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

:root {
    --primary-color: #4a90e2;
    --primary-dark: #357abd;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-color: #333333;
    --text-light: #666666;
    --border-color: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

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

/* ===== 头部样式 ===== */
.header {
    text-align: center;
    padding: 40px 0;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    border-radius: 12px;
    margin-bottom: 30px;
    position: relative;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

.header .btn-small {
    position: absolute;
    top: 20px;
    left: 20px;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

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

/* ===== 卡片样式 ===== */
.card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
    transition: box-shadow 0.3s ease;
}

.card:hover {
    box-shadow: var(--shadow-hover);
}

.card h2 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

/* ===== 按钮样式 ===== */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.3s ease;
    text-align: center;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background-color: #5a6268;
}

.btn-success {
    background-color: var(--success-color);
    color: white;
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.875rem;
}

.btn-large {
    padding: 16px 32px;
    font-size: 1.125rem;
}

/* ===== 首页样式 ===== */
.test-selection {
    margin-bottom: 30px;
}

.test-selection label {
    font-weight: 600;
    margin-right: 10px;
}

.test-selection select {
    padding: 10px 20px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    background: white;
    cursor: pointer;
}

.part-selection {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.part-selection .btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 30px 20px;
}

.part-number {
    font-size: 2rem;
    font-weight: bold;
    margin-bottom: 10px;
}

.part-name {
    font-size: 1rem;
    opacity: 0.9;
}

/* ===== 信息卡片样式 ===== */
.info-card {
    background: #e3f2fd;
    border-left: 4px solid var(--primary-color);
    padding: 15px 20px;
    margin-bottom: 20px;
    border-radius: 8px;
}

.info-card p {
    margin: 0;
    color: var(--text-color);
}

/* ===== 可点击文本样式 ===== */
.clickable-text .word {
    cursor: pointer;
    padding: 2px 4px;
    border-radius: 4px;
    transition: background-color 0.2s;
    display: inline-block;
}

.clickable-text .word:hover {
    background-color: #e3f2fd;
    color: var(--primary-color);
}

/* ===== 考试页面样式 ===== */
.exam-content {
    max-width: 900px;
    margin: 0 auto;
}

.passage-container {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: var(--shadow);
}

.passage-title {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 20px;
    color: var(--primary-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 10px;
}

.passage-content {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 8px;
    cursor: pointer;
    user-select: text;
    white-space: pre-wrap; /* 保留换行符 */
    word-wrap: break-word; /* 自动换行 */
}

/* Part 6 文章文本样式 */
.passage-text {
    background: var(--background);
    padding: 15px;
    border-radius: 8px;
    line-height: 1.8;
    font-size: 1.1rem;
    margin-top: 10px;
    margin-bottom: 20px;
    white-space: pre-wrap; /* 保留换行符 */
    word-wrap: break-word; /* 自动换行 */
}

.passage-content .word {
    cursor: pointer;
    padding: 2px 4px;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.passage-content .word:hover {
    background-color: #e3f2fd;
}

.questions-container {
    margin-top: 30px;
}

.question-item {
    padding: 20px;
    margin-bottom: 20px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    transition: all 0.3s ease;
}

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

.question-item.answered {
    border-color: var(--success-color);
    background-color: #f0fff4;
}

.question-item.incorrect {
    border-color: var(--danger-color);
    background-color: #fff5f5;
}

.question-number {
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.question-text {
    font-size: 1.1rem;
    margin-bottom: 15px;
}

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

.option {
    display: flex;
    align-items: center;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.option:hover {
    border-color: var(--primary-color);
    background-color: #f0f7ff;
}

.option.selected {
    border-color: var(--primary-color);
    background-color: #e3f2fd;
}

.option.correct {
    border-color: var(--success-color);
    background-color: #d4edda;
}

.option.incorrect {
    border-color: var(--danger-color);
    background-color: #f8d7da;
}

.option input[type="radio"] {
    margin-right: 10px;
}

.option-label {
    font-weight: 600;
    margin-right: 10px;
    min-width: 25px;
}

.answer-feedback {
    margin-top: 15px;
    padding: 15px;
    border-radius: 8px;
    display: none;
}

.answer-feedback.show {
    display: block;
}

.answer-feedback.correct {
    background-color: #d4edda;
    color: #155724;
}

.answer-feedback.incorrect {
    background-color: #f8d7da;
    color: #721c24;
}

.exam-actions {
    text-align: center;
    margin: 40px 0;
}

/* 单题提交按钮样式 */
.submit-question-btn {
    margin-top: 15px;
    padding: 8px 20px;
    font-size: 0.9rem;
}

.submit-question-btn.submitted {
    background-color: var(--success-color);
    cursor: not-allowed;
}

/* 已禁用题目的样式 */
.question-item.answered .option,
.question-item.incorrect .option {
    opacity: 0.8;
}

/* 文章提交按钮样式 */
.submit-passage-btn {
    margin-top: 20px;
    padding: 10px 30px;
    font-size: 1rem;
    display: block;
    width: 100%;
    max-width: 300px;
    margin-left: auto;
    margin-right: auto;
}

.submit-passage-btn.submitted {
    background-color: var(--success-color);
    cursor: not-allowed;
}

/* ===== 弹窗样式 ===== */
.word-popup,
.translation-popup {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.word-popup.hidden,
.translation-popup.hidden {
    display: none;
}

.popup-content {
    background: white;
    padding: 30px;
    border-radius: 12px;
    max-width: 400px;
    width: 90%;
    text-align: center;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.popup-content h4 {
    margin-bottom: 15px;
    color: var(--primary-color);
}

.popup-content p {
    font-size: 1.2rem;
    margin-bottom: 20px;
    word-break: break-all;
}

.popup-content .btn {
    margin: 5px;
}

/* ===== 生词本样式 ===== */
.vocabulary-content {
    max-width: 800px;
    margin: 0 auto;
}

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

.vocab-item {
    background: var(--card-bg);
    padding: 20px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.vocab-word {
    font-size: 1.3rem;
    font-weight: bold;
    color: var(--primary-color);
}

.vocab-translation {
    color: var(--text-light);
    margin-top: 5px;
}

.vocab-context {
    font-size: 0.9rem;
    color: var(--secondary-color);
    margin-top: 5px;
    font-style: italic;
}

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

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-light);
}

.empty-state p {
    font-size: 1.2rem;
    margin-bottom: 20px;
}

/* ===== 页脚样式 ===== */
.footer {
    text-align: center;
    padding: 20px;
    color: var(--text-light);
    margin-top: 40px;
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .header h1 {
        font-size: 1.8rem;
    }
    
    .part-selection {
        grid-template-columns: 1fr;
    }
    
    .passage-container {
        padding: 20px;
    }
    
    .vocab-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }
}

/* ===== 图片内容样式 ===== */
.passage-image {
    margin: 10px 0 20px 0;
    text-align: center;
}

.passage-img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

/* ===== 动画效果 ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.passage-container,
.question-item,
.vocab-item {
    animation: fadeIn 0.3s ease;
}