/* ============================================================
   CSS 变量系统（参考 english-quiz-app 天蓝色主题）
   ============================================================ */
:root {
    --color-primary: #0ea5e9;
    --color-primary-light: #38bdf8;
    --color-primary-dark: #0284c7;
    --color-primary-bg: #e0f2fe;
    --color-primary-hover: #f0f9ff;
    --color-success: #10b981;
    --color-success-light: #34d399;
    --color-success-bg: #d1fae5;
    --color-danger: #ef4444;
    --color-danger-light: #f87171;
    --color-danger-bg: #fee2e2;
    --color-warning: #f59e0b;
    --color-warning-bg: #fef3c7;
    --color-info: #0ea5e9;
    --color-info-bg: #e0f2fe;

    --color-bg: #f1f5f9;
    --color-surface: #ffffff;
    --color-border: #e2e8f0;
    --color-border-light: #f1f5f9;

    --color-text: #1e293b;
    --color-text-secondary: #475569;
    --color-text-muted: #94a3b8;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-xl: 16px;

    --sidebar-width: 260px;
    --nav-width: 280px;
    --header-height: 56px;
    --mobile-nav-height: 60px;

    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    --font-mono: "SF Mono", "Fira Code", "Consolas", monospace;

    --transition: 0.2s ease;
}

/* ============================================================
   全局重置
   ============================================================ */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-family);
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    color: var(--color-primary);
    text-decoration: none;
}

button {
    cursor: pointer;
    font-family: inherit;
    border: none;
    background: none;
    font-size: inherit;
}

ul, ol {
    list-style: none;
}

/* ============================================================
   顶部导航栏
   ============================================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    padding: 0 16px;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header__menu-btn {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 4px;
    margin-right: 12px;
}

.header__menu-btn span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
    transition: var(--transition);
}

.header__title {
    font-size: 1.2rem;
    font-weight: 600;
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.header__actions {
    display: flex;
    gap: 8px;
}

.header__btn {
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: var(--color-bg);
    transition: var(--transition);
    white-space: nowrap;
}

.header__btn:hover {
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.header__btn--active {
    background: var(--color-primary);
    color: #fff;
}

.header__btn--active:hover {
    background: var(--color-primary-dark);
    color: #fff;
}

/* ============================================================
   三栏布局
   ============================================================ */
.app-container {
    display: flex;
    padding-top: var(--header-height);
    min-height: 100vh;
}

/* 左侧栏 */
.sidebar {
    position: fixed;
    top: var(--header-height);
    bottom: 0;
    background: var(--color-surface);
    border-right: 1px solid var(--color-border);
    overflow-y: auto;
    z-index: 50;
    transition: transform var(--transition);
}

.sidebar--left {
    left: 0;
    width: var(--sidebar-width);
    transition: transform 0.3s ease;
}

.sidebar--left.sidebar--hidden {
    transform: translateX(-100%);
}

.main-content--no-left {
    margin-left: 0 !important;
}

.sidebar--right {
    right: 0;
    width: var(--nav-width);
    border-right: none;
    border-left: 1px solid var(--color-border);
    transition: right 0.3s ease, transform 0.3s ease;
}

.sidebar--right.sidebar--hidden {
    right: calc(-1 * var(--nav-width));
}

.main-content--no-right {
    margin-right: 0 !important;
}

.sidebar__header {
    padding: 16px 16px 12px;
    border-bottom: 1px solid var(--color-border-light);
}

.sidebar__header h2 {
    font-size: 0.95rem;
    font-weight: 600;
}

.sidebar__footer {
    padding: 12px 16px;
    border-top: 1px solid var(--color-border-light);
}

/* 主内容区 */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    margin-right: var(--nav-width);
    padding: 24px;
    padding-bottom: calc(var(--mobile-nav-height) + 16px);
    min-height: calc(100vh - var(--header-height));
}

/* ============================================================
   科目列表
   ============================================================ */
.subject-list {
    padding: 8px 0;
}

.subject-item {
    padding: 12px 16px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: 10px;
    transition: var(--transition);
    border-left: 3px solid transparent;
    position: relative;
}

