/* ============================================================
   EVENT HORIZON — an interactive black hole exhibition
   Design language: antique star-atlas cartography over deep space.
   - small-caps, letter-spaced annotation labels with hairline rules
   - roman-numeral chapter marks on a constellation journey spine
   - warm disk-palette accents (amber #ffb567 / ember #ff8a3d)
   ============================================================ */

:root {
  --bg: #04050a;
  --ink: #f4eee2;
  --ink-dim: rgba(244, 238, 226, 0.66);
  --ink-faint: rgba(244, 238, 226, 0.42);
  --amber: #ffb567;
  --ember: #ff8a3d;
  --hot: #ffd9a8;
  --blue: #8fb8ff;
  --panel: rgba(13, 16, 28, 0.78);
  --panel-solid: rgba(11, 14, 26, 0.94);
  --hairline: rgba(255, 214, 165, 0.22);
  --hairline-strong: rgba(255, 214, 165, 0.45);
  --serif: Georgia, "Iowan Old Style", "Palatino Linotype", Palatino, serif;
  --sans: "Avenir Next", "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --radius: 10px;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.55);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

button { font-family: inherit; color: inherit; background: none; border: none; cursor: pointer; }
:focus-visible { outline: 2px solid var(--amber); outline-offset: 2px; }

/* ---------- canvas stack ---------- */
#stage { position: fixed; inset: 0; }
#gl-canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; touch-action: none; }
#path-canvas { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; }

/* ---------- cartographic annotation primitives ---------- */
.maplabel {
  font-family: var(--serif);
  text-transform: uppercase;
  letter-spacing: 0.22em;
  font-size: 10.5px;
  color: var(--ink-faint);
}
.rule { height: 1px; background: linear-gradient(90deg, var(--hairline-strong), transparent); flex: 1; }
.roman { font-family: var(--serif); font-variant: small-caps; letter-spacing: 0.12em; }

.panel {
  background: var(--panel);
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

/* ---------- top chrome ---------- */
#topbar {
  position: fixed; top: 0; left: 0; right: 0;
  display: flex; align-items: center; gap: 18px;
  padding: 14px 20px;
  pointer-events: none;
  z-index: 30;
}
#brand { pointer-events: auto; }
#brand h1 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 19px;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--ink);
  white-space: nowrap;
}
#brand .sub {
  display: flex; align-items: center; gap: 10px; margin-top: 3px;
}
#brand .sub span { white-space: nowrap; }

#nav { margin-left: auto; display: flex; gap: 6px; pointer-events: auto; flex-wrap: wrap; justify-content: flex-end; }
.navbtn {
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--hairline);
  background: rgba(10, 13, 24, 0.6);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-dim);
  transition: color .18s, border-color .18s, background .18s;
  min-height: 34px;
}
.navbtn:hover, .navbtn.active { color: var(--hot); border-color: var(--hairline-strong); background: rgba(35, 25, 15, 0.65); }

/* ---------- HUD readout strip ---------- */
#hud {
  position: fixed;
  left: 296px;
  right: 292px;
  bottom: 18px;
  display: flex;
  align-items: stretch;
  justify-content: center;
  gap: 0;
  padding: 8px 10px;
  z-index: 25;
  overflow: hidden;
}
.hud-cell { flex: 1 1 auto; }
.hud-cell {
  padding: 2px 10px;
  border-right: 1px solid var(--hairline);
  display: flex; flex-direction: column; justify-content: center;
  min-width: 74px;
}
.hud-cell:last-child { border-right: none; }
.hud-label {
  font-family: var(--serif);
  text-transform: uppercase;
  font-size: 9px;
  letter-spacing: 0.2em;
  color: var(--ink-faint);
  margin-bottom: 1px;
  white-space: nowrap;
}
.hud-value {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--hot);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}
.hud-value small { color: var(--ink-dim); font-size: 10px; margin-left: 2px; }

#compass { width: 34px; height: 34px; align-self: center; margin-left: 12px; opacity: .85; }

/* ---------- controls dock ---------- */
#dock {
  position: fixed;
  left: 20px;
  bottom: 20px;
  width: 262px;
  z-index: 26;
  padding: 12px 14px 10px;
}
#dock header { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
#dock header button#dock-toggle { margin-left: auto; color: var(--ink-faint); font-size: 15px; line-height: 1; padding: 2px 6px; min-height: 28px; }
.dockbody { display: flex; flex-direction: column; gap: 8px; }
#dock.collapsed .dockbody { display: none; }

