/* KALÓN — kalon.css
 * A small, calm design system. System fonts only (nothing fetched). One paper,
 * one ink, one gold accent, a few muted tones. Serif for the voice, sans for the
 * controls. Generous whitespace; the canvases carry the motion, the page stays still.
 */

/* ---------- tokens ---------- */
:root {
  --paper: #f4efe6;
  --paper-2: #efe7d9;
  --ink: #1c1a17;                      /* 15.2:1 on paper */
  --ink-soft: #5b554c;                 /* 6.4:1 — secondary text */
  --ink-mute: rgba(28, 26, 23, 0.42);  /* NON-TEXT only (hairlines, decorative marks) — fails text contrast */
  --ink-faint: rgba(28, 26, 23, 0.14);
  --gold: #b8843f;                     /* GRAPHIC marks only (canvas) — 2.9:1, fails text */
  --gold-deep: #7d5620;                /* gold for TEXT / UI / focus — 5.7:1 on paper (AA) */
  --gold-text: var(--gold-deep);
  --accent: var(--gold-deep);

  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  --maxw: 70rem;
  --measure: 42ch;
  --radius: 4px;

  /* modular scale (~1.25) on an 18px base */
  --t-0: 1.125rem;
  --t-1: 1.406rem;
  --t-2: 1.758rem;
  --t-3: 2.197rem;
  --t-4: 2.75rem;
  --t-5: clamp(2.6rem, 7vw, 4.3rem);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: var(--t-0);
  line-height: 1.62;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3 { line-height: 1.12; font-weight: 600; margin: 0; }
p { margin: 0 0 1.1em; }
em { font-style: italic; }
strong { font-weight: 600; }
img, canvas { max-width: 100%; display: block; }
:focus-visible { outline: 2px solid var(--gold-deep); outline-offset: 3px; border-radius: 2px; }

.visually-hidden {
  position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}
.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 100;
  background: var(--ink); color: var(--paper); padding: 0.6em 1em; border-radius: var(--radius);
  font-family: var(--sans); font-size: 0.9rem; text-decoration: none;
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; }

/* ---------- masthead ---------- */
.masthead {
  position: sticky; top: 0; z-index: 20;
  background: rgba(244, 239, 230, 0.9);                          /* fallback where color-mix() is unsupported */
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--ink-faint);
}
.masthead__inner {
  max-width: var(--maxw); margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; padding: 0.7rem 1.25rem;
}
.wordmark {
  font-family: var(--serif); font-weight: 600; letter-spacing: 0.24em;
  font-size: 1.15rem; color: var(--ink); text-decoration: none; padding-left: 0.24em;
}
.masthead__controls { display: flex; gap: 0.5rem; }
.toggle {
  font-family: var(--sans); font-size: 0.78rem; letter-spacing: 0.02em;
  color: var(--ink-soft); background: transparent; border: 1px solid var(--ink-faint);
  border-radius: 999px; padding: 0.34em 0.85em; cursor: pointer;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.toggle:hover { color: var(--ink); border-color: var(--ink-mute); }
.toggle[aria-pressed="true"] { color: var(--gold-deep); border-color: color-mix(in srgb, var(--gold) 55%, transparent); }

/* ---------- overture ---------- */
main { display: block; }
section { scroll-margin-top: 4.5rem; }
.overture {
  max-width: 48rem; margin: 0 auto; text-align: center;
  padding: min(20vh, 9rem) 1.25rem min(12vh, 6rem);
}
.kicker {
  font-family: var(--sans); text-transform: uppercase; letter-spacing: 0.32em;
  font-size: 0.76rem; color: var(--gold-deep); margin-bottom: 1.5rem;
}
.display { font-size: var(--t-5); letter-spacing: -0.015em; margin-bottom: 1.2rem; }
.lede { font-size: var(--t-1); color: var(--ink); max-width: 34rem; margin: 0 auto; }
.lede em { color: var(--gold-deep); font-style: italic; }
.scroll-hint {
  margin-top: 2.6rem; font-size: 1.3rem; color: var(--ink-soft);
  animation: bob 2.4s ease-in-out infinite;
}
.scroll-hint__label {
  display: block; font-family: var(--sans); font-size: 0.76rem;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--gold-deep); margin-bottom: 0.35rem;
}
@keyframes bob { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(8px); } }

