/* ============================================================
   机器人知识库 - 全局样式（统一版）
   - CSS 变量驱动亮/暗双主题（html[data-theme] 切换）
   - 响应式断点：640 / 1024 / 1440
   - 首页样式以 body.home 作用域隔离
   ============================================================ */

/* ---------- 主题变量 ---------- */
:root,
[data-theme="dark"] {
    --bg-body: #16213e;
    --bg-gradient: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --text-muted: #999999;
    --accent: #00d4ff;
    --accent-2: #7b2cbf;
    --accent-2-light: #c77dff;
    --link: #00d4ff;
    --card-bg: linear-gradient(135deg, rgba(255,255,255,0.08) 0%, rgba(255,255,255,0.03) 100%);
    --card-bg-hover: linear-gradient(135deg, rgba(255,255,255,0.12) 0%, rgba(255,255,255,0.05) 100%);
    --card-border: rgba(255,255,255,0.1);
    --card-border-hover: #00d4ff;
    --surface: rgba(255,255,255,0.05);
    --surface-soft: rgba(255,255,255,0.03);
    --input-bg: rgba(255,255,255,0.1);
    --input-bg-focus: rgba(255,255,255,0.15);
    --input-border: #333;
    --dropdown-bg: #1c2743;
    --dropdown-border: rgba(255,255,255,0.15);
    --content-text: #ccc;
    --content-border: #333;
    --fab-bg: rgba(255,255,255,0.1);
    --fab-border: rgba(255,255,255,0.2);
    --fab-color: #fff;
    --h1-gradient: linear-gradient(90deg, #00d4ff, #7b2cbf);
    --card-top-bar: linear-gradient(90deg, #00d4ff, #7b2cbf);
    --card-shadow: 0 10px 40px rgba(0,212,255,0.2);
    --code-bg: rgba(0,212,255,0.1);
    --table-border: #333;
    --th-bg: rgba(0,212,255,0.15);
    --hr-border: rgba(255,255,255,0.08);
    --selection-bg: rgba(0,212,255,0.3);
}

[data-theme="light"] {
    --bg-body: #eef1f7;
    --bg-gradient: linear-gradient(135deg, #f6f8fc 0%, #eef1f7 50%, #e6ecf5 100%);
    --text-primary: #1a2233;
    --text-secondary: #5a6478;
    --text-muted: #6b7486;
    --accent: #0284a7;
    --accent-2: #6b2fb3;
    --accent-2-light: #7c3aed;
    --link: #0284a7;
    --card-bg: #ffffff;
    --card-bg-hover: #ffffff;
    --card-border: rgba(20,40,80,0.14);
    --card-border-hover: #0284a7;
    --surface: #ffffff;
    --surface-soft: rgba(20,40,80,0.04);
    --input-bg: #ffffff;
    --input-bg-focus: #ffffff;
    --input-border: rgba(20,40,80,0.25);
    --dropdown-bg: #ffffff;
    --dropdown-border: rgba(20,40,80,0.15);
    --content-text: #333a48;
    --content-border: rgba(20,40,80,0.15);
    --fab-bg: #ffffff;
    --fab-border: rgba(20,40,80,0.2);
    --fab-color: #1a2233;
    --h1-gradient: linear-gradient(90deg, #0284a7, #6b2fb3);
    --card-top-bar: linear-gradient(90deg, #0284a7, #6b2fb3);
    --card-shadow: 0 10px 30px rgba(2,132,167,0.18);
    --code-bg: rgba(2,132,167,0.08);
    --table-border: rgba(20,40,80,0.15);
    --th-bg: rgba(2,132,167,0.1);
    --hr-border: rgba(20,40,80,0.12);
    --selection-bg: rgba(2,132,167,0.25);
}

/* ---------- 重置与基础 ---------- */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', Roboto, Arial, sans-serif;
    background: var(--bg-gradient);
    background-attachment: fixed;
    min-height: 100vh;
    color: var(--text-primary);
}
::selection { background: var(--selection-bg); }

/* 键盘焦点可见性（无障碍） */
a:focus-visible,
button:focus-visible,
input:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
}

/* 跳转到主内容链接（无障碍） */
.skip-link {
    position: absolute; top: -48px; left: 12px;
    background: var(--accent); color: #04212b;
    padding: 10px 18px; border-radius: 8px; z-index: 999;
    font-weight: bold; text-decoration: none;
    transition: top 0.2s;
}
.skip-link:focus { top: 12px; }

