/* retinal — 해설판 실험실. 색은 tokens.css 의 변수만 쓴다.
 * 상태 열쇠: .lab[data-x][data-phase][data-paused][data-ans][data-render] — main.js 가 바꾼다.
 * 색면 계열(--color-field-* · --color-stim-* · --color-ring-*)은 색면과 견본 칸에만. 강조(--color-accent)는 점·선·링·눈금에만.
 */

:root {
  --dock: calc(var(--spacing-dock) + env(safe-area-inset-bottom));
  --gutter: var(--spacing-4);
}
@media (min-width: 720px) {
  :root { --gutter: var(--spacing-10); }
}
@media (min-width: 1024px) {
  :root { --gutter: var(--spacing-14); }
}

/* ── 리셋 ─────────────────────────────────────────────── */
:where(*, *::before, *::after) { box-sizing: border-box; }
:where(body, h1, h2, h3, p, ul, ol, dl, dd, figure) { margin: 0; }
:where(ul, ol) { padding: 0; list-style: none; }
:where(button) { font: inherit; color: inherit; }
:where(a) { color: inherit; }

html {
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-body);
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-padding-bottom: var(--dock);
}
body {
  font-size: var(--text-body);
  line-height: var(--text-body--line-height);
  padding-bottom: var(--dock);
  word-break: keep-all;
  overflow-wrap: break-word;
  -webkit-tap-highlight-color: transparent;
  font-variant-numeric: tabular-nums;
}

:focus-visible {
  outline: 2px solid transparent;
  outline-offset: 2px;
  box-shadow: var(--shadow-focus);
}

.skip {
  position: absolute;
  left: var(--spacing-4);
  top: var(--spacing-4);
  z-index: 20;
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  padding: 0 var(--spacing-4);
  background: var(--color-ink);
  color: var(--color-bg);
  border-radius: var(--radius-control);
  text-decoration: none;
  transform: translateY(-200%);
}
.skip:focus-visible { transform: none; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.lat { font-family: var(--font-display); font-style: italic; }

/* ── 상태 칸 ── .sw = 하나만 보임(자리 차지 0) · .stack > .st = 한 칸에 겹쳐 Crossfade(자리 고정) ── */
.sw:not(.on) { display: none !important; }
.stack { display: grid; }
.stack > .st {
  grid-area: 1 / 1;
  opacity: 0;
  visibility: hidden;
  transition: opacity 320ms var(--ease-in-out), visibility 0s linear 320ms;
}
.stack > .st.on {
  opacity: 1;
  visibility: visible;
  transition: opacity 320ms var(--ease-in-out), visibility 0s;
}

/* ── 실험실 — 모바일(<720) 한 열 ─────────────────────── */
.lab {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  grid-template-areas: "mrow" "lead" "cmd" "plate" "safe" "cap" "act";
  container-type: inline-size;
  padding: var(--spacing-4) var(--gutter) var(--spacing-8);
}
.panel, .pbody { display: contents; }
.topline { grid-area: top; display: none; }
.mrow { grid-area: mrow; }
.lead { grid-area: lead; margin-top: var(--spacing-2); }
.xname { grid-area: name; }
.cmd { grid-area: cmd; margin-top: var(--spacing-3); }
.act { grid-area: act; margin-top: var(--spacing-6); }
.safe { grid-area: safe; margin-top: var(--spacing-3); }
.stage, .bezel { display: contents; }
.plate { grid-area: plate; justify-self: center; margin-top: var(--spacing-4); }
.cap { grid-area: cap; margin-top: var(--spacing-1); }

.topline, .safe, .cap, .proc, .ask, .wait, .note, .rnote, .d-title, .r-legend {
  font-size: var(--text-caption);
  line-height: 1.5;
  color: var(--color-ink-muted);
}
.cap { font-variant-numeric: tabular-nums; }

/* 라벨 줄(모바일) — 워드마크 · 실험 이름 · 남은 초 */
.mrow {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: baseline;
  column-gap: var(--spacing-2);
  min-height: 1.5rem;
}
.mmark {
  font-family: var(--font-numeric);
  font-size: var(--text-body);
  letter-spacing: 0.08em;
  text-decoration: none;
  line-height: 1.5rem;
  /* 누르는 면적 44px — 라벨 줄 높이(24px)는 그대로 두려고 바깥 여백으로 상쇄한다 */
  display: inline-block;
  padding-block: 0.625rem;
  margin-block: -0.625rem;
}
.mname { font-size: var(--text-caption); color: var(--color-ink-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.mname::before { content: "· "; }
.mstat { font-size: var(--text-caption); color: var(--color-ink-muted); justify-items: end; }
.mstat b { font-family: var(--font-numeric); font-weight: 400; font-size: var(--text-label); color: var(--color-ink); margin-inline-end: 0.15em; }
.mline { grid-column: 1 / -1; margin-top: var(--spacing-1); }

