/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* 头部样式 */
header {
    background: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
    color: white;
    padding: 1.5rem 2rem;
    border-radius: 15px;
    margin-bottom: 2rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

header h1 {
    font-size: 2.2rem;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.header-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 1rem;
}

.btn-back {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(255,255,255,0.2);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    text-decoration: none;
    transition: all 0.3s ease;
}

.btn-back:hover {
    background: rgba(255,255,255,0.3);
    transform: translateX(-5px);
}

/* 卡片样式 */
.welcome-card, .feature-card, .knowledge-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
}

.feature-card {
    text-decoration: none;
    color: inherit;
    display: block;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: #3498db;
}

.feature-badge {
    position: absolute;
    top: 15px;
    right: 15px;
    background: #e74c3c;
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
}

/* 网格布局 */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.knowledge-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.knowledge-card {
    text-decoration: none;
    color: inherit;
    text-align: center;
    padding: 1.5rem 1rem;
}

.knowledge-card:hover {
    background: #f8f9fa;
    transform: translateY(-5px);
}

.knowledge-icon {
    font-size: 2.5rem;
    color: #3498db;
    margin-bottom: 0.5rem;
}

/* 快速统计 */
.quick-stats {
    display: flex;
    justify-content: space-around;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid #eee;
}

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

.stat-item i {
    font-size: 2rem;
    color: #3498db;
    margin-bottom: 0.5rem;
}

.stat-item span {
    display: block;
    font-size: 1.8rem;
    font-weight: bold;
    color: #2c3e50;
}

/* 练习页面样式 */
.practice-container {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 2rem;
}

.sidebar {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.knowledge-list {
    margin-top: 1rem;
}

.knowledge-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 0.8rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: 10px;
    text-decoration: none;
    color: #555;
    transition: all 0.3s ease;
}

.knowledge-item:hover {
    background: #f8f9fa;
}

.knowledge-item.active {
    background: #3498db;
    color: white;
}

/* 题目容器 */
.question-container {
    background: white;
    border-radius: 15px;
    padding: 2rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    margin-bottom: 1.5rem;
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #f0f0f0;
}

.question-type {
    padding: 0.4rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: bold;
}

.question-type.单选题 {
    background: #e3f2fd;
    color: #1976d2;
}

.question-type.填空题 {
    background: #f3e5f5;
    color: #7b1fa2;
}

.question-type.判断题 {
    background: #e8f5e9;
    color: #388e3c;
}

/* 选项样式 */
.options {
    margin: 1.5rem 0;
}

.option {
    display: flex;
    align-items: center;
    padding: 1rem;
    margin-bottom: 0.8rem;
    background: #f8f9fa;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.option:hover {
    background: #e9ecef;
    border-color: #3498db;
}

.option input[type="radio"] {
    margin-right: 1rem;
    width: 1.2rem;
    height: 1.2rem;
}

.option-letter {
    font-weight: bold;
    margin-right: 0.5rem;
    color: #3498db;
}

/* 填空题样式 */
.fill-blank input {
    width: 100%;
    padding: 1rem;
    border: 2px solid #ddd;
    border-radius: 10px;
    font-size: 1.1rem;
    margin-top: 1rem;
}

.fill-blank input:focus {
    outline: none;
    border-color: #3498db;
}

/* 导航按钮 */
.navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.btn-nav {
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 25px;
    background: #3498db;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.btn-nav:hover:not(:disabled) {
    background: #2980b9;
    transform: translateY(-2px);
}

.btn-nav:disabled {
    background: #bdc3c7;
    cursor: not-allowed;
}

.btn-submit {
    padding: 0.8rem 2rem;
    background: #2ecc71;
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    transition: all 0.3s ease;
}

.btn-submit:hover:not(:disabled) {
    background: #27ae60;
    transform: translateY(-2px);
}

.btn-submit:disabled {
    background: #95a5a6;
    cursor: not-allowed;
}

/* 反馈样式 */
.answer-feedback {
    margin-top: 1.5rem;
    padding: 1.5rem;
    border-radius: 15px;
}

.feedback-correct {
    background: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
    padding: 1.5rem;
    border-radius: 10px;
}

.feedback-wrong {
    background: #f8d7da;
    border: 1px solid #f5c6cb;
    color: #721c24;
    padding: 1.5rem;
    border-radius: 10px;
}

/* 考试页面样式 */
.exam-info {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.timer {
    background: rgba(255,255,255,0.2);
    padding: 0.5rem 1.5rem;
    border-radius: 25px;
    font-size: 1.2rem;
    font-weight: bold;
    display: flex;
    align-items: center;
    gap: 10px;
}

.question-palette {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.palette-grid {
    display: grid;
    grid-template-columns: repeat(10, 1fr);
    gap: 0.5rem;
    margin-top: 1rem;
}

.palette-btn {
    width: 40px;
    height: 40px;
    border: 2px solid #ddd;
    background: white;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.palette-btn:hover {
    border-color: #3498db;
}

.palette-btn.current {
    background: #3498db;
    color: white;
    border-color: #3498db;
}

.palette-btn.answered {
    background: #2ecc71;
    color: white;
    border-color: #27ae60;
}

/* 结果页面样式 */
.result-card {
    background: white;
    border-radius: 15px;
    padding: 3rem;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    max-width: 600px;
    margin: 2rem auto;
}

.score-display {
    margin: 2rem 0;
}

.total-score {
    font-size: 3rem;
    font-weight: bold;
    color: #3498db;
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 10px;
}

