/* ========================================
   错题本 APP - 优质设计系统
   玻璃态 + 流畅动画 + 亮/暗主题
   ======================================== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

:root {
    /* 浅色主题 - 清新绿调 */
    --primary: #10b981;
    --primary-dark: #059669;
    --primary-light: #34d399;
    --primary-soft: rgba(16, 185, 129, 0.08);
    --primary-glow: rgba(16, 185, 129, 0.35);

    --chinese: #f59e0b;
    --chinese-soft: rgba(245, 158, 11, 0.1);
    --math: #3b82f6;
    --math-soft: rgba(59, 130, 246, 0.1);
    --english: #8b5cf6;
    --english-soft: rgba(139, 92, 246, 0.1);

    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --info: #3b82f6;

    /* 浅色 */
    --bg: #f5f7fa;
    --bg-elevated: #ffffff;
    --bg-overlay: rgba(255, 255, 255, 0.7);
    --text: #1e293b;
    --text-soft: #475569;
    --text-muted: #94a3b8;
    --border: rgba(15, 23, 42, 0.08);
    --border-strong: rgba(15, 23, 42, 0.12);
    --glass: rgba(255, 255, 255, 0.6);
    --glass-border: rgba(255, 255, 255, 0.5);
    --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.04);
    --shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
    --shadow-lg: 0 16px 48px rgba(15, 23, 42, 0.1);

    --radius-sm: 8px;
    --radius: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    --transition: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    --transition-fast: 0.2s cubic-bezier(0.16, 1, 0.3, 1);

    --bg-gradient: radial-gradient(at 0% 0%, rgba(16, 185, 129, 0.1) 0px, transparent 50%),
                   radial-gradient(at 100% 0%, rgba(59, 130, 246, 0.08) 0px, transparent 50%),
                   radial-gradient(at 100% 100%, rgba(139, 92, 246, 0.08) 0px, transparent 50%);
}

[data-theme="dark"] {
    --bg: #0a0e1a;
    --bg-elevated: #131826;
    --bg-overlay: rgba(19, 24, 38, 0.8);
    --text: #f1f5f9;
    --text-soft: #cbd5e1;
    --text-muted: #64748b;
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.12);
    --glass: rgba(19, 24, 38, 0.6);
    --glass-border: rgba(255, 255, 255, 0.08);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);

    --primary-soft: rgba(16, 185, 129, 0.15);
    --chinese-soft: rgba(245, 158, 11, 0.15);
    --math-soft: rgba(59, 130, 246, 0.15);
    --english-soft: rgba(139, 92, 246, 0.15);

    --bg-gradient: radial-gradient(at 0% 0%, rgba(16, 185, 129, 0.12) 0px, transparent 50%),
                   radial-gradient(at 100% 0%, rgba(59, 130, 246, 0.1) 0px, transparent 50%),
                   radial-gradient(at 100% 100%, rgba(139, 92, 246, 0.1) 0px, transparent 50%);
}

html, body {
    height: 100%;
    overflow: hidden;
}

body {
    font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    background-image: var(--bg-gradient);
    background-attachment: fixed;
    color: var(--text);
    line-height: 1.6;
    transition: background var(--transition), color var(--transition);
    font-feature-settings: 'cv02', 'cv03', 'cv04', 'cv11';
    -webkit-font-smoothing: antialiased;
}

/* ============ 滚动条 ============ */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--border-strong);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ============ 主题切换 ============ */
.theme-toggle {
    position: fixed;
    top: 16px;
    right: 16px;
    z-index: 100;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--glass);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border: 1px solid var(--glass-border);
    color: var(--text);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow);
    transition: all var(--transition);
}
.theme-toggle:hover {
    transform: scale(1.08) rotate(15deg);
    box-shadow: var(--shadow-lg);
}
.theme-toggle svg {
    width: 20px;
    height: 20px;
    position: absolute;
    transition: all var(--transition);
}
.icon-sun { opacity: 1; transform: rotate(0); }
.icon-moon { opacity: 0; transform: rotate(-90deg); }
[data-theme="dark"] .icon-sun { opacity: 0; transform: rotate(90deg); }
[data-theme="dark"] .icon-moon { opacity: 1; transform: rotate(0); }