/* ---------- instruments ---------- */
.instrument {
  max-width: 46rem; margin: 0 auto;
  padding: clamp(3rem, 9vh, 7rem) 1.25rem;
  border-top: 1px solid var(--ink-faint);
}
.instrument__text { max-width: 40rem; margin: 0 auto 2.2rem; text-align: center; }
.numeral {
  font-family: var(--serif); font-size: var(--t-2); color: var(--gold-deep);
  margin: 0 0 0.2em; letter-spacing: 0.08em; font-style: italic; font-weight: 600;
}
.instrument__text h2 { font-size: var(--t-3); margin-bottom: 0.7rem; }
.instrument__text p { color: var(--ink-soft); text-align: left; max-width: 40ch; margin-inline: auto; }
.lineage {
  font-family: var(--sans); font-size: 0.76rem; color: var(--ink-soft);
  letter-spacing: 0.01em; margin: 0.9rem auto 0; max-width: 42ch; font-style: normal;
}
.lineage em { font-style: italic; color: var(--ink-soft); }
.hint {
  font-family: var(--sans); font-size: 0.8rem; color: var(--gold-deep);
  text-align: center; margin: 0 0 0.2rem; transition: opacity 0.4s ease;
}
.hint.is-hidden { opacity: 0; }

.instrument__stage { margin: 0; }
.instrument__stage > canvas {
  width: 100%; max-width: 34rem; aspect-ratio: 1 / 1; height: auto;
  margin: 0 auto; background: var(--paper-2);
  border: 1px solid var(--ink-faint); border-radius: var(--radius);
}
.instrument[data-instrument="proportion"] canvas { touch-action: pan-y; cursor: ew-resize; }

/* ---------- controls ---------- */
.controls {
  max-width: 26rem; margin: 1.4rem auto 0;
  display: flex; flex-direction: column; gap: 1rem; align-items: stretch;
}
.control { display: flex; flex-direction: column; gap: 0.4rem; }
.control__label {
  font-family: var(--sans); font-size: 0.72rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--ink-soft); text-align: center;
}
.control--text input {
  font-family: var(--serif); font-size: 1.05rem; text-align: center;
  padding: 0.4em 0.6em; background: var(--paper); color: var(--ink);
  border: 1px solid var(--ink-faint); border-radius: var(--radius);
}
.readout {
  font-family: var(--sans); font-size: 0.82rem; color: var(--ink-soft);
  text-align: center; min-height: 1.4em; margin: 0; font-variant-numeric: tabular-nums;
}
.readout em { color: var(--gold-deep); font-style: normal; }

.btn-row { display: flex; gap: 0.6rem; justify-content: center; flex-wrap: wrap; }
.btn {
  font-family: var(--sans); font-size: 0.85rem; letter-spacing: 0.02em;
  color: var(--ink); background: transparent; cursor: pointer;
  border: 1px solid var(--ink-mute); border-radius: 999px; padding: 0.5em 1.15em;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.btn:hover { border-color: var(--ink); background: color-mix(in srgb, var(--ink) 5%, transparent); }
.btn--gold { color: var(--gold-deep); border-color: color-mix(in srgb, var(--gold) 55%, transparent); }
.btn--gold:hover { background: color-mix(in srgb, var(--gold) 12%, transparent); border-color: var(--gold); }

.chips { display: flex; flex-wrap: wrap; gap: 0.5rem; justify-content: center; }
.chip {
  font-family: var(--sans); font-size: 0.82rem; color: var(--ink-soft);
  background: transparent; border: 1px solid var(--ink-faint); border-radius: 999px;
  padding: 0.4em 0.85em; cursor: pointer; transition: all 0.2s;
}
.chip span { color: var(--ink-soft); font-variant-numeric: tabular-nums; margin-left: 0.15em; }
.chip:hover { border-color: var(--ink-mute); color: var(--ink); }
.chip[aria-pressed="true"] {
  color: var(--paper); background: var(--gold-deep); border-color: var(--gold-deep);
}
.chip[aria-pressed="true"] span { color: color-mix(in srgb, var(--paper) 80%, transparent); }