.lead { font-size: var(--text-small); color: var(--color-ink-muted); }
.xname {
  /* 모바일에서는 라벨 줄이 이름을 보인다 — 제목은 읽는 기계에만 */
  position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap;
  grid-area: auto;
}
.xname { font-size: var(--text-small); font-weight: 400; }
.xname .ko { font-family: var(--font-body); font-size: var(--text-small); color: var(--color-ink-muted); }
.xname .lat { font-size: var(--text-label); font-weight: 400; }
.xname .dotsep { margin-inline: 0.5em; font-family: var(--font-body); color: var(--color-ink-faint); }

.cmd > .st { display: block; }
.xname { margin: 0; }
.cmd {
  margin-bottom: 0;
  font-family: var(--font-display);
  font-size: var(--text-display);
  line-height: var(--text-display--line-height);
  font-weight: 400;
  letter-spacing: -0.01em;
  font-optical-sizing: auto;
  transition: opacity 600ms var(--ease-out);
}

/* 응시 중에는 지시판을 낮춘다 — 타이머는 그대로 1.0(시선을 색면에 둔다) */
.lab[data-phase="stare"]:not([data-paused]) :is(.topline, .lead, .xname, .cmd, .safe, .mname) { opacity: 0.6; }
.topline, .lead, .safe, .mname { transition: opacity 600ms var(--ease-out); }

/* ── 진행 선 — 타이머 아래 2px, 채움만 강조색 ── */
.pline {
  display: block;
  position: relative;
  height: 2px;
  overflow: hidden;
  background: var(--color-line);
}
.pline i {
  position: absolute;
  inset: 0;
  background: var(--color-accent);
  transform-origin: left center;
}
.mline { visibility: hidden; }
.lab[data-phase="stare"] .mline { visibility: visible; }

/* ── 조작부(act) ── */
.act .trow { display: none; }
.act .a-stare .pline { display: none; }
.a-ready, .a-stare, .a-ans, .a-paused { display: flex; flex-direction: column; gap: var(--spacing-4); align-content: start; }
.a-ans { gap: var(--spacing-3); }
.lab[data-phase="explain"] .ask { display: none; }
/* 모바일·중간 폭 — 자동 전환(응시 → 확인)에서 아래 블록이 밀리지 않게 확인 단계 높이를 미리 잡는다 */
.act { min-height: 11rem; }
.brow { display: flex; flex-wrap: wrap; align-items: center; gap: var(--spacing-3) var(--spacing-6); }
.brow.stack { display: grid; }
.brow.stack > .st { display: flex; flex-wrap: wrap; align-items: center; gap: var(--spacing-3) var(--spacing-6); }

.timer { display: inline-flex; align-items: baseline; gap: 0.2em; }
.timer b {
  font-family: var(--font-numeric);
  font-weight: 400;
  font-size: var(--text-timer);
  line-height: 1;
  font-variant-numeric: tabular-nums lining-nums;
  font-optical-sizing: auto;
  min-width: 1.2em;
  text-align: end;
}
.timer .tu { font-size: var(--text-small); color: var(--color-ink-muted); }

.btn-main {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3rem;
  padding: 0 var(--spacing-6);
  border: 0;
  border-radius: var(--radius-control);
  background: var(--color-ink);
  color: var(--color-bg);
  font-size: var(--text-body);
  font-weight: 600;
  cursor: pointer;
  transition: transform 120ms var(--ease-out), box-shadow 160ms var(--ease-out);
}
.btn-main:active { transform: scale(0.98); }
.btn-main:focus-visible { box-shadow: var(--shadow-focus); }

.btn-text {
  display: inline-flex;
  align-items: center;
  gap: 0.35em;
  min-height: 2.75rem;
  padding: 0;
  border: 0;
  background: none;
  color: var(--color-ink-muted);
  font-size: var(--text-small);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.3em;
  cursor: pointer;
  transition: color 160ms var(--ease-out);
}
.btn-text .arr { font-family: var(--font-body); text-decoration: none; display: inline-block; }

.btn-line {
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  padding: 0 var(--spacing-4);
  border: 1px solid var(--color-ink-muted);
  border-radius: var(--radius-control);
  background: none;
  color: var(--color-ink);
  font-size: var(--text-small);
  font-weight: 600;
  cursor: pointer;
  transition: transform 120ms var(--ease-out), background-color 160ms var(--ease-out);
}
.btn-line:active { transform: scale(0.98); }

@media (hover: hover) and (pointer: fine) {
  .btn-main:hover { box-shadow: 0 0 0 2px var(--color-bg), 0 0 0 3px var(--color-ink); }
  .btn-main:hover:focus-visible { box-shadow: var(--shadow-focus); }
  .btn-text:hover { color: var(--color-ink); }
  .btn-line:hover { background: var(--color-surface); }
}

/* 움직임 줄이기·정지 색면에서만 보이는 것 */
.rnote, .rskip { display: none; }
.lab[data-render="static"] .rnote.on { display: block; }
.lab[data-render="static"] .rskip.on { display: inline-flex; }

