/* 
  主题颜色变量定义
  主色调：深蓝色 (#0D2C54) 表现专业与科技感
  辅助色：灰色 (#F1F3F5) 提供中立背景，避免视觉杂乱
  点缀色：
    橙色 (#FF9800) 用于按钮和链接，突出关键操作
    绿色 (#8BC34A) 用于次要按钮和高亮元素，增加活力
*/

/* 根元素设置，方便全局变量应用 */
:root {
    --primary-color: #0D2C54; /* 主色调深蓝 */
    --secondary-color: #F1F3F5; /* 辅助色灰 */
    --accent-orange: #FF9800; /* 点缀色橙 */
    --accent-green: #8BC34A; /* 点缀色绿 */
    --text-color: #333333; /* 正文字体颜色 */
    --background-gradient: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-green) 100%);
}

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

/* 设置网页背景，避免纯白色，采用渐变色增强科技感 */
body {
    background: var(--secondary-color);
    color: var(--text-color);
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    font-size: 16px;
}

/* 导航栏样式 */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--primary-color);
    padding: 20px 40px;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.navbar .logo {
    font-size: 1.8rem;
    color: #ffffff;
    text-decoration: none;
}

.navbar .nav-links {
    display: flex;
    gap: 20px;
}

.navbar .nav-links a {
    color: #ffffff;
    text-decoration: none;
    font-size: 1rem;
    position: relative;
    transition: color 0.3s ease;
}

.navbar .nav-links a::after {
    content: '';
    display: block;
    width: 0%;
    height: 2px;
    background-color: var(--accent-orange);
    transition: width 0.3s;
    position: absolute;
    bottom: -5px;
    left: 0;
}

.navbar .nav-links a:hover::after {
    width: 100%;
}

.navbar .nav-links a:hover {
    color: var(--accent-orange);
}

/* 主视觉区样式 */
.hero-section {
    background: var(--background-gradient);
    color: #ffffff;
    padding: 150px 40px 100px;
    text-align: center;
    position: relative;
    margin-top: 80px; /* 避免导航栏覆盖 */
}

.hero-section h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.hero-section p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    margin-bottom: 40px;
}

.hero-section .cta-button {
    background-color: var(--accent-orange);
    color: #ffffff;
    border: none;
    padding: 15px 30px;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.3s ease;
}

.hero-section .cta-button:hover {
    background-color: var(--accent-green);
    transform: scale(1.05);
}

/* 功能模块展示区 */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    padding: 60px 40px;
    background-color: var(--secondary-color);
}

.feature-card {
    background-color: #ffffff;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    padding: 30px 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 24px rgba(0,0,0,0.15);
}

.feature-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.feature-card p {
    color: #666666;
    font-size: 1rem;
}

/* 客户评价区 */
.testimonial-section {
    padding: 60px 40px;
    background: radial-gradient(circle at top left, var(--accent-green), transparent 70%);
}

.testimonial-section h2 {
    text-align: center;
    margin-bottom: 40px;
    font-size: 2rem;
    color: var(--primary-color);
}

.testimonial-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.testimonial-card {
    background-color: #ffffff;
    border-left: 5px solid var(--accent-orange);
    padding: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: border-color 0.3s, box-shadow 0.3s;
}

.testimonial-card:hover {
    border-color: var(--accent-green);
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

.testimonial-card p {
    color: #555555;
    font-size: 1rem;
    margin-bottom: 10px;
}

.testimonial-card .author {
    font-weight: bold;
    color: var(--primary-color);
}

/* 底部信息 */
.footer {
    background-color: var(--primary-color);
    color: #ffffff;
    padding: 40px;
    text-align: center;
}

.footer a {
    color: var(--accent-orange);
    text-decoration: none;
    margin: 0 10px;
}

.footer a:hover {
    color: var(--accent-green);
}

/* 响应式图片样式 */
.image-responsive {
    width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.image-responsive:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

/* 图文排版 */
.article-content {
    padding: 60px 40px;
    max-width: 1200px;
    margin: 0 auto;
}

.article-content h2, .article-content h3, .article-content h4 {
    color: var(--primary-color);
    margin-bottom: 20px;
}

.article-content p {
    margin-bottom: 20px;
    font-size: 1rem;
    color: #555555;
}

.article-content pre {
    background-color: #f5f5f5;
    padding: 15px;
    border-radius: 5px;
    overflow-x: auto;
    margin-bottom: 20px;
}

.article-content code {
    background-color: #e8e8e8;
    padding: 2px 4px;
    border-radius: 3px;
}

.article-content a {
    color: var(--accent-orange);
    text-decoration: none;
}

.article-content a:hover {
    color: var(--accent-green);
}

/* 折叠区域 */
.collapsible {
    background-color: #ffffff;
    color: var(--primary-color);
    cursor: pointer;
    padding: 18px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 1rem;
    transition: background-color 0.3s;
    border-radius: 5px;
    margin-bottom: 10px;
}

.collapsible:hover {
    background-color: #f1f1f1;
}

.collapsible:after {
    content: '\002B'; /* 加号符号 */
    font-size: 1.2rem;
    float: right;
}

.collapsible.active:after {
    content: "\2212"; /* 减号符号 */
}

.content {
    padding: 0 18px;
    display: none;
    overflow: hidden;
    background-color: #f9f9f9;
    border-radius: 5px;
    margin-bottom: 20px;
}

/* 章节导航样式 */
.chapter-nav {
    position: fixed;
    top: 100px;
    right: 20px;
    background-color: rgba(13, 44, 84, 0.9);
    padding: 20px;
    border-radius: 8px;
    z-index: 500;
}

.chapter-nav h3 {
    color: #ffffff;
    margin-bottom: 10px;
    font-size: 1.2rem;
}

.chapter-nav ul {
    list-style: none;
}

.chapter-nav ul li {
    margin-bottom: 10px;
}

.chapter-nav ul li a {
    color: #ffffff;
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s;
}

.chapter-nav ul li a:hover {
    color: var(--accent-orange);
}

/* CSS3代码示例样式 */
.css-sample {
    background-color: #2d2d2d;
    color: #f8f8f2;
    padding: 20px;
    border-radius: 5px;
    overflow-x: auto;
    font-family: 'Courier New', Courier, monospace;
    margin-bottom: 20px;
}

.css-sample ::selection {
    background: var(--accent-green);
}

.css-sample code {
    color: #f8f8f2;
}

/* 动画与过渡效果 */
@keyframes flow {
    0% { background-position: 0% 50%; }
    100% { background-position: 100% 50%; }
}

/* 数据可视化图表容器 */
.chart-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    padding: 40px;
    background-color: #ffffff;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.chart-container .chart {
    background-color: var(--secondary-color);
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}