:root{--orange:#ff7417;--warm:#ffc078;--ink:#07090b;--panel:#10151a;--line:#3b4248;--muted:#8f9aa4;--cell:min(7.1vh,6.25vw,72px)}*{box-sizing:border-box}html,body{margin:0;min-height:100%;background:#07090b;color:#eef2f5;font-family:Inter,Segoe UI,Arial,sans-serif}button,select{font:inherit;color:inherit}button{cursor:pointer}.screen{position:fixed;inset:0;overflow:hidden;background:#050607}.art{position:absolute;inset:0;background:url('image/forge_sudoku_artwork.png') center/cover no-repeat}.veil{position:absolute;inset:0;background:linear-gradient(90deg,#040506f2 0 38%,#0506078c 58%,#0002)}.splash-copy{position:absolute;left:7vw;top:50%;transform:translateY(-50%);width:min(520px,80vw)}.splash-copy img{width:56px}.splash-copy p,.eyebrow{color:var(--orange);font-weight:900;font-size:.72rem;letter-spacing:.18em}.splash-copy h1,.start-copy h1{margin:16px 0;font-size:clamp(3rem,7vw,7rem);line-height:.78;letter-spacing:-.06em}.splash-copy h1 b,.start-copy h1 b{display:block;color:var(--orange);font-weight:500}.heatline{height:3px;background:#343b41;margin:34px 0 14px;overflow:hidden}.heatline i{display:block;height:100%;width:42%;background:var(--orange);box-shadow:0 0 18px var(--orange);animation:load 1.7s ease-in-out infinite}.splash-copy small{letter-spacing:.18em;color:#b7c0c8}@keyframes load{0%{transform:translateX(-110%)}100%{transform:translateX(280%)}}.start-panel{position:relative;z-index:2;width:min(580px,calc(100% - 40px));height:calc(100% - 80px);margin:40px 0 40px 5vw;padding:38px 44px;border:1px solid #46505a;border-top:3px solid var(--orange);background:#090d11f5;box-shadow:0 30px 90px #000b;display:flex;flex-direction:column}.start-panel header,.start-panel footer{display:flex;justify-content:space-between;align-items:center;color:#91a1af;font-size:.68rem;letter-spacing:.08em}.start-panel header img{width:44px}.start-copy{margin:auto 0}.start-copy p{color:var(--orange);font-weight:900;letter-spacing:.16em}.start-copy h1{font-size:clamp(3.4rem,6vw,6.2rem)}#startLead{font-size:1.05rem;color:#d4dbe0}.start-actions{display:grid;gap:9px;margin-bottom:10px}.tools{display:flex;gap:8px}.start-panel footer{border-top:1px solid #3b4248;margin-top:28px;padding-top:18px}.btn,.tool,.difficulty-btn,.tab{border:1px solid #414951;background:linear-gradient(#20262c,#11151a);font-weight:850;text-transform:uppercase;letter-spacing:.04em;border-radius:8px;padding:11px 14px}.btn:hover,.tool:hover,.difficulty-btn:hover,.tab:hover{border-color:var(--orange)}.primary{background:linear-gradient(135deg,#ff922f,#e85d00);border-color:#ff9a3c;color:#160b03}.big{min-height:56px}.full{width:100%}.game{min-height:100vh;padding:12px clamp(10px,2vw,28px)}.topbar{max-width:1540px;margin:auto;display:flex;justify-content:space-between;align-items:center;padding:7px 0 13px}.brand{display:flex;gap:10px;align-items:center}.brand img{width:44px}.brand strong,.brand span{display:block}.brand span{font-size:.58rem;color:var(--orange);letter-spacing:.14em;margin-top:3px}.top-actions{display:flex;gap:7px}.game-layout{max-width:1540px;margin:auto;display:grid;grid-template-columns:230px minmax(560px,1fr) 245px;gap:14px;align-items:stretch}.panel,.forge-table{border:1px solid var(--line);border-top:2px solid #6a4a31;background:linear-gradient(150deg,#161b20,#080a0d 70%);box-shadow:0 22px 60px #0009;border-radius:10px}.panel{padding:18px}.mission h2{font-size:2.2rem;margin:3px 