/* 屏幕阅读器专用 */
.sr-only {
    position: absolute; width: 1px; height: 1px;
    overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap;
}

/* ---------- 容器 ---------- */
.container { max-width: 900px; margin: 0 auto; padding: 40px 20px; }
body.home .container { max-width: 1200px; }

/* ---------- 子页面头部 ---------- */
header { margin-bottom: 40px; }
body.home header { text-align: center; margin-bottom: 50px; }
.back-link {
    display: inline-block; color: var(--link); text-decoration: none;
    margin-bottom: 20px; font-size: 0.9rem; transition: color 0.3s;
}
.back-link:hover { color: var(--accent-2); }
h1 { font-size: 2rem; margin-bottom: 10px; color: var(--text-primary); }
.subtitle { color: var(--text-secondary); font-size: 1rem; }

/* ---------- 面包屑导航 ---------- */
.breadcrumb { margin-bottom: 25px; font-size: 0.85rem; color: var(--text-muted); }
.breadcrumb a { color: var(--link); text-decoration: none; }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb span { margin: 0 8px; color: var(--text-muted); }

/* ---------- 文件列表（分类页） ---------- */
.file-list { display: flex; flex-direction: column; gap: 10px; }
.file-item {
    display: flex; align-items: center; gap: 15px; padding: 20px;
    background: var(--surface);
    border: 1px solid var(--card-border);
    border-radius: 10px; text-decoration: none; color: inherit; transition: all 0.3s;
}
.file-item:hover {
    background: var(--surface-soft);
    border-color: var(--card-border-hover); transform: translateX(5px);
}
.file-icon { font-size: 1.5rem; }
.file-name { font-size: 1rem; color: var(--text-primary); }

/* ============================================================
   首页专属样式（body.home 作用域）
   ============================================================ */
body.home h1 {
    font-size: 3rem;
    margin-bottom: 15px;
    background: var(--h1-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
body.home .subtitle { font-size: 1.2rem; margin-bottom: 10px; }
body.home .tagline { font-size: 1rem; color: var(--accent); }

/* ---------- 搜索框 ---------- */
.search-box { max-width: 520px; margin: 30px auto; position: relative; }
.search-box input {
    width: 100%; padding: 15px 20px;
    border: 2px solid var(--input-border); border-radius: 30px;
    background: var(--input-bg); color: var(--text-primary);
    font-size: 1rem; outline: none; transition: all 0.3s;
}
.search-box input:focus { border-color: var(--accent); background: var(--input-bg-focus); }
.search-box input::placeholder { color: var(--text-muted); }

/* ---------- 搜索结果下拉 ---------- */
.search-results {
    position: absolute; top: calc(100% + 8px); left: 0; right: 0;
    background: var(--dropdown-bg);
    border: 1px solid var(--dropdown-border);
    border-radius: 14px;
    box-shadow: 0 12px 40px rgba(0,0,0,0.35);
    max-height: 420px; overflow-y: auto;
    z-index: 50; display: none; text-align: left;
}
.search-results.show { display: block; }
.search-result-item {
    display: block; padding: 12px 18px;
    text-decoration: none; color: var(--text-primary);
    border-bottom: 1px solid var(--dropdown-border);
    transition: background 0.15s;
}
.search-result-item:last-child { border-bottom: none; }
.search-result-item:hover, .search-result-item:hover .result-category { background: var(--surface-soft); }
.result-title { display: block; font-size: 0.95rem; font-weight: 600; color: var(--text-primary); margin-bottom: 3px; }
.result-category {
    display: inline-block; font-size: 0.72rem; color: var(--accent);
    background: var(--code-bg); border-radius: 10px; padding: 1px 9px; margin-bottom: 4px;
}
.result-snippet { display: block; font-size: 0.8rem; color: var(--text-secondary); line-height: 1.5; }
.result-snippet mark { background: var(--selection-bg); color: var(--accent); padding: 0 2px; border-radius: 2px; }
.search-empty { padding: 16px 18px; color: var(--text-muted); font-size: 0.88rem; text-align: center; }