.score-label {
    font-size: 1.5rem;
    color: #666;
}

.score-max {
    font-size: 1.5rem;
    color: #999;
}

/* 错题复习样式 */
.filter-panel {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    margin-bottom: 1.5rem;
}

.filter-group {
    margin-bottom: 1.5rem;
}

.filter-options {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 0.5rem;
}

.filter-option {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
}

/* 表格样式 */
.questions-table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.questions-table th {
    background: #3498db;
    color: white;
    padding: 1rem;
    text-align: left;
}

.questions-table td {
    padding: 1rem;
    border-bottom: 1px solid #eee;
}

.questions-table tr:hover {
    background: #f8f9fa;
}

/* 统计页面样式 */
.overview-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.overview-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.card-icon {
    font-size: 3rem;
    color: #3498db;
}

.card-value {
    font-size: 2.5rem;
    font-weight: bold;
    color: #2c3e50;
}

.charts-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.chart-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.chart-container {
    height: 300px;
    margin-top: 1rem;
}

/* 页脚 */
footer {
    text-align: center;
    margin-top: 3rem;
    padding: 1.5rem;
    color: #666;
    border-top: 1px solid #ddd;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .practice-container {
        grid-template-columns: 1fr;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .knowledge-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }

    .container {
        padding: 12px;
    }

    header {
        padding: 1.25rem;
        border-radius: 12px;
    }

    header h1 {
        font-size: 1.7rem;
        line-height: 1.2;
        flex-wrap: wrap;
    }

    .subtitle {
        font-size: 0.95rem;
    }

    .welcome-card,
    .feature-card,
    .knowledge-card,
    .progress-section {
        border-radius: 12px;
    }

    .welcome-card {
        padding: 1.1rem;
    }

    .welcome-header {
        flex-direction: column;
        align-items: stretch;
        gap: 0.8rem;
    }

    .welcome-header > div {
        display: flex;
        flex-direction: column;
        gap: 0.6rem;
        width: 100%;
    }

    .btn-feedback,
    .switch-bank-btn,
    .btn-notice-login {
        width: 100%;
        justify-content: center;
    }

    .announcement-section {
        padding: 14px;
        margin: 14px 0;
    }

    .quick-stats {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 0.75rem;
        margin-top: 1rem;
        padding-top: 1rem;
    }

    .stat-item {
        flex-direction: column;
        justify-content: center;
        gap: 0.3rem;
        padding: 0.85rem 0.5rem;
        min-height: 92px;
    }

    .stat-item i {
        font-size: 1.6rem;
        margin-bottom: 0;
    }

    .stat-item span {
        font-size: 1.35rem;
        line-height: 1.1;
    }

    .stat-item p {
        font-size: 0.85rem;
        text-align: center;
        line-height: 1.2;
        margin: 0;
    }

    .progress-section {
        padding: 1rem;
    }

    .progress-card {
        padding: 1rem;
    }

    .progress-stats {
        flex-direction: column;
        gap: 0.4rem;
    }
    
    .charts-section {
        grid-template-columns: 1fr;
    }
    
    .exam-info {
        grid-template-columns: 1fr;
    }
    
    .palette-grid {
        grid-template-columns: repeat(5, 1fr);
    }
    
    .header-actions {
        flex-direction: column;
        gap: 1rem;
    }

    .header-top {
        flex-direction: column;
        align-items: stretch;
    }

    .header-title,
    .user-section {
        width: 100%;
        min-width: 0;
    }

    .user-section {
        padding: 0.85rem;
    }

    .login-form {
        flex-direction: column;
        gap: 0.6rem;
    }

    .login-form input,
    .login-form button {
        width: 100%;
    }

    .login-section {
        width: 100%;
    }

    .user-info {
        flex-direction: column;
        align-items: flex-start;
    }

    .user-details {
        width: 100%;
    }

    .notice-content {
        flex-direction: column;
        align-items: flex-start;
    }

    .notice-content p {
        width: 100%;
    }

    .progress-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .quick-stats {
        grid-template-columns: 1fr;
    }

    .features-grid {
        gap: 1rem;
        margin: 1.5rem 0;
    }

    .feature-card {
        padding: 1.1rem;
    }

    .feature-card h3 {
        font-size: 1.1rem;
    }

    .feature-card p {
        font-size: 0.95rem;
    }

    .knowledge-grid {
        grid-template-columns: 1fr;
    }

    .welcome-section,
    .progress-section {
        margin-top: 1rem;
    }

    .announcement-header h3 {
        font-size: 1.1rem;
    }

    .announcement-content {
        font-size: 0.95rem;
    }
}

/* 加载动画 */
.loading {
    text-align: center;
    padding: 3rem;
    color: #666;
}

.fa-spin {
    animation: fa-spin 2s infinite linear;
}

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

/* 模态框样式 */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal-content {
    background: white;
    border-radius: 15px;
    max-width: 800px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid #eee;
}

.modal-close {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: #666;
}

.modal-body {
    padding: 1.5rem;
}

/* 进度条 */
.progress-bar {
    height: 10px;
    background: #eee;
    border-radius: 5px;
    overflow: hidden;
    margin-top: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    border-radius: 5px;
    transition: width 0.3s ease;
}

/* 工具提示 */
[title] {
    position: relative;
}

[title]:hover::after {
    content: attr(title);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: #333;
    color: white;
    padding: 0.5rem;
    border-radius: 4px;
    font-size: 0.9rem;
    white-space: nowrap;
    z-index: 100;
}
/* 在原有CSS后面添加这些样式 */

