:root{
  --bg:#f6f4ef; --surface:#ffffff; --ink:#1f2430; --muted:#5f6675; --line:#d9d5cb; --accent:#c2562a; --accent-ink:#ffffff;
  --good:#2c7a4b; --warn:#b3261e; --shadow:0 1px 2px rgba(20,20,30,.06),0 6px 20px rgba(20,20,30,.05);
  --rs:55%; --rl:84%; --cat:#2b2a33; --cat-eye:#f6f4ef; --gridline:rgba(0,0,0,.14); --edge:#1f2430;
  --gold:#dba50f; --gold-glow:rgba(212,160,23,.6);
  --prune:#d64545; --dead:#e3a008; --place:#2c7a4b;
  color-scheme: light;
}
:root[data-theme="dark"]{ --bg:#14161c; --surface:#1d2029; --ink:#ebe8e1; --muted:#9aa0ae; --line:#323644; --accent:#e58a5b; --accent-ink:#1a1209;
  --good:#6cc28f; --warn:#ff8a80; --shadow:none; --rs:34%; --rl:28%; --cat:#f1ede4; --cat-eye:#1d2029; --gridline:rgba(255,255,255,.12); --edge:#c9c4b8;
  --prune:#ff6b6b; --dead:#f2b84b; --place:#6cc28f; --gold:#f2c230; --gold-glow:rgba(242,194,48,.65); color-scheme: dark; }
@media (prefers-color-scheme: dark){
  :root[data-theme="auto"]{ --bg:#14161c; --surface:#1d2029; --ink:#ebe8e1; --muted:#9aa0ae; --line:#323644; --accent:#e58a5b; --accent-ink:#1a1209;
    --good:#6cc28f; --warn:#ff8a80; --shadow:none; --rs:34%; --rl:28%; --cat:#f1ede4; --cat-eye:#1d2029; --gridline:rgba(255,255,255,.12); --edge:#c9c4b8;
    --prune:#ff6b6b; --dead:#f2b84b; --place:#6cc28f; --gold:#f2c230; --gold-glow:rgba(242,194,48,.65); color-scheme: dark; }
}
*{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.55 system-ui,-apple-system,"Segoe UI","Noto Sans TC","PingFang TC","Microsoft JhengHei",sans-serif}
.wrap{max-width:980px;margin:0 auto;padding:0 16px}
.muted{color:var(--muted)} .small{font-size:13px}
h1{font-size:clamp(24px,4.5vw,36px);line-height:1.2;margin:0 0 8px;letter-spacing:-.01em}
h2{margin:0 0 8px;font-size:22px} h3{margin:0;font-size:16px}
.top{position:sticky;top:0;z-index:5;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.top-in{display:flex;align-items:center;gap:12px;min-height:56px;flex-wrap:wrap;padding-top:6px;padding-bottom:6px}
.brand{display:flex;align-items:center;gap:8px;font-weight:700;margin-right:auto}
.logo{width:24px;height:24px;color:var(--accent);--cat-eye:var(--bg)}
.tabs{display:flex;gap:4px}
.tabs button{border:0;background:none;padding:8px 12px;border-radius:999px;color:var(--muted);font-weight:600}
.tabs button[aria-selected="true"]{background:var(--surface);color:var(--ink);box-shadow:var(--shadow)}
.tools{display:flex;gap:6px}
button,select{font:inherit;color:var(--ink)}
button{border:1px solid var(--line);background:var(--surface);padding:8px 14px;border-radius:10px;cursor:pointer;min-height:40px}
button:hover:not(:disabled){border-color:var(--muted)}
button:disabled{opacity:.45;cursor:default}
button.primary{background:var(--accent);color:var(--accent-ink);border-color:var(--accent);font-weight:600}
button.ghost{background:transparent}
button:focus-visible,select:focus-visible,.cell:focus-visible,input:focus-visible,a:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
select{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:8px 10px;min-height:40px;max-width:100%}
.hero{padding:16px 0 0} .hero h1{font-size:clamp(22px,3.4vw,30px)} .hero p{max-width:90ch;color:var(--muted);margin:0;font-size:15px;line-height:1.45}
.panel{padding:16px 0 32px}