/* ---------- 分类卡片网格 ---------- */
body.home .categories {
    display: grid;
    grid-template-columns: 1fr;
    gap: 12px; margin-top: 40px;
}
.category-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 15px; padding: 25px;
    transition: all 0.3s ease;
    text-decoration: none; color: inherit; display: block;
    position: relative; overflow: hidden;
}
.category-card::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
    background: var(--card-top-bar);
    opacity: 0; transition: opacity 0.3s;
}
.category-card:hover {
    transform: translateY(-5px);
    background: var(--card-bg-hover);
    border-color: var(--card-border-hover);
    box-shadow: var(--card-shadow);
}
.category-card:hover::before { opacity: 1; }
.category-number { font-size: 0.9rem; color: var(--accent); margin-bottom: 10px; font-weight: bold; }
.category-title { font-size: 1.3rem; font-weight: 600; margin-bottom: 10px; color: var(--text-primary); }
.category-title-cn { font-size: 1rem; color: var(--text-secondary); margin-bottom: 15px; }
.category-desc { font-size: 0.9rem; color: var(--text-muted); line-height: 1.5; }

/* ---------- 统计数据 ---------- */
body.home .stats {
    display: flex; justify-content: center; flex-wrap: wrap; gap: 30px 50px;
    margin-top: 60px; padding: 30px;
    background: var(--surface-soft); border-radius: 15px;
    border: 1px solid var(--card-border);
}
.stat-item { text-align: center; }
.stat-number { font-size: 2.5rem; font-weight: bold; color: var(--accent); }
.stat-label { font-size: 0.9rem; color: var(--text-muted); margin-top: 5px; }

/* ---------- 页脚 ---------- */
footer { text-align: center; margin-top: 60px; padding: 20px; color: var(--text-muted); font-size: 0.9rem; }
footer a { color: var(--link); text-decoration: none; }
footer a:hover { text-decoration: underline; }
.visitor-counter { margin-top: 15px; color: var(--text-muted); font-size: 0.85rem; }
.feedback-hint {
    margin-top: 20px; padding: 15px;
    background: var(--surface-soft); border-radius: 10px;
    border-left: 3px solid var(--accent-2);
}
.feedback-hint p { margin: 0; color: var(--text-secondary); font-size: 0.85rem; }
.feedback-hint strong { color: var(--text-primary); }

/* ============================================================
   内容页面样式
   ============================================================ */
.md-content {
    background: var(--surface);
    border: 1px solid var(--card-border);
    border-radius: 15px; padding: 40px; line-height: 1.8;
}
.md-content h1 {
    font-size: 2rem; color: var(--accent);
    border-bottom: 2px solid var(--accent);
    padding-bottom: 15px; margin-bottom: 30px;
}
.md-content h2 {
    font-size: 1.3rem; color: var(--text-primary);
    margin-top: 30px; margin-bottom: 15px;
    padding-left: 10px; border-left: 4px solid var(--accent-2);
}
.md-content h3 { font-size: 1.15rem; color: var(--accent); margin-top: 20px; margin-bottom: 10px; }
.md-content h4 { font-size: 1rem; color: var(--text-secondary); margin-top: 15px; margin-bottom: 8px; }
.md-content p { margin-bottom: 12px; color: var(--content-text); }
.md-content ul, .md-content ol { margin-left: 25px; margin-bottom: 15px; color: var(--content-text); }
.md-content li { margin-bottom: 6px; }
.md-content strong { color: var(--text-primary); }
.md-content a { color: var(--link); text-decoration: none; }
.md-content a:hover { text-decoration: underline; }
.md-content code {
    background: var(--code-bg); padding: 2px 8px;
    border-radius: 4px; color: var(--accent); font-size: 0.9rem;
}

/* 表格 */
.md-content table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 0.9rem; }
.md-content th { background: var(--th-bg); color: var(--accent); padding: 12px; border: 1px solid var(--table-border); text-align: left; }
.md-content td { padding: 10px 12px; border: 1px solid var(--table-border); color: var(--content-text); }
.md-content tr:hover td { background: var(--surface-soft); }

/* 提示框 */
.tip-box {
    background: var(--surface-soft);
    border: 1px solid var(--card-border);
    border-radius: 10px; padding: 20px; margin: 20px 0;
}
.tip-title { color: var(--accent-2-light); font-weight: bold; margin-bottom: 10px; }

/* 里程碑 */
.milestone {
    background: var(--surface-soft);
    border-left: 4px solid var(--accent);
    padding: 15px 20px; margin: 15px 0;
    border-radius: 0 8px 8px 0;
}

/* 页脚（内容页） */
.page-footer {
    text-align: center; margin-top: 40px;
    padding: 20px; color: var(--text-muted); font-size: 0.85rem;
    border-top: 1px solid var(--card-border);
}

