/*
Theme Name: Your Blue Blog
Theme URI: https://example.com/your-blue-blog
Description: 以蓝色为主色调的 WordPress 博客主题。从底层实现免插件 Schema 结构化数据、替换古登堡编辑器、内置全部自定义小工具，并保留响应式 SEO 优化能力，完全适配全尺寸设备访问。
Version: 1.0.0
Requires at least: 5.8
Tested up to: 6.5
Requires PHP: 7.4
Author: WorkBuddy
Author URI: https://example.com
Text Domain: your-blue-blog
Tags: blog, blue, responsive, seo, custom-widgets, accessibility-ready
*/

/* =====================================================================
   0. 设计令牌 (Design Tokens) — 蓝色主色调体系
   Customizer 可覆盖 --color-primary 等变量，无需改代码即可换色。
   ===================================================================== */
:root {
    /* 蓝色主色体系（深 / 主 / 浅） */
    --color-primary: #1a6fd4;
    --color-primary-dark: #14529c;
    --color-primary-light: #4a93e6;
    --color-primary-50: #eaf3fd;
    --color-primary-100: #d4e6fb;

    /* 中性色 */
    --color-text: #1f2933;
    --color-text-light: #5b6776;
    --color-bg: #ffffff;
    --color-bg-alt: #f5f8fc;
    --color-border: #e3e9f2;
    --color-link: var(--color-primary);
    --color-link-hover: var(--color-primary-dark);

    /* 语义色 */
    --color-success: #2e9e5b;
    --color-warning: #e0a106;
    --color-danger: #d64545;

    /* 排版 — 流体字号（clamp 随视口平滑缩放） */
    --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;

    --fs-300: clamp(0.78rem, 0.74rem + 0.2vw, 0.86rem);
    --fs-400: clamp(0.9rem, 0.86rem + 0.25vw, 1rem);
    --fs-500: clamp(1.05rem, 0.98rem + 0.4vw, 1.2rem);
    --fs-600: clamp(1.25rem, 1.12rem + 0.7vw, 1.6rem);
    --fs-700: clamp(1.55rem, 1.3rem + 1.2vw, 2.2rem);
    --fs-800: clamp(1.9rem, 1.5rem + 2vw, 3rem);
    --fs-900: clamp(2.3rem, 1.7rem + 3vw, 4rem);

    /* 间距与圆角 */
    --space-1: 0.5rem;
    --space-2: 1rem;
    --space-3: 1.5rem;
    --space-4: 2rem;
    --space-5: 3rem;
    --radius: 10px;
    --radius-sm: 6px;
    --radius-lg: 16px;

    /* 布局 */
    --container: 1200px;
    --container-narrow: 760px;
    --header-h: 64px;

    /* 阴影 */
    --shadow-sm: 0 1px 3px rgba(20, 82, 156, 0.08);
    --shadow-md: 0 6px 20px rgba(20, 82, 156, 0.10);
    --shadow-lg: 0 14px 40px rgba(20, 82, 156, 0.14);

    /* 阅读字号缩放（由 JS 控制） */
    --reading-scale: 1;
}

/* 暗黑模式（由 body.dark-mode 或 prefers-color-scheme 触发） */
body.dark-mode {
    --color-text: #e6edf5;
    --color-text-light: #9fb0c3;
    --color-bg: #0f1622;
    --color-bg-alt: #16202f;
    --color-border: #25344a;
    --color-primary-50: #16263c;
    --color-primary-100: #1d3350;
    --color-link: var(--color-primary-light);
    --color-link-hover: #7db4f0;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 6px 20px rgba(0, 0, 0, 0.45);
    --shadow-lg: 0 14px 40px rgba(0, 0, 0, 0.5);
}
@media (prefers-color-scheme: dark) {
    body.auto-dark {
        --color-text: #e6edf5;
        --color-text-light: #9fb0c3;
        --color-bg: #0f1622;
        --color-bg-alt: #16202f;
        --color-border: #25344a;
        --color-link: var(--color-primary-light);
    }
}