/* ============ 主布局 ============ */
.app {
    display: grid;
    grid-template-columns: 260px 1fr;
    height: 100vh;
}

/* ============ 侧边栏 ============ */
.sidebar {
    background: var(--glass);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-right: 1px solid var(--border);
    padding: 24px 16px;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    transition: background var(--transition);
}
.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 12px 24px;
    margin-bottom: 8px;
}
.brand-logo {
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    box-shadow: 0 4px 16px var(--primary-glow);
}
.brand-logo svg {
    width: 24px;
    height: 24px;
}
.brand-text h1 {
    font-size: 18px;
    font-weight: 800;
    letter-spacing: -0.02em;
}
.brand-text p {
    font-size: 11px;
    color: var(--text-muted);
    font-weight: 500;
}

.nav {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    border-radius: var(--radius);
    color: var(--text-soft);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: all var(--transition-fast);
    cursor: pointer;
    position: relative;
}
.nav-item svg {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}
.nav-item:hover {
    background: var(--primary-soft);
    color: var(--primary);
    transform: translateX(2px);
}
.nav-item.active {
    background: var(--primary-soft);
    color: var(--primary);
    font-weight: 600;
}
.nav-item.active::before {
    content: '';
    position: absolute;
    left: -16px;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 20px;
    background: var(--primary);
    border-radius: 0 2px 2px 0;
}

.sidebar-footer {
    margin-top: auto;
    padding-top: 16px;
    border-top: 1px solid var(--border);
}
.storage-info {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 8px 12px;
}
.storage-bar {
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    overflow: hidden;
}
.storage-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--primary-light));
    border-radius: 2px;
    transition: width var(--transition);
    width: 0%;
}
.storage-info span {
    font-size: 11px;
    color: var(--text-muted);
}

/* ============ 主内容区 ============ */
.main {
    overflow-y: auto;
    padding: 32px 40px 100px;
    max-width: 1400px;
    width: 100%;
}
.view {
    display: none;
    animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}
.view.active {
    display: block;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

.page-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 28px;
    flex-wrap: wrap;
}
.page-title {
    font-size: 28px;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 4px;
}
.page-subtitle {
    color: var(--text-soft);
    font-size: 14px;
}
.gradient-text {
    background: linear-gradient(135deg, var(--primary), var(--math));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* ============ 按钮 ============ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: inherit;
    text-decoration: none;
    white-space: nowrap;
}
.btn svg {
    width: 16px;
    height: 16px;
}
.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: 0 4px 12px var(--primary-glow);
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--primary-glow);
}
.btn-primary:active {
    transform: translateY(0);
}
.btn-ghost {
    background: var(--bg-elevated);
    color: var(--text);
    border: 1px solid var(--border);
}
.btn-ghost:hover {
    background: var(--primary-soft);
    color: var(--primary);
    border-color: var(--primary);
}
.btn-danger {
    background: var(--danger);
    color: white;
}
.btn-danger:hover {
    background: #dc2626;
    transform: translateY(-1px);
}
.btn-success {
    background: var(--success);
    color: white;
}
.btn-success:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}
.btn-lg {
    padding: 14px 28px;
    font-size: 15px;
}
.btn-sm {
    padding: 6px 12px;
    font-size: 13px;
}
.btn-block {
    width: 100%;
    justify-content: center;
    margin-top: 16px;
}

