/* 全局样式设置 */
body {
    margin: 0;
    padding: 0;
    font-family: 'Open Sans', sans-serif; /* 正文字体 */
    background: linear-gradient(135deg, #4CAF50, #1976D2); /* 背景渐变，从绿色到深蓝 */
    color: #333333; /* 全局文字颜色 */
    line-height: 1.6;
    overflow-x: hidden; /* 防止左右滚动条出现 */
}

/* 导航栏样式 */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(25, 118, 210, 0.9); /* 半透明深蓝色 */
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1); /* 阴影效果 */
    z-index: 1000;
    padding: 20px 0;
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    margin: 0;
    padding: 0;
}

nav li {
    margin: 0 20px;
}

nav a {
    color: #E0E0E0; /* 链接颜色为银灰色 */
    text-decoration: none;
    font-weight: bold;
    font-size: 18px; /* 链接字体大小 */
    transition: color 0.3s ease;
}

nav a:hover {
    color: #FFFFFF; /* 悬停时颜色变为白色 */
}

/* 章节导航系统样式 */
.section-nav {
    position: fixed;
    top: 80px; /* 导航栏下方 */
    right: 20px;
    background-color: rgba(255, 255, 255, 0.8); /* 半透明白色背景 */
    padding: 10px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.section-nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.section-nav li {
    margin: 10px 0;
}

.section-nav a {
    color: #1976D2; /* 深蓝色 */
    text-decoration: none;
    font-size: 16px;
    transition: color 0.3s ease;
}

.section-nav a:hover {
    color: #4CAF50; /* 悬停时颜色变为绿色 */
}

/* 主内容区样式 */
.container {
    max-width: 1200px;
    margin: 140px auto 60px; /* 顶部留出导航栏和章节导航 */
    padding: 0 20px;
    display: flex;
    flex-direction: column;
    gap: 40px; /* 各段落之间的间距 */
}

.section {
    background-color: rgba(255, 255, 255, 0.9); /* 半透明白色背景 */
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    animation: fadeIn 1s ease-out forwards;
    opacity: 0;
    transform: translateY(20px);
}

.section.visible {
    opacity: 1;
    transform: translateY(0);
}

.section h2, .section h3, .section h4 {
    color: #1976D2; /* 深蓝色标题 */
    margin-bottom: 20px;
}

.section p {
    font-size: 16px;
    color: #555555;
    line-height: 1.8;
}

.section pre {
    background-color: #f5f5f5;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin-top: 20px;
    margin-bottom: 20px;
}

.section code {
    font-family: 'Courier New', Courier, monospace;
    background-color: #e0e0e0;
    padding: 2px 4px;
    border-radius: 4px;
}

/* 图片样式 */
.section img {
    width: 100%;
    max-width: 320px;
    height: auto;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.section img:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 12px rgba(0,0,0,0.2);
}

/* 卡片式布局 */
.card-container {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
}

.card {
    background-color: #FFFFFF;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    flex: 1 1 calc(33.333% - 20px);
    padding: 20px;
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.2);
}

.card img {
    width: 100%;
    border-radius: 8px;
    margin-bottom: 15px;
}

.card h3 {
    font-size: 18px;
    color: #1976D2;
    margin-bottom: 10px;
}

.card p {
    font-size: 15px;
    color: #555555;
}

/* 数据展示区样式 */
.chart {
    width: 100%;
    height: 400px;
    position: relative;
}

.tooltip {
    position: absolute;
    background-color: rgba(0, 0, 0, 0.7);
    color: #FFFFFF;
    padding: 10px;
    border-radius: 4px;
    opacity: 0;
    transition: opacity 0.3s;
}

.bar:hover + .tooltip {
    opacity: 1;
}

/* 轮播图样式 */
.carousel {
    position: relative;
    overflow: hidden;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

.carousel-track {
    display: flex;
    transition: transform 0.5s ease-in-out;
}

.carousel-slide {
    min-width: 100%;
    box-sizing: border-box;
}

.carousel-slide img {
    width: 100%;
    border-radius: 8px;
}

.carousel-button {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background-color: rgba(25, 118, 210, 0.7);
    border: none;
    color: #FFFFFF;
    padding: 10px;
    cursor: pointer;
    border-radius: 50%;
}

.carousel-button.prev {
    left: 10px;
}

.carousel-button.next {
    right: 10px;
}

/* 页脚样式 */
.footer {
    background-color: rgba(25, 118, 210, 0.9);
    color: #E0E0E0;
    padding: 40px 20px;
    text-align: center;
    font-family: 'Open Sans', sans-serif;
}

.footer a {
    color: #FFFFFF;
    margin: 0 10px;
    text-decoration: none;
    font-size: 16px;
    transition: text-decoration 0.3s;
}

.footer a:hover {
    text-decoration: underline;
}

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

@media (max-width: 1024px) {
    .card {
        flex: 1 1 calc(50% - 20px);
    }
}

@media (max-width: 768px) {
    nav ul {
        flex-direction: column;
        align-items: center;
    }

    nav li {
        margin: 10px 0;
    }

    .section-nav {
        position: static;
        width: 100%;
        margin: 20px 0;
    }

    .card {
        flex: 1 1 100%;
    }
}