/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* 头部样式 */
header {
    background: white;
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

header h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 20px;
    font-size: 2.5em;
}

nav {
    display: flex;
    justify-content: center;
    gap: 10px;
}

.tab-btn {
    padding: 12px 24px;
    border: none;
    background: #f8f9fa;
    color: #6c757d;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.tab-btn:hover {
    background: #e9ecef;
    transform: translateY(-2px);
}

.tab-btn.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

/* 主要内容区域 */
main {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* 卡片样式 */
.card {
    background: #f8f9fa;
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 20px;
    border: 1px solid #e9ecef;
}

.card h2 {
    color: #2c3e50;
    margin-bottom: 20px;
    font-size: 1.8em;
    border-bottom: 2px solid #667eea;
    padding-bottom: 10px;
}

.card h3 {
    color: #495057;
    margin-bottom: 15px;
    font-size: 1.3em;
}

/* 上传区域样式 */
.upload-area {
    border: 2px dashed #dee2e6;
    border-radius: 8px;
    padding: 30px;
    text-align: center;
    margin-bottom: 20px;
    transition: all 0.3s ease;
    background: white;
}

.upload-area:hover {
    border-color: #667eea;
    background: #f8f9ff;
}

.upload-btn {
    display: inline-block;
    padding: 12px 24px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.upload-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.upload-btn .icon {
    margin-right: 8px;
    font-size: 1.2em;
}

.file-name, .file-names {
    margin-top: 15px;
    color: #6c757d;
    font-size: 14px;
}

/* 按钮样式 */
.action-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #6c757d;
    color: white;
}

.action-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.action-btn:disabled {
    background: #dee2e6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.action-btn.primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.action-btn.primary:hover:not(:disabled) {
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

/* 结果区域 */
.result-area {
    margin-top: 20px;
    padding: 20px;
    background: white;
    border-radius: 8px;
    border: 1px solid #dee2e6;
    min-height: 100px;
}

/* 题库列表样式 */
.library-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 15px;
    margin-top: 15px;
}

.library-item {
    background: white;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    padding: 15px;
    transition: all 0.3s ease;
    cursor: pointer;
}

.library-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    border-color: #667eea;
}

.library-item.selected {
    border-color: #667eea;
    border-width: 3px;
    background: linear-gradient(135deg, #f8f9ff 0%, #e8f0ff 100%);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.3);
    position: relative;
    transform: translateY(-3px);
}

.library-item.selected::before {
    content: "✓";
    position: absolute;
    top: 10px;
    right: 10px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 14px;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.4);
}

.library-item h4 {
    color: #2c3e50;
    margin-bottom: 8px;
}

.library-item p {
    color: #6c757d;
    font-size: 14px;
    margin-bottom: 5px;
}

.library-item .question-count {
    font-weight: bold;
    color: #667eea;
}

/* 练习设置样式 */
.practice-controls {
    margin-top: 20px;
    padding: 20px;
    background: white;
    border-radius: 8px;
    border: 1px solid #dee2e6;
}

.settings {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 20px;
}

.settings label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
}

.settings select {
    padding: 8px 12px;
    border: 1px solid #dee2e6;
    border-radius: 4px;
    font-size: 14px;
}

.random-count-setting {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.random-count-setting label {
    margin-bottom: 0;
    white-space: nowrap;
}

.number-input {
    width: 80px;
    padding: 8px 12px;
    border: 1px solid #dee2e6;
    border-radius: 4px;
    font-size: 14px;
}

.number-input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* 测验界面样式 */
.quiz-container {
    max-width: 800px;
    margin: 0 auto;
}

.quiz-header {
    margin-bottom: 30px;
}

.progress-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
    font-weight: 500;
    color: #6c757d;
}

.progress-bar {
    height: 8px;
    background: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
    width: 0%;
}

.question-card {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    border: 1px solid #dee2e6;
}

.question-meta {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.type-tag, .difficulty-tag {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.type-tag {
    background: #e3f2fd;
    color: #1976d2;
}

