:root {
    --correct-color: #67c23a;
    --wrong-color: #f56c6c;
    --highlight-bg: #fff9c4;
    --highlight-border: #f9a825;
    --tip-bg: #fff8e1;
    --sidebar-width: 260px;
    --base-font-size: 18px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    /* 墨水屏优化：全局禁用动画和过渡 */
    transition: none !important;
    animation: none !important;
}

/* 墨水屏优化例外：加载旋转器需要动画以示程序运行中 */
.loading-spinner {
    animation: spin 1s linear infinite !important;
}

body {
    font-family: "Hiragino Mincho ProN", "Yu Mincho", "MS Mincho", serif;
    background: #fff;
    color: #000;
    display: flex;
    min-height: 100vh;
    padding-bottom: 72px;
    /* 为底部工具栏留出空间 */
    -webkit-font-smoothing: antialiased;
}

body.font-mincho {
    font-family: "Hiragino Mincho ProN", "Yu Mincho", "MS Mincho", serif;
}

body.font-gothic {
    font-family: "Hiragino Sans", "Yu Gothic", "Meiryo", sans-serif;
}

ruby {
    ruby-position: over;
    ruby-align: center;
}

rt {
    visibility: hidden;
    font-family: "Hiragino Sans", sans-serif;
    font-size: 0.55em;
    line-height: 1;
    color: #444;
    user-select: none;
    font-weight: bold;
}

body.show-furigana rt {
    visibility: visible;
}

.target-word rt {
    display: none !important;
}

.sidebar {
    width: var(--sidebar-width);
    background: #fff;
    border-right: 2px solid #000;
    height: 100vh;
    position: fixed;
    left: 0;
    top: 0;
    padding: 20px;
    display: flex;
    flex-direction: column;
    z-index: 100;
    transition: transform 0.3s ease;
}

.exam-header {
    border-bottom: 3px solid #000;
    margin-bottom: 32px;
    padding-bottom: 14px;
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
}

.exam-header h1 {
    font-size: 28px;
    font-weight: bold;
    margin-bottom: 6px;
}

.stats-card {
    border: 2px solid #000;
    padding: 12px;
    margin-bottom: 20px;
    background: #fff;
}

.stats-item {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 5px;
    font-size: 13px;
}

.stats-item .val {
    font-weight: bold;
    font-size: 24px;
    font-family: "Hiragino Sans", sans-serif;
}

.nav-section-title {
    font-size: 11px;
    font-weight: bold;
    margin: 15px 0 6px;
    padding-bottom: 2px;
    /* border-bottom: 1px solid #000; */
    text-transform: uppercase;
}

.nav-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(32px, 1fr));
    gap: 4px;
    margin-bottom: 10px;
}

.nav-grid a {
    aspect-ratio: 1/1;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid #000;
    font-size: 11px;
    text-decoration: none;
    color: #000;
    font-weight: bold;
    font-family: "Hiragino Sans", sans-serif;
}

.nav-grid a.done-correct {
    background: var(--correct-color);
    color: #000;
    border-width: 2px;
}

.nav-grid a.done-wrong {
    background: var(--wrong-color);
    color: #fff;
    border-width: 2px;
}

.custom-select-trigger,
.refresh-btn {
    height: 40px;
    padding: 0 16px;
    border: 2px solid #000;
    background: #fff;
    font-size: 14px;
    font-weight: bold;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
}

.custom-select-trigger::after {
    content: '▼';
    font-size: 10px;
    margin-left: 10px;
}

.custom-options {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: #fff;
    border: 2px solid #000;
    border-top: none;
    display: none;
    z-index: 1000;
}

.custom-select-wrapper.open .custom-options {
    display: block;
}

.custom-option {
    padding: 10px;
    cursor: pointer;
    font-size: 14px;
    text-align: center;
    border-bottom: 1px solid #eee;
}

.custom-option.selected {
    background: #000;
    color: #fff;
}

.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(2px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.modal-overlay.active {
    display: flex;
}

.modal-card {
    background: #fff;
    border: 1px solid #000;
    padding: 40px;
    max-width: 420px;
    width: 90%;
    box-shadow: 20px 20px 0px rgba(0, 0, 0, 0.03);
}

@keyframes modalFadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-card h2 {
    border: none;
    padding: 0;
    margin-bottom: 20px;
    font-size: 22px;
    text-align: center;
    letter-spacing: 0.05em;
}

.modal-card p {
    font-size: 15px;
    line-height: 1.8;
    color: #333;
    text-align: center;
    margin-bottom: 35px;
}

.modal-footer {
    display: flex;
    gap: 15px;
}

.modal-btn {
    flex: 1;
    padding: 14px;
    border: 1px solid #000;
    background: #fff;
    font-size: 14px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s;
}