/* ── 견본 띠 ── */
.sw-wrap { position: relative; }
.wait { position: absolute; inset: 0 0 auto; opacity: 0; transition: opacity 240ms var(--ease-out); }
.swg {
  display: grid;
  gap: var(--spacing-2);
  transition: opacity 240ms var(--ease-out), visibility 0s;
}
.swg-7 { grid-template-columns: repeat(7, minmax(2.75rem, 1fr)); }
.swg-5 { grid-template-columns: repeat(5, minmax(0, 1fr)); }
.swg-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.lab[data-ans="wait"] .wait { opacity: 1; }
.lab[data-ans="wait"] .swg { opacity: 0; visibility: hidden; transition: opacity 240ms var(--ease-out), visibility 0s linear 240ms; }

.swb {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-1);
  min-height: 2.75rem;
  padding: var(--spacing-2) var(--spacing-1);
  border: 0;
  border-radius: var(--radius-control);
  background: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-caption);
  line-height: 1.3;
  cursor: pointer;
  transition: transform 120ms var(--ease-out), box-shadow 160ms var(--ease-out);
}
.swb.has-chip { background: none; padding: 0; gap: var(--spacing-1); }
.sw-chip {
  display: block;
  width: 100%;
  aspect-ratio: 1;
  min-height: 2.75rem;
  border-radius: var(--radius-control);
  transition: box-shadow 160ms var(--ease-out);
}
.sw-l { font-family: var(--font-numeric); font-size: var(--text-small); }
.swb:not(.has-chip) .sw-l { font-family: var(--font-body); white-space: nowrap; }
.sw-sub { color: var(--color-ink-muted); font-size: var(--text-caption); white-space: nowrap; }
.swb:active { transform: scale(0.98); }
.swb:not(.has-chip)[aria-pressed="true"] { box-shadow: inset 0 0 0 2px var(--color-ink); }
.swb.has-chip[aria-pressed="true"] .sw-chip { box-shadow: 0 0 0 2px var(--color-bg), 0 0 0 4px var(--color-ink); }
.swb.has-chip:focus-visible { box-shadow: none; }
.swb.has-chip:focus-visible .sw-chip { box-shadow: var(--shadow-focus); }
@media (hover: hover) and (pointer: fine) {
  .swb:not(.has-chip):hover { box-shadow: inset 0 0 0 1px var(--color-ink); }
  .swb:not(.has-chip)[aria-pressed="true"]:hover { box-shadow: inset 0 0 0 2px var(--color-ink); }
  .swb.has-chip:hover .sw-chip { box-shadow: 0 0 0 2px var(--color-bg), 0 0 0 3px var(--color-ink); }
  .swb.has-chip[aria-pressed="true"]:hover .sw-chip { box-shadow: 0 0 0 2px var(--color-bg), 0 0 0 4px var(--color-ink); }
}

/* 견본 색 칸 · 목록 견본 */
.c-swatch-150 { background: var(--color-swatch-150); }
.c-swatch-170 { background: var(--color-swatch-170); }
.c-swatch-190 { background: var(--color-swatch-190); }
.c-ghost { background: var(--color-ghost); }
.c-swatch-230 { background: var(--color-swatch-230); }
.c-swatch-250 { background: var(--color-swatch-250); }
.c-swatch-270 { background: var(--color-swatch-270); }
.c-stim-warm { background: var(--color-stim-warm); }
.c-stim-warm-soft { background: var(--color-stim-warm-soft); }
.c-stim-cool-soft { background: var(--color-stim-cool-soft); }
.c-field-plate { background: var(--color-field-plate); }
.c-ring { background: repeating-linear-gradient(90deg, var(--color-ring-lo) 0 3px, var(--color-ring-hi) 3px 6px); }

/* ── 기록 눈금 — 예측(청록) · 당신(잉크). 전폭 눈금의 translateX(%) = 트랙 폭 기준 ── */
.ruler { display: grid; gap: var(--spacing-2); }
.r-track {
  position: relative;
  height: 1.5rem;
  overflow: hidden;
  background: linear-gradient(var(--color-line), var(--color-line)) center / 100% 1px no-repeat;
}
.r-tick { position: absolute; inset: 0; transition: transform 240ms var(--ease-out), opacity 240ms var(--ease-out); }
.r-tick::before { content: ""; position: absolute; left: -1px; top: 0.125rem; bottom: 0.125rem; width: 2px; }
.r-pred::before { background: var(--color-accent); top: 0.375rem; bottom: 0.375rem; }
.r-you::before { background: var(--color-ink); }
.ruler[data-you="none"] .r-you { opacity: 0; }
.r-legend { display: flex; flex-wrap: wrap; gap: var(--spacing-1) var(--spacing-6); }
.r-legend b { font-weight: 600; color: var(--color-ink); }
.lg i { display: inline-block; width: 2px; height: 0.75rem; margin-inline-end: 0.5em; vertical-align: -0.1em; }
.lg-pred i { background: var(--color-accent); }
.lg-you i { background: var(--color-ink); }

