/* ============================================================
   vhiccup — 主题样式
   设计基调：编辑部式排版（editorial typography）
   - 衬线大标题 + 无衬线正文，中文用系统宋体/黑体，零字体下载
   - 暖纸色底 + 单一品牌绿 + 琥珀点缀
   - 深色模式：跟随系统 + 手动切换（localStorage 记忆）
   - 动效克制，prefers-reduced-motion 下全部关闭
   ============================================================ */

/* ── 设计令牌 ── */
:root {
  color-scheme: light;

  --paper: #fbfaf7;
  --paper-2: #f4f2ec;
  --surface: #ffffff;
  --ink: #17191c;
  --ink-2: #3d4248;
  --ink-3: #6f7681;
  --line: #e4e0d7;
  --line-soft: #eeebe3;

  --accent: #1f6b4a;
  --accent-ink: #14503a;
  --accent-wash: #eaf3ee;
  --highlight: #b4551d;

  --code-bg: #f6f4ef;
  --code-line: #e6e2d8;
  --shadow-sm: 0 1px 2px rgba(23, 25, 28, .04);
  --shadow-md: 0 10px 30px -12px rgba(23, 25, 28, .18);

  --radius: 14px;
  --radius-sm: 9px;
  --measure: 44rem;      /* 正文阅读宽度 */
  --maxw: 72rem;         /* 页面容器 */
  --header-h: 60px;

  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "Times New Roman",
    Georgia, serif;
  --mono: "SFMono-Regular", "JetBrains Mono", Consolas, "Liberation Mono", Menlo, monospace;

  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* 深色：显式指定 */
:root[data-theme="dark"] {
  color-scheme: dark;

  --paper: #0f1113;
  --paper-2: #14171a;
  --surface: #171a1d;
  --ink: #e9e7e2;
  --ink-2: #b9b6ae;
  --ink-3: #8d8f95;
  --line: #272b2f;
  --line-soft: #1f2326;

  --accent: #74c69d;
  --accent-ink: #a4dcc0;
  --accent-wash: #16241d;
  --highlight: #e39462;

  --code-bg: #15181b;
  --code-line: #24282c;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);
  --shadow-md: 0 14px 34px -14px rgba(0, 0, 0, .75);
}

/* 深色：跟随系统（无 data-theme 时的默认分支） */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;

    --paper: #0f1113;
    --paper-2: #14171a;
    --surface: #171a1d;
    --ink: #e9e7e2;
    --ink-2: #b9b6ae;
    --ink-3: #8d8f95;
    --line: #272b2f;
    --line-soft: #1f2326;

    --accent: #74c69d;
    --accent-ink: #a4dcc0;
    --accent-wash: #16241d;
    --highlight: #e39462;

    --code-bg: #15181b;
    --code-line: #24282c;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);
    --shadow-md: 0 14px 34px -14px rgba(0, 0, 0, .75);
  }
}

/* ── 基础 ── */
* { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 20px);
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color .25s var(--ease), color .25s var(--ease);
}

::selection { background: var(--accent); color: var(--paper); }

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--accent-ink); }

img { max-width: 100%; }

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 10px 16px;
  border-radius: 0 0 var(--radius-sm) 0;
  z-index: 100;
}
.skip-link:focus { left: 0; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

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

/* ── 头部 ── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line-soft);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 19px;
  letter-spacing: .01em;
  color: var(--ink);
  text-decoration: none;
}
.brand:hover { color: var(--accent); }
.brand .dot {
  width: 9px; height: 9px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-wash);
}

.nav {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: auto;
}

.nav a {
  position: relative;
  color: var(--ink-3);
  text-decoration: none;
  font-size: 14.5px;
  padding: 6px 12px;
  border-radius: 999px;
  transition: color .18s var(--ease), background-color .18s var(--ease);
}
.nav a:hover { color: var(--ink); background: var(--paper-2); }
.nav a[aria-current="page"] { color: var(--accent-ink); background: var(--accent-wash); }

