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

/* 设定基础字体与背景色 */
body {
    font-family: 'Roboto', sans-serif;
    color: #FFFFFF;
    background: linear-gradient(135deg, #1E3A8A, #6B7280);
    line-height: 1.6;
    overflow-x: hidden;
}

/* 容器样式，采用响应式网格布局 */
.container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 40px;
    padding: 60px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

/* 头部导航栏样式 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(30, 58, 138, 0.9);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 30px;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

/* 导航菜单样式 */
.navbar .menu {
    display: flex;
    gap: 20px;
}

.navbar .menu a {
    color: #FFFFFF;
    text-decoration: none;
    font-size: 16px;
    transition: color 0.3s ease;
}

.navbar .menu a:hover {
    color: #56AFFF;
}

/* 移动设备下菜单图标 */
.navbar .menu-icon {
    display: none;
    cursor: pointer;
}

@media (max-width: 768px) {
    .navbar .menu {
        display: none;
    }

    .navbar .menu-icon {
        display: block;
    }
}

/* 主标题样式 */
.header-title {
    text-align: center;
    padding: 100px 20px 20px 20px; /* 考虑到固定导航栏的高度 */
    font-size: 2.5em;
    font-weight: 700;
    color: #FFFFFF;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

/* 文章内容样式 */
article {
    background: rgba(30, 58, 138, 0.8);
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

/* 文章标题样式 */
article h2, article h3 {
    color: #56AFFF;
    margin-bottom: 20px;
}

article h2 {
    font-size: 2em;
}

article h3 {
    font-size: 1.5em;
}

/* 段落样式 */
article p {
    font-size: 17px;
    margin-bottom: 20px;
    color: #FFFFFF;
}

/* 代码块样式 */
article pre {
    background: #1E3A8A;
    padding: 20px;
    border-radius: 5px;
    overflow: auto;
    position: relative;
}

article pre code {
    color: #F97316;
    font-family: 'Courier New', Courier, monospace;
    white-space: pre-wrap;
    display: block;
    overflow: visible; /* 防止::before被遮挡 */
}

article pre code::before {
    content: 'CSS3 示例代码';
    display: block;
    font-weight: bold;
    margin-bottom: 10px;
    color: #56AFFF;
}

/* 图片样式 */
.image-gallery {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
}

.image-gallery img {
    width: 100%;
    max-width: 300px;
    height: auto;
    border-radius: 15px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-gallery img:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 15px rgba(0,0,0,0.5);
}

/* 回顶部按钮样式 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: #F97316;
    color: #fff;
    padding: 10px 15px;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    transition: background-color 0.3s ease, transform 0.3s ease;
    z-index: 1000;
}

.back-to-top:hover {
    background-color: #56AFFF;
    transform: scale(1.1);
}

/* 提示信息样式 */
.prompt-message {
    text-align: center;
    font-size: 1.2em;
    color: #F97316;
    margin-bottom: 40px;
}

/* 动画加载器样式 */
.loader {
    border: 8px solid #f3f3f3;
    border-top: 8px solid #56AFFF;
    border-radius: 50%;
    width: 60px;
    height: 60px;
    animation: spin 1s linear infinite;
    margin: 50px auto;
}

/* 旋转动画关键帧 */
@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* 响应式调整 */
@media (max-width: 768px) {
    .header-title {
        font-size: 2em;
        padding: 80px 20px 20px 20px;
    }

    article {
        padding: 20px;
    }

    .image-gallery img {
        max-width: 100%;
    }
}

/* 模块化设计样式 */
.module {
    padding: 40px 20px;
    background-color: rgba(30, 58, 138, 0.9);
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    transition: background-color 0.3s ease, transform 0.3s ease;
}

.module:hover {
    background-color: rgba(86, 175, 255, 0.9);
    transform: translateY(-10px);
}

.module__title {
    font-size: 1.8em;
    margin-bottom: 15px;
    color: #F97316;
}

.module__content {
    font-size: 1em;
    color: #FFFFFF;
}

/* 折叠区域样式 */
.collapsible {
    background-color: rgba(30, 58, 138, 0.8);
    color: #FFFFFF;
    cursor: pointer;
    padding: 18px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 1.2em;
    transition: background-color 0.3s ease;
    border-radius: 5px;
}

.collapsible:hover {
    background-color: rgba(86, 175, 255, 0.8);
}

.collapsible:after {
    content: '\002B';
    color: #FFFFFF;
    float: right;
    margin-left: 5px;
}

.collapsible.active:after {
    content: "\2212";
}

.content {
    padding: 0 18px;
    display: none;
    overflow: hidden;
    background-color: rgba(30, 58, 138, 0.6);
    border-radius: 0 0 5px 5px;
}