.note { color: var(--color-ink); font-size: var(--text-small); line-height: 1.6; max-width: var(--spacing-measure); }

/* ── 해설 도표 ── */
.dia { display: grid; gap: var(--spacing-2); }
.d-rows { display: grid; gap: var(--spacing-2); }
.d-rows li {
  display: grid;
  grid-template-columns: minmax(0, 9.5rem) minmax(0, 1fr) 2.75rem;
  align-items: center;
  column-gap: var(--spacing-3);
  font-size: var(--text-caption);
  color: var(--color-ink-muted);
}
.d-bar { position: relative; height: 0.375rem; background: linear-gradient(var(--color-line), var(--color-line)) center / 100% 1px no-repeat; }
.d-bar i { position: absolute; inset: 0; background: var(--color-ink-muted); transform-origin: left center; }
.d-v { color: var(--color-ink); text-align: end; font-variant-numeric: tabular-nums; }

/* ── 색면 + 베젤(이중 받침: 바깥 둥근 판 · 안쪽 각진 도판) ── */
.plate {
  --side: min(100cqi, 100svh - var(--dock) - 17.75rem);
  padding: var(--spacing-bezel);
  background: var(--color-surface);
  border-radius: var(--radius-bezel);
  box-shadow: var(--shadow-bezel);
}
.field {
  position: relative;
  width: calc(var(--side) - 2 * var(--spacing-bezel));
  aspect-ratio: 1;
  overflow: hidden;
  border-radius: var(--radius-none);
  background: var(--color-field-plate);
  contain: strict;
}
.field canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }

.fcss, .fc { position: absolute; inset: 0; }
.fcss { background: var(--color-field-plate); }
.fc { display: none; }
.lab[data-x="afterimage"] .fc-a,
.lab[data-x="contrast"] .fc-b,
.lab[data-x="troxler"] .fc-c,
.lab[data-x="motion"] .fc-d { display: block; }
.fc i { position: absolute; display: block; }

/* ① 원반 — 지름 56% 단색 원(셰이더는 가장자리 1.5% 를 부드럽게 — 정지 색면은 각진 원) */
.fc-a .disc { left: 22%; top: 22%; width: 56%; aspect-ratio: 1; border-radius: 50%; background: var(--color-stim-warm); }
.fc-a .disc-l, .fc-a .disc-r { display: none; top: 32%; width: 36%; aspect-ratio: 1; border-radius: 50%; }
.fc-a .disc-l { left: 10%; background: var(--color-stim-warm); }
.fc-a .disc-r { left: 54%; background: var(--color-ghost); }
.lab:is([data-phase="reveal"], [data-phase="explain"]) .fc-a .disc { display: none; }
.lab[data-phase="explain"] .fc-a :is(.disc-l, .disc-r) { display: block; }

/* ② 둘레 둘 + 같은 회색 사각 둘(22%) + 다리 */
.fc-b .half-l { left: 0; top: 0; width: 50%; height: 100%; background: var(--color-stim-warm-soft); }
.fc-b .half-r { left: 50%; top: 0; width: 50%; height: 100%; background: var(--color-stim-cool-soft); }
.fc-b :is(.sq-l, .sq-r, .bridge) { top: 39%; height: 22%; background: var(--color-field-plate); }
.fc-b .sq-l { left: 14%; width: 22%; }
.fc-b .sq-r { left: 64%; width: 22%; }
.fc-b .bridge { left: 25%; width: 50%; display: none; }
.lab:is([data-phase="reveal"], [data-phase="explain"]) .fc-b .bridge { display: block; }
/* 셰이더가 둘레를 맞바꾼 뒤의 그림(캔버스 아래 면도 같게) */
.lab[data-render="gl"]:is([data-phase="reveal"], [data-phase="explain"]) .fc-b .half-l { background: var(--color-stim-cool-soft); }
.lab[data-render="gl"]:is([data-phase="reveal"], [data-phase="explain"]) .fc-b .half-r { background: var(--color-stim-warm-soft); }

