); stroke-width: 1; }
.rail-dot { fill: var(--bg); stroke-width: 2.6; transition: fill 0.2s, stroke 0.2s; }
.rail-dot-top { stroke: var(--f-own); }
.rail-dot-bot { stroke: var(--f-bind); }
.rail-svg[data-active='top'] .rail-dot-top { fill: var(--f-own); }
.rail-svg[data-active='bottom'] .rail-dot-bot { fill: var(--f-bind); }
.rail-svg[data-active='mid'] .rail-dot { fill: var(--f-walk); stroke: var(--f-walk); }
.tick {
  position: absolute; top: 0; width: 26px; margin-left: -13px; height: 26px; padding: 0;
  border: 0; background: transparent; color: var(--fg-faint); cursor: pointer;
  font: inherit;
}
.tick::before {
  content: ''; position: absolute; left: 10px; top: 10px; width: 6px; height: 6px; border-radius: 50%;
  background: var(--bg); border: 1.5px solid var(--border-strong);
  transition: border-color 0.2s, background 0.2s, transform 0.3s var(--ease);
}
.tick.past::before { border-color: var(--fg-faint); }
.tick.on::before { transform: scale(1.3); }
.tick span {
  position: absolute; left: 13px; transform: translateX(-50%);
  font-family: var(--mono); font-size: 10px; white-space: nowrap; transition: color 0.2s;
}
.tick[data-track='top'] span { bottom: 100%; margin-bottom: -7px; }
.tick[data-track='bottom'] span, .tick[data-track='mid'] span { top: 100%; margin-top: -7px; }
.tick[data-track='between'] span { top: 100%; margin-top: 0; }
.tick:hover span { color: var(--fg); }
.tick.on span { color: var(--fg); font-weight: 650; }
.rail-skip { flex: none; font-size: 12.5px; color: var(--fg-muted); white-space: nowrap; }

/* portrait: the action above, the words below */
.film-stage.is-portrait .btn { height: 40px; padding: 0 14px; font-size: 13.5px; border-radius: 10px; }
.film-stage.is-portrait .cap {
  left: 16px; right: 16px; width: auto;
  top: calc(100% - var(--cap-zone) + 6px);
  transform: none;
}
.film.is-live .film-stage.is-portrait .cap h2 { font-size: clamp(22px, 6.3vw, 30px); margin-top: 2px; }
.film-stage.is-portrait .cap > p { font-size: 14.5px; margin-top: 6px; }
.film-stage.is-portrait .cap-num { font-size: 10.5px; }
.film-stage.is-portrait .cap[data-chapter='gap'] > p { display: none; }
.film-stage.is-portrait .answer { padding: 6px 10px; border-radius: 10px; }
.film-stage.is-portrait .answer-text { font-size: 12.5px; line-height: 1.3; }
.film-stage.is-portrait .answers { gap: 5px; }
.film-stage.is-portrait .answer-guess .answer-label { display: none; }
.film-stage.is-portrait .answer-guess { padding-block: 5px; }
.is-mono .film-stage.is-portrait .answer-text { font-size: 11px; line-height: 1.32; }
.film-stage.is-portrait .answer-label { font-size: 9.5px; }
.film-stage.is-portrait .film-readout {
  left: auto; right: 14px; bottom: auto; top: calc(var(--head) + 4px); flex-direction: column; align-items: flex-end; gap: 0;
  z-index: 3;
}
.film-stage.is-portrait .film-readout b { font-size: 30px; }
.film-stage.is-portrait .film-readout span { font-size: 9.5px; }
.film-stage.is-portrait .film-tag { right: 14px; bottom: 54px; font-size: 9.5px; }
.film-stage.is-portrait .film-rail { height: 52px; gap: 8px; padding-inline: 12px; }
.film-stage.is-portrait .rail-track { height: 42px; }
.film-stage.is-portrait .tick span { display: none; top: var(--label-top); bottom: auto; margin: 0; }
.film-stage.is-portrait .tick.on span { display: block; }
.film-stage.is-portrait .rail-skip-opt { display: none; }
.film-stage.is-portrait .rail-play [data-play-label] { display: none; }
.film-stage.is-portrait .rail-play { padding: 0 10px; }

/* the same copy, held still */
.film.is-still { padding-top: 110px; }
.film.is-still .film-hero, .film.is-still .film-caps { max-width: 980px; }

/* ── limits ───────────────────────────────────────────────────────────────── */
.limits { border-block: 1px solid var(--border); background: var(--chip); position: relative; z-index: 1; }
.limits p {
  margin: 0 auto; max-width: 880px; padding: 22px var(--pad);
  font-family: var(--mono); font-size: 13px; line-height: 1.6; color: var(--fg-muted); text-align: center; text-wrap: balance;
}