.subject-item:hover {
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.subject-item--active {
    background: var(--color-primary-bg);
    color: var(--color-primary);
    border-left-color: var(--color-primary);
}

.subject-item__icon {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    flex-shrink: 0;
}

.subject-item__icon--computer { background: #e8f0fe; color: #4a90d9; }
.subject-item__icon--data { background: #e8f8ef; color: #27ae60; }
.subject-item__icon--network { background: #fef9e7; color: #f39c12; }
.subject-item__icon--history { background: #fdecea; color: #e74c3c; }
.subject-item__icon--testing { background: #eaf2f8; color: #8e44ad; }

.subject-item__badge {
    margin-left: auto;
    font-size: 0.75rem;
    background: var(--color-bg);
    padding: 2px 8px;
    border-radius: 10px;
    color: var(--color-text-secondary);
}

/* 进度信息 */
.progress-info {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    text-align: center;
}

/* ============================================================
   题目区域
   ============================================================ */
.question-area {
    max-width: 800px;
    margin: 0 auto;
}

.question-area__placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 300px;
    color: var(--color-text-muted);
    font-size: 1.1rem;
}

.question-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: 28px;
    margin-bottom: 20px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border-light);
}

.question-card__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 8px;
}

.question-card__number {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--color-primary);
}

.question-card__type {
    font-size: 0.8rem;
    padding: 3px 10px;
    border-radius: 12px;
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.question-card__type--choice { background: var(--color-primary-bg); color: var(--color-primary); }
.question-card__type--fill { background: var(--color-warning-bg); color: var(--color-warning); }
.question-card__type--judge { background: var(--color-success-bg); color: var(--color-success); }
.question-card__type--shortanswer { background: var(--color-info-bg); color: var(--color-info); }
.question-card__type--essay { background: var(--color-danger-bg); color: var(--color-danger); }

.question-card__body {
    font-size: 1rem;
    line-height: 1.8;
    margin-bottom: 20px;
}

.question-card__body p {
    margin-bottom: 8px;
}

/* 选项样式 */
.options-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.option-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 14px 16px;
    border: 2px solid var(--color-border);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.15s;
    background: var(--color-surface);
    position: relative;
}

.option-item:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-hover);
}

.option-item--selected {
    border-color: var(--color-primary);
    background: var(--color-primary-bg);
}

.option-item--correct {
    border-color: var(--color-success);
    background: var(--color-success-bg);
}

.option-item--wrong {
    border-color: var(--color-danger);
    background: var(--color-danger-bg);
}

.option-item--disabled {
    opacity: 0.7;
    pointer-events: none;
}

.option-item__marker {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 2px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    font-weight: 600;
    flex-shrink: 0;
    transition: var(--transition);
    background: var(--color-bg);
}

.option-item--selected .option-item__marker {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: #fff;
}

.option-item--correct .option-item__marker {
    border-color: var(--color-success);
    background: var(--color-success);
    color: #fff;
}

.option-item--wrong .option-item__marker {
    border-color: var(--color-danger);
    background: var(--color-danger);
    color: #fff;
}

.option-item__text {
    flex: 1;
    padding-top: 2px;
}

/* 多选题选项 */
.option-item--multi .option-item__marker {
    border-radius: var(--radius-sm);
}

/* 判断题选项 */
.judge-options {
    display: flex;
    gap: 16px;
}

.judge-option {
    flex: 1;
    padding: 16px;
    text-align: center;
    border: 2px solid var(--color-border-light);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 1.2rem;
    font-weight: 600;
    transition: var(--transition);
}

.judge-option:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-bg);
}

.judge-option--selected {
    border-color: var(--color-primary);
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.judge-option--correct {
    border-color: var(--color-success);
    background: var(--color-success-bg);
    color: var(--color-success);
}

.judge-option--wrong {
    border-color: var(--color-danger);
    background: var(--color-danger-bg);
    color: var(--color-danger);
}

/* 填空题输入 */
.fill-input-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.fill-input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--color-border-light);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
    outline: none;
    background: var(--color-bg);
}

.fill-input:focus {
    border-color: var(--color-primary);
    background: var(--color-surface);
}

