/* =========================
   全局 Reset
========================= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* =========================
   页面基础样式
========================= */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
        Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.8;
    color: #333;
    background-color: #f5f5f5;
}

/* =========================
   布局容器
========================= */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 20px;
    background-color: #fff;
    min-height: 100vh;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

/* =========================
   标题
========================= */
h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 2px solid #3498db;
    font-size: 2em;
}

h2 {
    color: #2c3e50;
    margin: 30px 0 15px;
    font-size: 1.5em;
}

h3 {
    color: #34495e;
    margin: 20px 0 10px;
    font-size: 1.2em;
}

/* =========================
   文本
========================= */
p {
    margin: 15px 0;
    text-align: justify;
}

.red-text {
    color: #e74c3c;
    font-weight: bold;
}

/* =========================
   图片
========================= */
.doc-image {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 10px 0;
    border: 1px solid #ddd;
    border-radius: 4px;
    padding: 5px;
}
.doc-image {
    cursor: zoom-in;
}
.image-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-start;
    align-items: flex-start;
    gap: 15px;
    margin: 20px 0;
}

.image-grid .doc-image {
    width: calc(33.33% - 10px);
    max-width: 280px;
    height: auto;
}

/* =========================
   返回链接
========================= */
.back-link {
    display: inline-block;
    margin-bottom: 30px;
    color: #3498db;
    text-decoration: none;
    font-size: 16px;
}

.back-link:hover {
    text-decoration: underline;
}

.bottom-back-link {
    display: block;
    text-align: right;
    margin-bottom: 30px;
    color: #3498db;
    text-decoration: none;
    font-size: 16px;
}

.bottom-back-link:hover {
    text-decoration: underline;
}
/* =========================
   目录 TOC
========================= */
.toc {
    list-style: none;
    padding: 0;
}

.toc li {
    margin: 15px 0;
}

.toc a {
    display: block;
    padding: 15px 20px;
    background-color: #f8f9fa;
    border-left: 4px solid #3498db;
    color: #2c3e50;
    text-decoration: none;
    font-size: 18px;
    transition: all 0.3s ease;
}

.toc a:hover {
    background-color: #e8f4f8;
    border-left-color: #2980b9;
    padding-left: 30px;
}

/* =========================
   列表
========================= */
ul,
ol {
    margin: 15px 0 15px 30px;
}

li {
    margin: 8px 0;
}