.sudoku-game {
    max-width: 480px;
    margin: 0 auto;
    background: #f6f7fa;
    padding: 16px;
    border-radius: 8px;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    position: relative;
    box-sizing: border-box;
}

.sudoku-game.loading::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(246, 247, 250, 0.85);
    z-index: 19;
    border-radius: 8px;
}

.sudoku-game.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40px;
    height: 40px;
    border: 4px solid #e0e0e0;
    border-top-color: #1E9FFF;
    border-radius: 50%;
    animation: sudoku-spin 0.8s linear infinite;
    z-index: 20;
}

@keyframes sudoku-spin {
    to { transform: translate(-50%, -50%) rotate(360deg); }
}

.sudoku-game *,
.sudoku-game *::before,
.sudoku-game *::after {
    box-sizing: border-box;
}

.sudoku-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 1px solid #e0e0e0;
}

.sudoku-mode-switch {
    display: flex;
    justify-content: center;
    gap: 0;
    margin-bottom: 14px;
    border-radius: 20px;
    overflow: hidden;
    width: fit-content;
    margin-left: auto;
    margin-right: auto;
    border: 2px solid #1E9FFF;
}

.sudoku-mode-btn {
    padding: 6px 24px;
    border: none;
    background: #fff;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    color: #1E9FFF;
    transition: all 0.2s ease;
}

.sudoku-mode-btn:hover {
    background: #f0f7ff;
}

.sudoku-mode-btn.active {
    background: #1E9FFF;
    color: #fff;
}

.sudoku-title {
    font-size: 18px;
    font-weight: bold;
    color: #333;
}

.sudoku-timer {
    font-size: 16px;
    font-weight: bold;
    color: #1E9FFF;
    font-variant-numeric: tabular-nums;
}

.sudoku-diff-bar {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-bottom: 14px;
}

.sudoku-diff {
    padding: 6px 18px;
    border: 2px solid #ddd;
    background: #fff;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.25s ease;
    color: #666;
    position: relative;
    z-index: 1;
}

.sudoku-game.loading .sudoku-diff,
.sudoku-game.loading .sudoku-btn,
.sudoku-game.loading .sudoku-num {
    pointer-events: none;
    opacity: 0.6;
    cursor: not-allowed;
}

.sudoku-diff:hover {
    background: #f0f0f0;
}

.sudoku-diff.active[data-diff="easy"] {
    background: #5FB878 !important;
    color: #fff !important;
    border: 2px solid #5FB878 !important;
}

.sudoku-diff.active[data-diff="medium"] {
    background: #1E9FFF !important;
    color: #fff !important;
    border: 2px solid #1E9FFF !important;
}

.sudoku-diff.active[data-diff="hard"] {
    background: #FF5722 !important;
    color: #fff !important;
    border: 2px solid #FF5722 !important;
}

.sudoku-diff.active[data-diff="expert"] {
    background: #673AB7 !important;
    color: #fff !important;
    border: 2px solid #673AB7 !important;
}

.sudoku-diff.active[data-diff="master"] {
    background: #FF9800 !important;
    color: #fff !important;
    border: 2px solid #FF9800 !important;
}

.sudoku-diff:not(.active)[data-diff="easy"] {
    color: #5FB878 !important;
    border: 2px solid #5FB878 !important;
}

.sudoku-diff:not(.active)[data-diff="medium"] {
    color: #1E9FFF !important;
    border: 2px solid #1E9FFF !important;
}

.sudoku-diff:not(.active)[data-diff="hard"] {
    color: #FF5722 !important;
    border: 2px solid #FF5722 !important;
}

.sudoku-diff:not(.active)[data-diff="expert"] {
    color: #673AB7 !important;
    border: 2px solid #673AB7 !important;
}

.sudoku-diff:not(.active)[data-diff="master"] {
    color: #FF9800 !important;
    border: 2px solid #FF9800 !important;
}

.sudoku-board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    grid-template-rows: repeat(9, 1fr);
    gap: 0;
    background: #fff;
    border: 3px solid #333;
    border-radius: 4px;
    margin: 0 auto;
    max-width: 400px;
    aspect-ratio: 1;
    overflow: hidden;
}

.sudoku-cell {
    background: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    user-select: none;
    transition: background 0.15s ease;
    position: relative;
    border-right: 1px solid #bbb;
    border-bottom: 1px solid #bbb;
    box-sizing: border-box;
}

.sudoku-cell:nth-child(9n) {
    border-right: none;
}

.sudoku-cell:nth-child(n+73) {
    border-bottom: none;
}

.sudoku-cell.col-border-right {
    border-right: 3px solid #333 !important;
}

.sudoku-cell.row-border-bottom {
    border-bottom: 3px solid #333 !important;
}

.sudoku-cell.fixed {
    background: #f0f0f0;
    color: #222;
    cursor: default;
}

.sudoku-cell.user-input {
    color: #0529ff;
}

.sudoku-cell.selected {
    background: #e2eaff;
    outline: 2px solid #1E9FFF;
    z-index: 2;
}

.sudoku-cell.highlighted {
    background: #eef2ff;
}

.sudoku-cell.error {
    color: #ed5565 !important;
}

.sudoku-cell.error::after {
    content: "";
    position: absolute;
    inset: 0;
    background: rgba(237, 85, 101, 0.12);
    pointer-events: none;
}

.sudoku-numpad {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 6px;
    margin-top: 14px;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
}

.sudoku-num {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #1E9FFF;
    color: #fff;
    border-radius: 6px;
    font-size: 18px;
    font-weight: bold;
    cursor: pointer;
    transition: opacity 0.2s;
}

