/* ==========================================================================
   海盐大晒场 —— 站点样式
   移动端适配要点：
     1. overflow-wrap 断行，避免长 URL 撑出横向滚动条
     2. 目录在手机上改为正文之前的可折叠卡片（桌面端仍是右侧固定栏）
     3. color-mix() 提供纯色回退，老版移动浏览器不会出现半透明标题栏
     4. env(safe-area-inset-*) 适配刘海屏 / 手势条
     5. 触摸目标不小于 40-44px，并去掉 300ms 点击延迟
   ========================================================================== */

*, *::before, *::after { box-sizing: border-box; }

:root {
  /* 让滚动条、表单控件、以及首帧画布底色跟着主题走 */
  color-scheme: light;
  --bg:           #f6f8f9;
  --bg-grad:      radial-gradient(1200px 420px at 50% -180px, #e6f2f6 0%, rgba(230,242,246,0) 70%);
  --surface:      #ffffff;
  --surface-2:    #eff3f6;
  --text:         #17212b;
  --text-2:       #56646f;
  --text-3:       #626f7b;
  --line:         #e3e9ee;
  --line-2:       #d3dde4;

  --brand:        #0e7490;
  --brand-2:      #0b5f76;
  --brand-soft:   #e3f1f5;
  --accent:       #d97706;

  --radius:       14px;
  --radius-sm:    9px;
  --shadow-1:     0 1px 2px rgba(14, 32, 44, .05);
  --shadow-2:     0 1px 2px rgba(14, 32, 44, .04), 0 14px 30px -16px rgba(14, 32, 44, .22);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC",
               "Noto Sans CJK SC", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, "Courier New", monospace;
  --wrap: 1140px;

  /* 刘海屏安全区，无刘海设备上为 0 */
  --safe-l: env(safe-area-inset-left, 0px);
  --safe-r: env(safe-area-inset-right, 0px);
  --safe-b: env(safe-area-inset-bottom, 0px);
  --safe-t: env(safe-area-inset-top, 0px);
}

/* --------------------------------------------------------------------------
   夜间模式
   暗色调色板需要写两遍：一份给「跟随系统」，一份给「页面里手动切换」。
   ★ 两处的数值必须保持一致，改了一处记得同步另一处 ★
   -------------------------------------------------------------------------- */

/* ① 跟随系统：用户还没手动选过主题时生效 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg:         #090d11;
    --bg-grad:    radial-gradient(1200px 420px at 50% -180px, #0f2933 0%, rgba(15, 41, 51, 0) 70%);
    --surface:    #121a21;
    --surface-2:  #18222b;
    --text:       #e6edf3;
    --text-2:     #9dafbc;
    --text-3:     #7c8c96;
    --line:       #1e2a33;
    --line-2:     #2b3944;

    --brand:      #4bb8d4;
    --brand-2:    #7fd4e8;
    --brand-soft: #0f2c35;
    --accent:     #f0a33c;

    --shadow-1:   0 1px 2px rgba(0, 0, 0, .5);
    --shadow-2:   0 1px 2px rgba(0, 0, 0, .5), 0 14px 30px -16px rgba(0, 0, 0, .92);
  }
}

/* ② 手动切到夜间：系统是浅色也照常变暗 */
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg:         #090d11;
  --bg-grad:    radial-gradient(1200px 420px at 50% -180px, #0f2933 0%, rgba(15, 41, 51, 0) 70%);
  --surface:    #121a21;
  --surface-2:  #18222b;
  --text:       #e6edf3;
  --text-2:     #9dafbc;
  --text-3:     #7c8c96;
  --line:       #1e2a33;
  --line-2:     #2b3944;

  --brand:      #4bb8d4;
  --brand-2:    #7fd4e8;
  --brand-soft: #0f2c35;
  --accent:     #f0a33c;

  --shadow-1:   0 1px 2px rgba(0, 0, 0, .5);
  --shadow-2:   0 1px 2px rgba(0, 0, 0, .5), 0 14px 30px -16px rgba(0, 0, 0, .92);
}