.difficulty-tag {
    background: #fff3e0;
    color: #f57c00;
}


.question-text {
    font-size: 1.2em;
    line-height: 1.6;
    margin-bottom: 25px;
    color: #2c3e50;
}

.options-container {
    margin-bottom: 25px;
}

.option-item {
    display: flex;
    align-items: flex-start;
    padding: 15px;
    margin-bottom: 10px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.option-item:hover {
    border-color: #667eea;
    background: #f8f9ff;
}

.option-item.selected {
    border-color: #667eea;
    background: #f8f9ff;
}

.option-item input[type="checkbox"],
.option-item input[type="radio"] {
    margin-right: 12px;
    margin-top: 2px;
}

.option-text {
    flex: 1;
    line-height: 1.5;
}

.question-actions {
    display: flex;
    justify-content: space-between;
    gap: 10px;
}

/* 解释样式 */
.explanation {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 20px;
    margin-top: 20px;
    border-left: 4px solid #667eea;
}

.explanation h4 {
    color: #2c3e50;
    margin-bottom: 10px;
}

.explanation p {
    color: #6c757d;
    line-height: 1.6;
}

/* 简答题样式 */
.short-answer-container {
    margin-bottom: 20px;
}

.short-answer-input {
    width: 100%;
    padding: 15px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 16px;
    line-height: 1.5;
    resize: vertical;
    min-height: 120px;
    font-family: inherit;
    transition: border-color 0.3s ease;
}

.short-answer-input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.short-answer-review {
    background: white;
    padding: 15px;
    border-radius: 8px;
    border-left: 4px solid #667eea;
}

.short-answer-review p {
    margin-bottom: 10px;
}

.short-answer-review p:last-child {
    margin-bottom: 0;
}

.short-answer-review strong {
    color: #2c3e50;
}

.review-item.short-answer-review-item {
    border-left-color: #17a2b8;
}

.review-item.ungraded {
    border-left-color: #ffc107;
}

/* 打分功能样式 */
.score-section {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #e9ecef;
}

.score-section p {
    margin-bottom: 10px;
    color: #2c3e50;
    font-weight: 500;
}

.score-options {
    display: flex;
    gap: 15px;
    margin-top: 10px;
}

.score-option {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 15px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
}

.score-option:hover {
    border-color: #667eea;
    background: #f8f9ff;
}

.score-option input[type="radio"] {
    margin: 0;
}

.score-option span {
    font-size: 14px;
    font-weight: 500;
    color: #495057;
}

.score-option input[type="radio"]:checked + span {
    color: #667eea;
}

/* 答案解析样式 */
.answer-review {
    background: white;
    padding: 15px;
    border-radius: 8px;
    border-left: 4px solid #667eea;
}

.answer-review p {
    margin-bottom: 10px;
}

.answer-review p:last-child {
    margin-bottom: 0;
}

.answer-review strong {
    color: #2c3e50;
}

.answer-review .correct {
    color: #28a745;
    font-weight: 500;
}

.answer-review .incorrect {
    color: #dc3545;
    font-weight: 500;
}

/* 判断题样式 */
.judgment-options {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
    justify-content: center;
}

.judgment-options .option-item {
    flex: 1;
    max-width: 200px;
    text-align: center;
    padding: 20px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
}

.judgment-options .option-item:hover {
    border-color: #667eea;
    background: #f8f9ff;
    transform: translateY(-2px);
}

.judgment-options .option-item.selected {
    border-color: #667eea;
    background: #f8f9ff;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.2);
}

.judgment-options .option-item input[type="radio"] {
    display: none;
}

.judgment-options .option-text {
    display: block;
    font-size: 18px;
    font-weight: 500;
    color: #2c3e50;
}

/* 结果页面样式 */
.result-container {
    max-width: 800px;
    margin: 0 auto;
}

.result-container h2 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 30px;
    font-size: 2em;
}

