/* How Big? — interface styles */
:root{
  --fg:#1f1d2a; --fg2:#57536a; --fg3:#8a8698; --panel:rgba(255,253,248,.84); --line:rgba(31,29,42,.12);
  --accent:#c2410c; --shadow:0 12px 32px rgba(31,29,42,.10);
  --sans:"IBM Plex Sans",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
body.dark{
  --fg:#eceaf4; --fg2:#aeabbf; --fg3:#7a778d; --panel:rgba(18,18,30,.72); --line:rgba(236,234,244,.14);
  --accent:#ff9466; --shadow:0 12px 32px rgba(0,0,0,.35);
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%;overflow:hidden}
body{font-family:var(--sans);color:var(--fg);background:#f4efe6;touch-action:none;user-select:none;-webkit-user-select:none;
  -webkit-font-smoothing:antialiased;transition:color .6s}
canvas#c{position:fixed;inset:0;width:100vw;height:100vh;display:block}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* top bar */
.top{position:fixed;top:0;left:0;right:0;height:64px;display:flex;align-items:center;justify-content:space-between;padding:0 20px;pointer-events:none;z-index:5}
.top > *{pointer-events:auto}
.brand{display:flex;align-items:center;gap:10px;color:var(--fg);text-decoration:none;font-weight:600;font-size:16px;letter-spacing:-.01em;transition:color .6s}
.brand svg{width:26px;height:26px}
.tools{display:flex;gap:8px}
.icon{width:38px;height:38px;border-radius:10px;border:1px solid var(--line);background:var(--panel);color:var(--fg);
  display:grid;place-items:center;cursor:pointer;backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);
  transition:border-color .2s,background .6s,color .6s;text-decoration:none;font:500 18px var(--sans)}
.icon:hover{border-color:var(--fg3)}
.icon:focus-visible,.btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.icon svg{width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}
.icon.on{color:var(--accent)}

/* chapter heading */
.chapter{position:fixed;top:74px;left:50%;transform:translateX(-50%);width:min(640px,calc(100vw - 40px));text-align:center;pointer-events:none;transition:opacity .45s;z-index:4}
.eyebrow{font:500 11px var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--accent);transition:color .6s}
.chapter h2{font-weight:600;font-size:26px;letter-spacing:-.015em;margin-top:6px}
.chapter p{font-size:14.5px;line-height:1.6;color:var(--fg2);margin-top:6px;transition:opacity 1.4s,color .6s}
.chapter p.dim{opacity:0}

/* object card */
.card{position:fixed;left:24px;bottom:96px;width:360px;background:var(--panel);border:1px solid var(--line);border-radius:16px;
  padding:18px 20px;box-shadow:var(--shadow);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  transition:opacity .22s,transform .22s,background .6s,border-color .6s;z-index:4;pointer-events:none}
.card.swap{opacity:0;transform:translateY(6px)}
.card .tag{font:500 11px var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--fg3)}
.card h2{font-size:21px;font-weight:600;letter-spacing:-.01em;margin-top:6px}
.card .size{font:500 14px var(--mono);color:var(--accent);margin-top:3px}
.card p{font-size:14px;line-height:1.55;color:var(--fg2);margin-top:10px}
.card .cmp{font:400 12px var(--mono);color:var(--fg3);margin-top:12px;padding-top:10px;border-top:1px solid var(--line)}
.card .cmp:empty{display:none}

/* ruler */
.ruler{position:fixed;left:0;right:0;bottom:0;height:76px;display:flex;align-items:center;justify-content:space-between;padding:0 14px;pointer-events:none;z-index:4}
.ruler .icon{pointer-events:auto;border-radius:50%}
.ruler-hit{position:absolute;left:66px;right:66px;top:6px;bottom:0;pointer-events:auto;cursor:ew-resize}

.toast{position:fixed;left:50%;bottom:96px;transform:translate(-50%,10px);background:var(--fg);color:var(--panel);font-size:13px;font-weight:500;
  padding:9px 14px;border-radius:10px;opacity:0;transition:opacity .25s,transform .25s;pointer-events:none;z-index:9}
.toast.show{opacity:1;transform:translate(-50%,0)}

/* intro */
.intro{position:fixed;inset:0;z-index:20;background:#f4efe6;color:#1f1d2a;display:flex;flex-direction:column;align-items:center;justify-content:center;
  text-align:center;padding:24px;transition:opacity .8s}
.intro.hidden{opacity:0;pointer-events:none}
.intro .mark{width:58px;height:58px;color:#1f1d2a}
.intro h1{font-weight:600;font-size:clamp(44px,8vw,76px);letter-spacing:-.035em;line-height:1;margin-top:18px}
.intro p{font-size:17px;line-height:1.55;color:#57536a;max-width:470px;margin-top:14px}
.intro canvas{width:min(560px,92vw);height:auto;margin-top:26px}
.intro .row{display:flex;gap:10px;flex-wrap:wrap;justify-content:center;margin-top:24px}
.btn{font:500 15px var(--sans);border-radius:10px;padding:13px 22px;cursor:pointer;border:1px solid transparent;transition:transform .15s,background .2s}
.btn:hover{transform:translateY(-1px)}
.btn.primary{background:#1f1d2a;color:#fbf8f2}
.btn.secondary{background:transparent;color:#1f1d2a;border-color:rgba(31,29,42,.22)}
.intro .hint{font-size:12.5px;color:#8a8698;margin-top:16px}
.intro .links{position:absolute;bottom:22px;font-size:13px;color:#8a8698}
.intro .links a{color:#57536a;text-decoration:none;border-bottom:1px solid rgba(31,29,42,.2);margin:0 6px}

@media (max-width:720px){
  .top{height:56px;padding:0 12px}
  .brand span{font-size:15px}
  .tools{gap:6px}
  .icon{width:34px;height:34px;border-radius:9px}
  .tools .hide-sm{display:none}
  .chapter{top:60px}
  .chapter h2{font-size:20px}
  .chapter p{font-size:13px;line-height:1.5}
  .card{left:12px;right:12px;width:auto;bottom:80px;padding:14px 16px;border-radius:14px}
  .card h2{font-size:18px}
  .card p{font-size:13.5px}
  .ruler{height:68px;padding:0 10px}
  .ruler-hit{left:54px;right:54px}
  .toast{bottom:84px}
}
@media (max-height:640px) and (max-width:720px){ .card p{display:none} }