/* ③ 手动切回浅色：系统是深色也保持亮底 */
:root[data-theme="light"] { color-scheme: light; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  /* 兜底：万一将来又出现超宽内容，也不至于让整页可以左右拖动。
     用 clip 而不是 hidden —— hidden 会让 html 变成滚动容器，sticky 顶栏就失效了。 */
  overflow-x: clip;
}

body {
  margin: 0;
  background-color: var(--bg);
  background-image: var(--bg-grad);
  background-repeat: no-repeat;
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  /* 长 URL / 长英文单词在窄屏上必须能断行，否则会撑出横向滚动条 */
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: rgba(14, 116, 144, .14);
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; }

a { color: var(--brand); text-decoration: none; }
a:hover { color: var(--brand-2); text-decoration: underline; text-underline-offset: 3px; }

/* 触摸设备上取消双击缩放等待，点击更跟手 */
a, button, summary, label { touch-action: manipulation; }

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding-left: max(24px, var(--safe-l));
  padding-right: max(24px, var(--safe-r));
}

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 999;
  /* 用页面底色当字色 = 在品牌色块上做反白。深色模式里 --brand 是亮青，
     固定用白色会掉到 2.3:1，跟着变量走两种主题都能过 AA。 */
  background: var(--brand); color: var(--bg);
  padding: 10px 16px; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------- 阅读进度条 ---------- */
#progress {
  position: fixed; top: 0; left: 0; height: 2px; width: 0;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  z-index: 60; transition: width .1s linear;
}

/* ---------- 顶栏 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  /* 纯色回退：不支持 color-mix() 的旧浏览器会保留这一条 */
  background: var(--bg);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.6) blur(12px);
  -webkit-backdrop-filter: saturate(1.6) blur(12px);
  border-bottom: 1px solid var(--line);
  transition: transform .26s ease;
}
/* 手机上向下滚动时收起顶栏，把屏幕让给正文（由 JS 按视口宽度决定是否启用） */
.site-header.is-hidden { transform: translateY(-100%); }

.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 20px; min-height: 68px;
}

.brand { display: inline-flex; align-items: center; gap: 12px; min-width: 0; color: inherit; }
.brand:hover { text-decoration: none; }
.brand-mark {
  flex: none; width: 38px; height: 38px; border-radius: 11px;
  display: grid; place-items: center;
  background: linear-gradient(145deg, var(--brand), #0a4f63);
  color: #fff; box-shadow: var(--shadow-1);
}
.brand-mark svg { width: 22px; height: 22px; display: block; }
.brand-text { display: flex; flex-direction: column; line-height: 1.25; min-width: 0; }
.brand-text strong {
  font-size: 16.5px; font-weight: 650; letter-spacing: .01em;
  /* 顶栏挤不下时让站名先省略，而不是把导航和主题开关推出屏幕 */
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.brand-text small { font-size: 12px; color: var(--text-3); letter-spacing: .01em; }

.site-nav { display: flex; align-items: center; gap: 4px; flex: none; }
.site-nav a {
  display: inline-flex; align-items: center;
  padding: 7px 13px; border-radius: 999px; font-size: 14.5px;
  color: var(--text-2); transition: background .16s, color .16s;
}
.site-nav a:hover { background: var(--surface-2); color: var(--text); text-decoration: none; }
.site-nav a[aria-current="page"] { background: var(--brand-soft); color: var(--brand-2); font-weight: 600; }

/* 导航与主题开关一起靠右 */
.header-actions { display: flex; align-items: center; gap: 6px; flex: none; }

/* 夜间模式开关 */
.theme-toggle {
  flex: none; display: grid; place-items: center;
  width: 36px; height: 36px; padding: 0;
  border: 1px solid var(--line); border-radius: 999px;
  background: var(--surface); color: var(--text-2);
  cursor: pointer; -webkit-appearance: none; appearance: none;
  transition: background .16s, color .16s, border-color .16s;
}
.theme-toggle:hover { background: var(--surface-2); color: var(--text); border-color: var(--line-2); }
.theme-toggle:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }
.theme-toggle svg { width: 17px; height: 17px; display: block; }

