/* ============================================================
   HALDEN GALLERY — overlay UI over the WebGL stage.
   ============================================================ */
:root{
  --fg:#f2efe9;
  --dim:#a49c90;
  --line:rgba(242,239,233,.16);
  --scrim:rgba(12,10,9,.62);
  --pad:clamp(18px,4vw,56px);
  --ease:cubic-bezier(.22,1,.36,1);
  --f:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:auto}
body{
  margin:0;background:#0b0a09;color:var(--fg);
  font-family:var(--f);font-size:16px;line-height:1.5;
  -webkit-font-smoothing:antialiased;
  font-feature-settings:"cv05" 1;
}
a{color:inherit;text-decoration:none}
h1,h2,p,dl,dd,dt{margin:0}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
::selection{background:var(--fg);color:#0b0a09}

/* ---------- WebGL stage ---------- */
.stage{position:fixed;inset:0;z-index:0}
.stage canvas{display:block;width:100%;height:100%}
.stage__vignette{
  position:absolute;inset:0;pointer-events:none;
  background:radial-gradient(120% 90% at 50% 42%,transparent 42%,rgba(6,5,4,.62) 100%);
}

/* ---------- boot ---------- */
.boot{
  position:fixed;inset:0;z-index:60;background:#0b0a09;
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:12px;
  transition:opacity .8s var(--ease),visibility .8s;
}
.boot__label{font-size:13px;letter-spacing:.34em;text-transform:uppercase}
.boot__sub{font-size:12px;color:var(--dim)}
body.is-ready .boot{opacity:0;visibility:hidden}

/* ---------- header ---------- */
.nav{
  position:fixed;top:0;left:0;right:0;z-index:40;
  display:grid;grid-template-columns:1fr auto 1fr;align-items:center;
  gap:16px;padding:20px var(--pad);
  border-bottom:1px solid var(--line);
  background:linear-gradient(180deg,rgba(11,10,9,.72),rgba(11,10,9,0));
  backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px);
}
.nav__logo{display:flex;align-items:center;gap:9px;font-size:13px;letter-spacing:.22em;text-transform:uppercase;font-weight:500}
.nav__mark{width:7px;height:7px;border-radius:50%;background:#c8a86a}
.nav__centre{justify-self:center;font-size:13px;letter-spacing:.05em;position:relative;padding-bottom:3px}
.nav__centre::after{content:"";position:absolute;left:0;right:0;bottom:0;height:1px;background:currentColor;opacity:.5}
.nav__right{justify-self:end;display:flex;align-items:center;gap:22px;font-size:13px;color:var(--dim)}
.nav__right a{transition:color .3s var(--ease)}
.nav__right a:hover{color:var(--fg)}
.nav__sep{opacity:.35}
.nav__auto{
  width:30px;height:30px;border:1px solid var(--line);border-radius:50%;
  display:grid;place-items:center;transition:background .3s var(--ease),border-color .3s var(--ease);
}
.nav__auto svg{width:11px;height:11px;fill:currentColor}
.nav__auto .pause{display:none}
.nav__auto:hover{border-color:var(--fg)}
.nav__auto.is-on{background:var(--fg);color:#0b0a09;border-color:var(--fg)}
.nav__auto.is-on .play{display:none}
.nav__auto.is-on .pause{display:block}

/* ---------- HUD ---------- */
.hud{
  position:fixed;right:var(--pad);top:50%;transform:translateY(-50%);z-index:35;
  display:flex;flex-direction:column;align-items:center;gap:14px;
  font-size:10px;letter-spacing:.2em;text-transform:uppercase;color:var(--dim);
}
.hud__track{width:1px;height:150px;background:var(--line);position:relative;overflow:hidden}
.hud__track i{position:absolute;inset:0;background:var(--fg);transform-origin:50% 0;transform:scaleY(0)}
.hud__room{writing-mode:vertical-rl;letter-spacing:.28em;color:var(--fg)}
@media (max-width:760px){.hud{display:none}}

/* ---------- chapters ---------- */
main{position:relative;z-index:20}
.ch{min-height:170svh;position:relative}
.ch__hold{
  position:sticky;top:0;height:100svh;
  display:flex;align-items:center;
  padding:calc(64px + var(--pad)) var(--pad) calc(var(--pad) + 34px);
  pointer-events:none;
}
.ch__in{
  max-width:min(430px,86vw);
  background:var(--scrim);
  backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  border:1px solid var(--line);border-radius:4px;
  padding:clamp(20px,2.6vw,34px);
  display:flex;flex-direction:column;gap:14px;
  opacity:0;transform:translateY(26px);
  transition:opacity .85s var(--ease),transform .85s var(--ease);
  pointer-events:auto;
}
.ch.is-on .ch__in{opacity:1;transform:none}
.ch:nth-child(even) .ch__hold{justify-content:flex-end}