.ctl { display: grid; grid-template-columns: 88px 1fr 44px; align-items: center; gap: 8px; }
.ctl label { font-size: 10px; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-dim); font-family: var(--serif); }
.ctl output { font-family: var(--mono); font-size: 11px; color: var(--amber); text-align: right; font-variant-numeric: tabular-nums; }

input[type="range"] {
  -webkit-appearance: none; appearance: none;
  width: 100%; height: 22px; background: transparent; cursor: pointer;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: 2px;
  background: linear-gradient(90deg, rgba(255, 138, 61, .75), rgba(255, 214, 165, .28));
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 13px; height: 13px; margin-top: -5.5px;
  border-radius: 50%;
  background: var(--hot);
  border: 1px solid rgba(120, 60, 10, .9);
  box-shadow: 0 0 8px rgba(255, 170, 90, .8);
}
input[type="range"]::-moz-range-track { height: 2px; background: rgba(255, 170, 100, .4); }
input[type="range"]::-moz-range-thumb { width: 12px; height: 12px; border-radius: 50%; background: var(--hot); border: none; }

.togglerow { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; padding-top: 6px; border-top: 1px solid var(--hairline); }
.togglechip {
  font-size: 10px; letter-spacing: .14em; text-transform: uppercase;
  padding: 6px 11px; border-radius: 999px;
  border: 1px solid var(--hairline);
  color: var(--ink-faint);
  min-height: 30px;
}
.togglechip.on {
  color: #1a0e02; background: linear-gradient(160deg, var(--hot), var(--ember));
  border-color: transparent; font-weight: 600;
}
.selectwrap { margin-left: auto; display: flex; align-items: center; gap: 6px; }
.selectwrap select {
  background: rgba(10, 13, 24, .8); color: var(--ink-dim);
  border: 1px solid var(--hairline); border-radius: 6px;
  font-size: 10.5px; padding: 4px 6px; font-family: var(--sans);
}

.hintline { font-size: 10.5px; color: var(--ink-faint); letter-spacing: .06em; margin-top: 6px; text-align: center; }
kbd {
  font-family: var(--mono); font-size: 9.5px;
  border: 1px solid var(--hairline-strong); border-bottom-width: 2px;
  border-radius: 4px; padding: 1px 5px; color: var(--ink-dim);
  background: rgba(255,255,255,.04);
}

/* ---------- journey spine (constellation node map) ---------- */
#journey {
  position: fixed;
  right: 20px;
  top: 96px;
  max-height: min(58vh, 520px);
  width: 250px;
  z-index: 24;
  padding: 12px 6px 10px 12px;
  display: flex; flex-direction: column;
  transition: transform .45s cubic-bezier(.6,.05,.25,1), opacity .35s;
}
#journey.hidden { transform: translateX(-115%); opacity: 0; pointer-events: none; }
#journey header { display: flex; align-items: center; gap: 10px; padding-right: 8px; }
#jprogress { margin-top: 2px; }
#jmap { flex: 1; overflow: hidden; position: relative; }
#jmap svg { width: 100%; height: 100%; overflow: visible; }
.jnode { cursor: pointer; }
.jnode circle.dot { fill: #10131f; stroke: var(--hairline-strong); stroke-width: 1.2; transition: fill .25s, stroke .25s; }
.jnode circle.glow { fill: none; stroke: var(--amber); opacity: 0; transition: opacity .3s; }
.jnode:hover circle.dot { stroke: var(--hot); }
.jnode.done circle.dot { fill: rgba(255, 149, 66, .35); stroke: var(--amber); }
.jnode.current circle.glow { opacity: .9; animation: pulse 2.2s ease-in-out infinite; }
@keyframes pulse { 0%,100% { r: 9; opacity:.85 } 50% { r: 13; opacity:.25 } }
.jnode text.num {
  font-family: var(--serif); font-size: 10px; fill: var(--ink-faint);
  text-anchor: middle; dominant-baseline: central; letter-spacing: 1px;
}
.jnode.done text.num, .jnode.current text.num { fill: var(--hot); }
.jnode text.t {
  font-family: var(--serif); font-size: 11.5px; fill: var(--ink-dim);
  letter-spacing: .04em;
}
.jnode.current text.t { fill: var(--hot); }
.spine-base { fill: none; stroke: rgba(255,214,165,.2); stroke-width: 1; stroke-dasharray: 1 5; stroke-linecap: round; }
.spine-done { fill: none; stroke: var(--amber); stroke-width: 1.4; opacity: .8; filter: drop-shadow(0 0 3px rgba(255,150,60,.8)); }
#jpulse { fill: #ffe9c9; filter: drop-shadow(0 0 5px rgba(255,180,100,1)); opacity: 0; }