/* 浅色下显示月亮，夜间显示太阳（点一下就是切到另一边） */
.theme-toggle .ico-sun { display: none; }
:root[data-theme="dark"] .theme-toggle .ico-moon { display: none; }
:root[data-theme="dark"] .theme-toggle .ico-sun { display: block; }
/* 禁用 JS 时页面不会有 data-theme，按系统偏好兜底 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .ico-moon { display: none; }
  :root:not([data-theme="light"]) .theme-toggle .ico-sun { display: block; }
}

/* ---------- 首页 Hero ---------- */
.hero { padding: 76px 0 44px; text-align: center; }
.hero h1 {
  margin: 0 0 14px; font-size: clamp(30px, 5vw, 44px); line-height: 1.22;
  font-weight: 700; letter-spacing: -.015em;
}
.hero p { margin: 0 auto; max-width: 620px; color: var(--text-2); font-size: 17px; }
.hero-rule {
  width: 52px; height: 3px; border-radius: 2px; margin: 26px auto 0;
  background: linear-gradient(90deg, var(--brand), var(--accent));
}

/* ---------- 文章列表 ---------- */
.post-list { padding: 8px 0 90px; display: grid; gap: 18px; }

.card {
  position: relative; background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow-1);
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow-2); border-color: var(--line-2); }
.card-link { display: block; padding: 26px 28px; color: inherit; }
.card-link:hover { text-decoration: none; }
.card h2 { margin: 0 0 10px; font-size: 21px; font-weight: 650; letter-spacing: -.01em; line-height: 1.4; }
.card h2 span { border-bottom: 1.5px solid transparent; transition: border-color .18s; }
.card:hover h2 span { border-color: var(--brand); }
.card p { margin: 0 0 16px; color: var(--text-2); font-size: 15px; }
.card-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-bottom: 12px; font-size: 13px; color: var(--text-3); }
.card-meta .dot { width: 3px; height: 3px; border-radius: 50%; background: var(--line-2); }

.tags { display: flex; flex-wrap: wrap; gap: 7px; }
.tag {
  font-size: 12.5px; padding: 3px 10px; border-radius: 999px;
  background: var(--surface-2); color: var(--text-2); border: 1px solid var(--line);
}

/* ---------- 文章页头部 ---------- */
.post-head { padding: 54px 0 30px; border-bottom: 1px solid var(--line); }
.crumbs { font-size: 13.5px; color: var(--text-3); margin-bottom: 18px; }
.crumbs a { color: var(--text-2); }
.post-head h1 {
  margin: 0 0 16px; font-size: clamp(26px, 4vw, 36px); line-height: 1.3;
  font-weight: 700; letter-spacing: -.018em;
}
.post-head .lede { margin: 0 0 20px; color: var(--text-2); font-size: 16.5px; max-width: 760px; }
.post-meta {
  --meta-gap: 12px;
  display: flex; flex-wrap: wrap; align-items: center;
  gap: 5px var(--meta-gap);
  font-size: 13.5px; color: var(--text-3);
}
/* 条目与分隔圆点绑在同一组里，窄屏换行时圆点不会孤零零跑到行首 */
.post-meta .meta-item { display: inline-flex; align-items: center; gap: var(--meta-gap); }
.post-meta .dot { width: 3px; height: 3px; border-radius: 50%; background: var(--line-2); }

.post-layout {
  display: grid; grid-template-columns: minmax(0, 1fr) 236px;
  gap: 52px; align-items: start; padding: 44px 0 80px;
}
.post-main { min-width: 0; }

/* ---------- 目录 ---------- */
.toc { position: sticky; top: 92px; font-size: 13.5px; }

/* 桌面端：summary 隐藏，<details> 靠 open 属性常开；标题用普通段落显示 */
.toc > .toc-title { display: none; }
.toc-caption {
  margin: 0 0 12px; font-size: 12px; font-weight: 650; letter-spacing: .09em;
  text-transform: uppercase; color: var(--text-3);
}
.toc-title::-webkit-details-marker { display: none; }
.toc-title::marker { content: ""; }
.toc ol { list-style: none; margin: 0; padding: 0; }
.toc li { margin: 0; }
.toc a {
  display: block; padding: 5px 12px; border-left: 2px solid var(--line);
  color: var(--text-2); line-height: 1.55;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.toc a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }
.toc a.active { border-left-color: var(--brand); color: var(--brand-2); font-weight: 600; background: var(--brand-soft); }
.toc .lvl-3 a { padding-left: 26px; font-size: 13px; }