.eyebrow{font-size:10px;letter-spacing:.24em;text-transform:uppercase;color:var(--dim)}
.ch h2{font-size:clamp(1.35rem,2.6vw,2rem);font-weight:500;letter-spacing:-.02em;line-height:1.14}
.ch p{font-size:14.5px;color:#cdc6bb;line-height:1.6}

.facts{display:flex;flex-wrap:wrap;gap:10px 26px;margin-top:4px;border-top:1px solid var(--line);padding-top:14px}
.facts div{display:flex;flex-direction:column;gap:3px}
.facts dt{font-size:10px;letter-spacing:.16em;text-transform:uppercase;color:var(--dim)}
.facts dd{font-size:15px}

/* hero chapter */
.ch--hero .ch__hold{align-items:flex-end;justify-content:center;text-align:center}
.ch--hero .ch__in{
  background:none;backdrop-filter:none;-webkit-backdrop-filter:none;border:0;
  align-items:center;max-width:min(720px,90vw);
  text-shadow:0 2px 34px rgba(6,5,4,.85);
}
.ch--hero h1{
  font-size:clamp(1.7rem,3.8vw,2.9rem);font-weight:400;
  letter-spacing:.03em;line-height:1.02;text-transform:uppercase;
}
.lede{max-width:44ch;font-size:clamp(.95rem,1.4vw,1.08rem);color:#d7d1c7}
.hint{
  margin-top:18px;display:flex;align-items:center;gap:10px;
  font-size:10px;letter-spacing:.2em;text-transform:uppercase;color:var(--dim);
}
.hint i{
  width:20px;height:32px;border:1px solid var(--line);border-radius:999px;position:relative;
}
.hint i::after{
  content:"";position:absolute;left:50%;top:6px;width:2px;height:6px;border-radius:2px;background:var(--dim);
  animation:wheel 2s var(--ease) infinite;
}
@keyframes wheel{0%{transform:translate(-50%,0);opacity:0}25%{opacity:1}100%{transform:translate(-50%,14px);opacity:0}}

/* closing chapter */
.ch--end .ch__hold{align-items:center;justify-content:flex-end}
.ch--end .ch__in{max-width:min(560px,90vw);align-items:flex-start}
.grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px 24px;width:100%;margin-top:4px}
.grid div{display:flex;flex-direction:column;gap:2px;border-top:1px solid var(--line);padding-top:10px}
.grid b{font-size:clamp(1.1rem,2vw,1.5rem);font-weight:500;letter-spacing:-.01em}
.grid span{font-size:12px;color:var(--dim)}
.btn{
  margin-top:8px;align-self:flex-start;
  border:1px solid var(--line);border-radius:999px;padding:12px 26px;font-size:14px;
  transition:background .35s var(--ease),color .35s var(--ease),border-color .35s var(--ease);
}
.btn:hover{background:var(--fg);color:#0b0a09;border-color:var(--fg)}

/* ---------- demo badge ---------- */
.demo-badge{
  position:fixed;left:50%;bottom:18px;transform:translateX(-50%);z-index:45;
  display:flex;align-items:center;gap:8px;
  padding:8px 14px 8px 10px;border-radius:999px;
  background:rgba(11,10,9,.72);border:1px solid var(--line);
  backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);
  font-size:12px;opacity:.45;transition:opacity .35s var(--ease),transform .35s var(--ease);
}
.demo-badge:hover{opacity:1;transform:translateX(-50%) translateY(-2px)}
.demo-badge b{font-weight:600}
.demo-badge i{font-style:normal;opacity:.55}

/* ---------- no WebGL ---------- */
.nogl{display:none}
body.no-gl .stage,body.no-gl .hud,body.no-gl .ch--hero .hint{display:none}
body.no-gl{background:#141210}
body.no-gl .nogl{
  display:block;position:fixed;left:50%;top:76px;transform:translateX(-50%);z-index:50;
  background:var(--scrim);border:1px solid var(--line);border-radius:4px;
  padding:14px 20px;font-size:13.5px;color:#cdc6bb;text-align:center;max-width:min(520px,90vw);
}
body.no-gl .ch__in{opacity:1;transform:none}
body.no-gl .ch{min-height:auto;padding-top:36px}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.001ms!important;transition-duration:.001ms!important}
  .ch__in{opacity:1;transform:none}
}

@media (max-width:760px){
  .ch__hold{padding-top:calc(70px + var(--pad))}
  .ch:nth-child(even) .ch__hold{justify-content:flex-start}
  .nav{grid-template-columns:1fr auto;padding:14px var(--pad)}
  .nav__centre{display:none}
  .nav__right{gap:14px;font-size:12px}
  .nav__right .hide-sm{display:none}
  .grid{grid-template-columns:1fr}
}