:root{
  --bg:#081420; --ink:#e8eef3; --dim:#9db0bf; --line:#1d3444; --panel:#0e2030;
  --accent:#4fc3f7; --warm:#f0b44a; --good:#6fd08c; --bad:#e8664a;
  --shadow:0 10px 40px rgba(0,0,0,.45);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--bg);color:var(--ink);
  font:15px/1.55 "Helvetica Neue",Helvetica,Arial,system-ui,sans-serif;-webkit-text-size-adjust:100%}
h1,h2,h3{font-weight:600;letter-spacing:.01em;margin:0 0 .5em}
a{color:var(--accent)}
kbd{font:600 12px/1 ui-monospace,Menlo,Consolas,monospace;background:#17293a;border:1px solid var(--line);
  border-radius:4px;padding:2px 5px;color:var(--ink)}
code{font:12px/1 ui-monospace,Menlo,Consolas,monospace;color:var(--warm)}
.skip{position:absolute;left:-9999px;top:0;z-index:50;background:var(--panel);padding:10px 14px}
.skip:focus{left:8px;top:8px}

#stage{position:relative;width:100%;height:100svh;min-height:320px;overflow:hidden;background:#5b7a94}
#gl,#hud{position:absolute;inset:0;width:100%;height:100%;display:block}
#hud{pointer-events:none}
body.racing #stage{touch-action:none;-webkit-user-select:none;user-select:none}
#tbtns{position:absolute;top:10px;right:12px;z-index:5;display:flex;gap:6px}
.tb{margin:0;padding:8px 12px;font-size:13px;background:rgba(8,20,32,.82)}
.tb[hidden]{display:none}

#topbar{position:absolute;left:0;right:0;top:0;padding:10px 14px;z-index:3;
  background:linear-gradient(180deg,rgba(4,12,20,.78),rgba(4,12,20,0));pointer-events:none}
#topbar h1{font-size:17px;margin:0 0 6px;text-shadow:0 1px 3px rgba(0,0,0,.6)}
#racebar{display:flex;flex-wrap:wrap;gap:6px 18px}
.stat{display:flex;flex-direction:column;min-width:74px}
.stat .k{font-size:10px;text-transform:uppercase;letter-spacing:.09em;color:#bcd2e2;opacity:.9}
.stat .v{font:600 19px/1.15 ui-monospace,Menlo,Consolas,monospace;text-shadow:0 1px 3px rgba(0,0,0,.6)}

#instruments{position:absolute;right:12px;bottom:12px;z-index:3;width:min(46vw,330px);
  background:rgba(8,20,32,.82);border:1px solid var(--line);border-radius:10px;padding:10px 11px 8px;
  backdrop-filter:blur(6px)}
#instruments h2{font-size:11px;text-transform:uppercase;letter-spacing:.09em;color:var(--dim);margin:0 0 6px}
#trace{width:100%;height:auto;display:block;border-radius:6px;background:#0a1826}
.read{font-size:12px;color:var(--dim);margin:6px 0 4px;min-height:2.6em}
#effRead{display:grid;grid-template-columns:1fr 1fr;gap:2px 10px;margin:0;font-size:11px}
#effRead div{display:flex;justify-content:space-between;gap:6px;border-top:1px solid var(--line);padding-top:2px}
#effRead dt{color:var(--dim)}
#effRead dd{margin:0;font:600 12px/1.3 ui-monospace,Menlo,Consolas,monospace}

#lanes{position:absolute;left:12px;bottom:12px;z-index:3;display:flex;flex-direction:column;gap:3px;
  background:rgba(8,20,32,.78);border:1px solid var(--line);border-radius:10px;padding:8px 10px;font-size:12px}
#lanes .ln{display:flex;align-items:center;gap:7px;font-variant-numeric:tabular-nums}
#lanes .sw{width:9px;height:9px;border-radius:2px;flex:none}
#lanes .me{font-weight:700}
#lanes .gap{color:var(--dim);font:11px/1 ui-monospace,Menlo,Consolas,monospace;margin-left:auto}

#coach{position:absolute;left:50%;top:38%;transform:translateX(-50%);z-index:4;margin:0;
  font:600 22px/1.2 "Helvetica Neue",Helvetica,Arial,sans-serif;text-align:center;
  text-shadow:0 2px 10px rgba(0,0,0,.8);pointer-events:none;opacity:0;transition:opacity .25s}
#coach.on{opacity:1}