/* =====================================================================
   1. 基础重置
   ===================================================================== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
    margin: 0;
    font-family: var(--font-base);
    font-size: var(--fs-400);
    line-height: 1.75;
    color: var(--color-text);
    background: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    transition: background-color .3s ease, color .3s ease;
}
img, video, svg { max-width: 100%; height: auto; display: block; }
a { color: var(--color-link); text-decoration: none; transition: color .2s ease; }
a:hover { color: var(--color-link-hover); }
h1, h2, h3, h4, h5, h6 {
    line-height: 1.25;
    font-weight: 700;
    margin: 1.4em 0 .6em;
    color: var(--color-text);
}
h1 { font-size: var(--fs-700); }
h2 { font-size: var(--fs-600); }
h3 { font-size: var(--fs-500); }
h4 { font-size: var(--fs-500); }
p { margin: 0 0 1.2em; }
ul, ol { padding-left: 1.4em; }
code, kbd, pre { font-family: var(--font-mono); }
pre {
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: var(--space-2);
    overflow-x: auto;
}
blockquote {
    margin: 1.5em 0;
    padding: .6em 1.2em;
    border-left: 4px solid var(--color-primary);
    background: var(--color-primary-50);
    color: var(--color-text-light);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
table { width: 100%; border-collapse: collapse; margin: 1.2em 0; }
th, td { border: 1px solid var(--color-border); padding: .6em .8em; text-align: left; }
th { background: var(--color-bg-alt); }

/* =====================================================================
   2. 布局容器 & 网格
   ===================================================================== */
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 var(--space-2); }
.site-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 320px;
    gap: var(--space-4);
    max-width: var(--container);
    margin: var(--space-4) auto;
    padding: 0 var(--space-2);
    align-items: start;
}
.site-main { min-width: 0; }
.site-main.full-width { grid-column: 1 / -1; }
.widget-area { min-width: 0; }

/* =====================================================================
   3. 头部 / 导航
   ===================================================================== */
.site-header {
    position: sticky; top: 0; z-index: 100;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}
.site-header__inner {
    display: flex; align-items: center; gap: var(--space-2);
    height: var(--header-h);
    max-width: var(--container); margin: 0 auto; padding: 0 var(--space-2);
}
.site-logo { display: flex; align-items: center; gap: .6em; font-weight: 800; font-size: var(--fs-500); color: var(--color-text); }
.site-logo img { height: 38px; width: auto; }
.site-logo:hover { color: var(--color-primary); }
.site-nav { margin-left: auto; }
.site-nav ul { list-style: none; display: flex; gap: .3em; margin: 0; padding: 0; }
.site-nav a {
    display: block; padding: .5em .9em; border-radius: var(--radius-sm);
    color: var(--color-text); font-weight: 500;
}
.site-nav a:hover, .site-nav .current-menu-item > a { background: var(--color-primary-50); color: var(--color-primary); }
.site-nav .menu-item-has-children { position: relative; }
.site-nav .sub-menu {
    position: absolute; top: 100%; left: 0; min-width: 200px;
    background: var(--color-bg); border: 1px solid var(--color-border);
    border-radius: var(--radius-sm); box-shadow: var(--shadow-md);
    display: none; flex-direction: column; gap: 0; padding: .4em;
}
.site-nav .menu-item-has-children:hover > .sub-menu { display: flex; }

.header-actions { display: flex; align-items: center; gap: .5em; margin-left: .5em; }
.header-search { display: flex; align-items: center; }
.header-search input {
    border: 1px solid var(--color-border); border-radius: 999px;
    padding: .4em 1em; font-size: var(--fs-300); width: 160px; background: var(--color-bg-alt);
}
.header-search input:focus { outline: 2px solid var(--color-primary-light); border-color: transparent; }
/* 适配核心 get_search_form() 默认结构 */
.header-search .search-form { display: flex; align-items: center; gap: .3em; margin: 0; }
.header-search .search-form label { margin: 0; }
.header-search .search-form input[type="search"] { border: 1px solid var(--color-border); border-radius: 999px; padding: .4em 1em; font-size: var(--fs-300); width: 160px; background: var(--color-bg-alt); }
.header-search .search-form input[type="submit"] {
    border: 0; background: var(--color-primary); color: #fff;
    border-radius: 999px; cursor: pointer; font-size: var(--fs-300);
    padding: .4em 1em; width: auto; min-width: 0; line-height: 1;
}
.icon-btn {
    border: 1px solid var(--color-border); background: var(--color-bg-alt);
    width: 38px; height: 38px; border-radius: 50%; cursor: pointer;
    display: inline-flex; align-items: center; justify-content: center;
    color: var(--color-text); font-size: 1.1rem; line-height: 1;
}
.icon-btn:hover { background: var(--color-primary-50); color: var(--color-primary); border-color: var(--color-primary-light); }

