@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@400;500;600;700;800;900&display=swap');
:root{--blue:#305ee8;--ink:#222b43;--muted:#7e8595;--line:#e6e8ef;--paper:#f7f7f2}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:'Noto Sans KR',system-ui,sans-serif}button,a,input{-webkit-tap-highlight-color:transparent}button{font:inherit;cursor:pointer}button:focus-visible,a:focus-visible{outline:3px solid #eeaa3a;outline-offset:2px}header{height:91px;max-width:1200px;margin:auto;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid #dddfdf}.brand{font-size:18px;font-weight:900;letter-spacing:-.5px;text-decoration:none;color:var(--ink);display:flex;align-items:center;gap:6px}.brand>span:last-child{font-weight:400}.logo{background:var(--blue);color:white;border-radius:10px;padding:0 8px;font-size:31px;margin-right:7px}.home{font-size:11px;letter-spacing:1px;text-decoration:none;color:#6b7281}main{max-width:1120px;margin:48px auto 0}.intro{display:flex;align-items:center;justify-content:space-between;margin-bottom:38px}.eyebrow{font-size:10px;font-weight:800;letter-spacing:2px;color:var(--blue);margin:0 0 15px}h1{font-size:42px;letter-spacing:-2px;line-height:1.4;margin:0;font-weight:800}.subtitle{color:#757c88;font-size:14px;margin-top:15px}.intro-note{display:flex;gap:25px;align-items:center;padding-right:18px}.intro-note>span{font-size:48px;font-weight:800;letter-spacing:-3px;color:#d7dccf}.intro-note p{font-size:12px;line-height:1.9;color:#92978a}.workspace{display:grid;grid-template-columns:minmax(0,660px) minmax(0,340px);gap:32px;align-items:start;justify-content:center}.game-card{background:white;border-radius:18px;padding:25px 32px 20px;box-shadow:0 10px 40px #242b4306;border:1px solid #e7e9e3}.game-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:23px}.difficulty{display:flex;background:#f3f4f8;border-radius:8px;padding:4px}.difficulty button{border:0;background:none;font-size:12px;color:#858c9b;padding:8px 18px;border-radius:6px}.difficulty .active{background:white;color:var(--blue);box-shadow:0 2px 6px #00000009;font-weight:700}.clock{display:flex;align-items:center;gap:12px;font-variant-numeric:tabular-nums;font-size:16px}.clock button{border:1px solid var(--line);border-radius:6px;background:white;font-weight:800;font-size:13px;width:28px;height:28px}.board-wrap{position:relative}#board{display:grid;grid-template-columns:repeat(9,1fr);aspect-ratio:1;border:2px solid #343e57;border-radius:3px;overflow:hidden;background:#fff}.cell{display:flex;align-items:center;justify-content:center;border:0;border-right:1px solid #dfe3ed;border-bottom:1px solid #dfe3ed;background:white;color:var(--blue);font-size:clamp(18px,2.5vw,29px);padding:0;position:relative;min-width:0}.cell:nth-child(3n){border-right:2px solid #343e57}.cell:nth-child(9n){border-right:0}.cell.row-end{border-bottom:2px solid #343e57}.cell:last-child{border-bottom:0}.cell.given{color:#27344d;font-weight:600}.cell.related{background:#f2f5fc}.cell.same{background:#e2eafe}.cell.selected{background:#d6e2ff;box-shadow:inset 0 0 0 2px var(--blue);z-index:1}.cell.error{color:#de5359;background:#fff0ef}.cell .pencil{display:grid;grid-template-columns:repeat(3,1fr);width:100%;height:100%;align-items:center;font-size:11px;color:#7c8dac;font-weight:400}.pencil span{line-height:1;text-align:center}.board-bottom{display:flex;justify-content:space-between;align-items:center;font-size:10px;color:#8d95a5;margin-top:18px}.board-bottom>span:first-child{display:flex;align-items:center;gap:5px}i{height:6px;width:6px;border-radius:50%;background:#83af93;margin-right:4px}.controls{border:1px solid #e4e6e1;background:#fff;border-radius:18px;padding:26px}.control-heading h2{font-size:23px;letter-spacing:-1px;margin:0 0 8px}.control-heading p{font-size:12px;color:var(--muted);margin:0 0 25px}.numbers{display:grid;grid-template-columns:repeat(3,1fr);gap:9px}.numbers button{height:63px;border:1px solid #e8ebf2;border-radius:9px;background:#f9faff;color:var(--blue);font-size:25px;font-weight:500;position:relative}.numbers button:hover{background:#edf2ff;border-color:#b4c6ff}.numbers