:root{color:#0f172a;font-synthesis:none;text-rendering:optimizelegibility;background:#e2e8f0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}*{box-sizing:border-box}html{background:#e2e8f0;min-width:320px;min-height:100%}body{min-width:320px;min-height:100vh;margin:0}button{font:inherit;touch-action:manipulation}button:focus-visible{outline-offset:2px;outline:3px solid #38bdf8}.app{width:min(100% - 24px,560px);padding:max(18px, env(safe-area-inset-top)) 0 max(28px, env(safe-area-inset-bottom));margin:0 auto}.topbar{justify-content:space-between;align-items:center;gap:16px;margin-bottom:16px;display:flex}.eyebrow{color:#64748b;letter-spacing:.08em;text-transform:uppercase;margin:0 0 2px;font-size:.8rem;font-weight:700}h1{margin:0;font-size:clamp(2rem,8vw,3rem);line-height:1}.new-game-button,.victory-card button{color:#fff;cursor:pointer;background:#0f172a;border:0;border-radius:12px;min-height:44px;padding:0 16px;font-weight:800}.status-card{background:#fff;border-radius:16px;grid-template-columns:repeat(3,1fr);margin-bottom:12px;display:grid;overflow:hidden;box-shadow:0 10px 30px #0f172a14}.status-card div{text-align:center;gap:2px;padding:12px 8px;display:grid}.status-card div+div{border-left:1px solid #e2e8f0}.status-card span{color:#64748b;text-transform:uppercase;font-size:.75rem;font-weight:700}.status-card strong{font-size:1.05rem}.difficulty-selector{grid-template-columns:repeat(3,1fr);gap:8px;margin-bottom:12px;display:grid}.difficulty-button{color:#334155;cursor:pointer;background:#f8fafc;border:1px solid #cbd5e1;border-radius:10px;min-height:40px;font-weight:800}.difficulty-button--active{color:#fff;background:#2563eb;border-color:#2563eb}.board{aspect-ratio:1;background:#0f172a;border:3px solid #0f172a;border-radius:8px;grid-template-rows:repeat(9,minmax(0,1fr));grid-template-columns:repeat(9,minmax(0,1fr));width:100%;display:grid;overflow:hidden}.cell{aspect-ratio:1;color:#2563eb;cursor:pointer;background:#fff;border:1px solid #cbd5e1;border-top:0;border-left:0;border-radius:0;place-items:center;width:100%;min-width:0;height:100%;min-height:0;padding:0;font-size:clamp(1rem,5.7vw,1.85rem);font-weight:700;line-height:1;display:grid}.cell:nth-child(3n){border-right:3px solid #0f172a}.cell:nth-child(9n){border-right:0}.cell:nth-child(n+19):nth-child(-n+27),.cell:nth-child(n+46):nth-child(-n+54){border-bottom:3px solid #0f172a}.cell:nth-child(n+73){border-bottom:0}.cell--fixed{color:#0f172a;font-weight:900}.cell--related{background:#eff6ff}.cell--same-value{background:#dbeafe}.cell--selected{z-index:1;background:#bfdbfe;position:relative;box-shadow:inset 0 0 0 3px #2563eb}.cell--incorrect{color:#dc2626;background:#fee2e2}.controls{margin-top:14px}.number-pad{grid-template-columns:repeat(9,minmax(0,1fr));gap:5px;display:grid}.number-button{color:#fff;cursor:pointer;background:#2563eb;border:0;border-radius:10px;place-items:center;min-width:0;min-height:56px;padding:4px 0;font-size:1.25rem;font-weight:900;display:grid}.number-button small{opacity:.8;font-size:.55rem;font-weight:700;display:block}.number-button:disabled{color:#94a3b8;cursor:default;background:#cbd5e1}.erase-button{color:#334155;cursor:pointer;background:#fff;border:1px solid #cbd5e1;border-radius:10px;width:100%;min-height:44px;margin-top:8px;font-weight:800}.erase-button:disabled{opacity:.55;cursor:default}.victory-card{color:#14532d;text-align:center;background:#dcfce7;border-radius:16px;gap:8px;margin-top:14px;padding:16px;display:grid}.victory-card strong{font-size:1.3rem}@media (width<=430px){.app{width:min(100% - 12px,560px)}.new-game-button{padding:0 12px}.number-pad{gap:3px}.number-button{border-radius:8px;min-height:50px}}