/* ── libraries ────────────────────────────────────────────────────────────── */
.libs { padding-block: clamp(56px, 8vw, 104px) clamp(40px, 6vw, 72px); }
.libs-intro { max-width: 720px; margin: 14px 0 0; font-size: clamp(16px, 1.3vw, 18px); color: var(--fg-muted); text-wrap: pretty; }
.libs-share { margin: 18px 0 0; }
.libs-groups { margin-top: clamp(26px, 4vw, 48px); display: grid; gap: clamp(26px, 3.4vw, 42px); }
.libs-cat { display: flex; flex-wrap: wrap; align-items: baseline; gap: 2px 14px; padding: 12px 0 0; margin-top: 8px; border-top: 2px solid var(--cat); }
.libs-cat[data-category='default'] { --cat: var(--g-own); }
.libs-cat[data-category='code'] { --cat: var(--g-bind); }
.libs-cat[data-category='read'] { --cat: var(--f-walk); }
.libs-cat-title { margin: 0; font-size: clamp(21px, 2.2vw, 28px); font-weight: 660; letter-spacing: -0.028em; color: var(--cat); }
.libs-cat-note { margin: 0; font-size: 14px; color: var(--fg-muted); }
.libs-group { display: grid; grid-template-columns: minmax(170px, 230px) 1fr; gap: clamp(16px, 3vw, 40px); align-items: start; }
.libs-group-head { position: sticky; top: 76px; padding-top: 10px; }
.libs-group-title {
  display: flex; align-items: center; gap: 9px; margin: 0;
  font-size: 19px; font-weight: 660; letter-spacing: -0.02em;
}
.libs-group-title::before { content: ''; flex: none; width: 10px; height: 10px; border-radius: 50%; background: var(--dot); }
.libs-group-note { margin: 5px 0 0; font-size: 13.5px; line-height: 1.4; color: var(--fg-muted); text-wrap: pretty; }
.libs-group[data-group='foundations'] { --dot: var(--g-foundations); }
.libs-group[data-group='own'] { --dot: var(--g-own); }
.libs-group[data-group='frameworks'], .libs-group[data-group='collectors'] { --dot: var(--g-bind); }
.libs-group[data-group='hybrid'] { --dot: var(--f-hybrid); }
.libs-group[data-group='lenses'] { --dot: var(--g-lenses); }
.libs-group[data-group='more'] { --dot: var(--g-more); }
.libs-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 280px), 1fr)); gap: 10px; align-items: start; }
.lib {
  position: relative;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 13px;
  overflow: hidden;
  transition: transform 0.25s var(--ease), border-color 0.2s, box-shadow 0.25s;
}
.lib::before {
  content: ''; position: absolute; inset: 0 0 auto 0; height: 2px;
  background: var(--dot); transform: scaleX(0); transform-origin: left; transition: transform 0.45s var(--ease);
}
.lib:hover { transform: translateY(-2px); border-color: var(--border-strong); box-shadow: var(--shadow); }
.lib:hover::before { transform: scaleX(1); }
.lib.flash { animation: libFlash 1.4s var(--ease); }
@keyframes libFlash { 0%, 60% { box-shadow: 0 0 0 3px var(--dot); } 100% { box-shadow: 0 0 0 3px transparent; } }
.lib-summary {
  display: grid; grid-template-columns: 22px 1fr 16px; gap: 10px; align-items: start;
  padding: 13px 13px 10px; cursor: pointer; list-style: none;
}
.lib-summary::-webkit-details-marker { display: none; }
.lib-icon { width: 20px; height: 20px; margin-top: 2px; color: var(--dot); }
.lib-name-row { display: flex; flex-wrap: wrap; align-items: baseline; gap: 2px 8px; }
.lib-name { margin: 0; font-size: 15.5px; font-weight: 650; letter-spacing: -0.015em; }
.lib-status {
  font-family: var(--mono); font-size: 9.5px; color: var(--yellow-ink);
  background: var(--yellow-bg); border-radius: 5px; padding: 1px 6px;
}
.lib-title { margin: 2px 0 0; font-size: 13.5px; line-height: 1.36; color: var(--fg-muted); text-wrap: pretty; }
.lib-more { position: relative; width: 14px; height: 14px; margin-top: 4px; color: var(--fg-faint); }
.lib-more::before, .lib-more::after {
  content: ''; position: absolute; left: 2px; right: 2px; top: 6px; height: 1.6px; background: currentColor; border-radius: 1px;
  transition: transform 0.25s var(--ease);
}
.lib-more::after { transform: rotate(90deg); }
details[open] .lib-more::after { transform: rotate(0); }
.lib-body { padding: 0 13px 8px 45px; animation: libOpen 0.3s var(--ease); }
@keyframes libOpen { from { opacity: 0; transform: translateY(-4px); } }
.lib-package { font-family: var(--mono); font-size: 11px; color: var(--fg-faint); }
.lib-desc { margin: 2px 0 0; font-size: 13px; line-height: 1.45; color: var(--fg-muted); }
.lib-links { display: flex; flex-wrap: wrap; gap: 3px 12px; padding: 0 13px 12px 45px; font-size: 12.5px; font-weight: 550; }
.lib-links a { color: var(--fg); border-bottom: 1px solid var(--border-strong); line-height: 1.5; }
.lib-links a:hover { border-color: currentColor; color: var(--yellow-ink); }
.lk-ver { font-family: var(--mono); font-size: 10.5px; font-weight: 500; color: var(--fg-faint); }
@media (max-width: 760px) {
  .libs-group { grid-template-columns: 1fr; gap: 10px; }
  .libs-group-head { position: static; padding-top: 0; }
}

