/* ==========================================================================
   如話記Blog · 极简白 + 衬线字
   设计原则：暖白底、墨色字、单一强调色、大量留白、正文列宽 ≤ 34em
   ========================================================================== */

:root {
  --bg:            #fffdf9;
  --bg-soft:       #f7f4ee;
  --bg-code:       #f4f1ea;
  --ink:           #1d1b18;
  --ink-soft:      #4a4640;
  --ink-muted:     #8b857c;
  --ink-faint:     #b6b0a6;
  --rule:          #e6e1d7;
  --rule-soft:     #efebe3;
  --accent:        #9b3d2f;
  --accent-soft:   #f3e3df;
  --mark:          #fbeeb0;

  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "SimSun", "STSong", Georgia, "Times New Roman", serif;
  --mono: "SFMono-Regular", "JetBrains Mono", Menlo, Consolas, "Courier New", monospace;

  --measure: 34em;
  --shell: 46rem;
  --radius: 3px;
  --ease: cubic-bezier(.2, .7, .3, 1);

  color-scheme: light dark;
}

/* ==========================================================================
   夜间模式 —— 只覆盖变量，组件规则全部复用上面的 :root 配色
   ========================================================================== */
html.dark {
  --bg:            #15130f;
  --bg-soft:       #1f1c17;
  --bg-code:       #221e18;
  --ink:           #ece6db;
  --ink-soft:      #c3bcae;
  --ink-muted:     #968f82;
  --ink-faint:     #6f685d;
  --rule:          #2c2820;
  --rule-soft:     #241f19;
  --accent:        #db897a;
  --accent-soft:   #3a231d;
  --mark:          #fbeeb0;

  color-scheme: dark;
}

* { box-sizing: border-box; }

/* 切换主题时的轻微淡入淡出：仅作用于配色相关属性。
   首屏前已由内联脚本定好主题，故初次加载不会闪烁；点击切换时才平滑过渡。 */
*,
*::before,
*::after {
  transition: background-color .3s ease, border-color .3s ease,
              color .3s ease, box-shadow .3s ease;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color .3s var(--ease), color .3s var(--ease);
}

a { color: inherit; text-decoration: none; }

::selection { background: var(--mark); color: var(--ink); }

/* ---------- 阅读进度条 ---------- */
.progress {
  position: fixed;
  inset: 0 auto auto 0;
  height: 2px;
  width: 0;
  background: var(--accent);
  z-index: 60;
  transition: width .12s linear;
}

/* ---------- 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--rule-soft);
  transition: background-color .3s var(--ease), border-color .3s var(--ease);
}

.site-header__inner {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 1.15rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand { display: flex; align-items: center; gap: .7rem; min-width: 0; }

.brand__avatar {
  width: 2.6rem;
  height: 2.6rem;
  border-radius: 50%;
  object-fit: cover;
  flex: none;
  border: 1px solid var(--rule);
  background: var(--bg-soft);
}

.brand__text { display: flex; flex-direction: column; align-items: flex-start; gap: .2rem; min-width: 0; }

.brand__title {
  font-size: 1.22rem;
  font-weight: 600;
  letter-spacing: .08em;
  white-space: nowrap;
}
.brand__title:hover { color: var(--accent); }

.brand__tagline {
  font-size: .74rem;
  color: var(--ink-faint);
  letter-spacing: .14em;
  white-space: normal;
}

.brand__social {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .5rem;
  margin-top: .25rem;
}
.brand__social-link {
  display: inline-flex;
  align-items: center;
  gap: .3em;
  font-size: .74rem;
  color: var(--ink-muted);
  text-decoration: none;
  transition: color .2s var(--ease);
}
.brand__social-link:hover { color: var(--accent); }
.brand__social-link svg { flex: none; }

@media (max-width: 560px) {
  .brand__social-link span { display: none; }
  .brand__social { gap: .65rem; margin-top: .15rem; }
}

.nav { display: flex; gap: 1.4rem; flex-shrink: 0; }

.nav a {
  font-size: .9rem;
  color: var(--ink-muted);
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}
.nav a:hover { color: var(--ink); }
.nav a.is-active { color: var(--ink); border-bottom-color: var(--accent); }

/* ---------- 头部操作区（导航 + 夜间切换） ---------- */
.header-actions {
  display: flex;
  align-items: center;
  gap: 1.2rem;
  flex-shrink: 0;
}