.controls{display:flex;flex-wrap:wrap;gap:10px 12px;align-items:flex-end;margin-bottom:16px}
.controls label{display:flex;flex-direction:column;gap:2px;font-size:12px;color:var(--muted)}
.controls label.grow{flex:1 1 260px}
.controls label.grow select{width:100%}
.card{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:14px 16px;box-shadow:var(--shadow)}
.card ul{margin:6px 0 0;padding-left:18px}
.lead{max-width:70ch;color:var(--muted);margin:0 0 16px}
.board-col{position:sticky;top:64px}
.play-grid{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:20px;align-items:start}
.statusbar{display:flex;justify-content:space-between;align-items:baseline;margin-bottom:8px;font-size:14px}
.timer{font-variant-numeric:tabular-nums;font-weight:700;font-size:20px}
.btnrow{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.msg{min-height:3.2em;margin:12px 0;padding:10px 12px;border-radius:10px;background:var(--surface);border:1px solid var(--line);font-size:14px}
.msg.good{border-color:var(--good);color:var(--good)} .msg.warn{border-color:var(--warn);color:var(--warn)}

/* board: fixed square grid; cells never change size (no borders, glyphs are absolutely positioned) */
.board{--n:6;--bw:3px;position:relative;display:grid;grid-template-columns:repeat(var(--n),minmax(0,1fr));grid-template-rows:repeat(var(--n),minmax(0,1fr));
  width:min(100%,620px,max(280px,calc(100svh - 300px)));aspect-ratio:1;margin:0 auto;border-radius:12px;overflow:hidden;background:var(--surface);
  user-select:none;-webkit-user-select:none;-webkit-tap-highlight-color:transparent;contain:layout paint}
.board.play{touch-action:none;-webkit-touch-callout:none}
.board::after{content:"";position:absolute;inset:0;border:var(--bw) solid var(--edge);border-radius:12px;pointer-events:none;z-index:3}
.cell{position:relative;min-width:0;min-height:0;overflow:hidden;background:hsl(var(--h) var(--rs) var(--rl));cursor:pointer;outline-offset:-3px}
.board.mini .cell{cursor:default}
.board.play .cell.hl::before{content:"";position:absolute;inset:0;background:rgba(255,255,255,.22);pointer-events:none}
.lines{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;z-index:2;overflow:visible}
.lines path{fill:none;vector-effect:non-scaling-stroke}
.lines .thin{stroke:var(--gridline);stroke-width:1}
.lines .thick{stroke:var(--edge);stroke-width:var(--bw);stroke-linecap:square}
.board.dense{--bw:2px}
.ic,.xm{position:absolute;left:50%;top:50%;pointer-events:none;opacity:0;transform:translate(-50%,-50%) scale(.55);
  transition:opacity .14s ease-out,transform .14s ease-out;will-change:transform,opacity}
.ic{width:72%;height:72%;color:var(--cat)}
.xm{width:52%;height:52%;color:var(--ink);fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round}
.cell.cat .ic{opacity:1;transform:translate(-50%,-50%) scale(1)}
.cell.x .xm{opacity:.55;transform:translate(-50%,-50%) scale(1)}
.board.mini .ic{transition:none;opacity:0}
.board.mini .cell.cat .ic{opacity:1}
.cell.gold{box-shadow:inset 0 0 0 5px var(--gold),inset 0 0 0 6px rgba(0,0,0,.4),inset 0 0 0 999px color-mix(in srgb,var(--gold) 30%,transparent)}
.cell.wrong{box-shadow:inset 0 0 0 5px var(--warn),inset 0 0 0 6px rgba(0,0,0,.4),inset 0 0 0 999px color-mix(in srgb,var(--warn) 22%,transparent)}