.modal-btn.primary {
    background: #000;
    color: #fff;
}

.modal-btn:hover {
    background: #f8f8f8;
    transform: translateY(-1px);
}

.modal-btn.primary:hover {
    background: #333;
}

/* toggle-btn は mobile-exam-bar のハンバーガーボタンに統合済み */
.toggle-btn {
    display: none;
}

body.collapsed .sidebar {
    transform: translateX(-100%);
}

.main-content {
    margin: 0 auto;
    padding: 40px 60px;
    max-width: 1000px;
    width: 100%;
}

h2 {
    font-size: 26px;
    /* margin: 45px 0 15px; */
    font-weight: bold;
    border-left: 8px solid #000;
    padding-left: 15px;
}

h3 {
    font-size: 20px;
    margin: 30px 0 12px;
    font-weight: bold;
    text-decoration: underline;
    text-decoration-thickness: 2px;
}

.instruction {
    border: 2px solid #000;
    padding: 15px;
    font-size: 15px;
    margin-bottom: 30px;
    background: #fff;
    font-weight: bold;
}

.question-block {
    margin-bottom: 50px;
    padding-bottom: 25px;
    border-bottom: 2px dashed #000;
}

.question-text {
    font-size: var(--base-font-size);
    margin-bottom: 20px;
    line-height: 2.5;
    font-weight: 500;
}

.target-word {
    background: var(--highlight-bg);
    padding: 0 4px;
    border: 1px solid var(--highlight-border);
    font-weight: bold;
}

.options {
    list-style: none;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.options li {
    padding: 12px 20px;
    border: 2px solid #000;
    font-size: calc(var(--base-font-size) * 0.9);
    cursor: pointer;
    font-weight: bold;
}

.options li.correct {
    background: var(--correct-color) !important;
    color: #000;
    border-color: #000;
}

.options li.wrong {
    background: var(--wrong-color) !important;
    color: #fff;
    border-color: #000;
}

.explanation {
    display: none;
    margin-top: 20px;
    padding: 15px;
    background: #fff;
    border: 2px solid #000;
    font-size: 16px;
    color: #000;
}

.explanation.show {
    display: block;
}

.passage {
    background: #fff;
    border: 2px solid #000;
    padding: 30px;
    margin: 25px 0;
    font-size: var(--base-font-size);
    line-height: 2.8;
}

.star-line {
    background: #fff;
    padding: 15px;
    margin-bottom: 15px;
    border: 2px solid #000;
    font-size: 17px;
    font-weight: bold;
}

/* Mobile Exam Bar — E-ink 最適化・全画面共通 */
.mobile-exam-bar {
    display: grid;
    grid-template-columns: auto auto 1fr auto auto auto;
    align-items: center;
    gap: 8px;
    position: fixed;
    left: 0;
    right: 0;
    margin: 0 auto;
    max-width: 880px;
    bottom: 16px;
    z-index: 1000;
    padding: 8px 12px;
    background: #fff;
    border: 2px solid #000;
}


.mobile-status {
    font-family: "Hiragino Sans", sans-serif;
    font-size: 12px;
    font-weight: bold;
    color: #000;
    text-align: center;
}

.mobile-exam-bar button {
    border: 2px solid #000;
    background: #fff;
    height: 40px;
    width: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    cursor: pointer;
    padding: 0;
}

.mobile-exam-bar button:active {
    background: #eee;
}

@media (max-width: 900px) {
    body {
        display: block;
    }

    .sidebar {
        width: 85vw;
        height: 100dvh;
        position: fixed;
        left: 0;
        top: 0;
        border-right: 3px solid #000;
        transform: translateX(-105%);
        z-index: 1002;
    }

    body.mobile-nav-open .sidebar {
        transform: translateX(0);
    }

    .sidebar-backdrop {
        display: none;
        position: fixed;
        inset: 0;
        background: rgba(0, 0, 0, 0.35);
        z-index: 1001;
    }

    body.mobile-nav-open .sidebar-backdrop {
        display: block;
    }

    .mobile-exam-bar {
        left: 0;
        bottom: 0;
        margin: 0;
        max-width: none;
    }

    .main-content {
        padding: 20px 15px;
    }
}

.sidebar-stats-link {
    /* margin-top: 20px; */
    padding-top: 10px;
    /* border-top: 1px solid #000; */
    font-size: 12px;
    color: #666;
    cursor: pointer;
    text-decoration: underline;
}



/* Sync UI */
.sync-prompt,
.sync-overlay {
    position: fixed;
    inset: 0;
    background: #fff;
    z-index: 3000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.sync-box {
    width: 100%;
    max-width: 460px;
    border: 1px solid #000;
    padding: 40px;
    background: #fff;
    box-shadow: 15px 15px 0px rgba(0, 0, 0, 0.05);
    position: relative;
}