/* 错误消息 */
.error-message {
    text-align: center;
    padding: 2rem;
    color: #e74c3c;
}

.error-message i {
    font-size: 3rem;
    margin-bottom: 1rem;
}

/* 重新开始按钮 */
.btn-restart {
    width: 100%;
    padding: 0.8rem;
    background: #e74c3c;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    margin-top: 1rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-restart:hover {
    background: #c0392b;
    transform: translateY(-2px);
}

/* 选项样式增强 */
.option input[type="radio"] {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border: 2px solid #ddd;
    border-radius: 50%;
    margin-right: 15px;
    position: relative;
    cursor: pointer;
    transition: all 0.3s ease;
}

.option input[type="radio"]:checked {
    border-color: #3498db;
    background-color: #3498db;
}

.option input[type="radio"]:checked::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 10px;
    height: 10px;
    background: white;
    border-radius: 50%;
}

.option input[type="radio"]:hover {
    border-color: #3498db;
}

/* 填空题输入框增强 */
.fill-blank input {
    width: 100%;
    padding: 1rem;
    border: 2px solid #ddd;
    border-radius: 10px;
    font-size: 1.1rem;
    margin-top: 1rem;
    transition: all 0.3s ease;
}

.fill-blank input:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

/* 反馈样式增强 */
.feedback-correct, .feedback-wrong {
    padding: 1.5rem;
    border-radius: 10px;
    margin-top: 1rem;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feedback-correct {
    background: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
}

.feedback-wrong {
    background: #f8d7da;
    border: 1px solid #f5c6cb;
    color: #721c24;
}

.feedback-correct i, .feedback-wrong i {
    font-size: 2rem;
    margin-right: 1rem;
    vertical-align: middle;
}

/* 图片样式 */
.question-image {
    margin: 1.5rem 0;
    text-align: center;
}

.question-image img {
    max-width: 100%;
    max-height: 400px;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

/* 按钮状态 */
.btn-nav:disabled, .btn-submit:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

/* 统计面板样式 */
.stats-panel {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid #eee;
}

.stat-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.8rem;
    padding: 0.5rem;
    background: #f8f9fa;
    border-radius: 6px;
}

.stat-item span {
    color: #666;
}

.stat-item strong {
    color: #2c3e50;
}

/* 加载动画 */
.loading {
    text-align: center;
    padding: 3rem;
    font-size: 1.2rem;
}

.fa-spin {
    margin-right: 10px;
}

/* 题目计数器 */
.question-counter {
    font-size: 1.2rem;
    font-weight: bold;
    color: #2c3e50;
    background: #f8f9fa;
    padding: 0.5rem 1.5rem;
    border-radius: 20px;
    min-width: 100px;
    text-align: center;
}
/* ====== Review Page Styles ====== */

/* 统计徽章 */
.accuracy-badge {
    background: #2ecc71;
    color: white;
    padding: 0.2rem 0.8rem;
    border-radius: 12px;
    font-size: 0.9rem;
    margin-left: 10px;
}

/* 筛选面板增强 */
.filter-actions {
    display: flex;
    gap: 10px;
    margin-top: 1.5rem;
}

.btn-clear-filter {
    background: #95a5a6;
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-clear-filter:hover {
    background: #7f8c8d;
}

/* 模式选择器 */
.review-mode-selector {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.mode-buttons {
    display: flex;
    gap: 10px;
}

.mode-btn {
    padding: 0.6rem 1.2rem;
    border: 2px solid #3498db;
    background: white;
    color: #3498db;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.mode-btn:hover {
    background: #f8f9fa;
}

.mode-btn.active {
    background: #3498db;
    color: white;
}

/* 练习模式样式 */
.practice-review-container {
    background: white;
    border-radius: 15px;
    padding: 2rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.practice-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #f0f0f0;
}

.practice-stats {
    display: flex;
    gap: 2rem;
    font-size: 1.1rem;
}

.practice-stats span {
    background: #f8f9fa;
    padding: 0.5rem 1rem;
    border-radius: 20px;
}

.practice-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 2rem;
    padding: 1.5rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.btn-exit-practice {
    background: #e74c3c;
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 25px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-exit-practice:hover {
    background: #c0392b;
}

.practice-feedback {
    margin-top: 1.5rem;
    animation: slideIn 0.3s ease;
}

/* 卡片模式样式 */
.card-review-container {
    background: white;
    border-radius: 15px;
    padding: 2rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.card-controls {
    display: flex;
    gap: 10px;
}

.card-control-btn {
    padding: 0.6rem 1.2rem;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.card-control-btn:hover {
    background: #2980b9;
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.question-card {
    height: 250px;
    perspective: 1000px;
    cursor: pointer;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.question-card.flipped .card-inner {
    transform: rotateY(180deg);
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 10px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.card-front {
    background: white;
    border: 2px solid #3498db;
}

.card-back {
    background: #f8f9fa;
    transform: rotateY(180deg);
    border: 2px solid #2ecc71;
}

.card-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.card-type {
    padding: 0.3rem 0.8rem;
    background: #3498db;
    color: white;
    border-radius: 12px;
    font-size: 0.9rem;
}

.card-knowledge {
    padding: 0.3rem 0.8rem;
    background: #f8f9fa;
    color: #666;
    border-radius: 12px;
    font-size: 0.9rem;
}

.card-content {
    flex: 1;
    overflow-y: auto;
    margin-bottom: 1rem;
    padding-right: 5px;
}