/* 汉堡按钮（移动端） */
.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: .4em; margin-left: auto; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--color-text); margin: 5px 0; transition: .3s; }

/* 流体排版头部（站点标题区，用于首页 hero） */
.hero {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: #fff; padding: clamp(2.5rem, 5vw, 5rem) 0; text-align: center;
}
.hero h1 { color: #fff; font-size: var(--fs-900); margin: 0 0 .3em; }
.hero p { color: rgba(255,255,255,.9); font-size: var(--fs-500); margin: 0; }

/* =====================================================================
   4. 文章卡片网格
   ===================================================================== */
.post-grid {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}
.post-card {
    background: var(--color-bg); border: 1px solid var(--color-border);
    border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow-sm);
    transition: transform .25s ease, box-shadow .25s ease;
    display: flex; flex-direction: row; align-items: stretch;
}
.post-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.post-card__thumb {
    position: relative;
    width: 260px; flex-shrink: 0;
    aspect-ratio: 16/9; overflow: hidden; background: var(--color-bg-alt);
}
.post-card__thumb img { width: 100%; height: 100%; object-fit: cover; }
.post-card__body {
    padding: var(--space-2) var(--space-3);
    display: flex; flex-direction: column; gap: .5em; flex: 1;
    justify-content: center;
}
.post-card__cat { font-size: var(--fs-300); color: var(--color-primary); font-weight: 700; text-transform: uppercase; letter-spacing: .04em; }
.post-card__title { font-size: var(--fs-500); margin: 0; line-height: 1.35; }
.post-card__title a { color: var(--color-text); }
.post-card__title a:hover { color: var(--color-primary); }
.post-card__excerpt { color: var(--color-text-light); font-size: var(--fs-400); margin: 0; flex: 1; }
.post-card__meta { font-size: var(--fs-300); color: var(--color-text-light); display: flex; gap: .8em; flex-wrap: wrap; border-top: 1px solid var(--color-border); padding-top: .6em; }
.post-card--sticky { border-color: var(--color-primary); box-shadow: 0 0 0 2px var(--color-primary-100), var(--shadow-md); }

/* =====================================================================
   5. 文章详情
   ===================================================================== */
.article { background: var(--color-bg); }
.article__header { margin-bottom: var(--space-3); }
.article__title { font-size: var(--fs-700); margin: .2em 0; }
.article__meta { display: flex; flex-wrap: wrap; align-items: center; gap: 1em; color: var(--color-text-light); font-size: var(--fs-300); margin-bottom: var(--space-2); }
.article__meta .author { display: flex; align-items: center; gap: .5em; }
.article__meta img.avatar { width: 32px; height: 32px; border-radius: 50%; }
.entry-content { font-size: calc(var(--fs-400) * var(--reading-scale)); line-height: 1.85; }
.entry-content img { border-radius: var(--radius-sm); margin: 1.2em 0; }
.entry-content h2, .entry-content h3 { scroll-margin-top: calc(var(--header-h) + 20px); }

/* 阅读工具栏 */
.reading-toolbar {
    position: sticky; top: var(--header-h); z-index: 50;
    display: flex; align-items: center; gap: .8em; flex-wrap: wrap;
    background: var(--color-bg-alt); border: 1px solid var(--color-border);
    border-radius: var(--radius); padding: .5em .9em; margin: 0 0 var(--space-3);
}
.reading-toolbar .tool { display: inline-flex; align-items: center; gap: .35em; font-size: var(--fs-300); }
.reading-toolbar button {
    border: 1px solid var(--color-border); background: var(--color-bg);
    border-radius: var(--radius-sm); padding: .25em .6em; cursor: pointer; color: var(--color-text);
}
.reading-toolbar button:hover { background: var(--color-primary-50); color: var(--color-primary); }