/* ---------- range input ---------- */
input[type="range"] {
  -webkit-appearance: none; appearance: none; width: 100%; height: 26px;
  background: transparent; cursor: pointer;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: 2px; background: var(--ink-faint); border-radius: 2px;
}
input[type="range"]::-moz-range-track { height: 2px; background: var(--ink-faint); border-radius: 2px; }
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none; width: 18px; height: 18px; margin-top: -8px;
  background: var(--paper); border: 2px solid var(--gold-deep); border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}
input[type="range"]::-moz-range-thumb {
  width: 18px; height: 18px; background: var(--paper); border: 2px solid var(--gold-deep);
  border-radius: 50%; box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}

/* ---------- beholder finale ---------- */
.beholder .instrument__stage > canvas { max-width: 30rem; border-radius: var(--radius); }
.artifact { margin: 1.4rem auto 0; text-align: center; max-width: 32rem; }
.artifact__name { font-family: var(--serif); font-size: var(--t-2); color: var(--ink); }
.artifact__line {
  font-family: var(--serif); font-style: italic; font-size: var(--t-1);
  color: var(--gold-deep); margin: 0.5rem auto 0; max-width: 28rem; line-height: 1.4;
}
.artifact__sig {
  font-family: var(--sans); font-size: 0.74rem; color: var(--ink-soft);
  letter-spacing: 0.04em; margin: 0.9rem 0 0; font-variant-numeric: tabular-nums;
}

/* ---------- colophon ---------- */
.colophon {
  max-width: 40rem; margin: 0 auto; padding: clamp(3rem, 9vh, 7rem) 1.25rem 6rem;
  border-top: 1px solid var(--ink-faint); color: var(--ink-soft); font-size: 0.98rem;
}
.colophon h2 { font-size: var(--t-2); color: var(--ink); margin-bottom: 1.2rem; text-align: center; }
.colophon__meta {
  font-family: var(--sans); font-size: 0.78rem; color: var(--ink-soft);
  letter-spacing: 0.02em; text-align: center; margin-top: 2rem; line-height: 1.9;
}
.colophon__link { color: var(--gold-deep); }

/* ---------- experimental concepts ---------- */
.experiments {
  max-width: 40rem; margin: 0 auto; padding: clamp(3rem, 9vh, 7rem) 1.25rem 2rem;
  border-top: 1px solid var(--ink-faint); color: var(--ink-soft);
}
.experiments h2 { font-size: var(--t-2); color: var(--ink); margin-bottom: 1.1rem; text-align: center; }
.experiments p { max-width: 42ch; margin: 0 auto 1.6rem; }
.experiments__list { list-style: none; margin: 0 auto; padding: 0; max-width: 34rem; }
.experiments__list li {
  display: flex; flex-direction: column; gap: 0.15rem; padding: 0.9rem 0;
  border-top: 1px solid var(--ink-faint); text-align: center;
}
.experiments__list a { font-family: var(--serif); font-size: var(--t-1); color: var(--ink); text-decoration: none; }
.experiments__list a:hover { color: var(--gold-deep); }
.experiments__list span { font-family: var(--sans); font-size: 0.76rem; color: var(--ink-soft); letter-spacing: 0.04em; }
.experiments__soon { opacity: 0.65; }
.experiments__soon span { font-style: italic; }

/* dark instrument (Contrast): frame the dark canvas so it reads as a framed image on the paper wall */
.instrument--dark .instrument__stage > canvas { background: #14110d; border-color: rgba(28, 26, 23, 0.4); }

/* ---------- wide screens: give instruments a touch more presence ---------- */
@media (min-width: 60rem) {
  .instrument { max-width: 52rem; }
  .instrument__stage > canvas { max-width: 36rem; }
}