.card-content::-webkit-scrollbar {
    width: 5px;
}

.card-content::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 5px;
}

.card-content::-webkit-scrollbar-thumb {
    background: #888;
    border-radius: 5px;
}

.card-content::-webkit-scrollbar-thumb:hover {
    background: #555;
}

.card-content p {
    margin-bottom: 0.5rem;
}

.card-footer {
    display: flex;
    justify-content: space-between;
    gap: 10px;
}

.card-flip-btn, .card-master-btn {
    flex: 1;
    padding: 0.6rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 5px;
    font-size: 0.9rem;
}

.card-flip-btn {
    background: #3498db;
    color: white;
}

.card-master-btn {
    background: #2ecc71;
    color: white;
}

.card-flip-btn:hover {
    background: #2980b9;
}

.card-master-btn:hover {
    background: #27ae60;
}

.question-card.mastered .card-front {
    border-color: #2ecc71;
    background: #d4edda;
}

.cards-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 2rem;
    padding: 1rem;
    background: #f8f9fa;
    border-radius: 10px;
}

.cards-stats {
    display: flex;
    gap: 2rem;
}

.btn-exit-cards {
    padding: 0.8rem 1.5rem;
    background: #95a5a6;
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-exit-cards:hover {
    background: #7f8c8d;
}

.no-cards {
    text-align: center;
    padding: 3rem;
    grid-column: 1 / -1;
}

.no-cards i {
    font-size: 3rem;
    color: #2ecc71;
    margin-bottom: 1rem;
}

/* 统计信息 */
.review-stats {
    margin-top: 2rem;
    padding: 2rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.stat-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1.5rem;
    border-radius: 10px;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    font-size: 2.5rem;
    opacity: 0.9;
}

.stat-content h4 {
    margin-bottom: 0.5rem;
    font-size: 1rem;
    opacity: 0.9;
}

.stat-value {
    font-size: 2rem;
    font-weight: bold;
}

.knowledge-distribution {
    margin-top: 2rem;
}

.distribution-chart {
    margin-top: 1rem;
}

.chart-bar {
    margin-bottom: 1rem;
}

.bar-label {
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: #333;
}

.bar-container {
    display: flex;
    align-items: center;
    gap: 10px;
}

.bar-fill {
    height: 20px;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    border-radius: 10px;
    min-width: 30px;
    transition: width 1s ease;
}

.bar-value {
    min-width: 60px;
    text-align: right;
    font-weight: bold;
}

/* 题目详情模态框增强 */
.detail-header {
    display: flex;
    gap: 10px;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.timestamp {
    background: #f8f9fa;
    padding: 0.3rem 0.8rem;
    border-radius: 12px;
    color: #666;
    display: flex;
    align-items: center;
    gap: 5px;
}

.answer-comparison {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin: 1.5rem 0;
}

.answer-item {
    padding: 1.5rem;
    border-radius: 10px;
}

.wrong-answer {
    background: #f8d7da;
    border: 1px solid #f5c6cb;
}

.correct-answer {
    background: #d4edda;
    border: 1px solid #c3e6cb;
}

.answer-item h5 {
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.detail-actions {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.btn-practice-single, .btn-mark-mastered {
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
}

.btn-practice-single {
    background: #3498db;
    color: white;
}

.btn-mark-mastered {
    background: #2ecc71;
    color: white;
}

.btn-practice-single:hover {
    background: #2980b9;
}

.btn-mark-mastered:hover {
    background: #27ae60;
}

/* 导出选项 */
.export-options {
    padding: 1rem;
}

.export-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 0.8rem;
    margin-bottom: 0.5rem;
    background: #f8f9fa;
    border-radius: 8px;
    cursor: pointer;
}

.export-option:hover {
    background: #e9ecef;
}

.export-option input[type="radio"] {
    width: 18px;
    height: 18px;
}

.export-preview {
    margin-top: 1.5rem;
    max-height: 300px;
    overflow-y: auto;
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid #ddd;
}

.export-preview pre {
    white-space: pre-wrap;
    word-wrap: break-word;
    margin: 0;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

.export-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
    justify-content: flex-end;
}

.btn-export {
    padding: 0.8rem 1.5rem;
    background: #2ecc71;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-cancel {
    padding: 0.8rem 1.5rem;
    background: #95a5a6;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
}

.btn-export:hover {
    background: #27ae60;
}

.btn-cancel:hover {
    background: #7f8c8d;
}

/* 空状态样式 */
.empty-cell {
    text-align: center;
    padding: 3rem !important;
}

.empty-cell i {
    font-size: 3rem;
    color: #2ecc71;
    margin-bottom: 1rem;
}

.empty-cell p {
    margin-bottom: 1rem;
    color: #666;
}

.btn-show-mastered {
    padding: 0.6rem 1.2rem;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-show-mastered:hover {
    background: #2980b9;
}

/* 表格操作列按钮 */
.questions-table .btn-view,
.questions-table .btn-practice {
    padding: 0.4rem 0.8rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-size: 0.9rem;
    margin-right: 5px;
}

.questions-table .btn-view {
    background: #3498db;
    color: white;
}

.questions-table .btn-practice {
    background: #2ecc71;
    color: white;
}

.questions-table .btn-view:hover {
    background: #2980b9;
}

.questions-table .btn-practice:hover {
    background: #27ae60;
}

/* 每页显示数量选择器 */
.page-size-select {
    padding: 0.5rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    background: white;
    margin-left: 1rem;
}