/* 文章目录（内嵌） */
.toc { background: var(--color-bg-alt); border: 1px solid var(--color-border); border-radius: var(--radius); padding: var(--space-2); margin: 0 0 var(--space-3); }
.toc__title { font-weight: 700; margin: 0 0 .5em; color: var(--color-primary); }
.toc ul { margin: 0; padding-left: 0; list-style: none; }
.toc a { color: var(--color-text-light); }
.toc a:hover { color: var(--color-primary); }
.toc .active > a { color: var(--color-primary); font-weight: 700; }

/* 文章目录（悬浮，长文） */
.toc-floating {
    position: fixed; right: 1.5em; top: 50%; transform: translateY(-50%);
    max-width: 240px; max-height: 70vh; overflow: auto;
    background: var(--color-bg); border: 1px solid var(--color-border);
    border-radius: var(--radius); box-shadow: var(--shadow-md); padding: var(--space-2);
    font-size: var(--fs-300); z-index: 60; display: none;
}
.toc-floating ul { margin: 0; padding-left: 0; list-style: none; }
.toc-floating.is-visible { display: block; }
@media (max-width: 1100px) { .toc-floating { display: none !important; } }

/* 作者信息栏 */
.author-box {
    display: flex; gap: var(--space-2); align-items: flex-start;
    background: var(--color-bg-alt); border: 1px solid var(--color-border);
    border-radius: var(--radius); padding: var(--space-3); margin: var(--space-4) 0;
}
.author-box img.avatar { width: 72px; height: 72px; border-radius: 50%; flex-shrink: 0; }
.author-box h4 { margin: 0 0 .3em; }
.author-box .social a { display: inline-block; margin-right: .6em; color: var(--color-primary); }

/* 相关文章 */
.related-posts { margin: var(--space-4) 0; }
.related-posts h3 { border-left: 4px solid var(--color-primary); padding-left: .5em; }
.related-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: var(--space-2); }

/* 点赞 / 阅读量 */
.post-stats { display: flex; gap: var(--space-2); align-items: center; margin: var(--space-2) 0; flex-wrap: wrap; }
.post-stats .like-btn {
    display: inline-flex; align-items: center; gap: .4em;
    border: 1px solid var(--color-primary); color: var(--color-primary);
    background: var(--color-bg); border-radius: 999px; padding: .4em 1.1em; cursor: pointer; font-weight: 600;
}
.post-stats .like-btn.liked { background: var(--color-primary); color: #fff; }
.post-stats .stat { color: var(--color-text-light); font-size: var(--fs-300); }

/* =====================================================================
   6. 归档 / 分类 / 标签
   ===================================================================== */
.archive-header { background: var(--color-bg-alt); border-radius: var(--radius); padding: var(--space-3); margin-bottom: var(--space-3); }
.archive-header__cover { width: 100%; border-radius: var(--radius); margin-bottom: var(--space-2); max-height: 240px; object-fit: cover; }
.archive-header h1 { margin: 0 0 .2em; }
.archive-header p { margin: 0; color: var(--color-text-light); }

.tag-cloud { display: flex; flex-wrap: wrap; gap: .5em; }
.tag-cloud a {
    display: inline-block; padding: .25em .8em; border-radius: 999px;
    background: var(--color-primary-50); color: var(--color-primary); font-size: var(--fs-300);
}
.tag-cloud a:hover { background: var(--color-primary); color: #fff; }

/* 分页 */
.pagination { display: flex; gap: .4em; justify-content: center; margin: var(--space-4) 0; flex-wrap: wrap; }
.pagination a, .pagination span {
    min-width: 38px; height: 38px; display: inline-flex; align-items: center; justify-content: center;
    border: 1px solid var(--color-border); border-radius: var(--radius-sm); padding: 0 .6em; color: var(--color-text);
}
.pagination .current { background: var(--color-primary); color: #fff; border-color: var(--color-primary); }
.pagination a:hover { background: var(--color-primary-50); color: var(--color-primary); }