/* ③ 흐린 점 여섯 — 반지름 34% 원 위, 가우스 σ 7%(2.5σ = 17.5% 에서 0) */
.fc-c {
  background:
    radial-gradient(17.5% 17.5% at 50% 84%, var(--color-stim-warm-soft), color-mix(in oklab, var(--color-stim-warm-soft) 61%, transparent) 40%, color-mix(in oklab, var(--color-stim-warm-soft) 32%, transparent) 60%, color-mix(in oklab, var(--color-stim-warm-soft) 14%, transparent) 80%, transparent),
    radial-gradient(17.5% 17.5% at 20.6% 67%, var(--color-stim-cool-soft), color-mix(in oklab, var(--color-stim-cool-soft) 61%, transparent) 40%, color-mix(in oklab, var(--color-stim-cool-soft) 32%, transparent) 60%, color-mix(in oklab, var(--color-stim-cool-soft) 14%, transparent) 80%, transparent),
    radial-gradient(17.5% 17.5% at 20.6% 33%, var(--color-stim-warm-soft), color-mix(in oklab, var(--color-stim-warm-soft) 61%, transparent) 40%, color-mix(in oklab, var(--color-stim-warm-soft) 32%, transparent) 60%, color-mix(in oklab, var(--color-stim-warm-soft) 14%, transparent) 80%, transparent),
    radial-gradient(17.5% 17.5% at 50% 16%, var(--color-stim-cool-soft), color-mix(in oklab, var(--color-stim-cool-soft) 61%, transparent) 40%, color-mix(in oklab, var(--color-stim-cool-soft) 32%, transparent) 60%, color-mix(in oklab, var(--color-stim-cool-soft) 14%, transparent) 80%, transparent),
    radial-gradient(17.5% 17.5% at 79.4% 33%, var(--color-stim-warm-soft), color-mix(in oklab, var(--color-stim-warm-soft) 61%, transparent) 40%, color-mix(in oklab, var(--color-stim-warm-soft) 32%, transparent) 60%, color-mix(in oklab, var(--color-stim-warm-soft) 14%, transparent) 80%, transparent),
    radial-gradient(17.5% 17.5% at 79.4% 67%, var(--color-stim-cool-soft), color-mix(in oklab, var(--color-stim-cool-soft) 61%, transparent) 40%, color-mix(in oklab, var(--color-stim-cool-soft) 32%, transparent) 60%, color-mix(in oklab, var(--color-stim-cool-soft) 14%, transparent) 80%, transparent),
    var(--color-field-plate);
}

/* ④ 동심 고리 — 원 반지름 46%(= closest-side 92%), 파장 = 반지름의 6%(= 5.52%) */
.fc-d {
  background:
    radial-gradient(closest-side, transparent 90.5%, var(--color-field-plate) 93.5%),
    repeating-radial-gradient(closest-side, var(--color-field-plate) 0, var(--color-ring-hi) 1.38%, var(--color-field-plate) 2.76%, var(--color-ring-lo) 4.14%, var(--color-field-plate) 5.52%);
}

/* 응시점 · 십자 — DOM, 색면 위 */
.fix { position: absolute; inset: 0; pointer-events: none; }
.fix-dot {
  position: absolute;
  left: 50%; top: 50%;
  width: 0.5rem; height: 0.5rem;
  margin: -0.25rem 0 0 -0.25rem;
  border-radius: 50%;
  background: var(--color-fixation);
  display: none;
  transition: opacity 320ms var(--ease-in-out);
}
.lab[data-x="afterimage"]:not([data-phase="explain"]) .fix-dot,
.lab[data-x="motion"] .fix-dot { display: block; }
.fix-cross { position: absolute; inset: 0; display: none; transition: transform 320ms var(--ease-out); }
.fix-cross i {
  position: absolute;
  left: 50%; top: 50%;
  width: 1rem; height: 1rem;
  margin: -0.5rem 0 0 -0.5rem;
  background:
    linear-gradient(var(--color-fixation), var(--color-fixation)) center / 2px 100% no-repeat,
    linear-gradient(var(--color-fixation), var(--color-fixation)) center / 100% 2px no-repeat;
}
.lab[data-x="troxler"] .fix-cross { display: block; }
.lab[data-x="troxler"][data-phase="reveal"] .fix-cross { transform: translateX(12%); }

/* ── 720–1023: 한 열이되 데스크톱 지시판 구성, 시작 단추는 색면 아래 ── */
@media (min-width: 720px) {
  .lab {
    grid-template-areas: "top" "lead" "name" "cmd" "stage" "safe" "act";
    padding-top: var(--spacing-10);
  }
  .topline { display: block; }
  .mrow { display: none; }
  .lead { margin-top: var(--spacing-8); font-size: var(--text-lead); color: var(--color-ink); }
  .xname { grid-area: name; position: static; width: auto; height: auto; overflow: visible; clip-path: none; white-space: normal; margin-top: var(--spacing-3); line-height: 1.4; }
  .cmd { margin-top: var(--spacing-5); }
  .stage { display: block; grid-area: stage; margin-top: var(--spacing-8); }
  .bezel { display: grid; justify-items: center; gap: var(--spacing-2); }
  .plate { --side: min(100cqi, 35rem); margin-top: 0; grid-area: auto; }
  .cap { grid-area: auto; margin-top: 0; text-align: center; }
  .safe { margin-top: var(--spacing-6); }
  .act { margin-top: var(--spacing-6); }
  .act .trow { display: flex; align-items: center; gap: var(--spacing-6); }
  .act .a-stare .pline { display: block; max-width: 28rem; }
}