.score-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.score-item {
    background: white;
    border-radius: 8px;
    padding: 20px;
    text-align: center;
    border: 1px solid #dee2e6;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.score-label {
    display: block;
    color: #6c757d;
    font-size: 14px;
    margin-bottom: 8px;
}

.score-value {
    display: block;
    color: #2c3e50;
    font-size: 24px;
    font-weight: bold;
}

.result-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.review-container {
    background: white;
    border-radius: 8px;
    padding: 20px;
    border: 1px solid #dee2e6;
}

.review-container h3 {
    color: #2c3e50;
    margin-bottom: 20px;
}

.review-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.review-item {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 15px;
    border-left: 4px solid #dee2e6;
}

.review-item.correct {
    border-left-color: #28a745;
}

.review-item.incorrect {
    border-left-color: #dc3545;
}

.review-question {
    font-weight: 500;
    margin-bottom: 8px;
    color: #2c3e50;
}

.review-answer {
    display: flex;
    gap: 15px;
    font-size: 14px;
    color: #6c757d;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    header h1 {
        font-size: 2em;
    }
    
    .settings {
        flex-direction: column;
    }
    
    .random-count-setting {
        flex-direction: column;
        align-items: flex-start;
        gap: 5px;
    }
    
    .question-actions {
        flex-direction: column;
    }
    
    .result-actions {
        flex-direction: column;
    }
    
    .score-summary {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .library-list {
        grid-template-columns: 1fr;
    }
    
    .score-summary {
        grid-template-columns: 1fr;
    }
    
    .question-meta {
        flex-direction: column;
        gap: 5px;
    }
}

/* 历史分数样式 */
.history-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 15px;
}

.history-stats {
    color: #6c757d;
    font-size: 16px;
    font-weight: 500;
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-top: 15px;
}

.history-item {
    background: white;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    padding: 20px;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.history-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #e9ecef;
}

.history-date {
    color: #6c757d;
    font-size: 14px;
    font-weight: 500;
}

.delete-btn {
    background: #dc3545;
    color: white;
    border: none;
    border-radius: 4px;
    padding: 6px 12px;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.delete-btn:hover {
    background: #c82333;
    transform: translateY(-1px);
}

.history-content {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.history-score {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 5px;
}

.history-score .score-value {
    font-size: 24px;
    font-weight: bold;
    color: #28a745;
}

.history-details {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
    font-size: 14px;
    color: #6c757d;
}

.history-libraries,
.history-filters {
    font-size: 14px;
    color: #6c757d;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.history-libraries span,
.history-filters span {
    background: #f8f9fa;
    padding: 4px 8px;
    border-radius: 4px;
    border: 1px solid #e9ecef;
}

/* 响应式设计 - 历史分数 */
@media (max-width: 768px) {
    .history-controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .history-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .history-details {
        flex-direction: column;
        gap: 5px;
    }
    
    .history-score .score-value {
        font-size: 20px;
    }
}

/* 历史记录详情页面样式 */
.history-detail-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid #e9ecef;
}

.history-detail-header h2 {
    margin: 0;
    color: #2c3e50;
}

.history-detail-info {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 20px;
    border: 1px solid #e9ecef;
}

.info-row {
    display: flex;
    margin-bottom: 10px;
    align-items: center;
}

.info-row:last-child {
    margin-bottom: 0;
}

.info-label {
    font-weight: 500;
    color: #495057;
    min-width: 100px;
}

.info-value {
    color: #2c3e50;
    flex: 1;
}

.history-detail-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    margin-bottom: 25px;
}

.stat-item {
    background: white;
    border-radius: 8px;
    padding: 15px;
    text-align: center;
    border: 1px solid #dee2e6;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.stat-label {
    display: block;
    color: #6c757d;
    font-size: 14px;
    margin-bottom: 8px;
}

.stat-value {
    display: block;
    color: #2c3e50;
    font-size: 20px;
    font-weight: bold;
}

.history-detail-controls {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 20px;
    border: 1px solid #e9ecef;
}