/* ====== 错题复习卡片模式新增样式 ====== */

/* 卡片选项样式 */
.card-options, .true-false-options {
    margin: 10px 0;
}

.card-options p, .true-false-options p {
    font-weight: bold;
    margin-bottom: 5px;
    color: #333;
}

.options-list {
    margin-top: 5px;
}

.option-item {
    padding: 8px 12px;
    margin: 5px 0;
    background: #f8f9fa;
    border-radius: 8px;
    border-left: 4px solid #ddd;
    font-size: 0.95rem;
    transition: all 0.3s ease;
}

.option-item:hover {
    background: #e9ecef;
}

.option-item.correct-option {
    background: #d4edda;
    border-left-color: #28a745;
    font-weight: bold;
    color: #155724;
}

/* 卡片答案对比 */
.correct-answer {
    color: #28a745;
    font-weight: bold;
    background: #d4edda;
    padding: 3px 8px;
    border-radius: 4px;
    display: inline-block;
    margin-left: 5px;
}

.wrong-answer {
    color: #dc3545;
    font-weight: bold;
    background: #f8d7da;
    padding: 3px 8px;
    border-radius: 4px;
    display: inline-block;
    margin-left: 5px;
}

/* 卡片解析 */
.card-explanation {
    margin: 15px 0;
    padding: 12px;
    background: #fff3cd;
    border-radius: 8px;
    border-left: 4px solid #ffc107;
}

.card-explanation p {
    margin: 0;
    color: #856404;
}

.card-explanation strong {
    color: #856404;
}

/* 卡片图片 */
.card-image {
    margin: 15px 0;
}

.card-image p {
    font-weight: bold;
    margin-bottom: 8px;
    color: #333;
}

.card-img {
    max-width: 100%;
    max-height: 200px;
    border-radius: 8px;
    display: block;
    margin: 0 auto;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

/* 题目详情模态框中的选项 */
.detail-content .options-list {
    margin: 15px 0;
}

.detail-content .option-item {
    padding: 10px 15px;
    margin: 8px 0;
}

/* 详情模态框的答案对比样式增强 */
.answer-item.wrong-answer .option-item,
.answer-item.correct-answer .option-item {
    background: white;
    margin: 5px 0;
}

.answer-item.wrong-answer h5 {
    color: #dc3545;
}

.answer-item.correct-answer h5 {
    color: #28a745;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .cards-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    }
    
    .answer-comparison {
        grid-template-columns: 1fr;
    }
    
    .question-card {
        height: 280px;
    }
}

@media (max-width: 768px) {
    .review-mode-selector {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .mode-buttons {
        width: 100%;
        justify-content: center;
    }
    
    .practice-stats {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
    }
    
    .practice-navigation {
        flex-wrap: wrap;
        gap: 1rem;
    }
    
    .practice-navigation > * {
        flex: 1;
        min-width: 120px;
        justify-content: center;
    }
    
    .question-card {
        height: 300px;
    }
    
    .card-content {
        font-size: 0.9rem;
    }
    
    .option-item {
        padding: 6px 10px;
        font-size: 0.9rem;
    }
}

/* 加载单元格样式 */
.loading-cell {
    text-align: center;
    padding: 3rem !important;
    color: #666;
}

.loading-cell i {
    margin-right: 10px;
}

/* 分页样式 */
.pagination {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 2rem;
    gap: 1rem;
}

.page-btn {
    width: 40px;
    height: 40px;
    border: 1px solid #ddd;
    background: white;
    border-radius: 5px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.page-btn:hover:not(:disabled) {
    background: #3498db;
    color: white;
    border-color: #3498db;
}

.page-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.page-info {
    font-size: 1rem;
    color: #666;
}
/* ====== 登录和反馈样式 ====== */

/* 头部用户区域 */
.header-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 1rem;
}

.header-title {
    flex: 1;
    min-width: 300px;
}

.user-section {
    background: rgba(255, 255, 255, 0.1);
    padding: 1rem;
    border-radius: 10px;
    min-width: 300px;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-avatar {
    font-size: 3rem;
    color: white;
}

.user-details {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}

.username {
    font-size: 1.2rem;
    font-weight: bold;
    color: white;
}

.student-id {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.8);
    background: rgba(0, 0, 0, 0.2);
    padding: 0.2rem 0.5rem;
    border-radius: 10px;
    display: inline-block;
}

.btn-logout {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: none;
    padding: 0.4rem 1rem;
    border-radius: 15px;
    cursor: pointer;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    margin-top: 0.5rem;
}

.btn-logout:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* 登录表单 */
.login-section {
    text-align: center;
}

.login-form {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

#student-id-input {
    flex: 1;
    padding: 0.8rem 1rem;
    border: none;
    border-radius: 25px;
    font-size: 1rem;
    background: rgba(255, 255, 255, 0.9);
    min-width: 150px;
}

#student-id-input:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.5);
}

.btn-login {
    background: #2ecc71;
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    display: flex;
    align-items: center;
    gap: 8px;
    white-space: nowrap;
}

.btn-login:hover {
    background: #27ae60;
}

.btn-login:disabled {
    background: #95a5a6;
    cursor: not-allowed;
}

.login-tips {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 5px;
}

/* 欢迎卡片头部 */
.welcome-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.btn-feedback {
    background: #9b59b6;
    color: white;
    border: none;
    padding: 0.6rem 1.2rem;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.btn-feedback:hover {
    background: #8e44ad;
}

/* 登录提示 */
.login-notice {
    background: #fff3cd;
    border: 1px solid #ffeaa7;
    border-radius: 10px;
    padding: 1rem;
    margin-top: 1.5rem;
}