/* 单按钮主题切换：点击在 跟随系统 / 浅色 / 深色 之间循环 */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: .4em;
  padding: .42em .8em;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: .82rem;
  line-height: 1;
  color: var(--ink-muted);
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 999px;
  cursor: pointer;
  white-space: nowrap;
  transition: color .2s var(--ease), border-color .2s var(--ease),
              background-color .2s var(--ease), transform .2s var(--ease);
}
.theme-toggle:hover {
  color: var(--accent);
  border-color: var(--accent);
  transform: translateY(-1px);
}
.theme-toggle:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.theme-toggle__icon { font-size: 1.05em; line-height: 1; }

@media (max-width: 560px) {
  .theme-toggle__label { display: none; }
}

/* ---------- 主体容器 ---------- */
.app {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 3.5rem 1.5rem 5rem;
  position: relative;
}
.app.is-narrow { max-width: 42rem; }

/* ---------- 评论区（Giscus 宿主） ---------- */
.comments-host {
  max-width: 42rem;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 5rem;
  border-top: 1px solid var(--rule-soft);
}
.comments-host[hidden] { display: none; }
.comments-host .comments-title {
  margin: 0 0 1.1rem;
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--ink);
}

/* Waline 暗色适配：跟随站点 html.dark（Waline 自身也会据 dark:'html.dark' 加 .dark 类） */
html.dark .wl-comment,
html.dark .wl-panel,
html.dark .wl-card,
html.dark .wl-cards,
html.dark .wl-header,
html.dark .wl-footer {
  --waline-white: #1c1c1e;
  --waline-light-gray: #2a2a2e;
  --waline-dark-gray: #b0b0b5;
  --waline-bgcolor: #1c1c1e;
  --waline-bgcolor-light: #242427;
  --waline-border-color: #3a3a42;
  --waline-disable-bgcolor: #2a2a2e;
  --waline-disable-color: #6b6b70;
  --waline-theme-color: var(--accent, #6b8cff);
}

/* ---------- 首页简介 ---------- */
.intro {
  margin: 0 0 3rem;
  padding-bottom: 2.25rem;
  border-bottom: 1px solid var(--rule-soft);
}
.intro p {
  margin: 0 0 .35rem;
  font-size: 1.06rem;
  color: var(--ink-soft);
  max-width: var(--measure);
}

/* ---------- 搜索 ---------- */
.search { position: relative; margin: 0 0 2.5rem; }

.search input {
  width: 100%;
  padding: .7rem 0 .7rem 1.6rem;
  font-family: var(--serif);
  font-size: 1rem;
  color: var(--ink);
  background: transparent;
  border: 0;
  border-bottom: 1px solid var(--rule);
  outline: none;
  transition: border-color .25s var(--ease);
}
.search__icon {
  position: absolute;
  left: 0;
  top: .9rem;
  font-size: 1rem;
  line-height: 1;
  color: var(--ink-faint);
  pointer-events: none;   /* 点击穿透到输入框，不挡输入 */
}
.search input::placeholder { color: var(--ink-faint); }
.search input:focus { border-bottom-color: var(--accent); }
.search input::-webkit-search-cancel-button { display: none; }

.search__clear {
  position: absolute;
  right: 0;
  top: .8rem;
  font-size: .82rem;
  color: var(--ink-muted);
  border-bottom: 1px solid var(--rule);
}
.search__clear:hover { color: var(--accent); border-bottom-color: var(--accent); }

.result-hint {
  margin: -1.6rem 0 2.2rem;
  font-size: .86rem;
  color: var(--ink-muted);
}
.result-hint strong { color: var(--ink); }

.empty {
  color: var(--ink-muted);
  padding: 2.5rem 0;
  border-top: 1px solid var(--rule-soft);
}
.empty a { color: var(--accent); border-bottom: 1px solid var(--accent-soft); }

/* ---------- 文章列表 ---------- */
.post-list { display: flex; flex-direction: column; }

.post-item {
  padding: 2.1rem 0;
  border-bottom: 1px solid var(--rule-soft);
}
.post-item:first-child { padding-top: 0; }

.post-item__meta,
.post__meta {
  display: flex;
  align-items: center;
  gap: .5rem;
  font-size: .78rem;
  color: var(--ink-faint);
  letter-spacing: .06em;
  font-variant-numeric: tabular-nums;
}
.dot { color: var(--ink-faint); }

.post-item__title {
  margin: .5rem 0 .55rem;
  font-size: 1.42rem;
  font-weight: 600;
  line-height: 1.45;
  letter-spacing: .01em;
}
.post-item__title a {
  background-image: linear-gradient(var(--accent), var(--accent));
  background-size: 0 1px;
  background-position: 0 100%;
  background-repeat: no-repeat;
  transition: background-size .35s var(--ease), color .2s var(--ease);
}
.post-item__title a:hover { color: var(--accent); background-size: 100% 1px; }