.filter-controls {
    display: flex;
    gap: 20px;
    align-items: center;
    flex-wrap: wrap;
}

.filter-controls label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
}

.filter-controls select {
    padding: 8px 12px;
    border: 1px solid #dee2e6;
    border-radius: 4px;
    font-size: 14px;
}

.history-detail-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.history-detail-item {
    background: white;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.history-detail-item.correct {
    border-left: 4px solid #28a745;
}

.history-detail-item.incorrect {
    border-left: 4px solid #dc3545;
}

.history-detail-item.ungraded {
    border-left: 4px solid #ffc107;
}

.detail-question-number {
    font-weight: bold;
    color: #667eea;
    margin-bottom: 5px;
}

.detail-question-type {
    display: inline-block;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 500;
    background: #e3f2fd;
    color: #1976d2;
    margin-bottom: 10px;
}

.detail-question-text {
    font-size: 16px;
    line-height: 1.5;
    color: #2c3e50;
    margin-bottom: 15px;
    font-weight: 500;
}

.detail-answer-section {
    border-top: 1px solid #e9ecef;
    padding-top: 15px;
}

.detail-answer-row {
    display: flex;
    margin-bottom: 8px;
    align-items: flex-start;
}

.detail-answer-row:last-child {
    margin-bottom: 0;
}

.answer-label {
    font-weight: 500;
    color: #495057;
    min-width: 80px;
    flex-shrink: 0;
}

.answer-text {
    color: #2c3e50;
    flex: 1;
    word-break: break-word;
}

.answer-text.correct {
    color: #28a745;
    font-weight: 500;
}

.answer-text.incorrect {
    color: #dc3545;
    font-weight: 500;
}

.answer-text.ungraded {
    color: #ffc107;
    font-weight: 500;
}

.history-actions {
    display: flex;
    gap: 10px;
}

.view-btn {
    background: #17a2b8;
    color: white;
    border: none;
    border-radius: 4px;
    padding: 6px 12px;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.view-btn:hover {
    background: #138496;
    transform: translateY(-1px);
}

/* 响应式设计 - 历史记录详情 */
@media (max-width: 768px) {
    .history-detail-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .history-detail-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .filter-controls {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .info-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 5px;
    }
    
    .info-label {
        min-width: auto;
    }
    
    .detail-answer-row {
        flex-direction: column;
        gap: 5px;
    }
    
    .answer-label {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .history-detail-stats {
        grid-template-columns: 1fr;
    }
    
    .history-detail-item {
        padding: 15px;
    }
}

@media (max-width: 480px) {
    .history-item {
        padding: 15px;
    }
    
    .history-score .score-value {
        font-size: 18px;
    }
}

/* 错题练习样式 */
.wrong-questions-controls {
    margin-bottom: 20px;
}

.wrong-questions-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 15px;
}

.wrong-questions-stats span {
    color: #6c757d;
    font-size: 16px;
    font-weight: 500;
}

.wrong-practice-controls {
    margin-top: 20px;
    padding: 20px;
    background: white;
    border-radius: 8px;
    border: 1px solid #dee2e6;
}

.wrong-questions-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-top: 15px;
}

.wrong-question-item {
    background: white;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    padding: 20px;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
    border-left: 4px solid #dc3545;
}

.wrong-question-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.wrong-question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #e9ecef;
}

.wrong-question-number {
    font-weight: bold;
    color: #dc3545;
    font-size: 16px;
}

.wrong-question-actions {
    display: flex;
    gap: 10px;
}

.wrong-question-content {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.wrong-question-meta {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 10px;
}

.library-tag {
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 500;
    background: #e8f5e8;
    color: #28a745;
}

.wrong-question-text {
    font-size: 16px;
    line-height: 1.5;
    color: #2c3e50;
    margin-bottom: 10px;
    font-weight: 500;
}

.wrong-question-answer {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    margin-bottom: 8px;
}

.wrong-question-answer .answer-label {
    font-weight: 500;
    color: #495057;
    min-width: 80px;
    flex-shrink: 0;
}