/* ── ≥1024: 2칸 split — 지시판 왼 · 색면 오른 ── */
@media (min-width: 1024px) {
  .lab {
    grid-template-columns: clamp(25rem, 38vw, 37.5rem) minmax(0, 1fr);
    grid-template-areas: none;
    min-height: calc(100svh - var(--dock));
    padding: 0;
    container-type: normal;
  }
  .panel {
    grid-area: 1 / 1;
    display: flex;
    flex-direction: column;
    container-type: inline-size;
    padding: var(--spacing-10) var(--spacing-10) var(--spacing-10) var(--spacing-14);
  }
  /* 본문은 위쪽 고정 — 단계가 바뀌어 아래가 늘어도 위 글자는 움직이지 않는다 */
  .pbody { display: flex; flex-direction: column; margin-block: 0 auto; padding-block: clamp(var(--spacing-8), 10svh, var(--spacing-24)) var(--spacing-8); }
  .act { min-height: 0; }
  .lead { margin-top: 0; }
  .act { margin-top: var(--spacing-8); }
  .safe { margin-top: 0; }
  .stage {
    grid-area: 1 / 2;
    align-self: start;
    position: sticky;
    top: 0;
    height: calc(100svh - var(--dock));
    display: grid;
    place-items: center;
    container-type: inline-size;
    padding: var(--spacing-10) var(--spacing-14);
    margin-top: 0;
  }
  .plate { --side: min(100cqi, 100svh - var(--dock) - 7rem); }
}
@media (min-width: 1024px) and (max-height: 820px) {
  .panel { padding-block: var(--spacing-6); }
  .pbody { padding-block: var(--spacing-6) var(--spacing-4); }
  .act { margin-top: var(--spacing-5); }
  .lead + .xname { margin-top: var(--spacing-2); }
}

/* ── 정적 블록 공통 ── */
.list, .notes, .why, .rec, .foot { padding-inline: var(--gutter); }
.list, .notes, .why, .rec { padding-block: var(--spacing-16); }
@media (min-width: 1024px) {
  .list, .notes, .why, .rec { padding-block: var(--spacing-32) 0; }
  .foot { margin-top: var(--spacing-32); }
}
.sec-head { display: grid; gap: var(--spacing-3); margin-bottom: var(--spacing-8); max-width: var(--spacing-measure); }
.sec-head p { color: var(--color-ink-muted); }
h2 {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: var(--text-h2);
  line-height: 1.2;
  letter-spacing: -0.01em;
}

/* 실험 목록 행 — 아래 머리카락 선, 링크 전체 */
.rows { border-top: 1px solid var(--color-line); }
.row {
  display: grid;
  grid-template-columns: 3.5rem minmax(0, 1fr) auto;
  grid-template-areas: "n name chips" "n line line" "n len len";
  align-items: baseline;
  column-gap: var(--spacing-4);
  row-gap: var(--spacing-1);
  padding: var(--spacing-5) var(--spacing-2);
  border-bottom: 1px solid var(--color-line);
  text-decoration: none;
  transition: background-color 160ms var(--ease-out);
}
.r-n { grid-area: n; font-family: var(--font-numeric); font-size: 1.5rem; line-height: 1; }
.r-name { grid-area: name; display: flex; flex-wrap: wrap; align-items: baseline; gap: 0 var(--spacing-3); }
.r-name .lat { font-size: var(--text-label); }
.r-name .ko { font-size: var(--text-small); color: var(--color-ink-muted); }
.r-line { grid-area: line; font-size: var(--text-small); }
.r-len { grid-area: len; font-size: var(--text-caption); color: var(--color-ink-muted); }
.r-chips { grid-area: chips; display: inline-flex; align-items: center; gap: var(--spacing-1); align-self: center; }
.r-chips i { display: block; width: 1.25rem; height: 1.25rem; }
.r-to, .r-go { font-family: var(--font-body); color: var(--color-ink-muted); font-size: var(--text-small); }
.r-go { display: none; transition: transform 160ms var(--ease-out); }
@media (min-width: 720px) {
  .row {
    grid-template-columns: 4.5rem minmax(0, 1.25fr) minmax(0, 2fr) 5rem 4.5rem 1.5rem;
    grid-template-areas: "n name line len chips go";
    align-items: center;
    column-gap: var(--spacing-6);
    padding: var(--spacing-6) var(--spacing-4);
  }
  .r-n { font-size: 2rem; }
  .r-name { flex-direction: column; gap: 0; }
  .r-go { display: block; grid-area: go; justify-self: end; }
}
@media (hover: hover) and (pointer: fine) {
  .row:hover { background: var(--color-surface); }
  .row:hover .r-go { transform: translateX(4px); }
}
.row:focus-visible { box-shadow: inset 0 0 0 2px var(--color-accent); }