.post-item__summary {
  margin: 0 0 .9rem;
  color: var(--ink-soft);
  max-width: var(--measure);
  font-size: .98rem;
  line-height: 1.8;
}

mark { background: var(--mark); color: var(--ink); padding: 0 .1em; }

/* ---------- 标签 chip ---------- */
.chips { display: flex; flex-wrap: wrap; gap: .45rem; }
.chips--all { margin-bottom: 2.5rem; padding-bottom: 2rem; border-bottom: 1px solid var(--rule-soft); }

.chip {
  font-size: .76rem;
  letter-spacing: .04em;
  color: var(--ink-muted);
  padding: .18rem .6rem;
  border: 1px solid var(--rule);
  border-radius: 100px;
  transition: all .2s var(--ease);
}
.chip::before { content: '#'; opacity: .45; margin-right: .12em; }
.chip:hover { color: var(--accent); border-color: var(--accent); }
.chip.is-active { color: #fff; background: var(--accent); border-color: var(--accent); }

/* ---------- 分页 ---------- */
.pager {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 3rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--rule-soft);
  font-size: .87rem;
}
.pager__btn { color: var(--ink-soft); }
.pager__btn:hover { color: var(--accent); }
.pager__btn.is-disabled { color: var(--ink-faint); cursor: default; }
.pager__info { color: var(--ink-faint); font-variant-numeric: tabular-nums; letter-spacing: .1em; }

/* ---------- 页面标题区 ---------- */
.page-head {
  margin-bottom: 2.6rem;
  padding-bottom: 1.8rem;
  border-bottom: 1px solid var(--rule-soft);
}
.page-head h1 {
  margin: .3rem 0 .5rem;
  font-size: 1.9rem;
  font-weight: 600;
  letter-spacing: .02em;
}
.page-head p { margin: 0; color: var(--ink-muted); font-size: .9rem; }

.back {
  display: inline-block;
  font-size: .82rem;
  color: var(--ink-muted);
  margin-bottom: 1.4rem;
  letter-spacing: .04em;
}
.back:hover { color: var(--accent); }

/* ---------- 文章详情 ---------- */
.post__header {
  margin-bottom: 2.8rem;
  padding-bottom: 1.9rem;
  border-bottom: 1px solid var(--rule-soft);
}
.post__title {
  margin: 0 0 .8rem;
  font-size: 2.1rem;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: .015em;
}
.post__meta { margin-bottom: 1.1rem; }

/* ---------- 正文排版 ---------- */
.prose { max-width: var(--measure); }

.prose > *:first-child { margin-top: 0; }

.prose p {
  margin: 0 0 1.5rem;
  text-align: justify;
  hyphens: auto;
}

.prose h1, .prose h2, .prose h3, .prose h4 {
  position: relative;
  font-weight: 600;
  line-height: 1.5;
  scroll-margin-top: 5.5rem;
}
.prose h1 { font-size: 1.7rem; margin: 3rem 0 1.1rem; }
.prose h2 {
  font-size: 1.32rem;
  margin: 3.2rem 0 1.15rem;
  padding-top: 1.1rem;
  border-top: 1px solid var(--rule-soft);
  letter-spacing: .02em;
}
.prose h3 { font-size: 1.1rem; margin: 2.2rem 0 .8rem; color: var(--ink-soft); }
.prose h4 { font-size: 1rem; margin: 1.8rem 0 .6rem; color: var(--ink-soft); }

.anchor {
  position: absolute;
  left: -1.1em;
  top: auto;
  color: var(--ink-faint);
  opacity: 0;
  font-weight: 400;
  transition: opacity .2s var(--ease);
}
.prose h2 .anchor { top: 1.1rem; }
.prose h1:hover .anchor,
.prose h2:hover .anchor,
.prose h3:hover .anchor { opacity: 1; }
.anchor:hover { color: var(--accent); }

.prose strong { font-weight: 700; color: var(--ink); }
.prose em { font-style: italic; }
.prose del { color: var(--ink-faint); }

.prose a {
  color: var(--ink);
  border-bottom: 1px solid var(--accent);
  padding-bottom: 1px;
  transition: background .2s var(--ease), color .2s var(--ease);
}
.prose a:hover { color: var(--accent); background: var(--accent-soft); }

.prose ul, .prose ol { margin: 0 0 1.5rem; padding-left: 1.4rem; }
.prose li { margin-bottom: .55rem; }
.prose li::marker { color: var(--ink-faint); }
.prose ul ul, .prose ol ol, .prose ul ol, .prose ol ul { margin: .55rem 0 0; }