/* ============ 统计卡片 ============ */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}
.stat-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
    display: flex;
    align-items: center;
    gap: 16px;
    position: relative;
    overflow: hidden;
    transition: all var(--transition);
}
.stat-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--bg-gradient);
    opacity: 0;
    transition: opacity var(--transition);
    pointer-events: none;
}
.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
    border-color: var(--border-strong);
}
.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    position: relative;
    z-index: 1;
}
.stat-icon svg {
    width: 22px;
    height: 22px;
}
.stat-1 .stat-icon { background: var(--primary-soft); color: var(--primary); }
.stat-2 .stat-icon { background: var(--chinese-soft); color: var(--chinese); }
.stat-3 .stat-icon { background: var(--math-soft); color: var(--math); }
.stat-4 .stat-icon { background: var(--english-soft); color: var(--english); }
.stat-content { position: relative; z-index: 1; }
.stat-label {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
    margin-bottom: 4px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.stat-value {
    font-size: 28px;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 2px;
    letter-spacing: -0.02em;
}
.stat-value-sm {
    font-size: 18px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 2px;
}
.stat-trend {
    font-size: 12px;
    color: var(--text-soft);
    font-weight: 500;
}

/* ============ 网格布局 ============ */
.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 24px;
}

/* ============ 卡片 ============ */
.card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 20px;
    transition: all var(--transition);
}
.card:hover {
    border-color: var(--border-strong);
}
.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 12px;
}
.card-header-actions {
    display: flex;
    align-items: center;
    gap: 10px;
}
.card-title {
    font-size: 16px;
    font-weight: 700;
    letter-spacing: -0.01em;
}
.card-badge {
    font-size: 12px;
    padding: 4px 10px;
    background: var(--primary-soft);
    color: var(--primary);
    border-radius: 12px;
    font-weight: 600;
}
.card-badge.accent {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
}
.card-hint {
    font-size: 12px;
    color: var(--text-muted);
}

/* ============ 学科分布图 ============ */
.subject-chart {
    display: flex;
    flex-direction: column;
    gap: 18px;
}
.chart-bar {
    display: grid;
    grid-template-columns: 60px 1fr 40px;
    align-items: center;
    gap: 12px;
}
.chart-label {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-soft);
}
.chart-track {
    height: 10px;
    background: var(--border);
    border-radius: 5px;
    overflow: hidden;
    position: relative;
}
.chart-fill {
    height: 100%;
    border-radius: 5px;
    transition: width 0.8s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    overflow: hidden;
}
.chart-fill::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: shimmer 2.5s infinite;
}
@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}
.chinese-fill { background: linear-gradient(90deg, var(--chinese), #fbbf24); }
.math-fill { background: linear-gradient(90deg, var(--math), #60a5fa); }
.english-fill { background: linear-gradient(90deg, var(--english), #a78bfa); }
.chart-value {
    font-size: 14px;
    font-weight: 700;
    text-align: right;
}

/* ============ 空状态 ============ */
.empty-state {
    text-align: center;
    padding: 48px 24px;
    color: var(--text-muted);
}
/* ============ 全部错题弹层 ============ */
.clickable {
    cursor: pointer;
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}
.clickable:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}
.clickable:active {
    transform: translateY(0) scale(0.98);
}
/* ============ 登录门禁 ============ */
.auth-gate {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: var(--bg);
    background-image: var(--bg-gradient);
}
.auth-gate[hidden] {
    display: none;
}
.auth-gate-card {
    width: 100%;
    max-width: 380px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    padding: 32px 28px 28px;
    text-align: center;
}
.auth-gate-logo {
    width: 52px;
    height: 52px;
    margin: 0 auto 14px;
}
.auth-gate-title {
    font-size: 20px;
    font-weight: 800;
    margin-bottom: 4px;
}
.auth-gate-subtitle {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 20px;
}
.auth-gate-card .form-group {
    text-align: left;
}
.auth-gate-error {
    color: var(--danger);
    font-size: 13px;
    margin-top: 10px;
}
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.45);
    z-index: 1000;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition);
}
.modal-overlay.show {
    opacity: 1;
    pointer-events: auto;
}
.modal-sheet {
    background: var(--bg);
    width: 100%;
    max-width: 560px;
    max-height: 85vh;
    border-radius: 20px 20px 0 0;
    display: flex;
    flex-direction: column;
    transform: translateY(100%);
    transition: transform var(--transition);
    box-shadow: 0 -8px 32px rgba(0, 0, 0, 0.18);
}
.modal-overlay.show .modal-sheet {
    transform: translateY(0);
}
.modal-handle {
    width: 40px;
    height: 4px;
    background: var(--border-strong);
    border-radius: 999px;
    margin: 10px auto 4px;
    flex-shrink: 0;
}
.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 20px 12px;
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}
.modal-title {
    margin: 0;
    font-size: 17px;
    font-weight: 700;
}
.modal-count {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-muted);
    background: var(--primary-soft);
    padding: 2px 10px;
    border-radius: 999px;
    margin-left: 6px;
}
.modal-close {
    background: none;
    border: none;
    font-size: 26px;
    line-height: 1;
    color: var(--text-muted);
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 8px;
}
.modal-close:hover {
    background: var(--border-strong);
    color: var(--text);
}
#allMistakesTabs {
    padding: 10px 16px 6px;
    flex-shrink: 0;
}
.modal-body {
    overflow-y: auto;
    padding: 8px 16px 24px;
    -webkit-overflow-scrolling: touch;
}
.empty-state .empty-icon {
    font-size: 48px;
    margin-bottom: 12px;
    opacity: 0.5;
}
.empty-state p {
    font-size: 15px;
    font-weight: 500;
    color: var(--text-soft);
    margin-bottom: 4px;
}
.empty-state small {
    font-size: 13px;
    color: var(--text-muted);
}
.empty-state .btn {
    margin-top: 16px;
}