/* ---------- chapter card ---------- */
#chapter-card {
  position: fixed;
  left: 296px; bottom: 96px;
  width: 360px;
  z-index: 27;
  padding: 16px 18px 14px;
  transition: transform .5s cubic-bezier(.6,.05,.25,1), opacity .4s;
}
#chapter-card.hidden { transform: translateY(130%); opacity: 0; pointer-events: none; }
#ch-head { display: flex; align-items: baseline; gap: 10px; margin-bottom: 6px; }
#ch-kicker { font-family: var(--serif); text-transform: uppercase; letter-spacing: .2em; font-size: 9.5px; color: var(--amber); }
#ch-title { font-family: var(--serif); font-size: 21px; font-weight: 500; letter-spacing: .01em; }
#ch-body { font-size: 13.8px; color: var(--ink-dim); }
#ch-body p + p { margin-top: 7px; }
#ch-body em { color: var(--hot); font-style: normal; }
.ch-try {
  margin-top: 10px; padding: 8px 11px;
  border: 1px dashed var(--hairline-strong); border-radius: 8px;
  font-size: 12px; color: var(--amber);
  background: rgba(255, 150, 70, .05);
}
#ch-nav { display: flex; align-items: center; gap: 10px; margin-top: 12px; }
.chbtn {
  font-size: 11px; letter-spacing: .16em; text-transform: uppercase;
  padding: 8px 14px; border-radius: 999px;
  border: 1px solid var(--hairline-strong); color: var(--ink-dim);
  transition: all .2s; min-height: 33px;
}
.chbtn.primary { background: linear-gradient(160deg, var(--hot), var(--ember)); color: #211102; border-color: transparent; font-weight: 600; }
.chbtn:hover { color: var(--hot); }
.chbtn.primary:hover { color: #fff; }
#ch-count { margin-left: auto; font-family: var(--mono); font-size: 10px; color: var(--ink-faint); }

/* ---------- part tooltip (click on the exhibit) ---------- */
#part-tip {
  position: fixed;
  width: 300px;
  z-index: 40;
  padding: 14px 16px 12px;
  transform-origin: top left;
  transition: opacity .22s, transform .22s;
}
#part-tip.hidden { opacity: 0; transform: scale(.92) translateY(6px); pointer-events: none; }
#pt-kicker { font-family: var(--serif); text-transform: uppercase; letter-spacing: .2em; font-size: 9px; color: var(--amber); margin-bottom: 3px; }
#pt-title { font-family: var(--serif); font-size: 17px; margin-bottom: 5px; }
#pt-body { font-size: 12.8px; color: var(--ink-dim); }
#pt-close { position: absolute; top: 8px; right: 10px; color: var(--ink-faint); font-size: 14px; min-height: 26px; min-width: 26px; }

/* ---------- drawers (glossary / extras / how real / quiz) ---------- */
.drawer {
  position: fixed;
  top: 64px; bottom: 20px;
  width: 420px;
  z-index: 45;
  padding: 18px 20px;
  overflow-y: auto;
  overscroll-behavior: contain;
  transition: transform .42s cubic-bezier(.65,.05,.25,1), opacity .32s;
}
#drawer-glossary { right: 20px; }
#drawer-extras { right: 20px; }
#drawer-real { right: 20px; }
#drawer-journey-m { left: 50%; transform: translateX(-50%); width: min(92vw, 430px); }
.drawer.hidden { opacity: 0; transform: translateX(40px); pointer-events: none; }
#drawer-journey-m.hidden { opacity: 0; transform: translate(-50%, 46px); pointer-events: none; }
.drawer h2 {
  font-family: var(--serif); font-weight: 500; font-size: 17px;
  letter-spacing: .24em; text-transform: uppercase; margin-bottom: 4px;
}
.drawer .d-sub { margin-bottom: 14px; }
.d-close { position: sticky; top: 0; float: right; margin: -6px -8px 0 0; color: var(--ink-faint); font-size: 18px; min-width: 34px; min-height: 34px; z-index: 2; background: rgba(10,12,22,.85); border-radius: 50%; }

.glossary-item { padding: 11px 0; border-bottom: 1px solid var(--hairline); }
.glossary-item dt { font-family: var(--serif); font-size: 14.5px; color: var(--hot); margin-bottom: 2px; }
.glossary-item dd { font-size: 12.8px; color: var(--ink-dim); }
.glossary-item dd .tie { color: var(--ink-faint); font-style: italic; }