.panel{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);z-index:10;
  width:min(92vw,560px);max-height:88svh;overflow:auto;background:var(--panel);
  border:1px solid var(--line);border-radius:14px;padding:20px 22px;box-shadow:var(--shadow)}
.panel[hidden]{display:none!important}
.panel h2{font-size:19px}
.row{display:flex;flex-direction:column;gap:4px;margin:0 0 12px}
.row label{font-size:12px;text-transform:uppercase;letter-spacing:.07em;color:var(--dim)}
select,input[type=range]{width:100%;font:inherit}
select{background:#132638;color:var(--ink);border:1px solid var(--line);border-radius:7px;padding:8px 10px}
input[type=range]{accent-color:var(--accent)}
button{font:600 14px/1 inherit;background:#17293a;color:var(--ink);border:1px solid var(--line);
  border-radius:8px;padding:11px 16px;cursor:pointer;margin:4px 6px 0 0}
button:hover{background:#1d344a}
button.primary{background:var(--accent);color:#062232;border-color:var(--accent)}
button.primary:hover{background:#7ad2f9}
.hint{font-size:12px;color:var(--dim);margin:10px 0 0}
output{font:600 13px/1 ui-monospace,Menlo,Consolas,monospace;color:var(--ink)}

#labOut{width:100%;border-collapse:collapse;font-size:12px;margin:8px 0}
#labOut th{text-align:left;font-weight:500;color:var(--dim);padding:3px 8px 3px 0;white-space:nowrap}
#labOut td{font:600 13px/1.4 ui-monospace,Menlo,Consolas,monospace;padding:3px 14px 3px 0}
#labTrace{width:100%;height:auto;border-radius:6px;background:#0a1826;display:block}

#rTable{width:100%;border-collapse:collapse;font-size:13px;margin:6px 0 2px}
#rTable td,#rTable th{padding:5px 8px 5px 0;border-bottom:1px solid var(--line);text-align:left}
#rTable td.t{font:600 13px/1 ui-monospace,Menlo,Consolas,monospace}
#rTable tr.me td{color:var(--accent)}

#help{max-width:820px;margin:0 auto;padding:34px 20px 90px}
#help h2{font-size:22px;margin-top:0}
#help h3{font-size:16px;margin-top:1.9em;color:var(--warm)}
#help p,#help li{color:#cddae4}
#help .eq{font:15px/1.6 ui-monospace,Menlo,Consolas,monospace;background:#0e2030;border-left:3px solid var(--accent);
  padding:10px 14px;border-radius:0 6px 6px 0;color:var(--ink);overflow-x:auto}
.toc{display:flex;flex-wrap:wrap;gap:8px 16px;margin:0 0 1.4em;font-size:13px}
.toc a{color:var(--accent);text-decoration:none;border-bottom:1px solid rgba(79,195,247,.35)}
.toc a:hover{border-bottom-color:var(--accent)}
.limits li,.src li{margin:0 0 .65em}
.tally{border-collapse:collapse;width:100%;font-size:13px;margin:10px 0}
.tally th,.tally td{border-bottom:1px solid var(--line);padding:6px 10px 6px 0;text-align:left}
.tally td:nth-child(2){font:600 13px/1 ui-monospace,Menlo,Consolas,monospace;text-align:right;width:64px}
.tally tr.tot td,.tally tr.tot th{border-top:2px solid var(--line);font-weight:600}
.src .u{display:block;font:11px/1.5 ui-monospace,Menlo,Consolas,monospace;color:#7e94a6;word-break:break-all}
.nojs{max-width:820px;margin:0 auto;padding:0 20px 40px;color:var(--warm)}

@media (max-width:720px){
  #instruments{width:calc(100% - 24px);right:12px;bottom:12px}
  #racebar{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:4px 10px}
  .stat{min-width:0}
  #lanes{left:12px;bottom:auto;top:124px;font-size:11px;gap:1px;padding:6px 8px}
  .stat .v{font-size:16px}
  #coach{font-size:17px;width:90%}
}
@media (max-width:900px) and (max-height:700px){
  #instruments .read,#effRead{display:none}
  #instruments h2{margin-bottom:4px}
}
@media (prefers-reduced-motion:reduce){#coach{transition:none}}