:root{--deep:#071f2f;--cyan:#69d2e7;--lime:#d5ff5f;--paper:#f2f1e9;--ink:#102638;--muted:#71848c;--line:#cad5d2;--bad:#c94d45}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:system-ui,-apple-system,"Segoe UI",sans-serif}header{height:66px;padding:0 max(18px,5vw);display:flex;align-items:center;justify-content:space-between;background:var(--deep)}header a{color:#bdd1d7;text-decoration:none;font-size:11px}.brand{display:flex;align-items:center;gap:9px;color:white;font-size:16px;font-weight:850}.brand span{display:grid;place-items:center;width:30px;height:30px;border:1px solid var(--cyan);border-radius:50%;color:var(--cyan)}.intro{padding:48px max(20px,7vw) 76px;background:var(--deep);color:white}.intro p,.game-head p{margin:0;color:var(--cyan);font-size:10px;font-weight:850;letter-spacing:1.6px;text-transform:uppercase}.intro h1{margin:8px 0;font-size:clamp(42px,6vw,72px);letter-spacing:-3px}.intro span{color:#a9bec5;font-size:12px}.game-shell{width:min(1050px,calc(100% - 28px));margin:-40px auto 55px;padding:24px;border:1px solid var(--line);border-radius:24px;background:white;box-shadow:0 24px 70px #16354514}.game-head{display:flex;align-items:center;justify-content:space-between}.game-head h2{margin:5px 0;font-size:26px}.stats{display:flex;gap:8px}.stats span{min-width:82px;padding:9px 12px;border-radius:12px;background:#eef4f2;text-align:center}.stats small{display:block;color:var(--muted);font-size:8px;text-transform:uppercase;letter-spacing:1px}.stats b{font-size:15px}.toolbar{display:flex;gap:8px;align-items:end;margin:18px 0}.toolbar label{display:grid;gap:4px;color:var(--muted);font-size:9px;text-transform:uppercase;letter-spacing:1px}.toolbar select,.toolbar button,.erase{min-height:42px;border:1px solid var(--line);border-radius:10px;background:white;color:var(--ink);padding:0 13px;font-weight:750}.toolbar button{cursor:pointer}.play-area{display:grid;grid-template-columns:minmax(310px,560px) 1fr;gap:28px;align-items:start}.sudoku-grid{display:grid;grid-template-columns:repeat(9,1fr);aspect-ratio:1;border:3px solid var(--ink);background:var(--ink);gap:1px}.cell{min-width:0;border:0;background:#fffdf7;color:#087f8c;font-size:clamp(16px,3vw,29px);font-weight:800;cursor:pointer}.cell.given{color:var(--ink);background:#f1f3ed}.cell.related{background:#e8f4f3}.cell.same{background:#d9f2f5}.cell.selected{background:var(--lime);box-shadow:inset 0 0 0 3px #8cae27}.cell.wrong{color:var(--bad);animation:shake .22s linear}.cell:nth-child(3n){border-right:2px solid var(--ink)}.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:2px solid var(--ink)}aside>p{min-height:38px;margin:2px 0 14px;color:var(--muted);font-size:12px;line-height:1.5}.number-pad{display:grid;grid-template-columns:repeat(3,1fr);gap:7px}.number-pad button{aspect-ratio:1.2;border:1px solid var(--line);border-radius:12px;background:#f5f7f3;color:var(--ink);font-size:22px;font-weight:900;cursor:pointer}.number-pad button:hover,.number-pad button:focus-visible{background:var(--cyan)}.number-pad button:disabled{opacity:.25}.erase{width:100%;margin-top:8px;cursor:pointer}.tip{display:grid;gap:5px;margin-top:18px;padding:15px;border-radius:13px;background:var(--deep);color:white}.tip b{font-size:11px}.tip span{color:#abc0c6;font-size:10px;line-height:1.5}.complete .sudoku-grid{animation:finish .7s ease}.complete .game-head h2{color:#087f8c}footer{padding:26px max(20px,5vw);display:flex;justify-content:space-between;background:var(--deep);color:#91a8af;font-size:10px}footer a{color:#bdd1d7}@keyframes shake{25%{transform:translateX(-3px)}75%{transform:translateX(3px)}}@keyframes finish{50%{transform:scale(1.015);box-shadow:0 0 0 10px #d5ff5f66}}@media(max-width:760px){.intro{padding:38px 20px 68px}.game-shell{padding:16px;border-radius:19px}.game-head{align-items:start}.game-head h2{font-size:20px}.stats span{min-width:68px;padding:7px}.play-area{grid-template-columns:1fr;gap:16px}.number-pad{grid-template-columns:repeat(9,1fr)}.number-pad button{aspect-ratio:1;padding:0;border-radius:8px;font-size:16px}.cell{font-size:clamp(16px,5.4vw,25px)}.tip{display:none}.toolbar{flex-wrap:wrap}.toolbar label{flex:1}.toolbar select{width:100%}}@media(prefers-reduced-motion:reduce){*{animation:none!important;scroll-behavior:auto!important}}