:root{--bg: #0d1117;--panel: #131a23;--line: #263243;--ink: #dce3ec;--dim: #8a97a8;--accent: #38bdf8;--good: #7dd3a0;--bad: #f87171;--warn: #f0a868;--cell: 46px}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font-family:ui-sans-serif,system-ui,-apple-system,Helvetica Neue,sans-serif;line-height:1.65}main{max-width:860px;margin:0 auto;padding:2.2rem 1.2rem 4rem}header h1{font-size:2.1rem;margin:0 0 .5rem;letter-spacing:-.02em}header h1 span{color:var(--accent)}.sub{color:var(--dim);margin:0 0 1.6rem;font-size:.95rem}.legend{display:flex;flex-wrap:wrap;gap:.4rem 1.4rem;color:var(--dim);font-size:.85rem;margin-bottom:1.2rem}.legend i{display:inline-block;width:16px;height:16px;border-radius:4px;vertical-align:-3px;margin-right:6px;background:var(--panel);border:1px solid var(--line)}.legend .dot-demo{border-radius:50%;background:var(--ink);border-color:var(--bg);box-shadow:0 0 0 2px var(--line)}.legend .pair-demo{background:linear-gradient(135deg,#47a3d1a6 50%,#47a3d1a6 50%)}.legend .mark-demo{border-radius:50%;background:var(--bad);border-color:var(--bg)}#wrap{display:flex;justify-content:center}#stage{position:relative;display:inline-block}#board{display:grid;background:var(--panel);border:2px solid var(--line);border-radius:6px;padding:6px;gap:0;touch-action:manipulation;user-select:none;-webkit-user-select:none}.cell{width:var(--cell);height:var(--cell);border:1px solid var(--line);background:transparent;cursor:pointer;position:relative}.cell.owned{border-color:color-mix(in srgb,var(--line) 55%,transparent)}#board.solved .cell{cursor:default}#dots{position:absolute;top:0;right:0;bottom:0;left:0;pointer-events:none;z-index:3}.dot{position:absolute;width:14px;height:14px;margin:-7px 0 0 -7px;border-radius:50%;background:var(--ink);border:2.5px solid var(--bg);box-shadow:0 0 0 1.5px var(--line);pointer-events:auto;cursor:pointer;transition:transform .08s ease}.dot:hover{transform:scale(1.25)}.dot.selected{background:var(--accent);box-shadow:0 0 0 2.5px var(--accent),0 0 12px 2px color-mix(in srgb,var(--accent) 60%,transparent)}#marks{position:absolute;top:0;right:0;bottom:0;left:0;pointer-events:none;z-index:4}.mark{position:absolute;width:9px;height:9px;margin:-4.5px 0 0 -4.5px;border-radius:50%;background:var(--bad);border:1.5px solid var(--bg)}#board.solved{border-color:var(--good);box-shadow:0 0 22px 2px color-mix(in srgb,var(--good) 35%,transparent)}.hud{text-align:center;min-height:1.8rem;margin:.8rem 0 .4rem;color:var(--dim);font-size:.92rem}.hud .good{color:var(--good)}.hud .bad{color:var(--bad)}.controls{display:flex;flex-wrap:wrap;gap:.6rem 1rem;justify-content:center;align-items:end;margin:.6rem 0 2rem}.controls label{display:flex;flex-direction:column;gap:.2rem;font-size:.8rem;color:var(--dim)}select,button{background:var(--panel);color:var(--ink);border:1px solid var(--line);border-radius:6px;padding:.45rem .8rem;font-size:.9rem;cursor:pointer}button:hover,select:hover{border-color:var(--accent)}.notes{border-top:1px solid var(--line);margin-top:1rem;padding-top:1rem}.notes h2{font-size:1.1rem;margin:1.4rem 0 .4rem}.notes p{color:var(--dim);font-size:.92rem;margin:.4rem 0}.notes strong{color:var(--ink)}footer{border-top:1px solid var(--line);margin-top:2rem;padding-top:1rem;color:var(--dim);font-size:.85rem}@media (max-width: 640px){:root{--cell: 34px}}