/* ============ 标签页 ============ */
.tabs {
    display: flex;
    gap: 4px;
    background: var(--border);
    padding: 3px;
    border-radius: var(--radius);
}
.tab {
    background: transparent;
    border: none;
    padding: 6px 14px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-soft);
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: inherit;
}
.tab.active {
    background: var(--bg-elevated);
    color: var(--primary);
    box-shadow: var(--shadow-sm);
}
.tab:hover:not(.active) {
    color: var(--text);
}

/* ============ 错题列表 ============ */
.mistake-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}
/* ============ 滑动删除 ============ */
.swipe-item {
    position: relative;
    overflow: hidden;
    border-radius: var(--radius);
}
.swipe-actions {
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    width: 88px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--danger);
    color: #fff;
    border-radius: 0 var(--radius) var(--radius) 0;
}
.swipe-delete-btn {
    background: transparent;
    border: none;
    color: #fff;
    font-size: 13px;
    font-weight: 600;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
    width: 100%;
    height: 100%;
    justify-content: center;
    font-family: inherit;
}
.swipe-delete-btn:active {
    background: rgba(0, 0, 0, 0.15);
}
.swipe-delete-btn svg {
    width: 22px;
    height: 22px;
}
.swipe-inner {
    position: relative;
    z-index: 1;
    touch-action: pan-y;
    will-change: transform;
    transition: transform var(--transition-fast);
}
.swipe-inner.swiping {
    transition: none !important;
}
.swipe-inner.open {
    transform: translateX(-88px) !important;
}
.mistake-item {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 14px;
    align-items: start;
    transition: all var(--transition-fast);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}
.mistake-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--mistake-color, var(--primary));
    border-radius: 0 2px 2px 0;
    transform: scaleY(0);
    transition: transform var(--transition-fast);
}
.mistake-item[data-subject="chinese"] { --mistake-color: var(--chinese); }
.mistake-item[data-subject="math"] { --mistake-color: var(--math); }
.mistake-item[data-subject="english"] { --mistake-color: var(--english); }
.mistake-item:hover {
    background: var(--bg-elevated);
    border-color: var(--border-strong);
    transform: translateX(4px);
    box-shadow: var(--shadow);
}
.mistake-item:hover::before {
    transform: scaleY(1);
}
.mistake-icon {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    flex-shrink: 0;
}
[data-subject="chinese"] .mistake-icon { background: var(--chinese-soft); }
[data-subject="math"] .mistake-icon { background: var(--math-soft); }
[data-subject="english"] .mistake-icon { background: var(--english-soft); }
.mistake-content {
    min-width: 0;
}
.mistake-question {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--text);
    line-height: 1.5;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}
.mistake-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    font-size: 12px;
    color: var(--text-muted);
}
.meta-tag {
    background: var(--bg-elevated);
    padding: 2px 8px;
    border-radius: 6px;
    font-weight: 500;
    border: 1px solid var(--border);
}
.meta-tag.review-due {
    background: var(--chinese-soft);
    color: var(--chinese);
    border-color: var(--chinese);
}
.meta-tag.mastered {
    background: var(--primary-soft);
    color: var(--primary);
    border-color: var(--primary);
}
.mistake-actions {
    display: flex;
    gap: 4px;
    flex-shrink: 0;
}
.icon-btn {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    border: none;
    background: transparent;
    color: var(--text-muted);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}
.icon-btn:hover {
    background: var(--primary-soft);
    color: var(--primary);
}
.icon-btn.icon-btn-danger:hover {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
}
.icon-btn svg {
    width: 16px;
    height: 16px;
}