.prose blockquote {
  margin: 2rem 0;
  padding: .2rem 0 .2rem 1.4rem;
  border-left: 2px solid var(--accent);
  color: var(--ink-soft);
  font-style: italic;
}
.prose blockquote p { margin-bottom: .7rem; }
.prose blockquote p:last-child { margin-bottom: 0; }

.prose hr {
  margin: 3rem auto;
  width: 5rem;
  border: 0;
  border-top: 1px solid var(--rule);
}

.prose img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 2rem 0;
  border-radius: var(--radius);
}

.prose code {
  font-family: var(--mono);
  font-size: .86em;
  background: var(--bg-code);
  padding: .12em .4em;
  border-radius: var(--radius);
  color: var(--accent);
}

/* ---------- 代码块 ---------- */
.code-block {
  position: relative;
  margin: 2rem 0;
  background: var(--bg-code);
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius);
  overflow: hidden;
}
.code-block::before {
  content: attr(data-lang);
  position: absolute;
  top: .45rem;
  left: .9rem;
  font-family: var(--mono);
  font-size: .66rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.code-block pre {
  margin: 0;
  padding: 1.9rem 1.1rem 1.1rem;
  overflow-x: auto;
}
.code-block code {
  background: none;
  padding: 0;
  color: var(--ink);
  font-size: .84rem;
  line-height: 1.75;
  white-space: pre;
}

.copy-btn {
  position: absolute;
  top: .4rem;
  right: .5rem;
  font-family: var(--serif);
  font-size: .72rem;
  color: var(--ink-muted);
  background: var(--bg);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  padding: .15rem .5rem;
  cursor: pointer;
  opacity: 0;
  transition: opacity .2s var(--ease), color .2s var(--ease);
}
.code-block:hover .copy-btn { opacity: 1; }
.copy-btn:hover { color: var(--accent); border-color: var(--accent); }

/* ---------- 表格 ---------- */
.table-wrap { margin: 2rem 0; overflow-x: auto; }
.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: .92rem;
}
.prose th, .prose td {
  padding: .6rem .8rem;
  border-bottom: 1px solid var(--rule-soft);
  vertical-align: top;
}
.prose thead th {
  border-bottom: 1px solid var(--rule);
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
}
.prose tbody tr:hover { background: var(--bg-soft); }

/* ---------- 目录（宽屏浮在右侧） ---------- */
.toc {
  margin: 0 0 2.5rem;
  padding: 1.1rem 1.2rem;
  background: var(--bg-soft);
  border-radius: var(--radius);
  font-size: .86rem;
}
.toc__title {
  font-size: .72rem;
  letter-spacing: .18em;
  color: var(--ink-faint);
  margin-bottom: .5rem;
}
.toc ul { list-style: none; margin: 0; padding: 0; }
.toc li { margin: .2rem 0; }
.toc li a { color: var(--ink-muted); transition: color .2s var(--ease); }
.toc li a:hover { color: var(--accent); }
.toc li.is-active > a { color: var(--ink); font-weight: 600; }
.toc__l3 { padding-left: 1rem; font-size: .95em; }

@media (min-width: 1180px) {
  .toc {
    position: fixed;
    top: 7rem;
    left: calc(50% + 22rem);
    width: 13rem;
    max-height: 70vh;
    overflow-y: auto;
    margin: 0;
    padding: 0 0 0 1rem;
    background: none;
    border-left: 1px solid var(--rule-soft);
    border-radius: 0;
  }
  .toc li.is-active > a::before {
    content: '';
    position: absolute;
    left: -1rem;
    width: 1px;
    height: 1.5em;
    background: var(--accent);
  }
  .toc li { position: relative; }
}

/* ---------- 相关 & 上下篇 ---------- */
.related {
  margin: 3.5rem 0 0;
  padding-top: 1.8rem;
  border-top: 1px solid var(--rule-soft);
}
.related h3 {
  margin: 0 0 .9rem;
  font-size: .78rem;
  font-weight: 400;
  letter-spacing: .18em;
  color: var(--ink-faint);
}
.related ul { list-style: none; margin: 0; padding: 0; }
.related li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  padding: .4rem 0;
}
.related li a { color: var(--ink-soft); }
.related li a:hover { color: var(--accent); }
.related__date {
  font-size: .76rem;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
}

.post-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 3rem;
  padding-top: 1.8rem;
  border-top: 1px solid var(--rule-soft);
}
.post-nav__item span {
  display: block;
  font-size: .74rem;
  letter-spacing: .1em;
  color: var(--ink-faint);
  margin-bottom: .3rem;
}
.post-nav__item strong {
  font-size: .95rem;
  font-weight: 600;
  color: var(--ink-soft);
  line-height: 1.5;
}
.post-nav__item:hover strong { color: var(--accent); }
.post-nav__item.is-next { text-align: right; }