/* 연구소 노트 · 해설 — 왼 노트(36rem) · 오른 수칙/도표 */
.notes, .w-art {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--spacing-12);
}
.n-main, .w-main { display: grid; gap: var(--spacing-4); max-width: var(--spacing-measure); }
.n-main p, .w-main p { font-size: var(--text-lead); line-height: 1.75; }
.n-main h2, .w-main h2 { margin-bottom: var(--spacing-4); }
.sign { color: var(--color-ink-muted); font-size: var(--text-small) !important; }
.w-sub { display: block; margin-top: var(--spacing-2); font-family: var(--font-body); font-size: var(--text-small); color: var(--color-ink-muted); letter-spacing: 0; }
.w-sub .lat { font-size: var(--text-body); }
.rules h3 { font-size: var(--text-small); font-weight: 600; color: var(--color-ink-muted); margin-bottom: var(--spacing-3); }
.rules li { display: grid; gap: var(--spacing-1); padding-block: var(--spacing-4); border-top: 1px solid var(--color-line); }
.rules li:last-child { border-bottom: 1px solid var(--color-line); }
.rules b { font-weight: 600; }
.rules span { font-size: var(--text-small); color: var(--color-ink-muted); }
.dia-static { align-self: start; padding-top: var(--spacing-4); border-top: 1px solid var(--color-line); }
@media (min-width: 1024px) {
  .notes, .w-art { grid-template-columns: minmax(0, 36rem) minmax(0, 1fr); gap: var(--spacing-24); }
  .rules, .dia-static { margin-top: var(--spacing-16); max-width: 32rem; }
}

/* 해설·다른 실험은 고른 실험만 */
html:not([data-x="afterimage"]) .w-art[data-only="afterimage"],
html:not([data-x="contrast"]) .w-art[data-only="contrast"],
html:not([data-x="troxler"]) .w-art[data-only="troxler"],
html:not([data-x="motion"]) .w-art[data-only="motion"],
html[data-x="afterimage"] .row-li[data-hide-current][data-for="afterimage"],
html[data-x="contrast"] .row-li[data-hide-current][data-for="contrast"],
html[data-x="troxler"] .row-li[data-hide-current][data-for="troxler"],
html[data-x="motion"] .row-li[data-hide-current][data-for="motion"] { display: none; }

/* 오늘의 기록 — 4칸 줄(모바일 2×2) */
.rec-cells {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--color-line);
}
.rc { display: grid; gap: var(--spacing-1); padding: var(--spacing-5) var(--spacing-4) var(--spacing-5) 0; border-bottom: 1px solid var(--color-line); }
.rc-n { font-family: var(--font-numeric); font-size: 1.5rem; line-height: 1.2; }
.rc-name { font-size: var(--text-small); color: var(--color-ink-muted); }
.rc dl { display: grid; gap: 0; margin-top: var(--spacing-2); font-size: var(--text-small); }
.rc dl div { display: flex; gap: var(--spacing-2); }
.rc dt { color: var(--color-ink-muted); min-width: 2.5rem; }
.rc dd { font-weight: 600; }
.rc dd[data-empty] { font-weight: 400; color: var(--color-ink-muted); }
@media (min-width: 720px) {
  .rec-cells { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .rc { padding-inline: var(--spacing-5); border-bottom: 0; }
  .rc + .rc { border-left: 1px solid var(--color-line); }
  .rec-cells { border-bottom: 1px solid var(--color-line); }
}

/* 꼬리 */
.foot {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--spacing-8);
  padding-block: var(--spacing-12) var(--spacing-16);
  border-top: 1px solid var(--color-line);
  font-size: var(--text-small);
  color: var(--color-ink-muted);
}
.foot .wm { font-family: var(--font-numeric); font-size: 1.25rem; letter-spacing: 0.08em; color: var(--color-ink); margin-bottom: var(--spacing-2); }
.f-h { color: var(--color-ink); font-weight: 600; margin-bottom: var(--spacing-2); }
.f-links { display: grid; gap: 0; }
.f-links a { display: inline-flex; align-items: center; min-height: 2.75rem; text-decoration: none; }
@media (hover: hover) and (pointer: fine) {
  .f-links a:hover { color: var(--color-ink); text-decoration: underline; text-underline-offset: 0.3em; }
}
@media (min-width: 720px) {
  .foot { grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr) minmax(0, 1fr); }
  .f-links a { min-height: 2rem; }
}