/* ============ 今日复习列表 ============ */
.today-review-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-height: 360px;
    overflow-y: auto;
}

/* ============ 录入错题 ============ */
.add-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.subject-picker {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
}
.subject-option {
    cursor: pointer;
}
.subject-option input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}
.subject-card {
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 16px;
    text-align: center;
    transition: all var(--transition-fast);
    background: var(--bg);
}
.subject-option input:checked + .subject-card {
    border-color: var(--primary);
    background: var(--primary-soft);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--primary-glow);
}
.subject-card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}
.type-picker {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}
.type-group {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    width: 100%;
}
.type-option {
    cursor: pointer;
}
.type-option input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}
.type-option span {
    display: inline-block;
    padding: 7px 14px;
    border: 1.5px solid var(--border);
    border-radius: 999px;
    font-size: 13px;
    color: var(--text);
    background: var(--bg);
    transition: all .2s;
}
.type-option:hover span {
    border-color: var(--primary);
}
.type-option input:checked + span {
    border-color: var(--primary);
    background: var(--primary-soft);
    color: var(--primary);
    font-weight: 600;
}
.subject-emoji {
    font-size: 36px;
    margin-bottom: 8px;
}
.subject-name {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 4px;
}
.subject-sub {
    font-size: 12px;
    color: var(--text-muted);
}

/* ============ 上传区域 ============ */
.upload-zone {
    border: 2px dashed var(--border-strong);
    border-radius: var(--radius);
    padding: 32px 24px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    background: var(--bg);
}
.upload-zone:hover {
    border-color: var(--primary);
    background: var(--primary-soft);
}
.upload-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 12px;
    background: var(--primary-soft);
    color: var(--primary);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
}
.upload-icon svg {
    width: 32px;
    height: 32px;
}
.upload-zone:hover .upload-icon {
    transform: scale(1.1) rotate(-5deg);
}
.upload-text {
    font-size: 15px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 4px;
}
.upload-zone small {
    font-size: 12px;
    color: var(--text-muted);
}
.upload-buttons {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    margin: 10px 0 8px;
}
.upload-buttons .btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.upload-buttons .btn svg {
    width: 16px;
    height: 16px;
}
.image-preview {
    position: relative;
    border-radius: var(--radius);
    overflow: hidden;
    max-width: 100%;
}
.image-preview img {
    width: 100%;
    max-height: 320px;
    object-fit: contain;
    background: var(--bg);
    border-radius: var(--radius);
}
.ocr-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 4px 2px;
    flex-wrap: wrap;
}
.ocr-bar .btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.ocr-bar .btn svg {
    width: 15px;
    height: 15px;
}
.ocr-status {
    font-size: 12px;
    color: var(--text-muted);
    line-height: 1.4;
    flex: 1;
    min-width: 120px;
}
.btn-remove {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    border: none;
    font-size: 20px;
    cursor: pointer;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}
.btn-remove:hover {
    background: var(--danger);
    transform: scale(1.1);
}