.factcard {
  border: 1px solid var(--hairline); border-radius: 10px;
  padding: 14px 15px; margin-bottom: 10px;
  background: linear-gradient(170deg, rgba(255,160,80,.06), rgba(255,160,80,.015));
}
.factcard .fnum { font-family: var(--serif); font-variant: small-caps; letter-spacing: .2em; font-size: 10px; color: var(--amber); }
.factcard p { font-size: 13.2px; color: var(--ink-dim); margin-top: 3px; }
.factcard p strong { color: var(--ink); font-weight: 600; }

.challenge-item {
  display: flex; gap: 12px; align-items: flex-start;
  padding: 11px 0; border-bottom: 1px solid var(--hairline);
}
.challenge-item .box {
  flex: 0 0 auto; width: 20px; height: 20px; margin-top: 2px;
  border: 1.5px solid var(--hairline-strong); border-radius: 5px;
  display: grid; place-items: center;
  font-size: 12px; color: transparent; transition: all .3s;
}
.challenge-item.done .box { background: var(--amber); border-color: var(--amber); color: #201002; }
.challenge-item .ct { font-size: 13px; color: var(--ink); }
.challenge-item .cd { font-size: 11.5px; color: var(--ink-faint); }
.challenge-item.done .ct { color: var(--hot); }

/* quiz */
.q-progress { display: flex; gap: 5px; margin: 10px 0 14px; }
.q-progress i { flex: 1; height: 3px; border-radius: 2px; background: rgba(255,214,165,.16); }
.q-progress i.past { background: var(--amber); }
.q-question { font-family: var(--serif); font-size: 17px; margin-bottom: 12px; line-height: 1.45; }
.q-answer {
  display: block; width: 100%; text-align: left;
  border: 1px solid var(--hairline); border-radius: 9px;
  padding: 11px 13px; margin-bottom: 8px;
  font-size: 13px; color: var(--ink-dim);
  transition: all .18s; min-height: 44px;
}
.q-answer:hover:not(:disabled) { border-color: var(--amber); color: var(--ink); }
.q-answer.correct { border-color: #79d98c; background: rgba(90, 200, 120, .1); color: #bdf0ca; }
.q-answer.wrong { border-color: #ff7a6a; background: rgba(255, 110, 90, .08); color: #ffc4bb; }
.q-answer:disabled { cursor: default; opacity: .85; }
.q-feedback { font-size: 12.5px; color: var(--ink-dim); min-height: 34px; padding: 6px 2px; font-style: italic; }
.q-score { text-align: center; padding: 18px 0 6px; }
.q-score .big { font-family: var(--serif); font-size: 42px; color: var(--amber); }
.q-score p { color: var(--ink-dim); font-size: 13px; margin: 4px 0 16px; }

.real-list { list-style: none; }
.real-list li { padding: 10px 0 10px 20px; border-bottom: 1px solid var(--hairline); font-size: 12.8px; color: var(--ink-dim); position: relative; }
.real-list li::before { content: "◆"; position: absolute; left: 0; top: 10px; font-size: 9px; color: var(--amber); }
.real-list b { color: var(--ink); }

/* ---------- welcome / help overlay ---------- */
#welcome {
  position: fixed; inset: 0; z-index: 60;
  display: grid; place-items: center;
  background: radial-gradient(ellipse at 50% 60%, rgba(4,5,10,.25), rgba(4,5,10,.88));
  transition: opacity .5s; 
}
#welcome.hidden { opacity: 0; pointer-events: none; }
#welcome .wcard { max-width: 520px; width: calc(100vw - 48px); padding: 34px 38px 28px; text-align: center; }
#welcome h2 { font-family: var(--serif); font-weight: 500; font-size: 30px; letter-spacing: .18em; text-transform: uppercase; }
#welcome .wk { margin-bottom: 6px; }
#welcome .rule-wrap { display: flex; align-items: center; gap: 12px; margin: 14px 0 18px; }
#welcome .rule-wrap::before, #welcome .rule-wrap::after { content: ""; height: 1px; flex: 1; background: var(--hairline-strong); }
#welcome .rule-wrap span { font-family: var(--serif); font-variant: small-caps; font-size: 12px; letter-spacing: .3em; color: var(--amber); }
#welcome p.intro { color: var(--ink-dim); font-size: 14.5px; margin-bottom: 20px; }
.wsteps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; text-align: left; margin-bottom: 24px; }
.wstep { border: 1px solid var(--hairline); border-radius: 10px; padding: 12px; }
.wstep .wnum { font-family: var(--serif); font-variant: small-caps; letter-spacing: .24em; font-size: 10px; color: var(--amber); margin-bottom: 4px; }
.wstep p { font-size: 12px; color: var(--ink-dim); }
#welcome .chbtn { margin: 0 auto; display: inline-block; }
.wkeys { margin-top: 14px; font-size: 11px; color: var(--ink-faint); }