.cell.gold.fresh{animation:goldglow .5s ease-out}
.cell.wrong.shake{animation:wrongflash .45s ease-out}
.stats-play{display:flex;gap:12px;align-items:baseline;flex-wrap:wrap;justify-content:flex-end}
.board.won{box-shadow:0 0 0 3px var(--good)}
@keyframes goldglow{0%{box-shadow:inset 0 0 0 5px var(--gold),inset 0 0 0 6px rgba(0,0,0,.4),inset 0 0 22px 8px var(--gold-glow)}100%{}}
@keyframes wrongflash{0%{box-shadow:inset 0 0 0 5px var(--warn),inset 0 0 0 6px rgba(0,0,0,.4),inset 0 0 0 999px color-mix(in srgb,var(--warn) 65%,transparent)}100%{}}

/* race */
.race-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.racer header{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:10px;flex-wrap:wrap}
.chip{font-size:12px;padding:2px 10px;border-radius:999px;border:1px solid var(--line);color:var(--muted);min-height:20px}
.chip:empty{visibility:hidden}
.chip.ok{color:var(--good);border-color:var(--good)} .chip.bad{color:var(--warn);border-color:var(--warn)} .chip.run{color:var(--accent);border-color:var(--accent)}
.stats{display:flex;gap:24px;margin-bottom:8px}
.stats .k{display:block;font-size:12px;color:var(--muted)}
.stats .v{font-size:clamp(18px,3.4vw,26px);font-weight:700;font-variant-numeric:tabular-nums}
.bar{height:6px;border-radius:3px;background:var(--line);overflow:hidden;margin-bottom:12px}
.bar i{display:block;height:100%;width:0;background:var(--accent);transition:width .1s linear}
.bar i.ok{background:var(--good)} .bar i.capped{background:var(--warn)}
.board.mini{width:100%;max-width:360px;--bw:2px}
.summary{margin-top:16px;padding:14px 16px;border-radius:12px;background:var(--surface);border:1px solid var(--line);font-size:17px;font-weight:600;min-height:0}
.summary:empty{display:none}
.summary.win{border-color:var(--good)}
.animbar{margin-top:14px}
.inline{flex-direction:row;display:flex;align-items:center;gap:8px;font-size:13px;color:var(--muted)}
.legend{display:flex;align-items:center;gap:6px;flex-wrap:wrap;margin-left:auto}
.lg{width:12px;height:12px;border-radius:3px;display:inline-block;margin-left:6px}
.lg.place{background:var(--place)} .lg.prune{background:var(--prune)} .lg.dead{background:var(--dead)}
.board.mini .cell.cat{box-shadow:inset 0 0 0 2px var(--place)}
.board.mini .cell.prune{box-shadow:inset 0 0 0 3px var(--prune);background:color-mix(in srgb,var(--prune) 35%,hsl(var(--h) var(--rs) var(--rl)))}
.board.mini .cell.dead{box-shadow:inset 0 0 0 3px var(--dead)}
.board.flash-prune{box-shadow:0 0 0 3px var(--prune)} .board.flash-dead{box-shadow:0 0 0 3px var(--dead)} .board.found{box-shadow:0 0 0 3px var(--good)}
#raceRef{margin-top:8px;word-break:break-word}
.findings{max-width:72ch} .findings p{margin:0 0 12px}
.btn-link{display:inline-block;padding:8px 14px;border:1px solid var(--accent);border-radius:10px;color:var(--accent);text-decoration:none;font-weight:600}
.foot{padding-bottom:32px}

@media (max-width:720px){
  .play-grid{grid-template-columns:1fr}
  .board-col{position:static}
  .hero p{display:none}
  .board{width:min(100%,calc(100svh - 190px))}
  .race-grid{grid-template-columns:1fr}
  .board.mini{max-width:100%}
  .tabs{order:3;width:100%;justify-content:center}
  .legend{margin-left:0}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}