.notice-content {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.notice-content i {
    font-size: 1.5rem;
    color: #f39c12;
}

.notice-content h4 {
    margin: 0;
    color: #d35400;
}

.notice-content p {
    margin: 0;
    color: #7d6608;
    flex: 1;
}

.btn-notice-login {
    background: #3498db;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 15px;
    cursor: pointer;
    font-size: 0.9rem;
}

.btn-notice-login:hover {
    background: #2980b9;
}

/* 进度区域 */
.progress-section {
    margin-top: 2rem;
    padding: 2rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
}

.progress-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 1.5rem;
}

@media (max-width: 768px) {
    .progress-grid {
        grid-template-columns: 1fr;
    }
}

.progress-card {
    padding: 1.5rem;
    background: #f8f9fa;
    border-radius: 10px;
}

.progress-bar-large {
    height: 20px;
    background: #eee;
    border-radius: 10px;
    overflow: hidden;
    margin: 1rem 0;
}

.progress-fill-large {
    height: 100%;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    border-radius: 10px;
    transition: width 1s ease;
}

.progress-stats {
    display: flex;
    justify-content: space-between;
    margin-top: 1rem;
    color: #666;
}

.knowledge-progress-list {
    max-height: 200px;
    overflow-y: auto;
}

.knowledge-progress-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.8rem;
    padding: 0.5rem;
    background: white;
    border-radius: 6px;
}

.progress-label {
    flex: 0 0 100px;
    font-size: 0.9rem;
    color: #333;
}

.progress-bar-small {
    flex: 1;
    height: 8px;
    background: #eee;
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill-small {
    height: 100%;
    background: #3498db;
    border-radius: 4px;
    transition: width 1s ease;
}

.progress-value {
    flex: 0 0 50px;
    text-align: right;
    font-size: 0.9rem;
    font-weight: bold;
    color: #2c3e50;
}

.no-progress {
    text-align: center;
    color: #999;
    padding: 2rem;
}

/* 公告栏样式 */
.announcement-section {
    background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
    border-radius: 15px;
    padding: 20px;
    margin: 20px 0;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
    border: 1px solid rgba(0, 0, 0, 0.05);
    position: relative;
    overflow: hidden;
}

.announcement-section::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: linear-gradient(to bottom, #f39c12, #e67e22);
}

.announcement-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #eee;
    flex-wrap: wrap;
    gap: 10px;
}

.announcement-header h3 {
    margin: 0;
    color: #2c3e50;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.4rem;
}

.announcement-header h3 i {
    color: #f39c12;
}

.announcement-date {
    font-size: 0.9rem;
    color: #7f8c8d;
    background: #f8f9fa;
    padding: 5px 12px;
    border-radius: 20px;
}

.announcement-content {
    margin-bottom: 15px;
    line-height: 1.7;
    font-size: 1.05rem;
    color: #34495e;
    padding: 10px 0;
}

.announcement-footer {
    text-align: right;
    font-size: 0.9rem;
    color: #7f8c8d;
    padding-top: 10px;
    border-top: 1px dashed #eee;
}

.announcement-author {
    font-weight: 500;
}

.no-announcement {
    text-align: center;
    color: #95a5a6;
    font-style: italic;
    padding: 20px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .announcement-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .announcement-date {
        align-self: flex-end;
    }
    
    .announcement-content {
        font-size: 1rem;
    }
}

/* 模态框样式增强 */
.login-modal-content {
    text-align: center;
    padding: 1rem;
}

.login-icon {
    font-size: 4rem;
    color: #3498db;
    margin-bottom: 1rem;
}

.login-description {
    color: #666;
    margin-bottom: 2rem;
    line-height: 1.6;
}

.login-input-group {
    margin-bottom: 1.5rem;
    text-align: left;
}

.login-input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: #333;
    display: flex;
    align-items: center;
    gap: 8px;
}

#modal-student-id {
    width: 100%;
    padding: 1rem;
    border: 2px solid #ddd;
    border-radius: 10px;
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

#modal-student-id:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.input-hint {
    font-size: 0.9rem;
    color: #666;
    display: flex;
    align-items: center;
    gap: 5px;
    margin-top: 0.3rem;
}

.login-actions {
    display: flex;
    gap: 1rem;
    margin: 2rem 0;
}

.btn-modal-login {
    flex: 1;
    padding: 1rem;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.btn-modal-cancel {
    flex: 1;
    padding: 1rem;
    background: #95a5a6;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1.1rem;
}

.btn-modal-login:hover {
    background: #2980b9;
}

.btn-modal-cancel:hover {
    background: #7f8c8d;
}

.login-features {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 10px;
    text-align: left;
    margin-top: 2rem;
}

.login-features h5 {
    margin-bottom: 1rem;
    color: #2c3e50;
    display: flex;
    align-items: center;
    gap: 8px;
}

.login-features ul {
    list-style: none;
    padding: 0;
}

.login-features li {
    margin-bottom: 0.8rem;
    color: #555;
    display: flex;
    align-items: center;
    gap: 8px;
}

/* 反馈模态框 */
.feedback-content {
    max-height: 80vh;
    overflow-y: auto;
    padding-right: 1rem;
}

.feedback-header {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 2px solid #f0f0f0;
}

.feedback-icon {
    font-size: 2.5rem;
    color: #f39c12;
}

.feedback-description {
    color: #666;
    line-height: 1.6;
}

.feedback-input-group {
    margin-bottom: 1.5rem;
}

.feedback-input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: #333;
    display: flex;
    align-items: center;
    gap: 8px;
}

