:root{--bg: #08131a;--panel: #0e1e28;--line: #24404e;--ink: #dceaf1;--dim: #8ba7b6;--accent: #f0c987;--water: #3fa9c9;--good: #6fd3a8;--bad: #f87171;--stone: #2f5266;--paper: #f2ecdf}*{box-sizing:border-box}body{margin:0;background:radial-gradient(1200px 600px at 50% -10%,#102836 0%,var(--bg) 60%);color:var(--ink);font-family:ui-sans-serif,system-ui,-apple-system,Helvetica Neue,sans-serif;line-height:1.65}main{max-width:880px;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(--water)}.sub{color:var(--dim);margin:0 0 1.4rem;font-size:.95rem}.sub strong{color:var(--ink)}.sub em{color:var(--accent);font-style:italic}.legend{display:flex;flex-wrap:wrap;gap:.4rem 1.4rem;color:var(--dim);font-size:.85rem;margin-bottom:1.1rem}.legend i{display:inline-flex;width:18px;height:18px;border-radius:4px;vertical-align:-4px;margin-right:6px}.legend .bank-demo{background:var(--stone);border:1px solid #5b8ba6}.legend .water-demo{background:transparent;border:1px solid var(--line);position:relative}.legend .water-demo:after{content:"";position:absolute;top:4px;right:4px;bottom:4px;left:4px;border-radius:50%;background:var(--water)}.legend .num-demo{background:var(--paper);color:#123;border-radius:50%;font-style:normal;font-weight:700;font-size:.75rem;align-items:center;justify-content:center}.legend .bad-demo{background:transparent;border:2px solid var(--bad);border-radius:50%}#wrap{overflow-x:auto;padding-bottom:.4rem}#stage{width:fit-content;margin:0 auto}#board{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:6px;line-height:0}#board.solved{border-color:var(--good);box-shadow:0 0 0 1px var(--good),0 0 24px #6fd3a838}#board svg{display:block}.cell{fill:transparent;stroke:var(--line);stroke-width:1;cursor:pointer}.cell:hover{fill:#3fa9c91f}.shade{fill:var(--stone);stroke:#5b8ba6;stroke-width:1;cursor:pointer}.creek{fill:var(--water);opacity:.9;pointer-events:none}.creek.bad{fill:var(--bad)}.link{stroke:var(--water);stroke-width:4;stroke-linecap:round;opacity:.55;pointer-events:none}.grid{fill:none;stroke:var(--line);stroke-width:1;pointer-events:none}.knot{fill:var(--paper);stroke:#b9ad97;stroke-width:1;pointer-events:none}.knot.bad{stroke:var(--bad);stroke-width:2.5}.knot.done{fill:#cfe6c9}.vnum{fill:#10222c;font-family:ui-sans-serif,system-ui,sans-serif;font-weight:700;pointer-events:none;-webkit-user-select:none;user-select:none;text-anchor:middle;dominant-baseline:central}#board.solved .knot{stroke:var(--good)}.hud{margin:.9rem 0 .6rem;min-height:1.6em;color:var(--dim);font-size:.92rem;text-align:center}.controls{display:flex;flex-wrap:wrap;gap:.6rem 1rem;align-items:end;justify-content:center;margin-bottom:2.2rem}.controls label{display:flex;flex-direction:column;gap:.25rem;color:var(--dim);font-size:.8rem}select,button{background:var(--panel);color:var(--ink);border:1px solid var(--line);border-radius:8px;padding:.45rem .8rem;font-size:.9rem;cursor:pointer}select:hover,button:hover,button#solve{border-color:var(--water)}.notes{border-top:1px solid var(--line);padding-top:1.4rem;color:var(--dim);font-size:.95rem}.notes h2{color:var(--ink);font-size:1.15rem;margin:1.4rem 0 .4rem}.notes p{margin:0 0 .8rem}.notes strong{color:var(--ink)}.notes em{color:var(--ink);font-style:italic}.notes code{background:#0b1c25;border:1px solid var(--line);border-radius:5px;padding:.05rem .35rem;font-size:.85em;color:var(--accent)}footer{border-top:1px solid var(--line);margin-top:2rem;padding-top:1.2rem;color:var(--dim);font-size:.85rem}