/* ============ 表单 ============ */
.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: 16px;
}
.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.form-group label {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-soft);
    display: flex;
    align-items: center;
    gap: 4px;
}
.label-hint {
    font-size: 11px;
    font-weight: 400;
    color: var(--text-muted);
}
.form-group input,
.form-group textarea,
.form-group select,
.input-search {
    background: var(--bg);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 14px;
    color: var(--text);
    font-family: inherit;
    transition: all var(--transition-fast);
    width: 100%;
    resize: vertical;
}
.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus,
.input-search:focus {
    outline: none;
    border-color: var(--primary);
    background: var(--bg-elevated);
    box-shadow: 0 0 0 3px var(--primary-glow);
}
.filter-group {
    flex: 1;
    max-width: 240px;
}
.action-bar {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    padding: 20px 0;
}

/* ============ 功能卡片 ============ */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}
.feature-card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}
.feature-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--feature-color, var(--primary-soft));
    opacity: 0;
    transition: opacity var(--transition);
    pointer-events: none;
}
.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--feature-color, var(--primary));
}
.feature-card:hover::before {
    opacity: 0.5;
}
.feature-card[data-feature="dictation"] { --feature-color: var(--chinese); }
.feature-card[data-feature="sentences"] { --feature-color: var(--primary); }
.feature-card[data-feature="reading"] { --feature-color: var(--math); }
.feature-card[data-feature="math-knowledge"] { --feature-color: var(--math); }
.feature-card[data-feature="math-related"] { --feature-color: var(--math); }
.feature-card[data-feature="english-word"] { --feature-color: var(--english); }
.feature-card[data-feature="english-knowledge"] { --feature-color: var(--english); }
.feature-card[data-feature="english-related"] { --feature-color: var(--english); }
.feature-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: var(--feature-color, var(--primary-soft));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-bottom: 14px;
    position: relative;
    z-index: 1;
}
.feature-card h3 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 6px;
    position: relative;
    z-index: 1;
}
.feature-card p {
    font-size: 13px;
    color: var(--text-soft);
    margin-bottom: 12px;
    position: relative;
    z-index: 1;
    line-height: 1.5;
}
.feature-stat {
    font-size: 12px;
    font-weight: 600;
    color: var(--feature-color, var(--primary));
    padding-top: 12px;
    border-top: 1px solid var(--border);
    position: relative;
    z-index: 1;
}
.feature-stat span {
    font-size: 18px;
    font-weight: 800;
}

/* ============ 知识点树 ============ */
.knowledge-tree {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.knowledge-item {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px 16px;
    transition: all var(--transition-fast);
    cursor: pointer;
}
.knowledge-item:hover {
    border-color: var(--math);
    background: var(--math-soft);
}
.knowledge-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 6px;
}
.knowledge-name {
    font-size: 14px;
    font-weight: 700;
    color: var(--text);
}
.knowledge-count {
    font-size: 12px;
    background: var(--math-soft);
    color: var(--math);
    padding: 2px 8px;
    border-radius: 6px;
    font-weight: 600;
}
.knowledge-questions {
    font-size: 12px;
    color: var(--text-muted);
}

/* ============ 艾宾浩斯时间线 ============ */
.ebbinghaus-timeline {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    position: relative;
    padding: 20px 0;
    gap: 4px;
}
.ebbinghaus-timeline::before {
    content: '';
    position: absolute;
    top: 38px;
    left: 24px;
    right: 24px;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--chinese), var(--math), var(--english));
    border-radius: 1px;
    z-index: 0;
}
.timeline-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    position: relative;
    z-index: 1;
}
.timeline-dot {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--bg-elevated);
    border: 3px solid var(--primary);
    margin-top: 28px;
    transition: all var(--transition);
}
.timeline-item:hover .timeline-dot {
    background: var(--primary);
    transform: scale(1.3);
    box-shadow: 0 0 0 6px var(--primary-glow);
}
.timeline-content {
    text-align: center;
}
.timeline-day {
    font-size: 14px;
    font-weight: 700;
    color: var(--primary);
}
.timeline-label {
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 2px;
}