.sudoku-num:hover {
    opacity: 0.85;
}

.sudoku-num:active {
    opacity: 0.7;
    transform: scale(0.95);
}

.sudoku-num.sudoku-erase {
    background: #ed5565;
}

.sudoku-btn {
    padding: 8px 20px;
    border: 1px solid #ccc;
    background: #fff;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    color: #555;
    transition: all 0.2s;
}

.sudoku-btn:hover {
    background: #f5f5f5;
    border-color: #999;
}

.sudoku-btn.sudoku-btn-primary {
    background: #1E9FFF;
    color: #fff;
    border-color: #1E9FFF;
}

.sudoku-btn.sudoku-btn-primary:hover {
    background: #1890e0;
    border-color: #1890e0;
}

.sudoku-overlay {
    display: none;
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.75);
    z-index: 10;
    border-radius: 8px;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: #fff;
}

.sudoku-overlay.show {
    display: flex;
}

.sudoku-overlay-title {
    font-size: 26px;
    margin-bottom: 10px;
    font-weight: bold;
}

.sudoku-overlay-time {
    font-size: 18px;
    margin-bottom: 20px;
    opacity: 0.9;
}

.sudoku-overlay-content {
    text-align: center;
}

.sudoku-overlay .sudoku-btn {
    color: #fff;
    background: #1E9FFF;
    border-color: #1E9FFF;
}

.sudoku-overlay .sudoku-btn:hover {
    background: #1890e0;
}

@media (max-width: 520px) {
    .sudoku-game {
        padding: 10px;
    }

    .sudoku-cell {
        font-size: 16px;
    }

    .sudoku-num {
        font-size: 16px;
    }

    .sudoku-diff {
        padding: 4px 10px;
        font-size: 12px;
    }
}

/* 打印版预览样式 */
.sudoku-print-options {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
    padding: 10px;
    background: #fff;
    border-radius: 6px;
}

.sudoku-print-options label {
    display: flex;
    align-items: center;
    gap: 5px;
    font-size: 14px;
    color: #333;
    cursor: pointer;
}

.sudoku-print-puzzles {
    max-width: 100%;
}

.sudoku-print-page {
    margin-bottom: 20px;
    background: #fff;
}

.sudoku-print-header {
    text-align: center;
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid #1E9FFF;
}

.sudoku-print-title {
    font-size: 18px;
    font-weight: 700;
    color: #333;
}

.sudoku-print-subtitle {
    font-size: 12px;
    color: #666;
    margin-top: 3px;
}

.sudoku-print-items {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.sudoku-print-item {
    background: #fff;
    padding: 10px;
}

.sudoku-print-item-title {
    text-align: center;
    font-size: 15px;
    font-weight: 700;
    color: #333;
    margin-bottom: 8px;
    padding-bottom: 5px;
    border-bottom: 1px solid #1E9FFF;
}

.sudoku-print-board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    aspect-ratio: 1;
    width: 100%;
    max-width: 420px;
    margin: 0 auto;
    border: 2px solid #333;
}

.sudoku-print-cell {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    font-weight: 700;
    border-right: 1px solid #bbb;
    border-bottom: 1px solid #bbb;
    background: #fff;
    color: #222;
    position: relative;
    z-index: 1;
}

.sudoku-print-cell:nth-child(9n) {
    border-right: none;
}

.sudoku-print-cell:nth-child(n+73) {
    border-bottom: none;
}

.sudoku-print-cell.col-border-right {
    border-right: 2px solid #333 !important;
    z-index: 2;
}

.sudoku-print-cell.row-border-bottom {
    border-bottom: 2px solid #333 !important;
    z-index: 2;
}

.sudoku-print-footer {
    text-align: center;
    margin-top: 12px;
    padding-top: 8px;
    border-top: 1px dashed #ddd;
    font-size: 11px;
    color: #999;
}

@media (max-width: 520px) {
    .sudoku-print-options {
        gap: 10px;
    }

    .sudoku-mode-btn {
        padding: 5px 16px;
        font-size: 13px;
    }
}

/* 打印样式 */
@media print {
    @page {
        size: A4;
        margin: 0.8cm;
    }

    body.sudoku-printing > *:not(.sudoku-print-puzzles) {
        display: none !important;
    }

    body.sudoku-printing .sudoku-print-puzzles {
        display: block !important;
        width: 100%;
        margin: 0;
        padding: 0;
    }

    body.sudoku-printing .sudoku-print-page {
        page-break-after: always;
        break-after: page;
        margin: 0 !important;
        padding: 0 !important;
        background: #fff;
    }

    body.sudoku-printing .sudoku-print-page:last-child {
        page-break-after: auto;
        break-after: auto;
    }

    body.sudoku-printing .sudoku-print-header {
        margin-bottom: 4px !important;
        padding-bottom: 3px !important;
    }

    body.sudoku-printing .sudoku-print-title {
        font-size: 13px;
    }

    body.sudoku-printing .sudoku-print-subtitle {
        font-size: 9px;
    }

    body.sudoku-printing .sudoku-print-items {
        gap: 4px !important;
    }

    body.sudoku-printing .sudoku-print-item {
        padding: 1px !important;
        margin: 0 !important;
    }

    body.sudoku-printing .sudoku-print-item-title {
        font-size: 13px;
        margin-bottom: 2px !important;
        padding-bottom: 1px !important;
    }

    body.sudoku-printing .sudoku-print-board {
        max-width: 360px;
    }

    body.sudoku-printing .sudoku-print-cell {
        font-size: 15px;
    }

    body.sudoku-printing .sudoku-print-footer {
        margin-top: 4px !important;
        padding-top: 2px !important;
        font-size: 9px;
    }
}