0 20px}.readouts{display:grid;gap:8px;margin-bottom:18px}.readouts div,.stats div{padding:10px;border:1px solid #30373e;background:#090c0f}.readouts span,.stats span,.label{display:block;color:var(--muted);font-size:.64rem;text-transform:uppercase;letter-spacing:.08em}.readouts strong{font-size:1.35rem;color:var(--warm)}.difficulty{display:grid;grid-template-columns:repeat(3,1fr);gap:5px;margin:7px 0 18px}.difficulty-btn{padding:9px 3px;font-size:.7rem}.difficulty-btn.active{border-color:var(--orange);box-shadow:inset 0 -2px var(--orange);color:var(--warm)}.mission>.btn{margin-top:8px}.error-mode{display:grid;gap:6px;margin-top:18px;color:var(--muted);font-size:.68rem;text-transform:uppercase}.error-mode select{background:#090c0f;border:1px solid #3d454d;padding:9px}.forge-table{padding:14px;min-width:0;background:radial-gradient(circle at 50% 35%,#222a30,#0a0d10 68%)}.table-head{display:flex;justify-content:space-between;padding:2px 5px 12px;color:#9ca7af;font-size:.68rem;letter-spacing:.15em}.table-head strong{color:var(--orange)}.board-chassis{position:relative;margin:auto;width:max-content;padding:clamp(10px,1.2vw,18px);border:1px solid #697078;border-radius:10px;background:linear-gradient(145deg,#343a3f,#15191d 42%,#080a0c);box-shadow:inset 0 1px #ffffff2c,inset 0 -22px 45px #000b,0 25px 50px #000a}.board-chassis>i{position:absolute;width:11px;height:11px;border-radius:50%;background:radial-gradient(circle at 35% 30%,#b9b9b9,#333 55%,#050505);box-shadow:0 1px 2px #000}.board-chassis>i:nth-child(1){left:7px;top:7px}.board-chassis>i:nth-child(2){right:7px;top:7px}.board-chassis>i:nth-child(3){left:7px;bottom:7px}.board-chassis>i:nth-child(4){right:7px;bottom:7px}.board{display:grid;grid-template-columns:repeat(9,var(--cell));grid-template-rows:repeat(9,var(--cell));background:#18120d;border:3px solid #08090a;box-shadow:0 0 0 2px #b36a2d55}.cell{width:var(--cell);height:var(--cell);border:0;border-right:1px solid #66513f;border-bottom:1px solid #66513f;background:linear-gradient(145deg,#d9cbb9,#b8a893);color:#17130f;font-size:clamp(1.05rem,2.2vw,2rem);font-weight:750;position:relative}.cell:nth-child(3n){border-right:3px solid #34261c}.cell:nth-child(n+19):nth-child(-n+27),.cell:nth-child(n+46):nth-child(-n+54){border-bottom:3px solid #34261c}.cell.given{font-weight:950;color:#0b0907;background:linear-gradient(145deg,#e7dac7,#c7b59e)}.cell.related{background:#d3b68f}.cell.same{box-shadow:inset 0 0 0 3px #c86b1c}.cell.selected{background:#ffb463;box-shadow:inset 0 0 0 3px #7a3100}.cell.user{color:#7a2c00}.cell.hint{color:#13505b}.cell.invalid{color:#a60000;background:#efb0a6}.notes-grid{position:absolute;inset:3px;display:grid;grid-template-columns:repeat(3,1fr);font-size:.46em;color:#5b4738}.pause-overlay{position:absolute;inset:18px;display:none;border:0;background:#07090be8;color:var(--orange);font-size:1.6rem;font-weight:900;letter-spacing:.12em}.pause-overlay.show{display:block}.message-line{height:38px;display:flex;align-items:center;justify-content:center;gap:8px;color:#b8c1c8;font-size:.8rem}.message-line span{width:7px;height:7px;border-radius:50%;background:var(--orange);box-shadow:0 0 10px var(--orange)}.console{display:flex;flex-direction:column;gap:12px}.keypad{display:grid;grid-template-columns:repeat(3,1fr);gap:7px}.keypad button{aspect-ratio:1;border:1px solid #4c555d;border-radius:7px;background:radial-gradient(circle