:root{--ink:#20304b;--muted:#738097;--gold:#e8902f;--gold2:#f6b84e;--cream:#fff8e8;--line:#dfe5ee;--blue:#3967d8;--shadow:0 18px 55px rgba(43,56,90,.12)}*{box-sizing:border-box}body{margin:0;min-height:100vh;background:radial-gradient(circle at 82% 6%,#fff0bd 0,transparent 27%),linear-gradient(180deg,#fffaf0,#f2f6fb);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif}.topbar{height:72px;padding:0 5vw;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid rgba(220,224,232,.9);background:rgba(255,255,255,.82);backdrop-filter:blur(16px)}.brand{display:flex;align-items:center;gap:11px;color:inherit;text-decoration:none}.brand>span{display:grid;width:42px;height:42px;place-items:center;border-radius:13px;background:linear-gradient(145deg,var(--gold),var(--gold2));color:#fff;font-size:20px;font-weight:900;box-shadow:0 8px 20px rgba(232,144,47,.25)}.brand strong,.brand small{display:block}.brand small{margin-top:2px;color:var(--muted);font-size:10px}.back{color:#5e6980;font-size:13px;text-decoration:none}.sudoku-icon{background:linear-gradient(145deg,#e8902f,#f6b84e)}main{max-width:1140px;margin:auto;padding:48px 25px 54px}.intro{text-align:center}.eyebrow{margin:0 0 10px;color:var(--gold);font-size:10px;font-weight:900;letter-spacing:.2em}.intro h1{margin:0;font-size:clamp(32px,4vw,50px);letter-spacing:-.04em}.intro h1 span{color:var(--gold)}.intro>p:last-of-type{margin:13px auto 23px;color:var(--muted);font-size:13px;line-height:1.7}.levels{display:grid;grid-template-columns:repeat(3,1fr);gap:11px;max-width:790px;margin:auto}.level{position:relative;display:grid;grid-template-columns:auto 1fr;align-items:center;gap:10px;padding:13px;border:1px solid #dce2eb;border-radius:17px;background:rgba(255,255,255,.9);color:var(--ink);cursor:pointer;text-align:left;transition:.18s}.level:hover{transform:translateY(-2px)}.level i{display:grid;grid-row:1/3;width:37px;height:37px;place-items:center;border-radius:12px;background:#edf1f7;color:#798399;font-style:normal;font-weight:900}.level b,.level small{display:block}.level b{font-size:14px}.level small{margin-top:2px;color:var(--muted);font-size:10px}.level em{position:absolute;top:7px;right:8px;padding:3px 6px;border-radius:99px;background:#f2f4f8;color:#8992a3;font-size:8px;font-style:normal}.level.active{border-color:#f0b35f;background:#fff9ec;box-shadow:0 9px 25px rgba(232,144,47,.13)}.level.active i{background:var(--gold);color:#fff}.level.active em{background:#ffebc9;color:#bd6f17}.game-shell{display:grid;grid-template-columns:minmax(500px,1.45fr) minmax(240px,.55fr);gap:18px;margin-top:26px}.game-panel,.guide{border:1px solid var(--line);border-radius:24px;background:rgba(255,255,255,.94);box-shadow:var(--shadow)}.game-panel{padding:23px}.game-head{display:flex;align-items:center;justify-content:space-between;gap:16px}.game-head>div:first-child span,.game-head>div:first-child strong{display:block}.game-head>div:first-child span{color:var(--gold);font-size:10px;font-weight:900}.game-head>div:first-child strong{margin-top:4px;font-size:18px}.stats{display:flex;gap:8px}.stats span{padding:7px 10px;border-radius:10px;background:#f5f7fa;color:var(--muted);font-size:10px}.stats b{margin-left:4px;color:var(--ink)}.board-wrap{display:grid;place-items:center;margin:20px auto 16px}.board{--size:4;--box-r:2;--box-c:2;display:grid;grid-template-columns:repeat(var(--size),1fr);width:min(100%,510px);aspect-ratio:1;border:3px solid #273854;border-radius:8px;overflow:hidden;background:#273854;gap:1px}.cell{position:relative;display:grid;place-items:center;border:0;background:#fff;color:#263752;font-size:clamp(18px,3vw,28px);font-weight:750;cursor:pointer;outline:0}.cell.fixed{background:#f3f5f8;color:#1e2c43;font-weight:900}.cell.selected{background:#ffedc7}.cell.peer{background:#fff8ea}.cell.same{color:#d87919}.cell.wrong{background:#ffe1df;color:#c43d37}.cell.hinted{background:#e7f6ed;color:#178250}.cell.box-right{border-right:2px solid #273854}.cell.box-bottom{border-bottom:2px solid #273854}.number-pad{display:flex;justify-content:center;gap:7px;flex-wrap:wrap}.number-pad button{width:43px;height:43px;border:1px solid #d6deea;border-radius:12px;background:#f7f9fc;color:#263752;font-size:17px;font-weight:900;cursor:pointer}.number-pad button:hover{border-color:var(--gold);background:#fff7e8}.game-actions{display:flex;justify-content:center;gap:8px;margin-top:16px;flex-wrap:wrap}.game-actions button{padding:10px 14px;border-radius:11px;font-weight:800;cursor:pointer}.secondary{border:1px solid #d7deea;background:#fff;color:#5e6980}.primary{border:1px solid var(--gold);background:var(--gold);color:#fff}.status{min-height:20px;margin:13px 0 0;color:#788397;font-size:11px;text-align:center}.status.success{color:#178250;font-weight:800}.status.error{color:#c43d37}.guide{align-self:start;padding:22px}.guide-title{display:flex;align-items:center;justify-content:space-between}.guide-title span{font-size:15px;font-weight:900}.guide-title b{color:var(--gold);font-size:10px}.progress{height:7px;margin:13px 0 21px;border-radius:99px;background:#edf0f5;overflow:hidden}.progress i{display:block;width:0;height:100%;border-radius:inherit;background:linear-gradient(90deg,var(--gold),var(--gold2));transition:width .3s}.guide ol{display:grid;gap:15px;margin:0;padding:0;list-style:none}.guide li{display:grid;grid-template-columns:45px 1fr;gap:10px;align-items:center}.guide li span{display:grid;height:34px;place-items:center;border-radius:10px;background:#fff5e1;color:#c47319;font-size:11px;font-weight:900}.guide li p{margin:0;color:#68758b;font-size:11px;line-height:1.5}.rule-card{margin-top:21px;padding:15px;border-radius:15px;background:#f5f7fb}.rule-card strong{font-size:12px}.rule-card p{margin:6px 0 0;color:#6d788d;font-size:11px;line-height:1.65}.unique{margin:15px 0 0;color:#2b8b66;font-size:10px}.celebration{position:fixed;z-index:100;inset:0;display:grid;place-items:center;padding:20px;background:rgba(22,31,50,.5);backdrop-filter:blur(7px)}.celebration.hidden{display:none}.celebration>div{width:min(390px,100%);padding:35px;border-radius:25px;background:#fff;text-align:center;box-shadow:0 24px 70px rgba(19,29,51,.3)}.celebration span{display:grid;width:60px;height:60px;margin:auto;place-items:center;border-radius:50%;background:#fff0cd;color:var(--gold);font-size:30px}.celebration h2{margin:15px 0 7px}.celebration p{color:var(--muted);font-size:13px}.celebration button{padding:11px 24px;border:0;border-radius:12px;background:var(--gold);color:#fff;font-weight:850;cursor:pointer}footer{padding:20px;text-align:center;color:#929baa;font-size:10px}@media(max-width:1280px){main{padding-left:90px}}@media(max-width:850px){main{padding:35px 16px}.game-shell{grid-template-columns:1fr}.guide{display:none}}@media(max-width:620px){body{padding-bottom:75px}.topbar{height:64px;padding:0 15px}.back{font-size:11px}.levels{grid-template-columns:1fr}.level{padding:10px 12px}.game-panel{padding:15px;border-radius:19px}.game-head{align-items:flex-start}.stats{display:grid;gap:4px}.board{width:100%}.cell{font-size:clamp(17px,6vw,24px)}.number-pad button{width:37px;height:39px}.game-actions button{flex:1;padding-inline:8px;font-size:11px}}