:root{font-family:system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:#243f42;background:#f3f1e8;font-synthesis:none;--ink:#243f42;--muted:#536568;--paper:#fffdf5;--line:#b7c6bc;--accent:#ae6225;--soft:#deeadf;--warn:#9b3928;--cell:64px}*{box-sizing:border-box}[hidden]{display:none!important}body{margin:0}button,input,select{font:inherit;color:inherit;font-size:14px;min-height:44px;max-width:100%;border:1px solid var(--line);border-radius:10px;padding:9px 12px;background:var(--paper)}button{font-weight:650;cursor:pointer;touch-action:manipulation}button:hover{background:#e7eee4}button:disabled{opacity:.48;cursor:default}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,[tabindex]:focus-visible{outline:3px solid var(--accent);outline-offset:3px}a{color:inherit}.shell{max-width:560px;margin:auto;padding:20px 18px 28px}header{display:flex;justify-content:space-between;align-items:center;gap:10px}.brand{font-size:23px;font-weight:800;letter-spacing:-1px}.tag{font-size:9px;letter-spacing:1px;color:var(--muted);font-weight:750}.title{display:flex;align-items:baseline;justify-content:center;gap:14px;margin:22px 0}.title h1{font-family:Georgia,serif;font-size:38px;font-weight:500;letter-spacing:-1px;margin:0}.title span{font-size:12px;color:var(--muted)}.welcome{text-align:center;padding:5px 6px 16px}.welcome-art{display:block;width:min(280px,100%);margin:8px auto 18px}.welcome h2{font-family:Georgia,serif;font-size:28px;font-weight:500;margin:10px 0}.welcome p{font-size:14px;line-height:1.65;color:var(--muted)}.welcome>button{display:block;min-width:210px;margin:10px auto}.primary{background:var(--ink);color:white;border-color:var(--ink)}.primary:hover{background:#172e31}.play-top,.stats,.dialog-head{display:flex;align-items:center;justify-content:space-between;gap:8px}.play-top{font-size:12px}.play-top #level{text-align:center;line-height:1.5}.play-top button{flex-shrink:0}.quick-rule{font-size:13px;line-height:1.5;margin:13px 0 8px;color:var(--muted)}.stats{margin:8px 2px;font-size:12px;color:var(--muted)}.selection-note{font-size:12px;line-height:1.45;min-height:36px;background:var(--soft);border-radius:8px;padding:8px 10px;margin:10px 0}.board-wrap{position:relative;width:max-content;max-width:100%;margin:0 auto;border:2px solid #9aac9c;border-radius:11px;overflow:hidden;isolation:isolate}.board{display:grid;grid-template-columns:repeat(var(--cols),var(--cell));gap:0;width:max-content;position:relative}.cell{position:relative;width:var(--cell);height:var(--cell);min-width:var(--cell);min-height:var(--cell);border:1px solid #c2cdc0;border-radius:0;background:var(--paper);padding:0;line-height:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;scroll-margin:8px;user-select:none;-webkit-user-select:none}.cell:disabled{opacity:1}.cell-number{position:relative;z-index:3;font-size:19px;font-weight:700;line-height:23px;min-width:24px;padding:0 2px;background:var(--paper);border-radius:4px}.cell.fixed .cell-number{outline:1.5px solid var(--ink);font-family:Georgia,serif;font-weight:700}.cell-arrow{position:relative;z-index:3;font-family:Arial,sans-serif;font-size:25px;line-height:25px;font-weight:700;background:var(--paper);border-radius:4px;padding:0 2px}.cell.selected{background:#fbe2b3;box-shadow:inset 0 0 0 3px var(--accent)}.cell.in-chain:not(.selected){background:#e0eadf}.cell.candidate{background:#e6eee8;box-shadow:inset 0 0 0 2px #486c5e}.cell.candidate .cell-number,.cell.candidate .cell-arrow,.cell.in-chain .cell-number,.cell.in-chain .cell-arrow{background:#e0eadf}.cell.selected .cell-number,.cell.selected .cell-arrow{background:#fbe2b3}.destination{position:absolute;right:3px;top:2px;z-index:4;font-size:17px;font-weight:900;color:#243f42;background:#fffdf5;border-radius:50%;width:17px;height:17px;line-height:16px}.connection-marks{position:absolute;z-index:3;right:2px;bottom:1px;letter-spacing:1px;font-size:9px;color:#536568;background:var(--paper);border-radius:3px}.cell:focus-visible{outline-offset:-4px;z-index:5}.chain-lines{position:absolute;inset:0;z-index:2;width:100%;height:100%;pointer-events:none;overflow:visible}.chain-lines line{stroke:#557c6f;stroke-width:1.6;stroke-dasharray:1.1 .65;opacity:.7;vector-effect:non-scaling-stroke}.chain-note{font-size:11px;line-height:1.5;color:var(--muted);margin:8px 0;text-align:center;overflow-wrap:anywhere;min-height:32px}.unlink-tools{display:flex;justify-content:center;gap:6px}.unlink-tools button{font-size:12px;padding:8px 9px;flex:1;max-width:135px}.feedback{font-size:12px;line-height:1.6;margin:12px 0;min-height:56px;text-align:center}.toolbar{display:flex;justify-content:center;gap:8px;flex-wrap:wrap}.toolbar button{flex:1;min-width:72px}.success{text-align:center;background:var(--soft);border:1px solid #a9c0b2;border-radius:16px;padding:15px;margin-top:16px}.success h2,dialog h2{font-family:Georgia,serif;font-weight:500}.success h2{font-size:26px;margin:0 0 8px}.success p{font-size:13px;margin:0;line-height:1.5}.muted{font-size:12px;color:var(--muted);line-height:1.6}#historical{text-align:center}.save-panel{text-align:center;margin:18px 0;font-size:12px;line-height:1.6}.save-panel button{margin:4px;font-size:12px}#save-note{min-height:2em}.save-panel.error{color:var(--warn);border:1px solid #d4a08e;border-radius:12px;padding:10px}.temporary-note{background:#fff0c8;border:2px solid #b57d27;border-radius:12px;color:#6f4915;padding:12px;font-size:13px;line-height:1.6}footer{text-align:center;font-size:11px;line-height:1.6;color:var(--muted);margin-top:25px}dialog{width:min(540px,calc(100vw - 24px));max-height:calc(100dvh - 24px);border:1px solid var(--line);border-radius:18px;padding:22px;background:var(--paper);color:var(--ink);overflow:auto}dialog::backdrop{background:#263b3a99}dialog h2{font-size:25px;margin:0 0 12px}.dialog-head{position:sticky;top:-22px;z-index:10;background:var(--paper);padding:8px 0}.dialog-head h2{margin:0;font-size:24px}.dialog-head button{font-size:12px;min-width:60px}.levels{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin:15px 0}.levels button{font-size:16px;min-height:58px;padding:7px 3px}.levels small{display:block;font-size:11px;margin-top:3px}.levels .current{outline:2px solid var(--accent);outline-offset:1px}.levels .done{background:var(--soft)}#group,#progress-filter{display:block;width:100%;margin:8px 0 12px}#next-unfinished{display:block;width:100%;margin-top:10px}#page-range,#page-notice{font-size:12px;line-height:1.5}dialog ol{padding-left:22px;line-height:1.7;font-size:14px}dialog li{margin:12px 0}dialog>p{font-size:13px;line-height:1.7}.example{display:flex;justify-content:center;gap:8px;margin:14px auto}.example span{display:grid;place-items:center;width:65px;height:55px;border:1px solid var(--line);border-radius:7px;font-size:22px;font-weight:650}.example span:last-child{background:var(--soft)}
@media(max-width:430px){:root{--cell:58px}.shell{padding:12px 12px 24px}.title{margin:12px 0}.title h1{font-size:32px}.title span{font-size:11px}.quick-rule{font-size:12px;margin:10px 0 7px}.selection-note{font-size:11px;line-height:1.4;min-height:34px;margin:8px 0;padding:7px 9px}.stats{margin:7px 2px}.feedback{font-size:11px;min-height:51px}.chain-note{font-size:10px;min-height:30px}.tag{font-size:8px;letter-spacing:.5px}.play-top button{padding:8px 10px;font-size:12px}}
@media(max-width:350px){:root{--cell:55px}.shell{padding-left:10px;padding-right:10px}.title span{display:none}.brand{font-size:22px}.play-top{gap:5px}.play-top #level{font-size:10px}.play-top button{padding:8px}.cell-number{font-size:18px;line-height:21px}.cell-arrow{font-size:24px;line-height:24px}.destination{font-size:15px;width:15px;height:15px;right:2px}dialog{padding:16px}.dialog-head{top:-16px}.dialog-head h2{font-size:21px}.unlink-tools button{font-size:11px;padding:8px}}
@media(max-height:450px) and (min-width:620px){:root{--cell:52px}.shell{max-width:780px;padding-top:8px}.title{margin:6px 0}.title h1{font-size:28px}.title span{display:none}#play{display:grid;grid-template-columns:minmax(0,1fr) 264px;gap:0 15px;align-items:start}#play>*{grid-column:1}#play>.board-wrap{grid-column:2;grid-row:1 / span 6;margin:0;justify-self:end}.play-top button{padding:7px;font-size:12px}.play-top #level{font-size:11px}.quick-rule{font-size:11px;margin:8px 0}.selection-note{font-size:11px;min-height:0}.chain-note{font-size:10px;min-height:0}.feedback{font-size:11px;min-height:0;margin:8px 0}.cell-number{font-size:17px;line-height:20px}.cell-arrow{font-size:23px;line-height:23px}#play .success,#play #historical{grid-column:1 / -1}.save-panel{margin:12px 0}}
@media(prefers-reduced-motion:no-preference){button{transition:background .12s}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}@media(forced-colors:active){.cell.selected{outline:3px solid Highlight;outline-offset:-4px}.cell.candidate{border:3px dashed Highlight}.cell.fixed .cell-number{outline:2px solid CanvasText}.chain-lines line{stroke:CanvasText}.destination{background:Canvas;color:CanvasText}.cell-number,.cell-arrow{background:Canvas!important;color:CanvasText}}

.cell-arrow{display:flex;align-items:center;justify-content:center}.cell-arrow svg{display:block;width:24px;height:24px}.example svg{width:23px;height:23px}
/* Bounded volume navigation: visible controls keep the original44px targets. */
.pager{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin-top:12px}.page-jump{display:flex;align-items:center;flex-wrap:wrap;gap:8px;margin-top:12px}.page-jump input{width:72px;min-width:0}.page-jump button{flex:1;min-width:110px}