.theme-toggle {
  flex: none;
  margin-left: 10px;
  width: 34px; height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--surface);
  color: var(--ink-2);
  cursor: pointer;
  transition: transform .18s var(--ease), color .18s var(--ease), border-color .18s var(--ease);
}
.theme-toggle:hover { color: var(--accent); border-color: var(--accent); transform: rotate(-18deg); }
.theme-toggle:active { transform: scale(.92); }
.theme-toggle svg { width: 17px; height: 17px; }
.theme-toggle .icon-sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; }
  :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; }
}

/* ── 主体 ── */
main { min-height: 62vh; padding-bottom: 72px; }

/* ── 首页 Hero ── */
.hero {
  padding: clamp(48px, 8vw, 96px) 0 clamp(36px, 5vw, 60px);
  border-bottom: 1px solid var(--line-soft);
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 20px;
}
.hero-eyebrow::before {
  content: "";
  width: 26px; height: 1px;
  background: var(--highlight);
}

.hero h1 {
  font-family: var(--serif);
  font-size: clamp(34px, 7vw, 62px);
  line-height: 1.16;
  letter-spacing: -.01em;
  margin: 0 0 18px;
  font-weight: 700;
}
.hero h1 em {
  font-style: normal;
  color: var(--accent);
  background-image: linear-gradient(transparent 62%, var(--accent-wash) 62%);
  padding: 0 2px;
}

.hero-lede {
  max-width: 34rem;
  font-size: clamp(16px, 2.2vw, 18.5px);
  color: var(--ink-2);
  margin: 0;
}

.hero-meta {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  font-size: 13.5px;
  color: var(--ink-3);
}
.hero-meta b { color: var(--ink); font-weight: 600; font-variant-numeric: tabular-nums; }

/* ── Bento 网格 ── */
.bento {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
  margin-top: 34px;
}
.bento > .tile { grid-column: span 2; }
.bento > .tile-wide { grid-column: span 3; }

.tile {
  position: relative;
  display: block;
  padding: 24px 24px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow-sm);
  transition: transform .22s var(--ease), box-shadow .22s var(--ease), border-color .22s var(--ease);
  overflow: hidden;
}
.tile::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(140deg, var(--accent-wash), transparent 58%);
  opacity: 0;
  transition: opacity .25s var(--ease);
  pointer-events: none;
}
.tile:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}
.tile:hover::after { opacity: .7; }
.tile:active { transform: translateY(-1px); }

.tile-kicker {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 14px;
}
.tile h3 {
  font-family: var(--serif);
  font-size: 22px;
  line-height: 1.3;
  margin: 0 0 8px;
  color: var(--ink);
}
.tile p { margin: 0; font-size: 14.5px; color: var(--ink-2); }
.tile .arrow {
  position: absolute;
  right: 22px; bottom: 20px;
  color: var(--accent);
  opacity: .5;
  transition: transform .22s var(--ease), opacity .22s var(--ease);
}
.tile:hover .arrow { transform: translateX(4px); opacity: 1; }

/* ── 区块标题 ── */
.section {
  margin-top: clamp(48px, 7vw, 80px);
}
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 12px;
  margin-bottom: 26px;
  border-bottom: 1px solid var(--line);
}
.section-head h2 {
  font-family: var(--serif);
  font-size: clamp(20px, 3vw, 26px);
  margin: 0;
  letter-spacing: .01em;
}
.section-head .more {
  font-size: 13.5px;
  color: var(--ink-3);
  text-decoration: none;
  white-space: nowrap;
}
.section-head .more:hover { color: var(--accent); }

/* ── 文章卡片网格 ── */
.post-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 16px;
}

.post-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 22px 22px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow-sm);
  transition: transform .22s var(--ease), box-shadow .22s var(--ease), border-color .22s var(--ease);
}
.post-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}
.post-card time {
  font-size: 12.5px;
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
  letter-spacing: .04em;
}
.post-card h3 {
  font-family: var(--serif);
  font-size: 19px;
  line-height: 1.4;
  margin: 0;
  color: var(--ink);
}
.post-card .summary {
  margin: 0;
  font-size: 14px;
  color: var(--ink-2);
  line-height: 1.65;
}
.post-card .card-foot {
  margin-top: auto;
  padding-top: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  font-size: 12.5px;
  color: var(--ink-3);
}
.post-card .card-foot > span:first-child {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}
.post-card .card-foot .arrow { color: var(--accent); transition: transform .22s var(--ease); }
.post-card:hover .card-foot .arrow { transform: translateX(4px); }

