/* 錯覚の美術館
   展示室の壁（深い青緑）と、作品の横の真鍮の名札。展示そのものは各展示が自分の背景色で描く。
   1つのテーマに固定（錯視は背景の明るさで見え方が変わるので、ライト／ダークで変えない）。 */
:root {
  --wall: #1c2627;
  --wall-2: #243133;
  --wall-3: #2e3d40;
  --line: #3b4c4f;
  --ink: #ede7da;
  --muted: #a6b0aa;
  --plate: #d8c79a;
  --plate-2: #c4b07c;
  --plate-ink: #2b2415;
  --focus: #f0d68c;
  --sure: #8fd1a8;
  --theory: #e8c46a;
  --open: #b5a6e6;
  --f-disp: "Zen Old Mincho", "Yu Mincho", "Hiragino Mincho ProN", serif;
  --f-body: "Zen Kaku Gothic New", "Hiragino Sans", "Yu Gothic", "Meiryo", sans-serif;
  --f-mono: "IBM Plex Mono", ui-monospace, "Consolas", monospace;
  color-scheme: dark;
}
html, body { height: 100%; }
body { margin: 0; background: var(--wall); color: var(--ink); font-family: var(--f-body); font-size: 15px; line-height: 1.75; }
* { box-sizing: border-box; }
a { color: var(--plate); }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
button { font: inherit; color: inherit; }

#top {
  position: sticky; top: env(safe-area-inset-top, 0px); z-index: 5;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 10px 20px; background: var(--wall); border-bottom: 1px solid var(--line);
}
#logo { font-family: var(--f-disp); font-weight: 700; font-size: 20px; color: var(--ink); text-decoration: none; display: flex; align-items: baseline; gap: 10px; }
#logo span { font-family: var(--f-mono); font-size: 10px; letter-spacing: .18em; color: var(--muted); }
#top nav { display: flex; gap: 6px; align-items: center; }
#top nav a, #top nav button { background: none; border: 1px solid transparent; border-radius: 6px; padding: 4px 10px; color: var(--muted); text-decoration: none; font-size: 14px; cursor: pointer; }
#top nav a:hover, #top nav button:hover { color: var(--ink); border-color: var(--line); }

/* ---------- 入口 ---------- */
#home { max-width: 1120px; margin: 0 auto; padding: 28px 20px 60px; }
.intro { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: 32px; align-items: center; margin-bottom: 36px; }
.intro h1 { font-family: var(--f-disp); font-size: clamp(28px, 4.4vw, 44px); line-height: 1.35; margin: 0 0 14px; text-wrap: balance; }
.intro p { color: var(--muted); margin: 0 0 10px; max-width: 34em; }
.intro .heroBox { background: #fff; border-radius: 4px; padding: 0; box-shadow: 0 0 0 10px var(--wall-2), 0 0 0 11px var(--line); }
.intro canvas { display: block; width: 100%; aspect-ratio: 16 / 9; }
.intro .heroCap { font-size: 13px; color: var(--muted); margin-top: 18px; }
.roomSec { margin-top: 34px; }
.roomSec h2 { font-family: var(--f-disp); font-size: 22px; margin: 0; display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.roomSec h2 small { font-family: var(--f-body); font-size: 13px; color: var(--muted); font-weight: 400; }
.roomSec .roomNote { color: var(--muted); font-size: 14px; margin: 2px 0 14px; }
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 22px; }
.card { display: flex; flex-direction: column; gap: 10px; text-decoration: none; color: var(--ink); }
.card .frame { background: var(--wall-2); padding: 8px; border: 1px solid var(--line); transition: border-color .15s, transform .15s; }
.card canvas { display: block; width: 100%; aspect-ratio: 1; }
.card:hover .frame { border-color: var(--plate-2); transform: translateY(-2px); }
.card .lbl { background: var(--plate); color: var(--plate-ink); padding: 6px 10px 7px; border-radius: 2px; align-self: start; max-width: 100%; }
.card .lbl b { display: block; font-family: var(--f-disp); font-size: 15px; line-height: 1.4; }
.card .lbl span { display: block; font-size: 11.5px; line-height: 1.5; opacity: .85; }
.soon { color: var(--muted); font-size: 13px; border: 1px dashed var(--line); padding: 14px; display: flex; align-items: center; justify-content: center; text-align: center; aspect-ratio: 1; }
.homeFoot { margin-top: 48px; color: var(--muted); font-size: 13px; border-top: 1px solid var(--line); padding-top: 16px; }