#feedback-content {
    width: 100%;
    padding: 1rem;
    border: 2px solid #ddd;
    border-radius: 10px;
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
}

#feedback-content:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.char-counter {
    text-align: right;
    font-size: 0.9rem;
    color: #666;
    margin-top: 0.3rem;
}

/* 图片上传区域 */
.image-upload-area {
    border: 2px dashed #ddd;
    border-radius: 10px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #f8f9fa;
}

.image-upload-area:hover {
    border-color: #3498db;
    background: #f0f7ff;
}

.image-upload-area.dragover {
    border-color: #2ecc71;
    background: #f0fff4;
}

.upload-placeholder i {
    font-size: 3rem;
    color: #95a5a6;
    margin-bottom: 1rem;
}

.upload-placeholder p {
    margin: 0.5rem 0;
    color: #666;
}

.upload-hint {
    font-size: 0.9rem;
    color: #999;
}

.image-preview {
    position: relative;
    margin-top: 1rem;
}

#preview-image {
    max-width: 100%;
    max-height: 200px;
    border-radius: 8px;
    display: block;
    margin: 0 auto;
}

.btn-remove-image {
    position: absolute;
    top: 10px;
    right: 10px;
    background: rgba(231, 76, 60, 0.8);
    color: white;
    border: none;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-remove-image:hover {
    background: #c0392b;
}

/* 当前信息 */
.feedback-current-info {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 10px;
    margin: 1.5rem 0;
}

.feedback-current-info h5 {
    margin-bottom: 1rem;
    color: #2c3e50;
    display: flex;
    align-items: center;
    gap: 8px;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.info-item {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem;
    background: white;
    border-radius: 6px;
}

.info-item span {
    color: #666;
}

.info-item strong {
    color: #2c3e50;
}

/* 反馈操作按钮 */
.feedback-actions {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.btn-submit-feedback {
    flex: 1;
    padding: 1rem;
    background: #2ecc71;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.btn-cancel-feedback {
    flex: 1;
    padding: 1rem;
    background: #95a5a6;
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1.1rem;
}

.btn-submit-feedback:hover {
    background: #27ae60;
}

.btn-submit-feedback:disabled {
    background: #bdc3c7;
    cursor: not-allowed;
}

.btn-cancel-feedback:hover {
    background: #7f8c8d;
}

/* 帮助模态框 */
.help-content {
    max-height: 70vh;
    overflow-y: auto;
    padding-right: 1rem;
}

.help-section {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid #eee;
}

.help-section h5 {
    margin-bottom: 1rem;
    color: #2c3e50;
    display: flex;
    align-items: center;
    gap: 8px;
}

.help-section ul {
    list-style: none;
    padding-left: 1.5rem;
}

.help-section li {
    margin-bottom: 0.8rem;
    color: #555;
    display: flex;
    align-items: flex-start;
    gap: 8px;
}

.help-section li i {
    color: #2ecc71;
    margin-top: 0.2rem;
}

.help-contact {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 10px;
    margin-top: 2rem;
}

.help-contact h5 {
    margin-bottom: 1rem;
    color: #2c3e50;
    display: flex;
    align-items: center;
    gap: 8px;
}

.help-contact p {
    color: #666;
    line-height: 1.6;
    margin: 0.5rem 0;
}

/* 页脚样式 */
.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-left p {
    margin: 0.3rem 0;
    color: #666;
}

.footer-right {
    display: flex;
    gap: 1rem;
}

.btn-help, .btn-feedback-small {
    background: #95a5a6;
    color: white;
    border: none;
    padding: 0.6rem 1.2rem;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.btn-help:hover, .btn-feedback-small:hover {
    background: #7f8c8d;
}

/* 消息提示 */
.toast-message {
    position: fixed;
    top: 20px;
    right: 20px;
    background: #2ecc71;
    color: white;
    padding: 1rem 1.5rem;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    display: flex;
    align-items: center;
    gap: 10px;
    z-index: 1000;
    transform: translateX(100%);
    opacity: 0;
    transition: all 0.3s ease;
}

.toast-message.show {
    transform: translateX(0);
    opacity: 1;
}

.toast-message i {
    font-size: 1.5rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .header-top {
        flex-direction: column;
    }
    
    .user-section, .header-title {
        width: 100%;
        min-width: auto;
    }
    
    .login-form {
        flex-direction: column;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
    
    .login-actions, .feedback-actions {
        flex-direction: column;
    }
}
/* ====== 练习页面样式增强 ====== */

/* 知识点进度 */
.knowledge-progress {
    margin-left: auto;
    font-size: 0.9rem;
    padding: 0.2rem 0.5rem;
    border-radius: 10px;
    background: #f8f9fa;
    color: #666;
    transition: all 0.3s ease;
}

.knowledge-item.active .knowledge-progress {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

.knowledge-progress.progress-zero {
    background: #ffebee;
    color: #c62828;
}

.knowledge-progress.progress-good {
    background: #e8f5e9;
    color: #2e7d32;
}

.knowledge-progress.progress-complete {
    background: #c8e6c9;
    color: #1b5e20;
    font-weight: bold;
}

/* 练习模式选项 */
.practice-mode {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid #eee;
}

.mode-options {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    margin-top: 1rem;
}

.mode-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 0.8rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.mode-option:hover {
    background: #f8f9fa;
}

.mode-option input[type="radio"]:checked + span {
    font-weight: bold;
    color: #3498db;
}