/* ── 列表页头部 ── */
.page-head {
  padding: clamp(36px, 6vw, 60px) 0 clamp(24px, 4vw, 34px);
  border-bottom: 1px solid var(--line);
  margin-bottom: 34px;
}
.page-head .eyebrow {
  font-size: 12.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink-3);
}
.page-head h1 {
  font-family: var(--serif);
  font-size: clamp(28px, 5vw, 44px);
  line-height: 1.2;
  margin: 10px 0 12px;
}
.page-head .desc {
  max-width: 40rem;
  color: var(--ink-2);
  font-size: 16px;
  margin: 0;
}
.page-head .count {
  margin-top: 14px;
  font-size: 13.5px;
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
}

/* ── 文章页 ── */
.article { max-width: var(--measure); margin: 0 auto; }

.article-head { padding: clamp(36px, 6vw, 56px) 0 26px; }
.article-head .kicker {
  font-size: 12.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}
.article-head h1 {
  font-family: var(--serif);
  font-size: clamp(27px, 5.2vw, 42px);
  line-height: 1.22;
  margin: 0 0 16px;
  letter-spacing: -.005em;
}
.article-head .byline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 18px;
  font-size: 13.5px;
  color: var(--ink-3);
}
.article-head .byline .dot-sep { color: var(--line); }

/* 目录 */
.toc {
  margin: 6px 0 34px;
  padding: 18px 22px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-sm);
  background: var(--surface);
}
.toc-title {
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 0 0 10px;
}
.toc #TableOfContents { display: block; }
.toc ul { margin: 0; padding: 0; list-style: none; }
.toc ul ul { padding-left: 18px; }
.toc li { margin: 4px 0; }
.toc a {
  color: var(--ink-2);
  text-decoration: none;
  font-size: 14.5px;
  border-bottom: 1px solid transparent;
}
.toc a:hover { color: var(--accent); border-bottom-color: currentColor; }

/* 正文排版 */
.content { font-size: 16.5px; line-height: 1.85; color: var(--ink); }
.content > *:first-child { margin-top: 0; }
.content h2, .content h3, .content h4 {
  font-family: var(--serif);
  line-height: 1.35;
  letter-spacing: .005em;
  scroll-margin-top: calc(var(--header-h) + 20px);
}
.content h2 {
  margin: 46px 0 16px;
  font-size: 25px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-soft);
}
.content h3 { margin: 34px 0 12px; font-size: 20px; }
.content h4 { margin: 26px 0 10px; font-size: 17px; }
.content p { margin: 16px 0; }
.content ul, .content ol { padding-left: 24px; }
.content li { margin: 7px 0; }
.content li::marker { color: var(--ink-3); }
.content strong { font-weight: 650; }
.content hr { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }
.content blockquote {
  margin: 22px 0;
  padding: 14px 20px;
  border-left: 3px solid var(--highlight);
  background: var(--paper-2);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--ink-2);
}
.content blockquote p { margin: 8px 0; }
.content img {
  border-radius: var(--radius-sm);
  border: 1px solid var(--line-soft);
  box-shadow: var(--shadow-sm);
}
.content figure { margin: 26px 0; }
.content figcaption { font-size: 13px; color: var(--ink-3); text-align: center; margin-top: 8px; }
.content table {
  border-collapse: collapse;
  width: 100%;
  margin: 0;
  font-size: 14.5px;
}
.content .table-wrap {
  overflow-x: auto;
  margin: 22px 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
}
.content .table-wrap table { min-width: 420px; }
.content th, .content td { border: 1px solid var(--line); padding: 9px 14px; text-align: left; }
.content th { background: var(--paper-2); font-weight: 600; }
.content tbody tr:nth-child(even) { background: color-mix(in srgb, var(--paper-2) 45%, transparent); }
.content code {
  background: var(--code-bg);
  border: 1px solid var(--code-line);
  padding: 1px 6px;
  border-radius: 5px;
  font-size: .875em;
  font-family: var(--mono);
  word-break: break-word;
}
.content pre {
  position: relative;
  background: var(--code-bg);
  border: 1px solid var(--code-line);
  padding: 18px 20px;
  border-radius: var(--radius-sm);
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.7;
}
.content pre code {
  background: none;
  border: 0;
  padding: 0;
  font-size: inherit;
  white-space: pre;
}