.sync-box::before {
    content: '';
    position: absolute;
    top: 10px;
    right: 10px;
    width: 60px;
    height: 60px;
    background: url('app_icon.png') no-repeat center/contain;
    opacity: 0.1;
}

.sync-box h2 {
    border: none;
    padding: 0;
    margin-bottom: 10px;
    font-size: 22px;
    text-align: center;
}

.sync-box p {
    font-size: 14px;
    color: #666;
    text-align: center;
    margin-bottom: 25px;
}

.sync-log-area {
    background: #f9f9f9;
    border: 1px solid #eee;
    padding: 12px;
    font-family: "Hiragino Sans", "Courier New", monospace;
    font-size: 11px;
    line-height: 1.6;
    height: 120px;
    overflow-y: auto;
    text-align: left;
    margin-bottom: 20px;
}

.sync-log-line {
    border-bottom: 1px solid #f0f0f0;
    padding: 2px 0;
}

.sync-log-line.new {
    color: #2e7d32;
    font-weight: bold;
}

/* 更新：绿色 */
.sync-log-line.ok {
    color: #999;
}

/* 已最新：灰色 */

.sync-btn {
    display: block;
    width: 100%;
    padding: 14px;
    background: #000;
    color: #fff;
    border: none;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.2s;
}

.sync-btn:hover {
    background: #333;
}

.progress-container {
    width: 100%;
    height: 4px;
    background: #eee;
    margin-top: 10px;
}

.progress-bar {
    height: 100%;
    background: #000;
    width: 0%;
}



/* Loading Overlay */
.loading-overlay {
    position: fixed;
    inset: 0;
    background: #fff;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.loading-overlay.hidden {
    display: none;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #000;
    border-radius: 50%;
    margin-bottom: 15px;
    /* Use simple step animation or none for E-ink, but standard for web */
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-text {
    font-weight: bold;
    font-size: 16px;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #fff;
}

::-webkit-scrollbar-thumb {
    background: #000;
    border: 2px solid #fff;
}

::-webkit-scrollbar-thumb:hover {
    background: #333;
}

/* 统一图标按钮尺寸与边框，确保与选择框对齐 */
.icon-btn {
    height: 40px !important;
    min-width: 40px !important;
    border: 2px solid #000 !important;
    box-sizing: border-box !important;
}

/* mobile-exam-bar button 样式已合并到全局规则中 */

/* --- 强制覆盖：高级设置面板 UI --- */
#modal-body {
    text-align: left !important;
    padding: 15px 5px !important;
}

.settings-container {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.settings-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px 0;
    border-bottom: 1px solid #eee;
}

.settings-label {
    font-weight: bold;
    font-size: 15px;
    color: #000;
}

/* 自定义开关 (Switch) 替代原生 Checkbox */
.switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider-round {
    position: absolute;
    cursor: pointer;
    inset: 0;
    background-color: #fff;
    border: 2.5px solid #000;
    transition: .3s;
}

.slider-round:before {
    position: absolute;
    content: "";
    height: 14px;
    width: 14px;
    left: 3px;
    bottom: 2.5px;
    background-color: #000;
    transition: .3s;
}

input:checked+.slider-round {
    background-color: #000;
}

input:checked+.slider-round:before {
    background-color: #fff;
    transform: translateX(19px);
}

/* 字体切换按钮：和纸质感 */
.font-btn {
    padding: 6px 14px;
    border: 2.5px solid #000;
    background: #fff;
    cursor: pointer;
    font-size: 13px;
    font-weight: bold;
    transition: all 0.2s;
    box-shadow: 4px 4px 0px rgba(0, 0, 0, 0.1);
}

.font-btn.active {
    background: #000;
    color: #fff;
    box-shadow: none;
    transform: translate(2px, 2px);
}

/* 自定义滑块：极简黑白 */
input[type="range"] {
    -webkit-appearance: none;
    width: 100px;
    height: 3px;
    background: #000;
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    background: #fff;
    border: 2.5px solid #000;
    cursor: pointer;
    border-radius: 0;
}
/* 文章翻译 */
.passage-container {
    position: relative;
}

.passage-translation {
    display: none;
    margin-top: -2px; /* 紧贴上方的文章边框 */
    padding: 20px;
    background: #fdfdfd;
    border: 2px solid #000;
    font-size: 16px;
    line-height: 1.8;
}

.passage-translation.show {
    display: block;
}

.trans-btn {
    position: absolute;
    right: 0;
    bottom: 0;
    width: 32px;
    height: 32px;
    background: #000;
    color: #fff;
    border: 2px solid #000;
    font-size: 12px;
    font-weight: bold;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}

.trans-btn.active {
    background: #fff;
    color: #000;
}