small{position:absolute;right:8px;bottom:6px;font-size:9px;color:#98a5c2}.tools{display:grid;grid-template-columns:repeat(4,1fr);margin:22px -10px}.tools button{background:none;border:0;font-size:10px;color:#7a8293;position:relative;white-space:nowrap}.tools button>span{display:block;font-size:23px;color:#515e77;margin-bottom:6px}.tools small{font-size:8px;background:#eef0f7;padding:2px 4px;border-radius:3px;color:#80899c}.tools button[aria-pressed=true]{color:var(--blue)}.tools button[aria-pressed=true] small{background:var(--blue);color:white}.toggle{display:flex;justify-content:space-between;align-items:center;border-top:1px solid #eef0f4;padding:18px 0;font-size:11px;color:#687186}.toggle input{appearance:none;width:30px;height:18px;border-radius:12px;background:#c9d0df;position:relative;cursor:pointer}.toggle input:checked{background:var(--blue)}.toggle input:before{content:'';width:12px;height:12px;position:absolute;top:3px;left:3px;background:white;border-radius:50%;transition:.2s}.toggle input:checked:before{left:15px}.primary{width:100%;padding:15px 18px;background:var(--blue);color:white;border:0;border-radius:9px;font-size:13px;font-weight:600;display:flex;justify-content:space-between}.primary:hover{background:#234dce}.save-status{font-size:9px;color:#9a9fae;text-align:center;margin:14px 0 0}#status{font-size:11px;color:var(--blue);margin:8px 0 0;min-height:16px;text-align:center}.tip{display:flex;gap:14px;margin-top:20px;background:#efefe6;border-radius:12px;padding:20px}.tip-icon{color:#989f76;font-size:22px}.tip h3{font-size:12px;margin:0 0 7px}.tip p{font-size:11px;color:#868978;line-height:1.9;margin:0}.tip button{border:0;background:none;padding:12px 0 0;font-size:10px;color:#707956}.info{display:grid;grid-template-columns:repeat(3,1fr);gap:45px;margin:48px 0 45px;border-top:1px solid #e0e3da;padding:29px 12px}.info span{color:#a3ac98;font-size:10px;font-weight:700}.info h3{font-size:13px;margin:9px 0}.info p{color:#909586;font-size:11px;line-height:1.8}footer{border-top:1px solid #e1e4dc;max-width:1200px;margin:auto;padding:22px 0 30px;display:flex;gap:25px;font-size:9px;color:#9c9fa0}footer span:last-child{margin-left:auto}.brand-mini{font-weight:800;letter-spacing:.8px;color:#737c84}#pause-overlay{position:absolute;inset:0;background:#f3f6ff;align-items:center;justify-content:center;flex-direction:column;gap:18px;z-index:2}#pause-overlay:not([hidden]){display:flex}#resume{background:var(--blue);color:#fff;border:0;padding:12px 20px;border-radius:8px}dialog{border:0;border-radius:18px;padding:36px;max-width:420px;width:calc(100% - 32px);box-shadow:0 20px 80px #11182730;color:var(--ink)}dialog::backdrop{background:#17213b65;backdrop-filter:blur(4px)}dialog h2{font-size:25px;letter-spacing:-1px}#dialog-body{font-size:13px;line-height:1.9;color:#727d92}#dialog-actions{display:flex;gap:10px;margin-top:22px}#dialog-actions button{border:0;background:var(--blue);color:white;padding:12px 16px;border-radius:8px}.close{position:absolute;right:15px;top:10px;border:0;background:none;font-size:25px;color:#8c93a0}@media(max-width:850px){header{margin:0 22px;height:72px}main{margin:30px 20px 0}.intro-note{display:none}.workspace{grid-template-columns:minmax(0,580px);gap:20px}.intro{max-width:580px;margin:0 auto 25px}h1{font-size:32px}.game-card{padding:20px}aside{display:grid;grid-template-columns:1fr}.controls{padding:20px}.control-heading{display:none}.numbers{grid-template-columns:repeat(9,1fr);gap:5px}.numbers button{height:48px;font-size:21px}.numbers small{right:4px;bottom:3px;font-size:8px}.tools{margin:18px 0}.toggle{padding:12px 0}.tip{margin-top:15px}.info{gap:20px;margin:30px 0;padding:22px 0}.info h3{font-size:12px}.info p{font-size:10px}footer{margin:0 20px;flex-wrap:wrap;gap:10px}footer span:last-child{margin-left:0;width:100%}.cell{font-size:25px}}@media(max-width:400px){.brand{font-size:13px}.home{font-size:9px}.game-card{padding:13px}.difficulty button{padding:7px 12px}.cell{font-size:22px}.cell .pencil{font-size:9px}.board-bottom{font-size:9px}.info{gap:12px}h1{font-size:29px}.numbers button{font-size:18px}}