/* ---------- narrow screens: keep a control near the canvas (mobile fold) ---------- */
@media (max-width: 40rem) {
  .overture { padding: 2.4rem 1.25rem 2rem; }   /* shorter hero → the playable cue lands near the fold */
  .lede { font-size: 1.04rem; line-height: 1.5; }
  .instrument { padding: 3rem 1.1rem; }
  .instrument__text { margin-bottom: 1.3rem; }
  .instrument__stage > canvas,
  .beholder .instrument__stage > canvas { max-width: min(100%, 74vw); }
  .controls { margin-top: 0.9rem; }
  .display { font-size: clamp(2.3rem, 10vw, 3rem); }
  .toggle, .chip { min-height: 44px; display: inline-flex; align-items: center; }  /* thumb-friendly targets */
}

/* ---------- navigation (multi-page) ---------- */
.masthead__inner { flex-wrap: wrap; }
.masthead__nav { display: flex; flex-wrap: wrap; gap: 0.1rem 1.05rem; align-items: center; }
.masthead__nav a {
  font-family: var(--sans); font-size: 0.82rem; letter-spacing: 0.02em;
  color: var(--ink-soft); text-decoration: none; padding: 0.2rem 0; white-space: nowrap;
}
.masthead__nav a:hover { color: var(--ink); }
.masthead__nav a[aria-current="page"] { color: var(--gold-deep); }

.site-footer {
  max-width: var(--maxw); margin: 4rem auto 0; padding: 2rem 1.25rem 3rem;
  border-top: 1px solid var(--ink-faint); text-align: center;
}
.site-footer__nav { font-family: var(--sans); font-size: 0.82rem; color: var(--ink-soft); margin-bottom: 0.6rem; }
.site-footer__nav a { color: var(--ink-soft); text-decoration: none; }
.site-footer__nav a:hover { color: var(--gold-deep); }
.site-footer p { font-family: var(--sans); font-size: 0.74rem; color: var(--ink-soft); margin: 0; letter-spacing: 0.02em; }

/* ---------- content pages (concepts / about / colophon) ---------- */
.page-section { border-top: none; padding-top: clamp(2.5rem, 8vh, 5rem); }
.page-section h1 { font-size: var(--t-2); color: var(--ink); text-align: center; margin-bottom: 1.3rem; line-height: 1.14; }

.about { max-width: 40rem; margin: 0 auto; padding: clamp(2.5rem, 8vh, 5rem) 1.25rem 2rem; color: var(--ink-soft); }
.about__lede { font-size: var(--t-1); color: var(--ink); margin: 0 0 2rem; }
.about h2 { font-family: var(--serif); font-size: var(--t-1); color: var(--ink); margin: 2.2rem 0 0.7rem; text-align: left; }
.about__list { padding-left: 1.1rem; }
.about__list li { margin-bottom: 0.7rem; }
.about code { font-size: 0.9em; background: var(--paper-2); padding: 0.05em 0.35em; border-radius: 3px; word-break: break-word; }
.about__metrics { width: 100%; border-collapse: collapse; margin: 0.5rem 0 1.5rem; font-size: 0.9rem; }
.about__metrics th, .about__metrics td { text-align: left; vertical-align: top; padding: 0.55rem 0.5rem; border-top: 1px solid var(--ink-faint); }
.about__metrics th { font-family: var(--sans); font-weight: 600; color: var(--ink); width: 40%; }
.about__meta { font-family: var(--sans); font-size: 0.78rem; color: var(--ink-soft); margin-top: 2rem; }

/* ---------- Windows High Contrast / forced-colors: preserve state without colour ---------- */
@media (forced-colors: active) {
  /* pressed chips/toggles lose their gold fill under forced colours — restore a non-colour cue */
  .chip[aria-pressed="true"],
  .toggle[aria-pressed="true"] { outline: 2px solid; outline-offset: -3px; }
  .toggle[aria-pressed="true"]::before { content: "● "; }
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .scroll-hint { animation: none; }
  * { transition-duration: 0.001ms !important; animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; }
}