/* =====================================================================
   7. 侧边栏小工具
   ===================================================================== */
.widget { background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius); padding: var(--space-2); margin-bottom: var(--space-3); box-shadow: var(--shadow-sm); }
.widget__title { font-size: var(--fs-500); margin: 0 0 var(--space-2); padding-bottom: .5em; border-bottom: 2px solid var(--color-primary-100); position: relative; }
.widget__title::after { content: ""; position: absolute; left: 0; bottom: -2px; width: 48px; height: 2px; background: var(--color-primary); }
.widget ul { list-style: none; margin: 0; padding: 0; }
.widget ul li { padding: .4em 0; border-bottom: 1px dashed var(--color-border); }
.widget ul li:last-child { border-bottom: 0; }

.widget-profile { text-align: center; }
.widget-profile img { width: 88px; height: 88px; border-radius: 50%; margin: 0 auto var(--space-1); }
.widget-profile .social a { display: inline-block; margin: .2em; color: var(--color-primary); }

.widget-posts li { display: flex; gap: .7em; align-items: center; }
.widget-posts img { width: 56px; height: 56px; object-fit: cover; border-radius: var(--radius-sm); flex-shrink: 0; }
.widget-posts .w-title { font-size: var(--fs-400); line-height: 1.4; }
.widget-posts .w-meta { font-size: var(--fs-300); color: var(--color-text-light); }

.widget-comments li { display: flex; gap: .6em; }
.widget-comments img { width: 40px; height: 40px; border-radius: 50%; flex-shrink: 0; }
.widget-comments .c-text { font-size: var(--fs-300); color: var(--color-text-light); }

.widget-ad img { width: 100%; border-radius: var(--radius-sm); }
.widget-ad a { display: block; }

.widget-gallery { display: grid; grid-template-columns: repeat(3, 1fr); gap: .4em; }
.widget-gallery img { width: 100%; aspect-ratio: 1; object-fit: cover; border-radius: var(--radius-sm); }

.widget-search form { display: flex; gap: .4em; }
.widget-search input { flex: 1; border: 1px solid var(--color-border); border-radius: var(--radius-sm); padding: .5em .8em; }
.widget-search button {
    border: 0; background: var(--color-primary); color: #fff;
    border-radius: var(--radius-sm); padding: .4em .8em; cursor: pointer;
    font-size: var(--fs-300); width: auto; min-width: 0; line-height: 1;
}

.widget-links ul { columns: 2; }
.widget-links a { color: var(--color-text-light); }
.widget-links a:hover { color: var(--color-primary); }

/* 日历小工具美化：居中、简洁、圆角 */
.widget_calendar { text-align: center; }
.widget_calendar .wp-calendar-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: .35em;
    font-size: var(--fs-300);
    text-align: center;
    table-layout: fixed;
    background: transparent;
    border: 0;
    margin: 0 auto;
}
.widget_calendar caption {
    caption-side: top;
    text-align: center;
    font-weight: 700;
    padding: .5em .2em .8em;
    color: var(--color-text);
    font-size: var(--fs-500);
    letter-spacing: .02em;
}
.widget_calendar thead th {
    background: transparent;
    color: var(--color-text-light);
    padding: .4em .2em;
    font-weight: 600;
    border: 0;
    font-size: var(--fs-300);
}
.widget_calendar tbody td {
    padding: 0;
    border: 0;
    color: var(--color-text);
    height: 2.4em;
    vertical-align: middle;
    border-radius: 50%;
    transition: background .2s, color .2s;
}
.widget_calendar tbody td a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.2em; height: 2.2em;
    border-radius: 50%;
    background: var(--color-primary-50);
    color: var(--color-primary);
    font-weight: 600;
    text-decoration: none;
    margin: 0 auto;
}
.widget_calendar tbody td a:hover {
    background: var(--color-primary);
    color: #fff;
}
.widget_calendar tbody td#today {
    background: var(--color-primary);
    color: #fff;
    font-weight: 700;
}
.widget_calendar tbody td#today a { background: transparent; color: #fff; }
.widget_calendar tbody td#today a:hover { background: rgba(255,255,255,.2); }
.widget_calendar tfoot td {
    padding: .8em .2em .2em;
    border: 0;
    background: transparent;
}
.widget_calendar tfoot a {
    color: var(--color-primary);
    font-weight: 600;
    padding: .35em .8em;
    border: 1px solid var(--color-primary);
    border-radius: 999px;
    font-size: var(--fs-300);
}
.widget_calendar tfoot a:hover {
    background: var(--color-primary);
    color: #fff;
}
.widget_calendar .wp-calendar-nav {
    display: flex; justify-content: space-between;
    padding: .6em .2em 0; font-size: var(--fs-300);
}
.widget_calendar .wp-calendar-nav a {
    color: var(--color-primary);
    padding: .3em .7em;
    border-radius: var(--radius-sm);
}
.widget_calendar .wp-calendar-nav a:hover { background: var(--color-primary-50); }