/* ============ 复习卡片 ============ */
.review-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-height: 400px;
    overflow-y: auto;
}
.review-list .mistake-item {
    cursor: default;
}
.review-session {
    /* 复习模式样式 */
}
.review-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
}
.review-progress {
    flex: 1;
    margin-right: 16px;
}
.review-progress span {
    font-size: 13px;
    color: var(--text-soft);
    font-weight: 600;
    display: block;
    margin-bottom: 6px;
}
.progress-bar {
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--primary-light));
    border-radius: 3px;
    transition: width 0.4s ease;
    width: 0%;
}
.review-card {
    background: linear-gradient(135deg, var(--bg-elevated), var(--bg));
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
    text-align: center;
}
.review-subject {
    display: inline-block;
    background: var(--math-soft);
    color: var(--math);
    font-size: 12px;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 12px;
    margin-bottom: 12px;
}
.review-tag {
    display: inline-block;
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 16px;
    margin-left: 8px;
}
.review-question {
    font-size: 20px;
    font-weight: 700;
    line-height: 1.6;
    margin-bottom: 24px;
    color: var(--text);
}
.review-answer {
    background: var(--primary-soft);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 24px;
    text-align: left;
    animation: fadeIn 0.3s ease;
}
.answer-label {
    font-size: 12px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.answer-content {
    font-size: 18px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 12px;
}
.answer-wrong {
    font-size: 13px;
    color: var(--danger);
    margin-bottom: 8px;
    padding: 6px 10px;
    background: rgba(239, 68, 68, 0.1);
    border-radius: 6px;
    display: inline-block;
}
.answer-note {
    font-size: 13px;
    color: var(--text-soft);
    background: var(--bg-elevated);
    padding: 10px 12px;
    border-radius: 6px;
    margin-top: 8px;
}
.review-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: center;
}
.review-answer-row {
    display: flex;
    gap: 10px;
    width: 100%;
    max-width: 360px;
}
.review-answer-row .btn {
    flex: 1;
    justify-content: center;
}
.btn-danger-text {
    background: transparent;
    color: var(--danger);
    border: 1.5px solid rgba(239, 68, 68, 0.4);
}
.btn-danger-text:hover {
    background: rgba(239, 68, 68, 0.08);
}
.review-buttons {
    display: flex;
    gap: 12px;
    width: 100%;
    max-width: 360px;
}
.review-buttons .btn {
    flex: 1;
    justify-content: center;
    padding: 12px 20px;
}

/* ============ 错误原因图表 ============ */
.reason-chart, .trend-chart {
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.reason-item {
    display: grid;
    grid-template-columns: 80px 1fr 40px;
    align-items: center;
    gap: 12px;
    font-size: 13px;
}
.reason-name { font-weight: 600; color: var(--text-soft); }
.reason-bar {
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
}
.reason-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--primary-light));
    border-radius: 4px;
    transition: width 0.6s ease;
}
.reason-count {
    font-weight: 700;
    text-align: right;
}
.trend-bar-group {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 8px;
    align-items: end;
    height: 140px;
    padding: 8px 0;
}
.trend-bar-wrap {
    display: flex;
    flex-direction: column;
    align-items: center;
    height: 100%;
    gap: 4px;
}
.trend-bar {
    width: 100%;
    background: linear-gradient(180deg, var(--primary), var(--primary-dark));
    border-radius: 6px 6px 0 0;
    min-height: 4px;
    transition: height 0.6s ease;
}
.trend-label {
    font-size: 11px;
    color: var(--text-muted);
    font-weight: 600;
}