/* ---------- 正文排版 ---------- */
.prose { font-size: 16px; line-height: 1.85; }
.prose > *:first-child { margin-top: 0; }

.prose h2 {
  margin: 56px 0 18px; padding-bottom: 10px; font-size: 23px; font-weight: 650;
  line-height: 1.4; letter-spacing: -.012em; border-bottom: 1px solid var(--line);
}
.prose h3 { margin: 40px 0 14px; font-size: 18.5px; font-weight: 650; line-height: 1.45; }
.prose h4 { margin: 30px 0 12px; font-size: 16.5px; font-weight: 650; color: var(--text-2); }
.prose h2:first-child, .prose h3:first-child { margin-top: 0; }

/* 点目录跳转时，让标题落在吸顶栏下方，而不是被盖住 */
.prose h2, .prose h3, .prose h4, .prose h5, .prose h6 { scroll-margin-top: 84px; }

.prose p { margin: 0 0 18px; }
.prose strong { font-weight: 650; color: var(--text); }
.prose ul, .prose ol { margin: 0 0 18px; padding-left: 25px; }
.prose li { margin: 5px 0; }
.prose li > ul, .prose li > ol { margin: 5px 0; }
.prose hr { margin: 40px 0; border: 0; border-top: 1px solid var(--line); }

.prose blockquote {
  margin: 22px 0; padding: 4px 20px; border-left: 3px solid var(--brand);
  background: var(--surface-2); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-2);
}
.prose blockquote p:last-child { margin-bottom: 0; }

.prose :not(pre) > code {
  font-family: var(--font-mono); font-size: .89em;
  padding: .14em .42em; border-radius: 5px;
  background: var(--brand-soft); color: var(--brand-2);
  word-break: break-word;
}
.prose pre {
  margin: 22px 0; padding: 16px 18px; overflow-x: auto;
  background: var(--surface-2); border: 1px solid var(--line);
  border-radius: var(--radius-sm); box-shadow: var(--shadow-1);
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-x: contain;
}
.prose pre code {
  display: block; padding: 0; background: none; border: 0;
  font-family: var(--font-mono); font-size: 13.5px; line-height: 1.72;
  color: var(--text); white-space: pre;
}

.prose table {
  width: 100%; margin: 22px 0; border-collapse: collapse; font-size: 14.5px;
  display: block; overflow-x: auto;
}
.prose th, .prose td { padding: 9px 14px; border: 1px solid var(--line); text-align: left; }
.prose th { background: var(--surface-2); font-weight: 650; }

/* 文档图片 */
.prose img {
  display: block; margin: 24px auto; max-width: 100%; height: auto;
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: #fff; box-shadow: var(--shadow-1); cursor: zoom-in;
}
/* 文档里的 <img> 会被包进 <p>，这里去掉由此产生的多余外边距 */
.prose p:has(> img) { margin-bottom: 0; }
.prose p:has(> img) img { margin-top: 24px; margin-bottom: 24px; }

/* 带 height 的文档图会被转成 max-height；宽度必须交回 auto，
   否则 max-height 只压高度、宽度不动，图会被纵向压扁。 */
.prose img[style*="max-height"] { width: auto; }

/* ---------- 数学公式（KaTeX） ---------- */
.prose .math-display {
  margin: 26px 0; padding: 2px 0;
  overflow-x: auto; overflow-y: hidden;
}
.prose .math-display .katex-display { margin: 0; }
.prose .katex { font-size: 1.05em; }

/* ---------- 文章页脚导航 ---------- */
.post-foot {
  margin-top: 56px; padding-top: 26px; border-top: 1px solid var(--line);
  display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font-size: 14.5px;
}