/* 屏幕阅读器文字：全局隐藏 */
.screen-reader-text {
    border: 0;
    clip: rect(1px, 1px, 1px, 1px);
    clip-path: inset(50%);
    height: 1px;
    margin: -1px;
    overflow: hidden;
    padding: 0;
    position: absolute;
    width: 1px;
    word-wrap: normal !important;
}

/* =====================================================================
   8. 评论
   ===================================================================== */
.comments-area { margin: var(--space-4) 0; }
.comment-list { list-style: none; padding: 0; margin: 0; }
.comment { padding: var(--space-2) 0; border-bottom: 1px solid var(--color-border); }
.comment .avatar { float: left; margin-right: 1em; border-radius: 50%; }
.comment-author { font-weight: 600; }
.comment-metadata { font-size: var(--fs-300); color: var(--color-text-light); }
.comment-form label { display: block; margin-bottom: .3em; font-weight: 600; }
.comment-form input[type=text], .comment-form input[type=email], .comment-form textarea {
    width: 100%; border: 1px solid var(--color-border); border-radius: var(--radius-sm); padding: .6em .8em; margin-bottom: var(--space-2); font-family: inherit;
}
.comment-form .submit { background: var(--color-primary); color: #fff; border: 0; border-radius: var(--radius-sm); padding: .6em 1.6em; cursor: pointer; font-weight: 600; }

/* =====================================================================
   9. 底部
   ===================================================================== */
.site-footer { background: var(--color-bg-alt); border-top: 1px solid var(--color-border); margin-top: var(--space-5); padding: var(--space-4) 0 var(--space-2); }
.footer-widgets { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: var(--space-3); max-width: var(--container); margin: 0 auto var(--space-3); padding: 0 var(--space-2); }
.footer-links { max-width: var(--container); margin: 0 auto var(--space-2); padding: 0 var(--space-2); }
.footer-links ul { list-style: none; display: flex; flex-wrap: wrap; gap: 1em; padding: 0; margin: 0; }
.footer-links a { color: var(--color-text-light); }
.copyright { text-align: center; color: var(--color-text-light); font-size: var(--fs-300); border-top: 1px solid var(--color-border); padding-top: var(--space-2); }

/* =====================================================================
   10. 404
   ===================================================================== */
.error-404 { text-align: center; padding: var(--space-5) 0; }
.error-404 h1 { font-size: var(--fs-900); color: var(--color-primary); }
.error-404 .btn { display: inline-block; background: var(--color-primary); color: #fff; padding: .7em 1.8em; border-radius: var(--radius); margin: .4em; }
.error-404 .btn:hover { background: var(--color-primary-dark); color: #fff; }

/* =====================================================================
   11. 表单 / 按钮
   ===================================================================== */
.btn { display: inline-block; background: var(--color-primary); color: #fff; padding: .6em 1.4em; border-radius: var(--radius); font-weight: 600; border: 0; cursor: pointer; }
.btn:hover { background: var(--color-primary-dark); color: #fff; }
.btn-outline { background: transparent; border: 1px solid var(--color-primary); color: var(--color-primary); }
.btn-outline:hover { background: var(--color-primary); color: #fff; }
input[type=text], input[type=email], input[type=url], input[type=search], textarea, select {
    font-family: inherit; font-size: var(--fs-400);
}
.page-template-contact .field { margin-bottom: var(--space-2); }
.page-template-contact label { display: block; font-weight: 600; margin-bottom: .3em; }