/* ── the working loop: one CSS clock, the comet and the list stay in step ── */
.build { padding-block: clamp(50px, 7vw, 92px); border-top: 1px solid var(--border); }
.build-in { display: grid; grid-template-columns: minmax(280px, 420px) 1fr; gap: clamp(26px, 5vw, 72px); align-items: center; }
.loop svg { display: block; width: 100%; height: auto; }
.loop-ring { fill: none; stroke: var(--border-strong); stroke-width: 2; }
.loop-comet {
  fill: none; stroke: var(--f-walk); stroke-width: 5; stroke-linecap: round;
  stroke-dasharray: 12 88; stroke-dashoffset: 12;
  animation: loopComet 12s linear infinite;
}
@keyframes loopComet { to { stroke-dashoffset: -88; } }
.loop-node { fill: var(--bg-elev); stroke: var(--border-strong); stroke-width: 1.5; transition: fill 0.3s; }
.loop-halo { fill: var(--f-walk); opacity: 0; }
.loop-ic { fill: none; stroke: var(--fg-muted); stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.loop-station .loop-halo { animation: loopHalo 12s linear infinite; animation-delay: calc(var(--i) * 3s); }
.loop-station .loop-node { animation: loopNode 12s linear infinite; animation-delay: calc(var(--i) * 3s); }
.loop-station .loop-ic { animation: loopIc 12s linear infinite; animation-delay: calc(var(--i) * 3s); }
@keyframes loopHalo { 0% { opacity: 0.26; transform: scale(0.8); } 6% { opacity: 0.26; transform: scale(1.08); } 22% { opacity: 0; transform: scale(1.14); } 100% { opacity: 0; } }
@keyframes loopNode { 0%, 18% { stroke: var(--f-walk); stroke-width: 2.4; } 25%, 100% { stroke: var(--border-strong); stroke-width: 1.5; } }
@keyframes loopIc { 0%, 18% { stroke: var(--f-walk); } 25%, 100% { stroke: var(--fg-muted); } }
.loop-word {
  font-family: var(--sans); font-size: 30px; font-weight: 660; letter-spacing: -0.03em;
  fill: var(--fg); text-anchor: middle; dominant-baseline: middle; opacity: 0;
  animation: loopWord 12s linear infinite; animation-delay: calc(var(--i) * 3s);
}
@keyframes loopWord { 0% { opacity: 0; transform: translateY(5px); } 3%, 21% { opacity: 1; transform: none; } 24%, 100% { opacity: 0; transform: translateY(-5px); } }
.build-lead { margin: 14px 0 0; font-size: clamp(16px, 1.3vw, 18px); color: var(--fg-muted); text-wrap: pretty; }
.build-steps { list-style: none; margin: 20px 0 0; padding: 0; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.build-steps li {
  padding: 10px 12px; border: 1px solid var(--border); border-radius: 11px; background: var(--bg-elev);
  animation: loopStep 12s linear infinite; animation-delay: calc(var(--i) * 3s);
}
@keyframes loopStep { 0%, 20% { border-color: var(--f-walk); } 25%, 100% { border-color: var(--border); } }
.build-steps h3 { margin: 0; font-size: 15px; font-weight: 650; letter-spacing: -0.012em; }
.build-steps p { margin: 2px 0 0; font-size: 13px; line-height: 1.4; color: var(--fg-muted); }
.build-note { margin: 14px 0 0; font-size: 12.5px; line-height: 1.5; color: var(--fg-faint); text-wrap: pretty; }
.build-links { display: flex; flex-wrap: wrap; gap: 6px 18px; margin-top: 14px; font-size: 14px; font-weight: 550; }
.build-links a { border-bottom: 1px solid var(--border-strong); }
@media (max-width: 860px) {
  .build-in { grid-template-columns: 1fr; }
  .loop { max-width: 240px; margin-inline: auto; }
}
@media (max-width: 460px) { .build-steps { grid-template-columns: 1fr; } }

