*{box-sizing:border-box}
:root{
  --bg:#020b12; --panel:#06202b; --line:#0e3a4a;
  --ink:#d9f6ff; --muted:#7fb8c9; --accent:#5df2d6;
}
html{background:var(--bg)}
body{
  margin:0; min-height:100vh;
  background:radial-gradient(1100px 700px at 80% -10%,rgba(40,180,200,.1),transparent 55%),linear-gradient(180deg,#03131d,var(--bg));
  color:var(--ink); font-family:ui-sans-serif,system-ui,-apple-system,sans-serif;
  display:flex; flex-direction:column;
}
.back{margin:18px 24px 0;color:var(--muted);text-decoration:none;font-size:14px}
.back:hover{color:var(--ink)}
.head{max-width:1000px;width:100%;margin:0 auto;padding:8px 24px 0}
.eyebrow{letter-spacing:.14em;text-transform:uppercase;font-size:12px;color:var(--accent);margin:0 0 6px}
h1{margin:0;font-size:44px;letter-spacing:-.02em;line-height:1;background:linear-gradient(90deg,#fff,#9ff2dd 55%,#59c8e8);-webkit-background-clip:text;background-clip:text;color:transparent}
.lede{color:var(--muted);max-width:66ch;line-height:1.5;margin:10px 0 0}
.layout{max-width:1000px;width:100%;margin:0 auto;padding:20px 24px 28px;flex:1;display:grid;gap:16px}
.controls{
  background:var(--panel);border:1px solid var(--line);border-radius:14px;
  padding:12px;display:flex;gap:10px;align-items:center;flex-wrap:wrap;
  box-shadow:0 10px 30px rgba(0,0,0,.4);
}
button{
  border:1px solid var(--line);background:#0a2c3a;color:var(--ink);
  padding:9px 14px;border-radius:10px;font:600 13px/1 system-ui;cursor:pointer;
}
button:hover{border-color:var(--accent)}
button:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
button.ghost{background:transparent}
.hint{flex:1;min-width:220px;font-size:12px;color:var(--muted);margin:0;text-align:right}
.stage-wrap{position:relative}
canvas{
  width:100%;height:470px;display:block;background:#011017;
  border:1px solid var(--line);border-radius:14px;cursor:crosshair;touch-action:none;
}
.controls button{min-height:44px}
canvas:focus-visible{outline:2px solid var(--accent);outline-offset:3px}
.overlay{
  position:absolute;left:14px;bottom:12px;pointer-events:none;
  font:11px 'DM Mono',monospace;text-transform:uppercase;letter-spacing:.1em;color:var(--muted);
  background:rgba(2,11,18,.62);border:1px solid var(--line);padding:5px 9px;border-radius:8px;
  transition:opacity 1.2s ease;
}
.overlay.done{opacity:0}
.readout{
  background:var(--panel);border:1px solid var(--line);border-radius:14px;
  padding:12px 14px;font-size:14px;color:var(--ink);min-height:42px;line-height:1.4;
}
.foot{
  display:flex;justify-content:space-between;gap:12px;
  padding:14px 24px 20px;color:var(--muted);font-size:13px;
  border-top:1px solid var(--line);max-width:1000px;width:100%;margin:0 auto;
}
.foot a{color:var(--muted);text-decoration:none}
.foot a:hover{color:var(--ink)}
@media(max-width:700px){
  h1{font-size:34px}
  canvas{height:340px}
  .hint{text-align:left}
}