/* 全局重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
    line-height: 1.8;
    color: #333;
    background: #f5f5f5;
    font-size: 16px;
}

/* 容器 - 居中显示 */
.container {
    max-width: 900px;
    margin: 0 auto;
    background: #fff;
    min-height: 100vh;
}

/* 主内容区 - 居中 */
main {
    padding: 40px;
    text-align: center;
}

/* 标题 - 居中 */
h2 {
    font-size: 24px;
    font-weight: 600;
    color: #1a1a1a;
    margin: 30px auto 16px;
    padding-bottom: 10px;
    border-bottom: 2px solid #e0e0e0;
    text-align: center;
    max-width: 800px;
}

h3 {
    font-size: 20px;
    font-weight: 600;
    color: #333;
    margin: 24px auto 12px;
    text-align: center;
}

h4 {
    font-size: 18px;
    font-weight: 600;
    color: #333;
    margin: 20px auto 10px;
    text-align: center;
}

/* 段落 - 居中 */
p {
    margin: 12px auto;
    color: #333;
    text-align: center;
    max-width: 800px;
    font-size: 16px;
    line-height: 1.8;
}

/* 超链接 */
a {
    color: #1a73e8;
    text-decoration: none;
    border-bottom: 1px solid #1a73e8;
    transition: all 0.2s;
}

a:hover {
    color: #0d47a1;
    border-bottom-color: #0d47a1;
}

/* 加粗 */
strong {
    font-weight: 600;
    color: #1a1a1a;
}

/* 斜体 */
em {
    font-style: italic;
}

/* 图片容器 - 居中 */
.img-box {
    margin: 20px auto;
    text-align: center;
    width: 100%;
}

.img-box img {
    max-width: 800px;
    width: 100%;
    height: auto;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    display: inline-block;
    cursor: pointer;
    transition: transform 0.2s;
}

.img-box img:hover {
    transform: scale(1.02);
}

/* 表格容器 - 居中 */
.table-box {
    margin: 20px auto;
    overflow-x: auto;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    max-width: 800px;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: #fff;
}

th, td {
    padding: 12px 16px;
    text-align: center;
    border-bottom: 1px solid #e0e0e0;
}

th {
    background: #f9fafb;
    font-weight: 600;
    color: #1a1a1a;
}

tr:last-child td {
    border-bottom: none;
}

/* 移动端适配 */
@media (max-width: 768px) {
    main {
        padding: 24px 16px;
    }

    h2 {
        font-size: 22px;
        margin: 24px auto 12px;
    }

    h3 {
        font-size: 19px;
    }

    h4 {
        font-size: 17px;
    }

    p {
        font-size: 15px;
    }

    .img-box img {
        max-width: 100%;
    }

    th, td {
        padding: 10px 12px;
        font-size: 15px;
    }
}

@media (max-width: 480px) {
    main {
        padding: 20px 12px;
    }

    h2 {
        font-size: 20px;
    }

    h3 {
        font-size: 18px;
    }

    h4 {
        font-size: 16px;
    }

    p {
        font-size: 15px;
    }

    .img-box img {
        max-width: 100%;
    }

    th, td {
        padding: 8px 10px;
        font-size: 14px;
    }
}

/* 滚动条 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: #c1c1c1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #a8a8a8;
}