@font-face{font-family:DM Sans;src:url(/fonts/DMSans-Regular.ttf)}@font-face{font-family:DM Sans;src:url(/fonts/DMSans-Medium.ttf);font-weight:500}@font-face{font-family:DM Sans;src:url(/fonts/DMSans-Semibold.ttf);font-weight:600}:root{font-family:DM Sans,system-ui,sans-serif;color-scheme:light;--paper: #f4f2ec;--ink: #242e29;--muted: #59655e;--soft: #e9e7df;--surface: #fffefa;--line: #c7ccc3;--accent: #426b58;--on-accent: #fff;--red: #ac4a46;--r0: #eca9a1;--r1: #e9ce85;--r2: #a9c7b1;--r3: #c2b0d4;--r4: #a9c8d9;--r5: #e5b995;background:var(--paper);color:var(--ink);font-synthesis:none;font-variant-numeric:tabular-nums}:root[data-theme=dark]{color-scheme:dark;--paper: #252d29;--ink: #f6f5ec;--muted: #c0cec1;--soft: #46534a;--surface: #343f38;--line: #607463;--accent: #a9c8ae;--on-accent: #252d29;--red: #f3a19b;--r0: #674a48;--r1: #655a37;--r2: #3d5846;--r3: #514a65;--r4: #3c5667;--r5: #665040}@media(prefers-color-scheme:dark){:root[data-theme=system]{color-scheme:dark;--paper: #252d29;--ink: #f6f5ec;--muted: #c0cec1;--soft: #46534a;--surface: #343f38;--line: #607463;--accent: #a9c8ae;--on-accent: #252d29;--red: #f3a19b;--r0: #674a48;--r1: #655a37;--r2: #3d5846;--r3: #514a65;--r4: #3c5667;--r5: #665040}}*{box-sizing:border-box}body{margin:0}button,input,select{font:inherit;color:inherit}button{cursor:pointer;touch-action:manipulation;-webkit-tap-highlight-color:transparent}button{border:0;background:transparent;border-radius:12px;min-height:44px;padding:10px 14px;transition:background-color .15s ease,color .15s ease}button:disabled{cursor:default}button:focus-visible,input:focus-visible,select:focus-visible{outline:2px solid var(--accent);outline-offset:3px}button:hover:not(:disabled){background:var(--soft)}button:active:not(:disabled){background:var(--line)}h1,h2,h3,p{margin:0}h1{font-size:38px;font-weight:500;letter-spacing:-1.4px;line-height:1.2}h2{font-size:25px;font-weight:500;letter-spacing:-.6px}h3{font-weight:500}svg{display:block;flex-shrink:0}small{display:block;color:var(--muted);font-size:12px;font-weight:400}.app{zoom:var(--ui-scale, 1);min-height:calc(100svh / var(--ui-scale, 1));padding:calc(24px + env(safe-area-inset-top) / var(--ui-scale, 1)) calc(16px + env(safe-area-inset-right) / var(--ui-scale, 1)) calc(24px + env(safe-area-inset-bottom) / var(--ui-scale, 1)) calc(16px + env(safe-area-inset-left) / var(--ui-scale, 1));background:var(--paper)}.content{width:100%;max-width:520px;margin:0 auto}.icon{display:inline-flex;align-items:center;justify-content:center;width:44px;height:44px;padding:10px;flex-shrink:0}.brand-row{display:flex;align-items:center;justify-content:space-between;margin-bottom:22px}.brand{display:grid;grid-template-columns:22px 22px;gap:2px}.brand i{width:22px;height:22px;background:var(--r0);border-radius:2px}.brand i:nth-child(n+3){background:var(--r1)}.brand i:first-child:after{content:"";display:block;width:14px;height:14px;border:1.5px solid var(--ink);border-radius:50%;margin:3px}.tagline{font-size:16px;color:var(--muted);margin-top:18px;line-height:1.6}.completed-count{color:var(--muted);font-size:14px;margin-top:14px}.menu-actions{display:grid;gap:10px;margin:36px 0 20px;padding:18px;border-radius:18px;border:1px solid var(--line);background:var(--surface)}.primary,.secondary{width:100%;min-height:52px;padding:15px 18px;font-weight:500;font-size:16px}.primary{background:var(--accent);color:var(--on-accent)}.primary:hover:not(:disabled){background:color-mix(in srgb,var(--accent),var(--ink) 9%)}.primary