/* fps chip */
#fps-chip {
  position: fixed; right: 14px; bottom: 14px; z-index: 23;
  font-family: var(--mono); font-size: 10px; color: var(--ink-faint);
  background: rgba(8,10,18,.55); border: 1px solid var(--hairline);
  padding: 3px 8px; border-radius: 999px; letter-spacing: .08em;
}

/* toasts */
#toasts { position: fixed; top: 70px; right: 18px; z-index: 70; display: flex; flex-direction: column; gap: 8px; pointer-events: none; }
.toast {
  padding: 10px 16px; border-radius: 9px; font-size: 12.5px;
  background: var(--panel-solid); border: 1px solid var(--hairline-strong);
  color: var(--hot); box-shadow: var(--shadow);
  animation: toastin .35s cubic-bezier(.2,.9,.3,1.2);
  max-width: 290px;
}
@keyframes toastin { from { transform: translateX(30px); opacity: 0; } }

/* fallback screen */
#gpu-fallback {
  position: fixed; inset: 0; z-index: 90; display: none;
  place-items: center; text-align: center; padding: 30px;
  background: radial-gradient(circle at 50% 45%, #2a1305, #04050a 70%);
}
#gpu-fallback.show { display: grid; }
#gpu-fallback h2 { font-family: var(--serif); letter-spacing: .2em; text-transform: uppercase; font-size: 20px; margin-bottom: 12px; }
#gpu-fallback p { color: var(--ink-dim); max-width: 480px; font-size: 14px; }

/* ============================================================
   MOBILE
   ============================================================ */
.mobile-only { display: none !important; }

@media (max-width: 900px) {
  #journey { display: none; }
  #chapter-card { left: 50%; transform: translateX(-50%); width: min(94vw, 420px); bottom: 96px; max-height: 42vh; overflow-y: auto; }
  #chapter-card.hidden { transform: translate(-50%, 130%); }
  #dock { left: 12px; right: 12px; bottom: 12px; width: auto; }
  #dock .dockbody { display: grid; grid-template-columns: 1fr 1fr; column-gap: 14px; }
  #hud { bottom: auto; top: 64px; padding: 7px 10px; max-width: 96vw; flex-wrap: wrap; justify-content: center; row-gap: 6px; }
  .hud-cell { padding: 2px 9px; min-width: 72px; }
  #brand h1 { font-size: 14px; letter-spacing: .26em; }
  #topbar { padding: 10px 12px; }
  #nav { gap: 4px; }
  .navbtn { padding: 7px 10px; font-size: 9.5px; letter-spacing: .12em; }
  .mobile-only { display: initial !important; }
  #hud { left:50%; right:auto; transform:translateX(-50%); max-width:min(96vw,430px);
         flex-wrap:wrap; justify-content:center; row-gap:4px; padding:7px 8px;
         top:118px; bottom:auto; }
  #topbar { flex-wrap:wrap; row-gap:8px; }
  #brand { flex:1 1 100%; min-width:0; }
  #brand .sub { max-width:100%; }
  #brand .sub span:last-child { display:none; }
  #nav { flex:1 1 100%; justify-content:center; }
  #welcome .wsteps { grid-template-columns: 1fr; }
  .drawer { top: 54px; left: 12px; right: 12px; width: auto; bottom: 12px; }
  .drawer.hidden { transform: translateY(40px); }
  #drawer-journey-m { left: 12px; right: 12px; width: auto; transform: none; top: 56vh; }
  #drawer-journey-m.hidden { transform: translateY(60px); }
  #fps-chip { display: none; }
  #part-tip { left: 50% !important; bottom: 116px !important; top: auto !important; transform: translateX(-50%) !important; width: min(92vw, 340px); }
  #part-tip.hidden { transform: translateX(-50%) scale(.95) translateY(8px) !important; }
}

@media (max-height: 560px) and (min-width: 901px) {
  #journey { top: 70px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .001s !important; transition-duration: .15s !important; }
}