/* =====================================================================
   12. 响应式断点
   ===================================================================== */
/* 桌面端：双栏（内容 + 侧边栏） */
/* 平板：单栏，侧边栏移到内容下方 */
@media (max-width: 992px) {
    .site-layout { grid-template-columns: 1fr; }
    .widget-area { margin-top: var(--space-4); }
}
/* 移动端：导航折叠为汉堡菜单 */
@media (max-width: 768px) {
    .nav-toggle { display: block; }
    .site-nav {
        position: fixed; inset: var(--header-h) 0 auto 0;
        background: var(--color-bg); border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-md); display: none; max-height: calc(100vh - var(--header-h)); overflow-y: auto;
    }
    .site-nav.is-open { display: block; }
    .site-nav ul { flex-direction: column; padding: var(--space-2); gap: 0; }
    .site-nav .sub-menu { position: static; box-shadow: none; border: 0; border-left: 2px solid var(--color-primary); display: none; padding-left: 1em; }
    .site-nav .menu-item-has-children.open > .sub-menu { display: flex; }
    .header-search input { width: 110px; }
    .hero h1 { font-size: var(--fs-700); }
    .author-box { flex-direction: column; text-align: center; align-items: center; }
    .related-grid { grid-template-columns: 1fr; }
    .post-card { flex-direction: column; }
    .post-card__thumb { width: 100%; }
}
@media (max-width: 480px) {
    :root { --space-4: 1.2rem; }
    .header-search { display: none; }
}

/* 移动端：禁用非必要动画，提升性能 */
@media (max-width: 768px) {
    * { scroll-behavior: auto !important; }
    .post-card { transition: none; }
    .post-card:hover { transform: none; }
}

/* 无障碍：键盘聚焦可见 */
a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible {
    outline: 3px solid var(--color-primary-light); outline-offset: 2px;
}

/* 懒加载淡入 */
img.lazy { opacity: 0; transition: opacity .4s ease; }
img.lazy.loaded { opacity: 1; }

/* 搜索关键词高亮 */
mark.search-hl { background: #fff3a8; color: inherit; padding: 0 .1em; border-radius: 2px; }

/* =====================================================================
   13. 分类渐变封面占位 & 卡片增强
   ===================================================================== */
.post-card__thumb { position: relative; }
.post-card__ph {
    display: flex; align-items: center; justify-content: center;
    width: 100%; height: 100%; min-height: 100%;
}
.post-card__ph-label {
    color: #fff; font-weight: 800; font-size: var(--fs-500);
    letter-spacing: .05em; text-shadow: 0 2px 10px rgba(0,0,0,.28);
    padding: 0 1em; text-align: center;
}
.post-card__flag {
    position: absolute; top: .6em; left: .6em; z-index: 2;
    background: var(--color-warning); color: #1f2933;
    font-size: var(--fs-300); font-weight: 700;
    padding: .15em .6em; border-radius: 999px;
    box-shadow: var(--shadow-sm);
}
.post-card--sticky .post-card__thumb { box-shadow: inset 0 0 0 3px var(--color-primary-light); }

/* 首页分类切换 */
.ybb-cat-section { margin: var(--space-4) 0; }
.ybb-cat-tabs {
    display: flex; flex-wrap: wrap; gap: .5em;
    margin-bottom: var(--space-3);
    border-bottom: 2px solid var(--color-border);
    padding-bottom: .6em;
}
.ybb-cat-tab {
    border: 1px solid var(--color-border); background: var(--color-bg);
    color: var(--color-text); border-radius: 999px;
    padding: .5em 1.2em; cursor: pointer; font-weight: 600;
    font-size: var(--fs-400); transition: .2s; font-family: inherit;
}
.ybb-cat-tab:hover { border-color: var(--color-primary); color: var(--color-primary); }
.ybb-cat-tab.is-active { background: var(--color-primary); border-color: var(--color-primary); color: #fff; }
.ybb-cat-panel[hidden] { display: none; }
.ybb-cat-more { margin-top: var(--space-2); }

.ybb-section-title {
    font-size: var(--fs-700); margin: var(--space-5) 0 var(--space-3);
    padding-left: .5em; border-left: 4px solid var(--color-primary);
}

/* 响应式：移动端分类切换标签横向滚动 */
@media (max-width: 768px) {
    .ybb-cat-tabs { flex-wrap: nowrap; overflow-x: auto; -webkit-overflow-scrolling: touch; }
    .ybb-cat-tab { flex: 0 0 auto; }
}