/* ---------- 页脚 ---------- */
.site-footer {
  margin-top: 40px; border-top: 1px solid var(--line);
  background: var(--surface);
  background: color-mix(in srgb, var(--surface) 55%, transparent);
  padding-bottom: var(--safe-b);
}
.footer-inner {
  display: flex; justify-content: space-between; align-items: center;
  gap: 14px; flex-wrap: wrap; padding: 30px 0; font-size: 13.5px; color: var(--text-3);
}
.footer-inner p { margin: 0; }
.footer-inner a { color: var(--text-2); }
.footer-links { display: flex; gap: 16px; flex-wrap: wrap; }

/* ---------- 图片灯箱 ---------- */
#lightbox {
  position: fixed; inset: 0; z-index: 100; display: none;
  padding: calc(40px + var(--safe-t)) max(24px, var(--safe-r)) calc(40px + var(--safe-b)) max(24px, var(--safe-l));
  background: rgba(9, 18, 24, .9);
  backdrop-filter: blur(4px);
  cursor: zoom-out;
  align-items: center; justify-content: center;
  overscroll-behavior: contain;
}
#lightbox.open { display: flex; }
#lightbox img {
  max-width: 100%; max-height: 100%; border-radius: 8px;
  box-shadow: 0 24px 60px rgba(0, 0, 0, .5); background: #fff; cursor: default;
  transition: transform .18s ease;
}
#lightbox .lb-close {
  position: absolute; width: 44px; height: 44px;
  top: calc(10px + var(--safe-t)); right: calc(12px + var(--safe-r));
  border: 0; border-radius: 50%; cursor: pointer;
  background: rgba(255, 255, 255, .16); color: #fff; font-size: 22px; line-height: 1;
}
#lightbox .lb-close:hover { background: rgba(255, 255, 255, .28); }
/* 手指下滑时的跟手位移 */
#lightbox.dragging img { transition: none; }

/* ---------- 回到顶部 ---------- */
#to-top {
  position: fixed; right: calc(26px + var(--safe-r)); bottom: calc(26px + var(--safe-b)); z-index: 55;
  width: 46px; height: 46px; border-radius: 50%; cursor: pointer;
  display: grid; place-items: center; opacity: 0; pointer-events: none;
  background: var(--surface); color: var(--brand);
  border: 1px solid var(--line); box-shadow: var(--shadow-2);
  transition: opacity .2s, transform .2s;
}
#to-top.show { opacity: 1; pointer-events: auto; }
#to-top:hover { transform: translateY(-2px); }

/* ---------- 关于页 ---------- */
.page-shell { padding: 60px 0 90px; max-width: 760px; }
.page-shell h1 { margin: 0 0 22px; font-size: clamp(26px, 3.4vw, 34px); letter-spacing: -.018em; }
.info-list { margin: 34px 0 0; border-top: 1px solid var(--line); }
.info-row {
  display: flex; gap: 16px; padding: 14px 0; border-bottom: 1px solid var(--line); font-size: 14.5px;
}
.info-row dt { flex: none; width: 96px; color: var(--text-3); margin: 0; }
.info-row dd { margin: 0; color: var(--text-2); word-break: break-all; }

/* ---------- 404 ---------- */
.err-shell { padding: 110px 0 130px; text-align: center; }
.err-shell .code { font-size: 74px; font-weight: 700; letter-spacing: -.03em; line-height: 1; color: var(--line-2); }
.err-shell h1 { margin: 20px 0 10px; font-size: 24px; }
.err-shell p { margin: 0 0 26px; color: var(--text-2); }

/* ==========================================================================
   窄屏 / 平板：目录改为正文之前的可折叠卡片
   ========================================================================== */
@media (max-width: 1040px) {
  .post-layout { grid-template-columns: minmax(0, 1fr); gap: 0; }

  .toc {
    order: -1;                 /* 关键：从"文章末尾"提到"正文之前" */
    position: static;
    margin-bottom: 26px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: var(--shadow-1);
    overflow: hidden;
    font-size: 14px;
  }
  .toc-caption { display: none; }