/* ---------- 标签云 ---------- */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: .8rem 1.6rem;
  align-items: baseline;
}
.tag-cloud__item {
  color: var(--ink-soft);
  transition: color .2s var(--ease);
}
.tag-cloud__item::before { content: '#'; color: var(--ink-faint); margin-right: .1em; }
.tag-cloud__item:hover { color: var(--accent); }
.tag-cloud__item sup {
  font-size: .58em;
  color: var(--ink-faint);
  margin-left: .18em;
  font-variant-numeric: tabular-nums;
}

/* ---------- 归档 ---------- */
.archive-year { margin-bottom: 2.8rem; }
.archive-year h2 {
  display: flex;
  align-items: baseline;
  gap: .7rem;
  margin: 0 0 .9rem;
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: .1em;
  color: var(--ink);
}
.archive-year h2 span {
  font-size: .74rem;
  font-weight: 400;
  letter-spacing: .06em;
  color: var(--ink-faint);
}
.archive-list { list-style: none; margin: 0; padding: 0; }
.archive-list li {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding: .5rem 0;
  border-bottom: 1px solid var(--rule-soft);
}
.archive-list__date {
  width: 3.2rem;
  flex-shrink: 0;
  font-size: .8rem;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}
.archive-list li a { flex: 1; color: var(--ink-soft); }
.archive-list li a:hover { color: var(--accent); }
.archive-list__min { font-size: .74rem; color: var(--ink-faint); flex-shrink: 0; }

/* ---------- 404 ---------- */
.notfound { padding: 3rem 0; }
.notfound h1 { font-size: 3.4rem; margin: 0 0 .6rem; color: var(--ink-faint); letter-spacing: .06em; }
.notfound p { color: var(--ink-soft); max-width: var(--measure); }
.btn {
  display: inline-block;
  margin-top: .6rem;
  padding: .45rem 1.1rem;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  font-size: .9rem;
}
.btn:hover { color: var(--accent); border-color: var(--accent); }

/* ---------- 页脚 ---------- */
.site-footer {
  border-top: 1px solid var(--rule-soft);
  padding: 2rem 1.5rem 3rem;
}
.site-footer__inner {
  max-width: var(--shell);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.site-footer p {
  margin: 0;
  font-size: .78rem;
  color: var(--ink-faint);
  letter-spacing: .04em;
}
/* 返回顶部按钮（固定悬浮，滚动超过一屏后淡入） */
.to-top {
  position: fixed;
  right: 1.4rem;
  bottom: 1.4rem;
  z-index: 40;
  display: inline-flex;
  align-items: center;
  gap: .4em;
  padding: .5em 1.05em;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: .82rem;
  line-height: 1;
  color: var(--ink-muted);
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 999px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, .12);
  cursor: pointer;
  /* 默认隐藏 */
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(48px);
  transition: opacity .35s var(--ease), transform .35s var(--ease),
              color .2s var(--ease), border-color .2s var(--ease),
              background-color .3s var(--ease);
}
.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateY(0);
}
.to-top:hover { color: var(--accent); border-color: var(--accent); transform: translateY(-2px); }
.to-top:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.to-top span { font-size: 1.1em; line-height: 1; }

@media (max-width: 560px) {
  .to-top { right: 1rem; bottom: 1rem; padding: .5em .8em; }
}

/* ---------- 响应式 ---------- */
@media (max-width: 720px) {
  body { font-size: 16px; line-height: 1.8; }
  .site-header__inner { padding: .9rem 1.1rem; flex-direction: column; align-items: flex-start; gap: .6rem; }
  .nav { gap: 1.1rem; }
  .app { padding: 2.2rem 1.1rem 3.5rem; }
  .post__title { font-size: 1.6rem; }
  .post-item__title { font-size: 1.24rem; }
  .page-head h1 { font-size: 1.5rem; }
  .prose p { text-align: left; }
  .prose h2 { font-size: 1.2rem; margin-top: 2.4rem; }
  .anchor { display: none; }
  .post-nav { grid-template-columns: 1fr; gap: 1.2rem; }
  .post-nav__item.is-next { text-align: left; }
  .copy-btn { opacity: 1; }
}

@media print {
  .site-header, .site-footer, .progress, .toc, .post-nav, .related, .search, .copy-btn { display: none !important; }
  body { font-size: 11pt; }
  .app { max-width: none; padding: 0; }
}