at 40% 25%,#303840,#101419);font-size:1.4rem;font-weight:900;box-shadow:inset 0 1px #ffffff20,0 3px 8px #000}.keypad button:hover{border-color:var(--orange);color:var(--warm)}.action-grid{display:grid;grid-template-columns:1fr 1fr;gap:7px}.stats{display:grid;gap:7px;margin-top:auto}.stats strong{display:block;margin-top:3px;color:var(--warm)}.game-footer{max-width:1540px;margin:12px auto 0;padding:10px 4px;border-top:1px solid #30363c;display:grid;grid-template-columns:1fr auto 1fr;color:var(--muted);font-size:.67rem}.game-footer span:nth-child(2){text-align:center}.game-footer strong{text-align:right;color:var(--orange)}dialog{width:min(620px,calc(100% - 30px));border:1px solid #505861;border-top:3px solid var(--orange);background:#10151a;color:#eef2f5;padding:24px;box-shadow:0 30px 100px #000}dialog::backdrop{background:#000c;backdrop-filter:blur(7px)}.dialog-head,.dialog-actions{display:flex;justify-content:space-between;gap:8px}.tabs{display:flex;gap:7px;margin:15px 0}.tab-panel{display:none;color:#c3cbd2;line-height:1.6}.tab-panel.active{display:block}.tab.active{border-color:var(--orange)}@media(max-width:1120px){:root{--cell:min(7.5vh,8vw,68px)}.game-layout{grid-template-columns:190px 1fr}.console{grid-column:1/-1;display:grid;grid-template-columns:1fr 1fr 1fr}.console>.eyebrow,.console>.stats{grid-column:1/-1}.keypad{grid-template-columns:repeat(9,1fr)}.keypad button{aspect-ratio:auto;min-height:45px}}@media(max-width:760px){:root{--cell:min(9.2vw,54px)}.start-panel{margin:16px;width:calc(100% - 32px);height:calc(100% - 32px);padding:26px}.veil{background:#050607bb}.game-layout{grid-template-columns:1fr}.mission{order:2}.forge-table{order:1}.console{order:3;display:block}.keypad{grid-template-columns:repeat(9,1fr);margin:10px 0}.keypad button{min-height:42px}.action-grid{margin:10px 0}.readouts{grid-template-columns:repeat(3,1fr)}.difficulty{max-width:360px}.topbar{align-items:flex-start}.top-actions{display:grid;grid-template-columns:repeat(2,auto)}.game-footer{grid-template-columns:1fr;text-align:center;gap:4px}.game-footer strong{text-align:center}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation-duration:.001ms!important;transition-duration:.001ms!important}}

/* BUILD 0017 · PRE-DELIVERY UI HARDENING */
button:focus-visible,select:focus-visible{outline:3px solid var(--orange);outline-offset:2px}
.tab{min-width:96px;color:#dbe2e8;background:linear-gradient(#20262c,#11151a);border:1px solid #414951;border-radius:8px;padding:10px 14px;font-weight:850;text-transform:uppercase;letter-spacing:.04em}
.tab.active{color:#160b03;background:linear-gradient(135deg,#ff922f,#e85d00);border-color:#ff9a3c}
dialog{max-height:min(82vh,720px);overflow:auto}
.dialog-head{align-items:flex-start}.close-dialog{min-width:44px;min-height:44px;font-size:1.25rem}
.dialog-actions{margin-top:20px;justify-content:flex-end}.dialog-actions .btn{min-width:130px}
html[data-theme="light"] .game{background:#15191d;color:#eef2f5}
html[data-theme="light"] .panel,html[data-theme="light"] .forge-table{background:linear-gradient(150deg,#252c32,#0d1115 72%)}
html[data-theme="light"] .topbar,html[data-theme="light"] .game-footer{color:#eef2f5}
@media(max-width:520px){dialog{padding:18px}.tabs{display:grid;grid-template-columns:1fr}.tab{width:100%}.dialog-actions{display:grid;grid-template-columns:1fr 1fr}.dialog-actions .btn{min-width:0}}