.fill-input--correct {
    border-color: var(--color-success);
    background: var(--color-success-bg);
}

.fill-input--wrong {
    border-color: var(--color-danger);
    background: var(--color-danger-bg);
}

.fill-submit-btn {
    align-self: flex-start;
    padding: 10px 24px;
    background: var(--color-primary);
    color: #fff;
    border-radius: var(--radius-sm);
    font-weight: 500;
    transition: var(--transition);
}

.fill-submit-btn:hover {
    background: var(--color-primary-dark);
}

/* 答案展示 */
.answer-reveal {
    margin-top: 16px;
    padding: 16px;
    background: var(--color-success-bg);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-success);
}

.answer-reveal--wrong {
    background: var(--color-danger-bg);
    border-left-color: var(--color-danger);
}

.answer-reveal__label {
    font-weight: 600;
    margin-bottom: 4px;
    font-size: 0.9rem;
}

.answer-reveal__content {
    color: var(--color-text);
    font-size: 0.95rem;
}

/* 阅读理解文章 */
.reading-passage {
    background: var(--color-bg);
    padding: 20px;
    border-radius: var(--radius-md);
    margin-bottom: 20px;
    font-size: 0.95rem;
    line-height: 1.8;
    border: 1px solid var(--color-border-light);
    max-height: 300px;
    overflow-y: auto;
}

/* 词汇匹配 */
.vocab-match {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 20px;
}

.vocab-match__word {
    padding: 8px 16px;
    background: var(--color-primary-bg);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    border: 2px solid transparent;
}

.vocab-match__word:hover {
    border-color: var(--color-primary);
}

.vocab-match__word--selected {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: #fff;
}

/* ============================================================
   底部导航按钮
   ============================================================ */
.question-nav-buttons {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 20px;
    gap: 12px;
}

.nav-btn {
    padding: 10px 24px;
    border-radius: 12px;
    font-weight: 500;
    font-size: 0.9rem;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
    border: none;
}

.nav-btn--prev {
    background: var(--color-bg);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.nav-btn--prev:hover {
    background: var(--color-border-light);
}

.nav-btn--next {
    background: var(--color-primary);
    color: #fff;
}

.nav-btn--next:hover {
    background: var(--color-primary-dark);
}

.nav-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.nav-btn:disabled:hover {
    background: inherit;
    color: inherit;
}

/* 主按钮样式（参考 english-quiz-app） */
.btn-primary {
    width: 100%;
    padding: 14px;
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}
.btn-primary:hover { background: var(--color-primary-dark); }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-secondary {
    padding: 10px 20px;
    background: var(--color-surface);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}
.btn-secondary:hover {
    background: var(--color-primary-bg);
    border-color: var(--color-primary);
    color: var(--color-primary);
}

/* 图标按钮 */
.icon-btn {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1.1rem;
}
.icon-btn:hover {
    background: var(--color-primary-bg);
    border-color: var(--color-primary);
    color: var(--color-primary);
}

/* ============================================================
   右侧题目导航
   ============================================================ */
.category-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    padding: 12px 16px;
    border-bottom: 1px solid var(--color-border-light);
}

.category-tab {
    padding: 4px 10px;
    font-size: 0.75rem;
    border-radius: 12px;
    background: var(--color-bg);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.category-tab:hover {
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.category-tab--active {
    background: var(--color-primary);
    color: #fff;
}

.question-nav {
    padding: 12px 16px;
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 6px;
    overflow-y: auto;
    max-height: calc(100vh - 360px);
}

.question-nav__item {
    width: 100%;
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
    background: var(--color-bg);
    border: 2px solid transparent;
    color: var(--color-text-secondary);
}

.question-nav__item:hover {
    border-color: var(--color-primary-light);
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.question-nav__item--current {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: #fff;
}

.question-nav__item--answered {
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.question-nav__item--correct {
    background: var(--color-success-bg);
    color: var(--color-success);
    border-color: var(--color-success);
}

.question-nav__item--wrong {
    background: var(--color-danger-bg);
    color: var(--color-danger);
    border-color: var(--color-danger);
}