/* ── 아래 도크 — 실험 기구의 조작대(전폭 평평한 띠) ── */
.dock {
  position: fixed;
  inset: auto 0 0;
  z-index: 10;
  padding-bottom: env(safe-area-inset-bottom);
  background: var(--color-surface);
  box-shadow: var(--shadow-dock);
}
.dock-in {
  height: var(--spacing-dock);
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--spacing-3);
  padding-inline: var(--spacing-4);
}
.d-mark { display: none; }
.d-mid { display: flex; align-items: center; gap: var(--spacing-8); min-width: 0; }
.d-tabs { display: flex; }
.d-tab {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.75rem;
  height: 2.75rem;
  border-radius: var(--radius-control);
  font-family: var(--font-numeric);
  font-size: var(--text-body);
  color: var(--color-ink-muted);
  text-decoration: none;
  transition: color 160ms var(--ease-out), transform 120ms var(--ease-out);
}
.d-tab .no { display: none; }
.d-tab::after {
  content: "";
  position: absolute;
  left: 25%;
  right: 25%;
  bottom: 0.375rem;
  height: 2px;
  background: var(--color-ink);
  opacity: 0;
}
.d-tab[aria-current="true"] { color: var(--color-ink); }
.d-tab[aria-current="true"]::after { opacity: 1; }
.d-tab:active { transform: scale(0.98); }
@media (hover: hover) and (pointer: fine) {
  .d-tab:hover { color: var(--color-ink); }
}
.d-phases { display: none; }
.d-ctl { display: flex; align-items: center; gap: var(--spacing-2); }
.d-btn { display: none; }
.d-main {
  min-height: 2.75rem;
  min-width: 8.75rem;
  padding: 0 var(--spacing-4);
  border: 0;
  border-radius: var(--radius-control);
  background: var(--color-ink);
  color: var(--color-bg);
  font-weight: 600;
  font-size: var(--text-body);
  cursor: pointer;
  transition: transform 120ms var(--ease-out);
}
.d-main:active { transform: scale(0.98); }
.d-links { display: none; }

@media (max-width: 719px) {
  .dock-in { grid-template-columns: auto minmax(0, 1fr); }
  .d-ctl { justify-content: stretch; }
  .d-main { flex: 1; }
}

@media (min-width: 720px) {
  .dock-in { grid-template-columns: auto minmax(0, 1fr) auto; gap: var(--spacing-6); padding-inline: var(--spacing-6); }
  .d-mark { display: inline-flex; align-items: baseline; gap: var(--spacing-3); text-decoration: none; min-height: 2.75rem; align-items: center; }
  .wm { font-family: var(--font-numeric); font-size: 1.25rem; letter-spacing: 0.08em; }
  .d-sub { display: none; font-size: var(--text-caption); color: var(--color-ink-muted); }
  .d-mid { justify-content: center; gap: var(--spacing-6); }
  .d-tab { min-width: 3.5rem; }
  .d-tab .no { display: inline; }
  .d-phases { display: flex; gap: var(--spacing-4); }
  .d-phases li { display: inline-flex; align-items: center; gap: 0.375rem; font-size: var(--text-caption); color: var(--color-ink-muted); white-space: nowrap; }
  .pdot { display: block; width: 0.5rem; height: 0.5rem; border-radius: 50%; box-shadow: inset 0 0 0 1px var(--color-ink-faint); }
  .d-phases li[aria-current="step"] { color: var(--color-ink); }
  .d-phases li[aria-current="step"] .pdot { background: var(--color-accent); box-shadow: none; }
  .d-btn {
    display: inline-flex;
    align-items: center;
    min-height: 2.5rem;
    padding: 0 var(--spacing-4);
    border: 1px solid var(--color-ink-muted);
    border-radius: var(--radius-control);
    background: none;
    color: var(--color-ink);
    font-size: var(--text-small);
    cursor: pointer;
    transition: transform 120ms var(--ease-out), background-color 160ms var(--ease-out);
  }
  .d-btn[hidden] { display: none; }
  .d-btn:disabled { color: var(--color-ink-faint); border-color: var(--color-ink-faint); cursor: default; }
  .d-btn:not(:disabled):active { transform: scale(0.98); }
  .d-main { display: none; }
}
@media (min-width: 720px) and (hover: hover) and (pointer: fine) {
  .d-btn:not(:disabled):hover { background: var(--color-bg); }
}
@media (min-width: 1024px) {
  .d-sub { display: inline; }
  .d-links { display: inline-flex; gap: var(--spacing-1); margin-inline-start: var(--spacing-4); }
  .d-links a { display: inline-flex; align-items: center; min-height: 2.5rem; padding-inline: var(--spacing-2); font-size: var(--text-small); color: var(--color-ink-muted); text-decoration: none; border-radius: var(--radius-control); }
  .d-mid { gap: var(--spacing-8); }
}
@media (min-width: 1024px) and (hover: hover) and (pointer: fine) {
  .d-links a:hover { color: var(--color-ink); }
}

/* ── 움직임 줄이기 — 모든 전환 0ms(색면 전환도 ΔY ≤ 0.02 라 순간 전환이 안전하다) ── */
@media (prefers-reduced-motion: reduce) {
  .stack > .st, .stack > .st.on, .cmd, .topline, .lead, .safe, .mname, .swg, .wait, .r-tick,
  .fix-cross, .fix-dot, .btn-main, .btn-line, .btn-text, .swb, .sw-chip, .row, .r-go, .d-tab, .d-btn, .d-main {
    transition: none;
  }
  .lab[data-ans="wait"] .swg { transition: none; }
}