/* ============ 数据操作 ============ */
.data-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* ============ 底部导航 ============ */
.bottom-nav {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--glass);
    backdrop-filter: blur(24px) saturate(180%);
    -webkit-backdrop-filter: blur(24px) saturate(180%);
    border-top: 1px solid var(--border);
    padding: 8px 8px 12px;
    z-index: 50;
}
.bottom-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    padding: 6px 4px;
    text-decoration: none;
    color: var(--text-muted);
    font-size: 10px;
    font-weight: 600;
    border-radius: 8px;
    transition: all var(--transition-fast);
}
.bottom-item svg {
    width: 22px;
    height: 22px;
}
.bottom-item.active {
    color: var(--primary);
}
.bottom-fab {
    margin-top: -20px;
    background: none;
    align-self: flex-start;
}
.fab-circle {
    width: 52px;
    height: 52px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    box-shadow: 0 8px 24px var(--primary-glow);
    transition: all var(--transition);
}
.fab-circle svg {
    width: 26px;
    height: 26px;
}
.bottom-fab:hover .fab-circle {
    transform: scale(1.08);
}

/* ============ PWA 安装引导条 ============ */
.install-banner {
    position: fixed;
    bottom: 90px;
    left: 50%;
    transform: translateX(-50%) translateY(120%);
    width: calc(100% - 32px);
    max-width: 420px;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    box-shadow: var(--shadow-lg);
    z-index: 150;
    transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}
.install-banner.show {
    transform: translateX(-50%) translateY(0);
}
.install-banner-icon {
    font-size: 28px;
    flex-shrink: 0;
}
.install-banner-text {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-width: 0;
}
.install-banner-text strong {
    font-size: 14px;
    color: var(--text);
}
.install-banner-text span {
    font-size: 12px;
    color: var(--text-muted);
    line-height: 1.4;
}
.install-banner .btn {
    flex-shrink: 0;
}
.install-banner-close {
    position: absolute;
    top: 6px;
    right: 6px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: none;
    background: var(--border);
    color: var(--text-muted);
    font-size: 14px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}
.install-banner-close:hover {
    background: var(--danger);
    color: white;
}
@media (min-width: 769px) {
    .install-banner {
        bottom: 24px;
    }
}

/* ============ Toast ============ */
.toast {
    position: fixed;
    top: 80px;
    left: 50%;
    transform: translateX(-50%) translateY(-100px);
    background: var(--text);
    color: var(--bg-elevated);
    padding: 12px 20px;
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: var(--shadow-lg);
    z-index: 200;
    transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    pointer-events: none;
}
.toast.show {
    transform: translateX(-50%) translateY(0);
}
.toast.success { background: var(--primary); }
.toast.error { background: var(--danger); }
.toast.warning { background: var(--chinese); }
.toast-icon {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.25);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: 800;
}

/* ============ 响应式 ============ */
@media (max-width: 1024px) {
    .app {
        grid-template-columns: 220px 1fr;
    }
    .main {
        padding: 24px 24px 100px;
    }
}

@media (max-width: 768px) {
    .app {
        grid-template-columns: 1fr;
    }
    .sidebar {
        display: none;
    }
    .bottom-nav {
        display: flex;
    }
    .main {
        padding: 20px 16px 100px;
    }
    .page-title {
        font-size: 22px;
    }
    .grid-2 {
        grid-template-columns: 1fr;
    }
    .subject-picker {
        grid-template-columns: 1fr;
    }
    .form-row {
        grid-template-columns: 1fr;
    }
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .stat-value {
        font-size: 22px;
    }
    .ebbinghaus-timeline {
        overflow-x: auto;
        justify-content: flex-start;
        gap: 16px;
        padding: 16px;
    }
    .ebbinghaus-timeline::before {
        display: none;
    }
    .timeline-item {
        min-width: 70px;
    }
    .mistake-item {
        grid-template-columns: auto 1fr;
    }
    .mistake-actions {
        grid-column: 1 / -1;
        justify-content: flex-end;
    }
}

@media (max-width: 480px) {
    .feature-grid {
        grid-template-columns: 1fr;
    }
    .stat-card {
        padding: 14px;
    }
    .stat-icon {
        width: 40px;
        height: 40px;
    }
    .stat-value {
        font-size: 20px;
    }
}

/* ============ 打印 ============ */
@media print {
    .sidebar, .bottom-nav, .theme-toggle, .action-bar { display: none; }
    .app { grid-template-columns: 1fr; }
    .main { padding: 0; overflow: visible; }
    .view { display: block; }
}