  .toc > .toc-title {
    display: flex; align-items: center; justify-content: space-between; gap: 10px;
    margin: 0; padding: 15px 16px;
    font-size: 14.5px; font-weight: 600; letter-spacing: 0; text-transform: none;
    color: var(--text); cursor: pointer;
    list-style: none;
  }
  .toc > .toc-title:hover { background: var(--surface-2); }
  .toc-count { font-size: 12.5px; font-weight: 500; color: var(--text-3); }
  /* 自绘展开箭头 */
  .toc-title::after {
    content: ""; flex: none; width: 9px; height: 9px; margin-left: 6px;
    border-right: 2px solid var(--text-3); border-bottom: 2px solid var(--text-3);
    transform: rotate(45deg) translate(-2px, -2px);
    transition: transform .2s ease;
  }
  .toc[open] .toc-title::after { transform: rotate(-135deg) translate(-1px, -1px); }

  .toc nav { padding: 4px 0 8px; border-top: 1px solid var(--line); }
  .toc a {
    padding: 12px 16px;                 /* 触摸目标约 42px 高 */
    white-space: normal;
    border-left: 0;
  }
  .toc a.active { background: var(--brand-soft); box-shadow: inset 3px 0 0 var(--brand); }
  .toc .lvl-3 a { padding-left: 32px; font-size: 13.5px; }
}

/* ==========================================================================
   手机
   ========================================================================== */
@media (max-width: 640px) {
  .wrap {
    padding-left: max(18px, var(--safe-l));
    padding-right: max(18px, var(--safe-r));
  }

  .header-inner { min-height: 58px; gap: 12px; }
  .brand-text small { display: none; }
  .brand-mark { width: 34px; height: 34px; border-radius: 10px; }
  .brand-mark svg { width: 20px; height: 20px; }
  .site-nav a { padding: 11px 14px; font-size: 14.5px; }   /* 触摸目标约 44px */
  /* 主题开关也按 44px 触摸目标来 */
  .theme-toggle { width: 42px; height: 42px; }
  .theme-toggle svg { width: 18px; height: 18px; }
  .header-actions { gap: 4px; }

  .hero { padding: 52px 0 32px; }
  .hero p { font-size: 15.5px; }

  .card-link { padding: 22px 20px; }
  .card h2 { font-size: 19px; }
  .card p { font-size: 14.5px; }

  .post-head { padding: 34px 0 24px; }
  .post-head .lede { font-size: 15.5px; }
  .post-meta { font-size: 13px; --meta-gap: 9px; }
  .post-layout { padding: 28px 0 60px; }

  /* 中文在窄屏上适当放大更易读 */
  .prose { font-size: 16.5px; line-height: 1.9; }
  .prose h2 { margin-top: 44px; font-size: 20.5px; }
  .prose h3 { font-size: 17.5px; }
  .prose h4 { font-size: 16px; }
  .prose ul, .prose ol { padding-left: 21px; }
  .prose h2, .prose h3, .prose h4, .prose h5, .prose h6 { scroll-margin-top: 70px; }
  .prose pre { padding: 13px 14px; }
  .prose pre code { font-size: 12.5px; line-height: 1.7; }
  .prose .katex { font-size: 1em; }
  .prose .math-display { margin: 20px 0; }

  .post-foot { margin-top: 44px; }

  .footer-inner { padding: 24px 0; gap: 10px; }

  #to-top { right: calc(16px + var(--safe-r)); bottom: calc(16px + var(--safe-b)); width: 44px; height: 44px; }
}

/* 超窄屏（≤380px）把顶栏再收紧一档，保证品牌名 + 导航 + 主题开关排得下 */
@media (max-width: 380px) {
  .header-inner { gap: 8px; }
  .brand { gap: 9px; }
  .brand-mark { width: 30px; height: 30px; border-radius: 9px; }
  .brand-mark svg { width: 18px; height: 18px; }
  .brand-text strong { font-size: 15px; }
  .site-nav a { padding: 9px 11px; font-size: 13.5px; }
  .theme-toggle { width: 38px; height: 38px; }
  .theme-toggle svg { width: 17px; height: 17px; }
}

/* 触摸设备：hover 效果没意义，去掉卡片的位移避免误触抖动 */
@media (hover: none) {
  .card:hover { transform: none; }
  .toc > .toc-title:hover { background: transparent; }
}

/* 尊重系统的"减少动态效果"设置 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}