/* ============================================================
   亮色模式对内容页的兜底覆盖
   （内容页自带 <style> 使用硬编码暗色，此处以更高优先级修正关键文字）
   ============================================================ */
[data-theme="light"] .md-content { background: #ffffff; border-color: rgba(20,40,80,0.12); }
[data-theme="light"] .md-content p,
[data-theme="light"] .md-content li,
[data-theme="light"] .md-content td { color: #333a48 !important; }
[data-theme="light"] .md-content strong { color: #111827 !important; }
[data-theme="light"] .md-content h2 { color: #1a2233 !important; }
[data-theme="light"] .md-content h1,
[data-theme="light"] .md-content h3 { color: #0277a0 !important; }
[data-theme="light"] .md-content h4 { color: #5a6478 !important; }
[data-theme="light"] .md-content code { color: #0277a0 !important; background: rgba(2,119,160,0.08) !important; }
[data-theme="light"] .md-content .note-box p { color: #8a6d00 !important; }
[data-theme="light"] .md-content .highlight { color: #0277a0 !important; background: rgba(2,119,160,0.12) !important; }
[data-theme="light"] .md-content th { background: rgba(2,119,160,0.1) !important; color: #0277a0 !important; border-color: rgba(20,40,80,0.15) !important; }
[data-theme="light"] .md-content td { border-color: rgba(20,40,80,0.12) !important; }
[data-theme="light"] .md-content .level-table td { border-color: rgba(20,40,80,0.12) !important; color: #333a48 !important; }
[data-theme="light"] .md-content .level-table th { background: rgba(2,119,160,0.1) !important; color: #0277a0 !important; border-color: rgba(20,40,80,0.15) !important; }
[data-theme="light"] .file-desc,
[data-theme="light"] .file-item span[style*="color:#888"] { color: #6b7486 !important; }
[data-theme="light"] .subtitle { color: #5a6478 !important; }
[data-theme="light"] .page-footer { color: #6b7486 !important; }

/* ============================================================
   浮动按钮（主题切换 / 返回顶部，由 theme.js 注入）
   ============================================================ */
.rk-fab {
    position: fixed; right: 24px; z-index: 90;
    width: 46px; height: 46px; border-radius: 50%;
    background: var(--fab-bg); color: var(--fab-color);
    border: 1px solid var(--fab-border);
    font-size: 19px; line-height: 1; cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: transform 0.2s, opacity 0.3s, background 0.2s;
    -webkit-backdrop-filter: blur(6px); backdrop-filter: blur(6px);
}
.rk-fab:hover { transform: scale(1.08); }
.rk-theme-toggle { bottom: 24px; }
.rk-back-top { bottom: 80px; opacity: 0; pointer-events: none; }
.rk-back-top.show { opacity: 1; pointer-events: auto; }

/* ============================================================
   响应式断点：640 / 1024 / 1440
   ============================================================ */

/* 平板及以上：卡片两列 */
@media (min-width: 640px) {
    body.home .categories { grid-template-columns: repeat(2, 1fr); gap: 16px; }
}

/* 桌面：三列 */
@media (min-width: 1024px) {
    body.home .categories { grid-template-columns: repeat(3, 1fr); gap: 20px; }
    body.home .container { padding: 40px 30px; }
}

/* 大屏：四列 + 更宽容器 */
@media (min-width: 1440px) {
    body.home .container { max-width: 1360px; }
    body.home .categories { grid-template-columns: repeat(4, 1fr); }
}

/* 移动端优化 */
@media (max-width: 639px) {
    body.home h1 { font-size: 1.75rem; }
    body.home .subtitle { font-size: 1rem; }
    body.home .tagline { font-size: 0.9rem; }
    .search-box input {
        font-size: 16px;        /* 防止 iOS 聚焦缩放 */
        padding: 14px 18px;     /* 增大触摸区域 */
    }
    body.home .stats { gap: 18px 30px; padding: 22px; }
    .stat-number { font-size: 2rem; }
    .container { padding: 24px 16px; }
    .md-content { padding: 22px 16px; }
    .file-item { flex-wrap: wrap; padding: 16px; }
    .file-desc { width: 100%; margin-left: 44px !important; margin-top: 4px; }
    .rk-fab { right: 16px; width: 42px; height: 42px; }
    .rk-theme-toggle { bottom: 16px; }
    .rk-back-top { bottom: 68px; }
}

/* 减少动态偏好（无障碍） */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { transition: none !important; animation: none !important; }
    .category-card:hover { transform: none; }
}

/* 打印优化 */
@media print {
    body { background: #fff; color: #000; }
    .rk-fab, .search-box, .skip-link, .back-link, footer, .visitor-counter { display: none !important; }
    .md-content { border: none; }
}