/* ── writing ──────────────────────────────────────────────────────────────── */
.writing { padding-block: clamp(44px, 6vw, 76px); border-top: 1px solid var(--border); }
.writing-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 236px), 1fr)); gap: 10px; margin-top: 22px; }
.writing-grid a {
  display: grid; gap: 2px; padding: 14px;
  border: 1px solid var(--border); border-radius: 13px; background: var(--bg-elev);
  transition: transform 0.25s var(--ease), box-shadow 0.25s, border-color 0.2s;
}
.writing-grid a:hover { transform: translateY(-2px); border-color: var(--border-strong); box-shadow: var(--shadow); color: inherit; }
.writing-art { width: 100%; max-width: 150px; height: auto; margin-bottom: 8px; fill: none; stroke: var(--fg-faint); stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; overflow: visible; }
.writing-art circle { fill: var(--bg-elev); }
.writing-art .hot { fill: var(--f-walk); stroke: var(--f-walk); }
.writing-art .hot-box { stroke: var(--f-walk); stroke-width: 2.2; }
.writing-art .hot-fill { fill: var(--f-walk); stroke: var(--f-walk); }
.writing-grid a:hover .writing-art path { stroke: var(--f-walk); }
.writing-kind { font-family: var(--mono); font-size: 11px; color: var(--fg-faint); }
.writing-title { font-size: 15.5px; font-weight: 640; letter-spacing: -0.015em; line-height: 1.26; }

/* ── questions: collapsed, so the page stays quiet, and still there for search ── */
.faq { padding-block: clamp(44px, 6vw, 76px); border-top: 1px solid var(--border); }
.faq-list { display: grid; gap: 8px; max-width: 820px; margin-top: 20px; }
.faq-item { border: 1px solid var(--border); border-radius: 12px; background: var(--bg-elev); }
.faq-item summary { position: relative; padding: 13px 40px 13px 15px; cursor: pointer; list-style: none; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item h3 { margin: 0; font-size: 15.5px; font-weight: 620; letter-spacing: -0.012em; line-height: 1.32; }
.faq-item summary::before, .faq-item summary::after {
  content: ''; position: absolute; right: 16px; top: 22px; width: 11px; height: 1.6px; background: var(--fg-faint); border-radius: 1px;
  transition: transform 0.25s var(--ease);
}
.faq-item summary::after { transform: rotate(90deg); }
.faq-item[open] summary::after { transform: rotate(0); }
.faq-item p { margin: 0; padding: 0 15px 14px; font-size: 14.5px; line-height: 1.5; color: var(--fg-muted); text-wrap: pretty; }

/* ── footer ───────────────────────────────────────────────────────────────── */
.ft { border-top: 1px solid var(--border); padding-block: 36px 24px; }
.ft-in { display: grid; grid-template-columns: minmax(220px, 300px) 1fr auto; gap: clamp(20px, 5vw, 64px); }
.ft-brand { display: flex; align-items: center; gap: 8px; }
.ft-about p { margin: 8px 0 0; font-size: 13px; color: var(--fg-muted); }
.ft-col { display: flex; flex-direction: column; gap: 3px; font-size: 13px; }
.ft-col-h { font-family: var(--mono); font-size: 11px; color: var(--fg-faint); margin-bottom: 4px; }
.ft-col a { color: var(--fg-muted); }
.ft-col a:hover { color: var(--fg); }
.ft-links { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 2px 14px; font-size: 12px; }
.ft-bottom { display: flex; flex-wrap: wrap; gap: 4px 8px; margin-top: 26px; font-size: 12px; color: var(--fg-faint); }
@media (max-width: 760px) { .ft-in { grid-template-columns: 1fr; } }

/* ── a view switch reads as a change of voice, not a page reload ──────────── */
.view-swap .hero-tagline, .view-swap .lib-title, .view-swap #limits-text, .view-swap .build-copy, .view-swap .libs-group-head {
  animation: viewSwap 0.42s var(--ease);
}
@keyframes viewSwap { from { opacity: 0.2; transform: translateY(4px); } }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .loop-comet { stroke-dasharray: none; }
  .loop-word:first-child { opacity: 1; }
}