small{color:inherit;opacity:.8;margin-top:5px}.secondary{background:var(--soft);color:var(--ink)}.menu-row{display:flex;align-items:center;justify-content:space-between;width:100%;text-align:left;padding:14px 12px;font-size:16px;min-height:54px}.menu-row span{font-size:23px;color:var(--muted)}.menu-footer{margin-top:36px}.music{display:flex;align-items:center;width:100%;min-height:56px;gap:2px}.music-title{min-width:0;flex:1;text-align:left;padding:10px 12px;overflow:hidden}.music-title strong,.music-title small{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.music-title strong{display:block;font-size:14px;font-weight:500}.music-title small{margin-top:4px;font-size:11px}.music-toggle{min-width:48px;min-height:46px;background:var(--soft);font-size:14px;padding:10px}.music-toggle.enabled{background:var(--accent);color:var(--on-accent)}.transport{width:40px}.transport:hover:not(:active){background:transparent}.offline-status{display:flex;align-items:center;gap:6px;color:var(--muted);font-size:11px;flex-wrap:wrap;margin:14px 10px}.offline-status button{font-size:12px;padding:4px 8px;min-height:36px;text-decoration:underline}.offline-dot{width:5px;height:5px;border-radius:50%;background:var(--muted)}.offline-dot.ready{background:var(--accent)}.game{position:relative;max-width:min(520px,max(240px,calc(100svh / var(--ui-scale, 1) - 392px)))}.game-header{display:flex;align-items:center;justify-content:space-between;position:relative;min-height:44px}.game-header>strong{font-size:14px;font-weight:500;position:absolute;left:50%;transform:translate(-50%);pointer-events:none}.game-header>div{display:flex}.game-meta{display:flex;align-items:center;justify-content:space-between;margin:20px 0 18px;color:var(--muted);font-size:14px}.hearts{display:flex;gap:8px;color:var(--red)}.hearts svg{fill:currentColor;stroke-width:0}.hearts .empty svg{fill:none;stroke:currentColor;stroke-width:1.3;opacity:.4}.board-space{width:100%;display:flex;justify-content:center}.board{position:relative;display:grid;grid-template-columns:48px calc(var(--side) * var(--n));grid-template-rows:48px calc(var(--side) * var(--n));flex-shrink:0}.column-targets{grid-column:2;grid-row:1;display:grid;grid-template-columns:repeat(var(--n),1fr);align-items:start;justify-items:center}.row-targets{grid-column:1;grid-row:2;display:grid;grid-template-rows:repeat(var(--n),1fr);justify-items:start;align-items:center}.target{position:relative;display:flex;align-items:flex-end;justify-content:center;width:38px;height:40px;padding-bottom:4px;background:var(--soft);border-radius:8px;font-size:18px;transition:opacity .25s}.target small{position:absolute;top:3px;right:4px;font-size:10px;line-height:1}.target.complete{opacity:.18}.cells{grid-row:2;grid-column:2;display:grid;grid-template-columns:repeat(var(--n),1fr);grid-template-rows:repeat(var(--n),1fr);outline:1px solid color-mix(in srgb,var(--ink),transparent 85%);isolation:isolate}.cell{position:relative;border-radius:0;padding:0;width:var(--side);height:var(--side);min-height:0;display:grid;place-items:center;font-size:clamp(20px,calc(var(--side) * .36),34px);line-height:1;color:var(--ink);background:var(--region, var(--soft));border-right:1px solid color-mix(in srgb,var(--ink),transparent 91%);border-bottom:1px solid color-mix(in srgb,var(--ink),transparent 91%);transition:background-color .2s;touch-action:manipulation}.cell:hover:not(:disabled){background:color-mix(in srgb,var(--region),var(--paper) 12%)}.cell:active:not(:disabled){background:color-mix(in