.wrong-question-answer .answer-text {
    color: #2c3e50;
    flex: 1;
    word-break: break-word;
}

.wrong-question-answer .answer-text.correct {
    color: #28a745;
    font-weight: 500;
}

.wrong-question-answer .answer-text.incorrect {
    color: #dc3545;
    font-weight: 500;
}

.wrong-question-date {
    color: #6c757d;
    font-size: 12px;
    margin-top: 10px;
    text-align: right;
}

/* 错题详情模态框样式 */
.wrong-question-detail-modal .modal-content {
    background: white;
    border-radius: 12px;
    padding: 0;
    max-width: 800px;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.wrong-question-detail-modal .modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid #e9ecef;
}

.wrong-question-detail-modal .modal-header h3 {
    margin: 0;
    color: #2c3e50;
}

.wrong-question-detail-modal .close-btn {
    background: none;
    border: none;
    font-size: 24px;
    color: #6c757d;
    cursor: pointer;
    padding: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.3s ease;
}

.wrong-question-detail-modal .close-btn:hover {
    background: #f8f9fa;
    color: #dc3545;
}

.wrong-question-detail-modal .modal-body {
    padding: 20px;
}

/* 响应式设计 - 错题练习 */
@media (max-width: 768px) {
    .wrong-questions-stats {
        flex-direction: column;
        align-items: stretch;
    }
    
    .wrong-question-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .wrong-question-actions {
        align-self: stretch;
        justify-content: space-between;
    }
    
    .wrong-question-meta {
        flex-direction: column;
        gap: 5px;
    }
    
    .wrong-question-answer {
        flex-direction: column;
        gap: 5px;
    }
    
    .wrong-question-answer .answer-label {
        min-width: auto;
    }
}

/* 暂存练习样式 */
.saved-practice-controls {
    margin-bottom: 20px;
}

.saved-practice-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 15px;
}

.saved-practice-stats span {
    color: #6c757d;
    font-size: 16px;
    font-weight: 500;
}

.saved-practice-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-top: 15px;
}

.saved-practice-item {
    background: white;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    padding: 20px;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
    border-left: 4px solid #17a2b8;
}

.saved-practice-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.saved-practice-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #e9ecef;
}

.saved-practice-title {
    font-weight: bold;
    color: #2c3e50;
    font-size: 16px;
}

.saved-practice-actions {
    display: flex;
    gap: 10px;
}

.resume-btn {
    background: #17a2b8;
    color: white;
    border: none;
    border-radius: 4px;
    padding: 6px 12px;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.resume-btn:hover {
    background: #138496;
    transform: translateY(-1px);
}

.saved-practice-content {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.saved-practice-meta {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 10px;
}

.progress-tag {
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 500;
    background: #e8f5e8;
    color: #28a745;
}

.saved-practice-details {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
    font-size: 14px;
    color: #6c757d;
}

.saved-practice-details span {
    background: #f8f9fa;
    padding: 4px 8px;
    border-radius: 4px;
    border: 1px solid #e9ecef;
}

.saved-practice-date {
    color: #6c757d;
    font-size: 12px;
    margin-top: 10px;
    text-align: right;
}

/* 响应式设计 - 暂存练习 */
@media (max-width: 768px) {
    .saved-practice-stats {
        flex-direction: column;
        align-items: stretch;
    }
    
    .saved-practice-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .saved-practice-actions {
        align-self: stretch;
        justify-content: space-between;
    }
    
    .saved-practice-meta {
        flex-direction: column;
        gap: 5px;
    }
    
    .saved-practice-details {
        flex-direction: column;
        gap: 5px;
    }
}

@media (max-width: 480px) {
    .saved-practice-item {
        padding: 15px;
    }
}

@media (max-width: 480px) {
    .wrong-question-item {
        padding: 15px;
    }
    
    .wrong-question-detail-modal .modal-content {
        margin: 10px;
        max-width: calc(100% - 20px);
    }
}