:root {
    --primary-color: #1976d2;
    --secondary-color: #e3f2fd;
    --accent-color: #ff9800;
    --text-color: #333;
    --bg-color: #f5f5f5;
    --white: #fff;
    --border-radius: 8px;
    --shadow: 0 2px 5px rgba(0,0,0,0.1);
    --spacing: 20px;
    --spacing-small: 10px;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html, body {
    height: 100%;
    width: 100%;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1000px;
    width: 100%;
    margin: 0 auto;
    padding: var(--spacing);
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

header {
    text-align: center;
    margin-bottom: var(--spacing);
    display: flex;
    flex-direction: column;
    align-items: center;
}

h1, h2, h3, h4 {
    margin-bottom: 15px;
    color: var(--primary-color);
}

.progress-container {
    height: 8px;
    width: 100%;
    background-color: #ddd;
    border-radius: 4px;
    margin: 15px 0;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background-color: var(--primary-color);
    width: 0;
    transition: width 0.3s ease;
}

.timer {
    font-weight: bold;
    color: var(--accent-color);
}

main {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.question {
    background-color: var(--white);
    padding: var(--spacing);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing);
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.question-text {
    font-weight: 600;
    margin-bottom: 15px;
}

.options {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 15px;
}

.option {
    display: flex;
    padding: 10px 15px;
    background-color: var(--secondary-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.option:hover {
    background-color: #bbdefb;
    transform: translateY(-2px);
}

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

.reading-content {
    background-color: var(--white);
    padding: 15px;
    border-radius: var(--border-radius);
    margin-bottom: 15px;
    border-left: 4px solid var(--primary-color);
    overflow-y: auto;
    max-height: 300px;
}

.audio-container {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 15px;
}

.audio-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: transform 0.2s;
}

.audio-btn:hover {
    transform: scale(1.1);
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 600;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.primary-btn:hover {
    background-color: #1565c0;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.primary-btn:active {
    transform: translateY(0);
}

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

.nav-btn:hover {
    background-color: #bbdefb;
}

.navigation {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: var(--spacing) 0;
    flex-wrap: wrap;
    gap: 10px;
}

.pagination {
    display: flex;
    gap: 5px;
    flex-wrap: wrap;
    justify-content: center;
    max-width: 100%;
    overflow-x: auto;
    padding: 5px 0;
}

/* 分页按钮样式 */
.page-btn {
    margin: 0 2px;
    padding: 5px 0;
    min-width: 35px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid #ccc;
    background-color: #fff;
    cursor: pointer;
    border-radius: 3px;
    transition: all 0.2s;
}

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

.page-btn.active {
    border-color: #1976d2;
    font-weight: bold;
    background-color: #fff; /* 当前题目使用白色背景 */
    box-shadow: 0 0 0 2px rgba(25, 118, 210, 0.3);
}

.page-btn.answered {
    background-color: rgba(76, 175, 80, 0.2); /* 淡绿色背景 - 已回答 */
}

.page-btn.unanswered {
    background-color: rgba(255, 152, 0, 0.2); /* 淡桔色背景 - 未回答 */
}

.submit-container {
    text-align: center;
    margin: var(--spacing) 0;
    display: flex;
    justify-content: center;
}

.results-container {
    background-color: var(--white);
    padding: var(--spacing);
    border-radius: var(--border-radius);
    margin: var(--spacing) 0;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
}

.score-overview {
    display: flex;
    flex-direction: column;
    gap: var(--spacing);
    margin-bottom: var(--spacing);
}

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

.chart-container {
    height: 300px;
    margin-bottom: var(--spacing);
    width: 100%;
}

.detailed-results {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing);
}

.category-result {
    margin-bottom: 15px;
    padding: 15px;
    background-color: var(--secondary-color);
    border-radius: var(--border-radius);
    transition: transform 0.2s;
}

.category-result:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
}

.stars {
    color: var(--accent-color);
    font-size: 20px;
    margin: 5px 0;
}

.overall-feedback {
    margin: var(--spacing) 0;
    padding: 15px;
    background-color: var(--secondary-color);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
}

footer {
    text-align: center;
    margin-top: var(--spacing);
    padding: var(--spacing-small);
    color: #666;
}

.hidden {
    display: none;
}

.start-screen {
    text-align: center;
    padding: 30px;
    background-color: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    gap: 15px;
    align-items: center;
}

/* 导航按钮图标样式 */
.nav-btn-prev::before,
.nav-btn-next::before {
    content: '';
    display: inline-block;
    width: 12px;
    height: 12px;
    border-style: solid;
    border-width: 3px 3px 0 0;
    vertical-align: middle;
}

.nav-btn-prev::before {
    transform: rotate(-135deg); /* 左箭头 */
    margin-right: -4px; /* 微调位置 */
}

.nav-btn-next::before {
    transform: rotate(45deg); /* 右箭头 */
    margin-left: -4px; /* 微调位置 */
}

/* 确保按钮有足够的宽度容纳图标 */
.nav-btn {
    min-width: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* 子问题样式增强 */
.sub-question {
    margin-bottom: 20px;
    padding: 15px;
    border-left: 3px solid var(--primary-color);
    background-color: rgba(227, 242, 253, 0.3);
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
}

/* 响应式设计 */
@media (max-width: 900px) {
    :root {
        --spacing: 15px;
    }

    .container {
        max-width: 100%;
    }

    .detailed-results {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    :root {
        --spacing: 12px;
        --spacing-small: 8px;
    }

    .container {
        padding: var(--spacing-small);
    }

    .navigation {
        flex-direction: column;
    }

    .pagination {
        order: -1;
        margin-bottom: 10px;
        padding: 0;
    }

    .question {
        padding: 15px;
    }

    .reading-content {
        max-height: 250px;
    }
}

/* 增强页底题号和提交按钮在大屏手机上的可用性 */
@media (min-width: 481px) and (max-width: 768px) {
    /* 大屏手机特别优化 */
    .page-btn {
        min-width: 42px;
        height: 42px;
        font-size: 1.1rem;
        font-weight: 500;
    }

    .submit-container .primary-btn {
        padding: 12px 30px;
        font-size: 1.2rem;
        min-height: 50px;
    }

    /* 确保按钮间距合适 */
    .pagination {
        gap: 8px;
    }
}

/* 调整所有移动设备的按钮样式 */
@media (max-width: 768px) {
    .submit-container {
        padding: 5px 0 15px 0;
    }

    .submit-container .primary-btn {
        width: auto;
        min-width: 200px;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing: 10px;
        --spacing-small: 5px;
    }

    h1 {
        font-size: 1.5rem;
    }

    .question {
        padding: 12px;
    }

    .option {
        padding: 8px 12px;
    }

    .btn {
        padding: 8px 16px;
        width: 100%;
    }

    .page-btn {
        min-width: 32px;
        height: 32px;
        padding: 0;
        font-size: 1rem;
    }

    .submit-container .primary-btn {
        padding: 10px 20px;
        font-size: 1.1rem;
    }

    .reading-content {
        max-height: 200px;
        padding: 10px;
    }

    .audio-container {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* 触摸屏优化 */
@media (hover: none) {
    .option:hover {
        transform: none;
    }

    .page-btn:hover {
        transform: none;
    }

    .btn:hover {
        transform: none;
    }

    .category-result:hover {
        transform: none;
    }

    /* 增强触屏设备的按钮点击体验 */
    .page-btn:active {
        transform: scale(0.95);
    }

    .btn:active {
        transform: scale(0.98);
    }
}