.question-nav__item--current.question-nav__item--correct {
    background: var(--color-success);
    color: #fff;
}

.question-nav__item--current.question-nav__item--wrong {
    background: var(--color-danger);
    color: #fff;
}

/* 统计信息 */
.sidebar__stats {
    display: flex;
    padding: 12px 16px;
    border-top: 1px solid var(--color-border-light);
    gap: 8px;
}

.stat-item {
    flex: 1;
    text-align: center;
}

.stat-label {
    display: block;
    font-size: 0.7rem;
    color: var(--color-text-muted);
    margin-bottom: 2px;
}

.stat-value {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--color-text);
}

.stat-value--correct {
    color: var(--color-success);
}

.stat-value--wrong {
    color: var(--color-danger);
}

/* ============================================================
   操作菜单
   ============================================================ */
.action-menu {
    position: fixed;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    z-index: 200;
    min-width: 160px;
    padding: 6px 0;
    animation: menuFadeIn 0.15s ease;
}

@keyframes menuFadeIn {
    from { opacity: 0; transform: translateY(-4px); }
    to { opacity: 1; transform: translateY(0); }
}

.action-menu__item {
    display: block;
    width: 100%;
    padding: 10px 20px;
    text-align: left;
    font-size: 0.9rem;
    color: var(--color-text);
    transition: var(--transition);
    cursor: pointer;
}

.action-menu__item:hover {
    background: var(--color-primary-bg);
    color: var(--color-primary);
}

.action-menu__item--danger {
    color: var(--color-danger);
}

.action-menu__item--danger:hover {
    background: var(--color-danger-bg);
    color: var(--color-danger);
}

/* ============================================================
   遮罩层
   ============================================================ */
.overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.4);
    z-index: 80;
}

.overlay--visible {
    display: block;
}

/* ============================================================
   底部导航栏（全尺寸通用）
   ============================================================ */
.mobile-nav {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--mobile-nav-height);
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    z-index: 100;
    justify-content: space-around;
    align-items: center;
}

.mobile-nav__item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    padding: 6px 12px;
    font-size: 0.7rem;
    color: var(--color-text-secondary);
    transition: var(--transition);
    flex: 1;
    border: none;
    background: none;
    cursor: pointer;
}

.mobile-nav__item--active {
    color: var(--color-primary);
}

.mobile-nav__item--submit {
    color: var(--color-success);
    font-weight: 600;
}

.mobile-nav__item--submit.mobile-nav__item--active {
    color: var(--color-success);
}

.mobile-nav__item:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.mobile-nav__icon {
    font-size: 1.3rem;
    line-height: 1;
}

/* ============================================================
   响应式设计
   ============================================================ */

/* 中等屏幕 <= 1200px */
@media (max-width: 1200px) {
    :root {
        --sidebar-width: 220px;
        --nav-width: 240px;
    }

    .main-content {
        padding: 16px;
    }

    .question-card {
        padding: 20px;
    }
}

/* 平板 <= 900px */
@media (max-width: 900px) {
    :root {
        --sidebar-width: 0;
        --nav-width: 0;
    }

    .header__menu-btn {
        display: flex;
    }

    .sidebar--left {
        transform: translateX(-100%);
        width: 280px;
        z-index: 90;
    }

    .sidebar--left.sidebar--open {
        transform: translateX(0);
    }

    .sidebar--right {
        transform: translateX(100%);
        width: 280px;
        z-index: 90;
    }

    .sidebar--right.sidebar--open {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
        margin-right: 0;
        padding: 16px;
        padding-bottom: calc(var(--mobile-nav-height) + 16px);
    }

    .question-card {
        padding: 16px;
    }

    .question-nav {
        max-height: calc(100vh - 420px);
    }
}

/* 手机 <= 480px */
@media (max-width: 480px) {
    .header__title {
        font-size: 1rem;
    }

    .header__btn {
        padding: 4px 10px;
        font-size: 0.8rem;
    }

    .header__actions {
        gap: 4px;
    }

    .question-card {
        padding: 14px;
        border-radius: var(--radius-md);
    }