srgb,var(--region),var(--ink) 8%)}.cell.cleared{background:var(--paper)}.region-0{--region: var(--r0)}.region-1{--region: var(--r1)}.region-2{--region: var(--r2)}.region-3{--region: var(--r3)}.region-4{--region: var(--r4)}.region-5{--region: var(--r5)}.region-target{position:absolute;top:4px;left:5px;font-size:11px;line-height:1;color:var(--ink);opacity:.85}.cell.erased .number{opacity:0}.mark-ring{position:absolute;width:65%;height:65%;border:1.5px solid var(--ink);border-radius:50%;opacity:0;transform:scale(.85);transition:opacity .15s,transform .18s}.marked .mark-ring{opacity:1;transform:scale(1)}.progress{display:flex;justify-content:space-between;flex-wrap:wrap;gap:7px;font-size:11px;color:var(--muted);margin-top:18px}.progress progress{appearance:none;border:0;width:100%;height:3px;border-radius:3px;background:var(--line);overflow:hidden}.progress progress::-webkit-progress-bar{background:var(--line)}.progress progress::-webkit-progress-value{background:var(--accent)}.progress progress::-moz-progress-bar{background:var(--accent)}.mode{position:relative;display:flex;background:var(--soft);border:1px solid var(--line);border-radius:32px;padding:3px;margin-top:14px;isolation:isolate}.mode button{flex:1;z-index:1;border-radius:30px;min-height:50px;font-size:16px;background:none!important;color:var(--muted);transition:color .16s}.mode button[aria-pressed=true]{color:var(--on-accent)}.mode-thumb{position:absolute;top:3px;bottom:3px;left:3px;width:calc(50% - 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env(safe-area-inset-bottom));box-shadow:0 16px 80px #0002;overflow:hidden}.dialog::backdrop{background:#101d174d}.dialog[open]{display:flex;flex-direction:column}.dialog header{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:14px 14px 10px 22px;flex-shrink:0}.dialog header h2{font-size:21px;flex:1}.dialog-body{overflow:auto;overscroll-behavior:contain;padding:10px 22px 24px;touch-action:pan-y}.dialog-body>h3{font-size:13px;color:var(--muted);margin:20px 0 10px}.dialog-body>.primary,.dialog-body>.secondary{margin-top:12px}.intro{font-size:16px;line-height:1.65;color:var(--muted);margin:6px 0 20px}.intro strong{color:var(--ink);font-weight:500}.difficulty-row{display:flex;align-items:center;justify-content:space-between;text-align:left;width:100%;min-height:68px;border-bottom:1px solid var(--line);border-radius:0;padding:14px 8px}.difficulty-row:last-child{border-bottom:0}.difficulty-row strong,.track strong{font-weight:500;display:block}.difficulty-row small,.track small{margin-top:5px}.difficulty-row>span:last-child{font-size:24px;color:var(--muted)}.setting-row{width:100%;display:flex;justify-content:space-between;align-items:center;padding:10px 0;gap:16px;text-align:left;min-height:52px}.setting-row:hover{background:transparent!important}.switch{width:40px;height:24px;border-radius:20px;background:var(--line);padding:3px;flex-shrink:0}.switch i{display:block;border-radius:50%;width:18px;height:18px;background:var(--paper);transition:transform .18s}.switch.on{background:var(--accent)}.switch.on i{transform:translate(16px);background:var(--on-accent)}.volume{display:block;margin:12px 0 18px}.volume>span{display:flex;justify-content:space-between;font-size:13px;color:var(--muted)}.volume input{width:100%;accent-color:var(--accent);margin:12px 0;cursor:pointer;min-height:26px}.theme-options{display:flex;gap:6px;background:var(--soft);padding:4px;border-radius:12px}.theme-options button{flex:1;font-size:13px;min-height:40px;padding:8px}.theme-options .selected{background:var(--surface);box-shadow:0 1px 4px #0001}.library-now small{text-transform:uppercase;letter-spacing:1.4px;font-size:10px}.library-now h3{font-size:23px;margin:8px 0}.library-now p{color:var(--muted);font-size:12px}.library-now{padding:12px 0 18px}.track{display:flex;align-items:center;gap:14px;width:100%;text-align:left;padding:14px 8px;min-height:70px;border-radius:10px}.track>span:nth-child(2){flex:1}.track-index{font-size:11px;color:var(--muted)}.track.selected{background:var(--soft)}.track small{font-size:12px}.stats-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:20px 0}.stats-grid>div{display:flex;flex-direction:column;background:var(--soft);border-radius:12px;padding:18px;gap:8px}.stats-grid strong{font-size:25px;font-weight:500}.stats-grid span{font-size:12px;color:var(--muted)}.select-label{display:flex;align-items:center;justify-content:space-between;font-size:13px;color:var(--muted);gap:10px}select{background:var(--soft);border:0;border-radius:8px;padding:10px;max-width:70%}.fine-print{font-size:12px;line-height:1.65;color:var(--muted);margin-top:18px}.lesson-count{font-size:12px;color:var(--muted);margin:8px 0}.dialog-body>.lesson-title{font-size:24px;line-height:1.2;color:var(--ink);margin:14px 0 20px}.dialog-body>p:not([class]){font-size:15px;line-height:1.7;color:var(--muted);margin:14px 0}.example-row{display:flex;gap:0;align-items:center;justify-content:center;margin:24px 0;position:relative}.example-number{position:relative;display:grid;place-items:center;width:64px;height:64px;font-size:26px;background:var(--r2);color:var(--ink)}.example-number.chosen:after{content:"";position:absolute;inset:9px;border:1.5px solid var(--ink);border-radius:50%}.example-number.removed{opacity:.4;text-decoration:line-through}.example-target{margin-right:12px;background:var(--soft);border-radius:8px;padding:10px;font-size:22px}.example-equation{text-align:center;font-size:24px;margin:20px}.example-row.colored{background:var(--r2);padding:12px}.colored>small{position:absolute;left:5px;top:4px;color:var(--ink)}.notice{position:fixed;z-index:8;bottom:16px;left:50%;transform:translate(-50%);max-width:calc(100vw - 32px);width:460px;display:flex;align-items:center;gap:8px;padding:10px 14px;border:1px solid var(--line);border-radius:12px;background:var(--surface);font-size:13px;box-shadow:0 5px 24px #0001}.notice button{margin-left:auto;flex-shrink:0}.notice.error{border-color:var(--red)}.loading-puzzle{font-size:15px;color:var(--muted);line-height:1.7;padding:20px 0}.loading-dots{display:inline-block;width:10px;height:10px;border-radius:50%;background:var(--accent);margin-right:12px;animation:pulse 1s ease-in-out infinite alternate}@keyframes pulse{to{opacity:.25}}.reduce-motion *{animation:none!important;transition:none!important;scroll-behavior:auto!important}@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}@media(max-width:359px){.app{padding-left:8px;padding-right:8px}.dialog-body{padding-left:16px;padding-right:16px}.music-title{padding-left:6px}.transport{width:34px;padding:8px}h1{font-size:34px}.mode-hint{font-size:11px}}@media(max-height:650px){.game-meta,.mode-hint{margin:10px 0}.game-music{margin-top:10px}.game .game-meta{font-size:12px}.game-header{min-height:40px}}.cell .number{transition:opacity .18s ease}.cell.mistake{box-shadow:inset 0 0 0 2px var(--red)}.cell.mistake .number{animation:mistake-nudge .22s ease}@keyframes mistake-nudge{25%{translate:-3px}75%{translate:3px}}