:root{--paper:#f6f5f4;--ink:#31302e;--muted:#615d59;--blue:#0069c7;--line:#dedbd6;--light:#edf5fc;--selected:#c9e4fa;--error:#a72828}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,system-ui,-apple-system,'Segoe UI',sans-serif;font-size:15px;line-height:1.5}button,select{font:inherit;color:inherit;touch-action:manipulation}button{cursor:pointer;border:1px solid var(--line);background:#fff;border-radius:8px;min-height:44px;padding:9px 14px;font-weight:600}button:hover{background:var(--light);border-color:#9ac6eb}button:disabled{cursor:default;opacity:.45}button:focus-visible,select:focus-visible,summary:focus-visible,a:focus-visible{outline:3px solid var(--blue);outline-offset:3px}header{max-width:1120px;margin:auto;padding:25px 32px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line)}a.brand{text-decoration:none;color:var(--ink);display:flex;align-items:center;gap:12px;font-weight:700}.logo{font-size:30px;line-height:1}.brand-divider{color:#b4afa8;font-weight:400}.brand span:last-child{font-weight:400;color:var(--muted)}.badge{font-size:12px;color:var(--muted)}main{max-width:1000px;margin:auto;padding:48px 32px 24px}.intro{display:flex;align-items:center;justify-content:space-between;margin-bottom:32px}.eyebrow{font-size:10px;font-weight:700;letter-spacing:1.9px;color:var(--muted);margin:0 0 10px}h1{font-size:64px;letter-spacing:-3px;line-height:1.1;margin:0;font-weight:650}h1 span{color:var(--blue)}.subtitle{color:var(--muted);margin:12px 0 0;font-size:16px}.intro-mark{white-space:nowrap;flex-shrink:0;font-family:ui-monospace,monospace;font-size:22px;letter-spacing:8px;line-height:1.7;color:#a39e98;transform:rotate(8deg);margin-right:20px}.game-layout{display:grid;grid-template-columns:minmax(0,548px) minmax(240px,1fr);gap:44px;align-items:start}.game-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;font-size:13px}select{margin-left:6px;background:transparent;border:0;font-weight:650;padding:8px 4px;cursor:pointer}.clock{display:flex;gap:12px;align-items:center;font-family:ui-monospace,monospace}.clock button{min-height:32px;width:32px;padding:0;background:transparent}.board-wrap{position:relative}#board{display:grid;grid-template-columns:repeat(9,minmax(0,1fr));border:2px solid var(--ink);background:#fff;aspect-ratio:1;overflow:hidden}#board button{border:0;border-right:1px solid var(--line);border-bottom:1px solid var(--line);border-radius:0;padding:0;min-height:0;min-width:0;font-size:clamp(20px,3vw,29px);font-weight:500;color:var(--blue);position:relative;aspect-ratio:1}#board button:nth-child(3n){border-right:2px solid var(--ink)}#board button:nth-child(9n){border-right:0}#board button:nth-child(n+19):nth-child(-n+27),#board button:nth-child(n+46):nth-child(-n+54){border-bottom:2px solid var(--ink)}#board button:nth-child(n+73){border-bottom:0}#board button.given{color:var(--ink);font-weight:650}#board button.related{background:#f2f6f9}#board button.same{background:#e0eef9}#board button.selected{background:var(--selected);box-shadow:inset 0 0 0 2px var(--blue)}#board button.invalid{color:var(--error);background:#fde9e7;text-decoration:underline;text-decoration-style:dotted}#board button:focus-visible{outline:0;box-shadow:inset 0 0 0 3px var(--blue);z-index:1}.pencil{display:grid;grid-template-columns:repeat(3,1fr);height:100%;padding:2px;font-size:clamp(9px,1.3vw,12px);color:var(--muted);line-height:1;align-items:center}.pencil span{height:100%;display:grid;place-items:center}.progress-line{display:flex;justify-content:space-between;gap:8px;font-size:11px;color:var(--muted);margin:12px 0 16px}#keypad{display:grid;grid-template-columns:repeat(9,1fr);gap:6px}#keypad button{padding:8px 0;font-size:23px;font-weight:500;color:var(--blue);min-width:0}#status{min-height:48px;font-size:13px;margin-top:14px;color:var(--muted)}#status.success{background:#e3f3e8;color:#23623b;padding:14px;border-radius:8px;font-weight:650}aside{padding-top:1px}.primary{background:var(--blue);color:white;border-color:var(--blue)}.primary:hover{background:#005bab;color:#fff}.wide{width:100%;padding:14px 18px;text-align:center}.wide span{float:right}.tools{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;margin:18px 0 12px}.tools button{display:flex;flex-direction:column;align-items:center;gap:4px;padding:14px 6px;font-size:12px}.tools button span{font-size:26px;font-weight:400;line-height:1.3}.tools button[aria-pressed=true]{background:var(--selected);border-color:var(--blue);color:#004b90}.secondary{background:transparent;font-size:13px}.guide{margin-top:30px;padding:26px 24px;background:#eeece8;border-radius:12px}h2{font-size:22px;line-height:1.3;letter-spacing:-.6px;margin:0 0 14px}.guide p:not(.eyebrow){font-size:13px;color:var(--muted)}.divider{height:1px;background:#d9d5cd;margin:22px 0}.small{font-size:12px!important;line-height:1.7}summary{font-size:12px;cursor:pointer;margin-top:18px}kbd{font-size:11px;background:#fff;padding:1px 3px;border-radius:3px}footer{display:flex;justify-content:space-between;gap:16px;border-top:1px solid var(--line);padding-top:22px;margin-top:24px;color:var(--muted);font-size:11px}footer span:last-child{letter-spacing:1.5px;font-size:10px}#pause-cover{position:absolute;inset:0;background:var(--paper);border:2px solid var(--ink);display:flex;align-items:center;justify-content:center;flex-direction:column;gap:20px;font-size:22px}#pause-cover[hidden]{display:none}dialog{border:1px solid var(--line);border-radius:16px;padding:28px;max-width:440px;width:calc(100% - 32px);color:var(--ink);background:var(--paper)}dialog::backdrop{background:#24232170}dialog p{color:var(--muted)}.dialog-actions{display:flex;gap:10px;justify-content:flex-end;margin-top:24px}@media(max-width:760px){header{padding:16px 20px}main{padding:28px 20px 20px;max-width:590px}h1{font-size:48px}.intro-mark{font-size:18px;margin-right:0}.intro{margin-bottom:24px}.game-layout{grid-template-columns:1fr;gap:8px}.game-top{margin-bottom:10px}aside{display:flex;flex-direction:column}.tools{grid-template-columns:repeat(4,1fr);order:-2;margin-top:0}.tools button{padding:10px 3px}.secondary{order:-1;margin-bottom:12px}.guide{margin-top:24px;padding:22px}.guide h2 br{display:none}.progress-line{font-size:10px}#board button{font-size:26px}.pencil{font-size:10px}.badge{font-size:10px}footer{margin-top:24px}}@media(max-width:380px){main{padding-left:12px;padding-right:12px}.badge{display:none}.subtitle{font-size:14px}.intro-mark{display:none}#board button{font-size:22px}#save-status{max-width:150px;text-align:right}#keypad{gap:4px}}@media(prefers-reduced-motion:no-preference){button{transition:background .12s,border-color .12s}}