.mode-option input[type="radio"]:checked ~ .mode-option {
    border-color: #3498db;
    background: #e3f2fd;
}

/* 练习操作按钮 */
.practice-actions {
    display: flex;
    gap: 10px;
    margin-top: 1.5rem;
}

.btn-reset {
    width: 100%;
    padding: 0.8rem;
    background: #e74c3c;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-reset:hover {
    background: #c0392b;
    transform: translateY(-2px);
}

/* 导航按钮增强 */
.btn-skip {
    padding: 0.8rem 1.5rem;
    background: #f39c12;
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.btn-skip:hover {
    background: #d68910;
    transform: translateY(-2px);
}

/* 控制按钮 */
.practice-controls {
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

.control-btn {
    padding: 0.6rem 1.2rem;
    background: #95a5a6;
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.control-btn:hover {
    background: #7f8c8d;
}

#jump-select {
    padding: 0.6rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    background: white;
    min-width: 200px;
}

/* 难题标记 */
.difficult-badge {
    background: #f39c12;
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 12px;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    margin-left: 10px;
}

/* 题目笔记 */
.question-note {
    margin: 1.5rem 0;
    padding: 1rem;
    background: #fffde7;
    border: 1px solid #ffeb3b;
    border-radius: 10px;
}

.note-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 0.8rem;
    color: #f57c00;
}

.note-content {
    line-height: 1.6;
    color: #333;
}

/* 反馈样式增强 */
.feedback-correct, .feedback-wrong {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.feedback-content {
    flex: 1;
}

/* 模态框样式 */
.note-content, .hint-content {
    max-height: 70vh;
    overflow-y: auto;
    padding-right: 1rem;
}

.note-header {
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #eee;
}

#note-text {
    width: 100%;
    padding: 1rem;
    border: 2px solid #ddd;
    border-radius: 10px;
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    margin-bottom: 1.5rem;
}

#note-text:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.note-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
}

.btn-save-note, .btn-cancel-note {
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
}

.btn-save-note {
    background: #2ecc71;
    color: white;
}

.btn-cancel-note {
    background: #95a5a6;
    color: white;
}

.btn-save-note:hover {
    background: #27ae60;
}

.btn-cancel-note:hover {
    background: #7f8c8d;
}

.hint-body {
    line-height: 1.6;
    margin: 1.5rem 0;
}

.hint-body ul {
    padding-left: 1.5rem;
    margin: 1rem 0;
}

.hint-body li {
    margin-bottom: 0.5rem;
}

.btn-close-hint {
    padding: 0.8rem 1.5rem;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    float: right;
}

.btn-close-hint:hover {
    background: #2980b9;
}

/* 消息提示 */
.toast-message {
    position: fixed;
    top: 20px;
    right: 20px;
    background: #2ecc71;
    color: white;
    padding: 1rem 1.5rem;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    display: flex;
    align-items: center;
    gap: 10px;
    z-index: 1000;
    transform: translateX(100%);
    opacity: 0;
    transition: all 0.3s ease;
}

.toast-message.show {
    transform: translateX(0);
    opacity: 1;
}

.toast-message i {
    font-size: 1.5rem;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .practice-container {
        grid-template-columns: 1fr;
    }
    
    .sidebar {
        order: 2;
    }
    
    .main-content {
        order: 1;
    }
}

@media (max-width: 768px) {
    .navigation {
        flex-wrap: wrap;
        gap: 1rem;
    }
    
    .navigation > * {
        flex: 1;
        min-width: 120px;
        justify-content: center;
    }
    
    .practice-controls {
        flex-direction: column;
    }
    
    .control-group {
        flex-direction: column;
        width: 100%;
    }
    
    #jump-select {
        width: 100%;
    }
    
    .practice-actions {
        flex-direction: column;
    }
    
    .mode-options {
        flex-direction: row;
        flex-wrap: wrap;
    }
    
    .mode-option {
        flex: 1;
        min-width: 120px;
        justify-content: center;
    }
}

/* 错题复习的列表样式增强 */
.question-text {
    max-width: 300px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.question-type-badge {
    padding: 0.2rem 0.6rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: bold;
}

.question-type-badge.单选题 {
    background: #e3f2fd;
    color: #1976d2;
}

.question-type-badge.填空题 {
    background: #f3e5f5;
    color: #7b1fa2;
}

.question-type-badge.判断题 {
    background: #e8f5e9;
    color: #388e3c;
}

/* 导出预览样式增强 */
#preview-content {
    white-space: pre-wrap;
    word-wrap: break-word;
    font-family: 'Courier New', monospace;
    font-size: 0.85rem;
    line-height: 1.4;
    max-height: 250px;
    overflow-y: auto;
    padding: 10px;
    background: white;
    border: 1px solid #ddd;
    border-radius: 5px;
}

/* 筛选器样式增强 */
.filter-group h4 {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 10px;
    color: #2c3e50;
}

/* 列表操作按钮样式 */
.list-actions {
    display: flex;
    gap: 10px;
    margin-bottom: 1rem;
}

.btn-action {
    padding: 0.6rem 1.2rem;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.btn-action:hover {
    background: #2980b9;
}

.btn-action#mark-understood {
    background: #2ecc71;
}

.btn-action#mark-understood:hover {
    background: #27ae60;
}

.btn-action#export-wrong {
    background: #f39c12;
}

.btn-action#export-wrong:hover {
    background: #d68910;
}

/* 加载中样式 */
.loading-cell {
    text-align: center;
    padding: 3rem !important;
    color: #666;
}

.loading-cell i {
    margin-right: 10px;
}