:root{color:#111;background:#e5e5e5;font-family:ui-serif,Georgia,Times New Roman,serif;font-synthesis:none;text-rendering:optimizeLegibility}*{box-sizing:border-box}body{margin:0;min-width:0;min-height:100vh;overflow-x:hidden}button,select{font:inherit}.app{width:min(980px,100%);margin:0 auto;padding:16px}.hero{display:grid;gap:6px;margin-bottom:12px;text-align:center}.hero h1{margin:0;font-size:clamp(1.9rem,7vw,3.8rem);letter-spacing:0}.hero p{min-height:1.5em;margin:0;font-size:clamp(.95rem,3vw,1.25rem);font-weight:800}.toolbar,.settings{display:grid;gap:8px;margin-bottom:10px}.toolbar{grid-template-columns:repeat(auto-fit,minmax(82px,1fr))}.settings{grid-template-columns:repeat(auto-fit,minmax(150px,1fr));align-items:end}.toolbar button,.settings select,.toggle{width:100%;min-height:46px;border:2px solid #111;background:#f7f7f7;color:#111;border-radius:10px;font-weight:900}.toolbar button{padding:0 6px;font-size:clamp(.78rem,2.4vw,1rem)}.toolbar button:disabled{opacity:.45}.settings label{display:grid;gap:4px;min-width:0;font-size:.82rem;font-weight:900;text-transform:uppercase;letter-spacing:.06em}.toggle{display:flex!important;align-items:center;gap:10px!important;padding:0 12px;text-transform:none!important;letter-spacing:0!important;font-size:1rem!important}.toggle input{width:22px;height:22px;accent-color:#111}.play-area{display:grid;grid-template-columns:minmax(0,1fr) minmax(190px,250px);gap:14px;align-items:start}.board{width:min(100%,calc(100vh - 245px));aspect-ratio:1 / 1;justify-self:center;background:#fff;border:5px solid #111;border-radius:14px;overflow:hidden;box-shadow:0 18px 40px #00000029}.sudoku-board{display:grid;grid-template-columns:repeat(9,1fr);grid-template-rows:repeat(9,1fr)}.cell{position:relative;display:grid;place-items:center;min-width:0;min-height:0;padding:0;background:#fafafa;border:1px solid #777;border-radius:0;color:#111;cursor:pointer;font-size:clamp(1.1rem,5vw,2.3rem);font-weight:900}.cell:nth-child(3n){border-right-width:3px;border-right-color:#111}.cell:nth-child(9n){border-right-width:1px;border-right-color:#777}.cell:nth-child(n+19):nth-child(-n+27),.cell:nth-child(n+46):nth-child(-n+54){border-bottom-width:3px;border-bottom-color:#111}.cell.fixed{background:#e0e0e0}.cell.same{background:#ededed}.cell.selected{outline:4px solid #111;outline-offset:-4px;background:#d2d2d2;z-index:2}.cell.conflict:not(.fixed),.cell.mistake:not(.fixed){background:#c8c8c8;color:#000}.cell:focus-visible{outline:4px solid #111;outline-offset:-4px;z-index:3}.notes-grid{display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(3,1fr);width:100%;height:100%;padding:4px;font-size:clamp(.42rem,1.8vw,.78rem);line-height:1;color:#444}.notes-grid i{display:grid;place-items:center;font-style:normal;font-weight:800}.side-panel{display:grid;gap:10px;min-width:0}.status-card{border:3px solid #111;border-radius:14px;background:#f7f7f7;padding:12px}.status-card h2{margin:0 0 8px;font-size:1.05rem}.status-card p{margin:4px 0;font-weight:800}.keypad{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}.keypad button{min-height:54px;border:2px solid #111;border-radius:10px;background:#f7f7f7;font-size:1.4rem;font-weight:900}.keypad .wide{grid-column:1 / -1;font-size:1rem}@media(max-width:720px){.app{padding:10px}.play-area{grid-template-columns:1fr}.board{width:min(100%,calc(100vw - 20px))}.side-panel{grid-template-columns:minmax(0,1fr)}}