@charset "UTF-8";
/* 
*版本: v1.2
*说明: 排版优化，提高可读性。 
*时间: 2026-02-16 14:43
*/

/* =========================
   01. 设计变量
   ========================= */
:root {
    --primary-color: #0078d7;
    --primary-hover: #0053a1;
    --text-color: #333333;
    --text-content: #444444;
    --text-muted: #666666;
    --bg-color: #ffffff;
}

/* 响应式断点规范：移动端 <= 767px；桌面端 >= 768px */

/* =========================
   02. 全局重置与基础
   ========================= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    font-size: 16px;
    line-height: 1.8;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

/* =========================
   03. 页面布局
   ========================= */
header {
    padding: 1rem 0;
    text-align: center;
    color: inherit;
}

header h1 {
    font-size: 2rem;
    margin: 0;
}

main {
    max-width: 1000px;
    margin: auto;
    padding: 2rem;
}

section {
    margin-bottom: 2rem;
}

/* =========================
   04. 正文排版
   ========================= */
section h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    margin-bottom: 0.8rem;
}

section p {
    margin-bottom: 1rem;
    text-align: justify;
    color: var(--text-content);
}

ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

ul li {
    list-style-type: disc;
    margin: 0.5rem 0;
    color: var(--text-content);
}

/* =========================
   05. 链接与交互
   ========================= */
a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s;
}

a:hover {
    color: var(--primary-hover);
}

/* =========================
   06. 组件（页脚 / 返回首页）
   ========================= */
footer {
    padding: 2rem 1rem;
    text-align: center;
    font-size: 0.875rem;
    color: inherit;
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
}

.footer-link {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
}

.footer-link a {
    color: var(--text-muted);
    text-decoration: none;
}

.footer-link a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

.back-home {
    text-align: center;
    margin-top: 2rem;
}

.back-home a {
    color: var(--primary-color);
    text-decoration: none;
}

.back-home a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* =========================
   07. 暗色模式
   ========================= */
@media (prefers-color-scheme: dark) {
    :root {
        --text-color: #e0e0e0;
        --text-content: #c8c8c8;
        --text-muted: #a0a0a0;
        --bg-color: #121212;
        --primary-color: #80bfff;
        --primary-hover: #9cccff;
    }

    body {
        background-color: var(--bg-color);
        color: var(--text-color);
    }

    section h2 {
        color: var(--primary-color);
    }

    section p,
    ul li {
        color: var(--text-content);
    }
}

/* =========================
   08. 响应式
   ========================= */
@media (max-width: 767px) {
    main {
        padding: 1rem;
    }

    header h1 {
        font-size: 1.8rem;
    }

    section h2 {
        font-size: 1.5rem;
    }

    footer {
        flex-direction: column;
        font-size: 0.8rem;
    }
}