.sudoku-cell{text-align:center;--cell-bg:#fff;background-color:var(--cell-bg);color:var(--text-dark);caret-color:#0000;-webkit-user-select:none;user-select:none;border:none;outline:none;font-size:30px;font-weight:600}.sudoku-cell::selection{background:0 0}.sudoku-cell:hover{cursor:default}.sudoku-cell.prefilled{--cell-bg:#f7f7f7;color:#000;cursor:default;font-weight:700}.sudoku-cell.highlight{--cell-bg:var(--blue-light)}.sudoku-cell.highlight-value{--cell-bg:var(--blue-bg);font-weight:700}.sudoku-cell.invalid{color:var(--danger-red);--cell-bg:#fdecea}.sudoku-cell.selected{--cell-bg:var(--blue-medium)}.sudoku-cell-wrapper{box-sizing:border-box;border:1px solid var(--border-gray);width:48px;height:48px;position:relative}.sudoku-cell-wrapper.border-left{border-left:2px solid #000}.sudoku-cell-wrapper.border-right{border-right:2px solid #000}.sudoku-cell-wrapper.border-top{border-top:2px solid #000}.sudoku-cell-wrapper.border-bottom{border-bottom:2px solid #000}.sudoku-cell-wrapper input{z-index:1;width:100%;height:100%;padding:0;position:relative}.candidates{color:#666;z-index:2;pointer-events:none;grid-template-columns:repeat(3,1fr);font-size:10px;display:grid;position:absolute;inset:0}.candidates span{justify-content:center;align-items:center;display:flex}.candidates span.off{visibility:hidden}@media (max-width:480px){.sudoku-cell-wrapper{width:36px;height:36px}.sudoku-cell{font-size:22px}.candidates{font-size:8px}}
.sudoku-grid{border:2px solid #000;display:inline-block}.sudoku-row{display:flex}
.number-pad{grid-template-columns:repeat(3,1fr);gap:8px;display:grid}.num-btn{background:var(--blue-light);cursor:pointer;height:64px;box-shadow:var(--button-shadow);border:none;border-radius:10px;font-size:22px;font-weight:700;transition:transform 80ms,background .15s}.num-btn:hover:not(:disabled){background:var(--blue-medium);transform:translateY(-1px)}.num-btn:active:not(:disabled){transform:translateY(0)}.num-btn:disabled{opacity:.35;box-shadow:none}@media (max-width:480px){.number-pad{flex-wrap:wrap;justify-content:center;display:flex}.num-btn{width:25px;height:40px;font-size:20px}}
.app-container{flex-direction:column;justify-content:center;align-items:center;min-height:100vh;display:flex}.game-layout{align-items:flex-start;gap:32px;display:flex}.game-left{flex-shrink:0}.game-right{flex-direction:column;gap:10px;min-width:220px;display:flex}.panel-section{background:var(--blue-bg);box-shadow:var(--panel-shadow);border-radius:10px;padding:14px}.stats{color:var(--text-dark);flex-direction:row;gap:6px;font-size:14px;display:flex}.stats strong{color:#000;font-weight:700}.actions{flex-direction:row;justify-content:center;gap:12px;display:flex}.icon-btn{color:#3d3d3d;cursor:pointer;background:var(--blue-light);border:none;border-radius:10px;justify-content:center;align-items:center;width:44px;height:44px;font-size:30px;font-weight:600;line-height:1;display:flex}.icon-btn:hover{background:var(--blue-medium);transform:translateY(-1px);box-shadow:0 4px 10px #4a6cff40}.icon-btn:active{box-shadow:none;transform:translateY(0)}.icon-btn:disabled{opacity:.35;cursor:default;box-shadow:none;transform:none}.actions label{color:var(--text-muted);align-items:center;font-size:14px;display:flex}.checkbox{color:#444;align-items:center;gap:6px;font-size:14px;display:flex}.new-game button{background:var(--blue-strong);color:#fff;cursor:pointer;width:100%;height:48px;box-shadow:var(--button-shadow);border:none;border-radius:10px;font-size:15px;font-weight:700;transition:background .15s,transform 80ms}.new-game button:hover{background:#4b75ff;transform:translateY(-1px)}@media (max-width:768px){.game-layout{grid-template-columns:1fr;grid-template-areas:"stats""grid""numbers""actions""newgame";justify-items:center;gap:10px;display:grid}.game-left{grid-area:grid}.stats{grid-area:stats;width:100%}.number-pad{grid-area:numbers;width:100%}.actions{grid-area:actions;width:100%}.new-game{grid-area:newgame;width:100%}.game-right{display:contents}}@media (max-width:480px){.panel-section{width:300px}.stats{flex-wrap:wrap;justify-content:center}.icon-btn{width:35px;height:35px;font-size:24px}.actions{gap:12px}.new-game button{height:44px;margin-bottom:30px}}
.modal-backdrop{z-index:1000;background:#0006;justify-content:center;align-items:center;display:flex;position:fixed;inset:0}.modal{text-align:center;background:#fff;border-radius:12px;min-width:280px;padding:24px;position:relative}.modal h2{margin-bottom:12px}.modal-close{cursor:pointer;color:#555;background:0 0;border:none;border-radius:10px;font-size:22px;position:absolute;top:8px;right:8px}.modal-close:hover{color:red}.difficulty{justify-content:center;gap:10px;margin-top:16px;display:flex}.difficulty button{background:var(--blue-light);cursor:pointer;border:none;border-radius:6px;padding:8px 14px;font-weight:600}.difficulty button:hover{background:var(--blue-medium)}