/* ---------- 展示室 ---------- */
#room { display: grid; grid-template-columns: minmax(0, 1fr) 390px; height: calc(100vh - 53px); min-height: 520px; }
#stageWrap { position: relative; display: flex; align-items: center; justify-content: center; padding: 22px; min-width: 0; }
#stageFrame { background: var(--wall-2); padding: 10px; border: 1px solid var(--line); box-shadow: 0 18px 40px rgba(0,0,0,.35); }
#stage { display: block; touch-action: manipulation; }
#stageNote { position: absolute; left: 50%; bottom: 14px; transform: translateX(-50%); background: var(--plate); color: var(--plate-ink); padding: 6px 14px; border-radius: 3px; font-size: 14px; max-width: calc(100% - 32px); }
#panel { background: var(--wall-2); border-left: 1px solid var(--line); overflow-y: auto; padding: 20px 22px 40px; display: flex; flex-direction: column; gap: 20px; min-width: 0; }
.plateBig { background: var(--plate); color: var(--plate-ink); padding: 12px 14px 12px; border-radius: 2px; }
.plateBig .eyebrow { font-size: 11.5px; letter-spacing: .12em; opacity: .8; }
.plateBig h1 { font-family: var(--f-disp); font-size: 25px; line-height: 1.35; margin: 2px 0 2px; text-wrap: balance; }
.plateBig .en { font-family: var(--f-mono); font-size: 11px; letter-spacing: .04em; opacity: .75; }
.plateBig .who { font-size: 13px; margin-top: 6px; border-top: 1px solid rgba(43,36,21,.25); padding-top: 6px; }
.lead { margin: 0; font-size: 15.5px; }
#panel h2 { font-size: 13px; letter-spacing: .14em; color: var(--plate); margin: 0 0 8px; font-weight: 700; }
.steps { margin: 0; padding-left: 1.4em; display: grid; gap: 6px; }
.steps li::marker { color: var(--plate); font-family: var(--f-mono); }
.ctrls { display: grid; gap: 12px; }
.ctrl { display: grid; gap: 4px; }
.ctrl .row { display: flex; justify-content: space-between; gap: 10px; font-size: 13.5px; }
.ctrl .val { font-family: var(--f-mono); font-size: 12.5px; color: var(--muted); font-variant-numeric: tabular-nums; }
input[type=range] { width: 100%; accent-color: var(--plate); }
.seg { display: flex; flex-wrap: wrap; gap: 6px; }
.seg button, .btn { background: var(--wall-3); border: 1px solid var(--line); border-radius: 5px; padding: 5px 12px; cursor: pointer; font-size: 13.5px; line-height: 1.5; }
.seg button[aria-pressed=true] { background: var(--plate); color: var(--plate-ink); border-color: var(--plate); }
.btn:hover, .seg button:hover { border-color: var(--plate-2); }
.btn.main { background: var(--plate); color: var(--plate-ink); border-color: var(--plate); font-weight: 700; }
.btns { display: flex; flex-wrap: wrap; gap: 8px; }
.measure { border: 1px solid var(--line); border-radius: 6px; padding: 12px 14px; display: grid; gap: 10px; }
.measure p { margin: 0; font-size: 14px; }
.result { background: var(--wall); border-radius: 5px; padding: 10px 12px; font-size: 14px; }
.result .big { font-family: var(--f-mono); font-size: 26px; color: var(--plate); font-variant-numeric: tabular-nums; line-height: 1.3; }
.result .typ { color: var(--muted); font-size: 12.5px; margin-top: 4px; }
.why { display: grid; gap: 10px; }
.why p { margin: 0; font-size: 14.5px; }
.tag { display: inline-block; font-size: 11px; font-weight: 700; padding: 0 6px; border-radius: 3px; margin-right: 6px; vertical-align: 1px; color: var(--plate-ink); }
.t-sure { background: var(--sure); }
.t-theory { background: var(--theory); }
.t-open { background: var(--open); }
.fact { font-size: 13.5px; color: var(--muted); border-left: 2px solid var(--line); padding-left: 10px; margin: 0; }
.nav2 { display: flex; justify-content: space-between; gap: 10px; border-top: 1px solid var(--line); padding-top: 14px; margin-top: auto; }
.nav2 a { font-size: 13px; color: var(--muted); text-decoration: none; max-width: 48%; }
.nav2 a:hover { color: var(--ink); }
.nav2 a b { display: block; color: var(--ink); font-weight: 500; }
.timer { font-family: var(--f-mono); font-size: 13px; color: var(--muted); font-variant-numeric: tabular-nums; }

dialog#about { max-width: 600px; width: calc(100% - 32px); background: var(--wall-2); color: var(--ink); border: 1px solid var(--line); border-radius: 8px; padding: 6px 22px 20px; }
dialog#about::backdrop { background: rgba(0,0,0,.6); }
dialog#about h2 { font-family: var(--f-disp); }
dialog#about h3 { font-size: 14px; color: var(--plate); margin: 16px 0 4px; }
dialog#about li, dialog#about p { font-size: 14px; }

@media (max-width: 860px) {
  .intro { grid-template-columns: 1fr; }
  #room { display: block; height: auto; }
  #stageWrap { padding: 12px 16px; }
  #panel { border-left: 0; border-top: 1px solid var(--line); overflow: visible; padding: 18px 16px 40px; }
  #top { padding: 8px 16px; }
  #logo span { display: none; }
}
@media (max-width: 480px) {
  #home { padding-inline: 16px; }
  .cards { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
}
@media (prefers-reduced-motion: reduce) {
  .card .frame { transition: none; }
}