    .question-card__body {
        font-size: 0.9rem;
    }

    .option-item {
        padding: 10px 12px;
        gap: 8px;
    }

    .option-item__marker {
        width: 24px;
        height: 24px;
        font-size: 0.75rem;
    }

    .judge-options {
        flex-direction: column;
    }

    .nav-btn {
        padding: 8px 16px;
        font-size: 0.85rem;
    }

    .question-nav {
        grid-template-columns: repeat(4, 1fr);
    }

    .sidebar--left,
    .sidebar--right {
        width: 260px;
    }

    .action-menu {
        min-width: 140px;
    }
}

/* ============================================================
   辅助样式
   ============================================================ */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-success {
    color: var(--color-success);
}

.text-danger {
    color: var(--color-danger);
}

.mt-8 { margin-top: 8px; }
.mt-12 { margin-top: 12px; }
.mt-16 { margin-top: 16px; }
.mb-8 { margin-bottom: 8px; }
.mb-16 { margin-bottom: 16px; }

/* 滚动条美化 */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-muted);
}

/* 进度条 */
.progress-bar {
    width: 100%;
    height: 6px;
    background: var(--color-border-light);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 16px;
}
.progress-bar__fill {
    height: 100%;
    background: var(--color-primary);
    border-radius: 3px;
    transition: width 0.3s ease;
}

/* 结果页 */
.result-page {
    display: none;
    max-width: 720px;
    margin: 0 auto;
    padding: 20px;
    animation: fadeIn 0.3s ease;
}
.result-page--visible {
    display: block;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}
.result-score {
    text-align: center;
    padding: 32px 20px;
}
.result-score__num {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
}
.result-score__label {
    font-size: 1rem;
    color: var(--color-text-secondary);
    margin-top: 8px;
}
.result-stats {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
}
.result-stat {
    flex: 1;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: 16px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border-light);
}
.result-stat__num {
    font-size: 1.5rem;
    font-weight: 700;
}
.result-stat__num--correct { color: var(--color-success); }
.result-stat__num--wrong { color: var(--color-danger); }
.result-stat__num--unanswered { color: var(--color-text-muted); }
.result-stat__label {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    margin-top: 4px;
}
.result-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
    border-bottom: 1px solid var(--color-border-light);
    padding-bottom: 8px;
}
.result-tab {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
    background: none;
    border: none;
    color: var(--color-text-secondary);
}
.result-tab:hover {
    background: var(--color-primary-bg);
    color: var(--color-primary);
}
.result-tab--active {
    background: var(--color-primary-bg);
    color: var(--color-primary);
    font-weight: 600;
}
.result-review-item {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: 16px;
    margin-bottom: 12px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border-light);
}
.result-review-item__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
}
.result-review-item__num {
    font-weight: 600;
    font-size: 0.9rem;
}
.result-review-item__status {
    font-size: 0.75rem;
    padding: 2px 8px;
    border-radius: 10px;
    font-weight: 500;
}
.result-review-item__status--correct {
    background: var(--color-success-bg);
    color: var(--color-success);
}
.result-review-item__status--wrong {
    background: var(--color-danger-bg);
    color: var(--color-danger);
}
.result-review-item__question {
    font-size: 0.95rem;
    margin-bottom: 8px;
    color: var(--color-text);
}
.result-review-item__your {
    font-size: 0.85rem;
    color: var(--color-danger);
    margin-bottom: 4px;
}
.result-review-item__correct {
    font-size: 0.85rem;
    color: var(--color-success);
    margin-bottom: 4px;
}
.result-review-item__analysis {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    padding: 8px;
    background: var(--color-bg);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--color-primary);
    margin-top: 8px;
}

/* 键盘快捷键提示 */
.keyboard-hint {
    position: fixed;
    bottom: 80px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.8);
    color: #fff;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.8rem;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
    z-index: 150;
}

.keyboard-hint--visible {
    opacity: 1;
}

/* 加载动画 */
.loading-spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: var(--color-text-muted);
}

.empty-state__icon {
    font-size: 3rem;
    margin-bottom: 12px;
}

.empty-state__text {
    font-size: 0.95rem;
}