:root{--bg:#151d2c;--panel:#1d2a40;--panel2:#293a59;--text:#f8fbff;--muted:#aeb9ca;--gold:#ffd166;--pink:#ff7a7a;--mint:#80f0b0;--line:rgba(255,255,255,.14)}.sudoku-board{width:min(540px,100%);margin:0 auto 14px;display:grid;grid-template-columns:repeat(9,1fr);border:3px solid var(--gold);background:var(--gold);gap:1px}.cell{aspect-ratio:1;border:0;color:white;background:rgba(29,42,64,.96);font-size:22px;font-weight:800;cursor:pointer}.cell.given{color:var(--gold);background:rgba(255,209,102,.13);cursor:default}.cell.selected{outline:3px solid var(--mint);z-index:2}.cell.peer{background:rgba(128,240,176,.09)}.cell.bad{background:rgba(255,122,122,.25)}.cell:nth-child(3n){border-right:2px solid var(--gold)}.cell:nth-child(n+19):nth-child(-n+27),.cell:nth-child(n+46):nth-child(-n+54){border-bottom:2px solid var(--gold)}.number-pad{display:grid;grid-template-columns:repeat(5,1fr);gap:8px}.num{min-height:48px;border:1px solid var(--line);border-radius:12px;color:white;background:var(--panel2);font-weight:800;cursor:pointer}@media(max-width:560px){.cell{font-size:16px}.number-pad{grid-template-columns:repeat(5,1fr)}}