/* 代码高亮（自建 Chroma 配色，浅/深两套） */
.chroma { background: var(--code-bg) !important; }
.chroma .k, .chroma .kc, .chroma .kd, .chroma .kn, .chroma .kp, .chroma .kr { color: #9a3b6b; }
.chroma .s, .chroma .s1, .chroma .s2, .chroma .sb, .chroma .sc, .chroma .sd, .chroma .se, .chroma .sh, .chroma .si, .chroma .sx, .chroma .sr, .chroma .ss { color: #2f6b3f; }
.chroma .m, .chroma .mb, .chroma .mf, .chroma .mh, .chroma .mi, .chroma .il, .chroma .mo { color: #1f5f8b; }
.chroma .c, .chroma .c1, .chroma .cm, .chroma .cp, .chroma .cs { color: var(--ink-3); font-style: italic; }
.chroma .n, .chroma .nn, .chroma .py { color: var(--ink); }
.chroma .nt { color: #1f5f8b; }
.chroma .p { color: var(--ink-2); }
.chroma .nx { color: var(--ink); }
.chroma .nf, .chroma .nb { color: #8a5a12; }
.chroma .o, .chroma .ow { color: #7a5aa6; }
.chroma .err { color: #b05a72; }
.chroma .gd { color: #b3261e; }
.chroma .gi { color: #2f6b3f; }

:root[data-theme="dark"] .chroma .k, :root[data-theme="dark"] .chroma .kc, :root[data-theme="dark"] .chroma .kd, :root[data-theme="dark"] .chroma .kn, :root[data-theme="dark"] .chroma .kp, :root[data-theme="dark"] .chroma .kr { color: #e48fb1; }
:root[data-theme="dark"] .chroma .s, :root[data-theme="dark"] .chroma .s1, :root[data-theme="dark"] .chroma .s2, :root[data-theme="dark"] .chroma .sb, :root[data-theme="dark"] .chroma .sc, :root[data-theme="dark"] .chroma .sd, :root[data-theme="dark"] .chroma .se, :root[data-theme="dark"] .chroma .sh, :root[data-theme="dark"] .chroma .si, :root[data-theme="dark"] .chroma .sx, :root[data-theme="dark"] .chroma .sr, :root[data-theme="dark"] .chroma .ss { color: #8fce9f; }
:root[data-theme="dark"] .chroma .m, :root[data-theme="dark"] .chroma .mb, :root[data-theme="dark"] .chroma .mf, :root[data-theme="dark"] .chroma .mh, :root[data-theme="dark"] .chroma .mi, :root[data-theme="dark"] .chroma .il, :root[data-theme="dark"] .chroma .mo { color: #86b8e8; }
:root[data-theme="dark"] .chroma .c, :root[data-theme="dark"] .chroma .c1, :root[data-theme="dark"] .chroma .cm, :root[data-theme="dark"] .chroma .cp, :root[data-theme="dark"] .chroma .cs { color: #7f848c; font-style: italic; }
:root[data-theme="dark"] .chroma .n, :root[data-theme="dark"] .chroma .nn, :root[data-theme="dark"] .chroma .py { color: var(--ink); }
:root[data-theme="dark"] .chroma .nt { color: #86b8e8; }
:root[data-theme="dark"] .chroma .p { color: var(--ink-2); }
:root[data-theme="dark"] .chroma .nx { color: var(--ink); }
:root[data-theme="dark"] .chroma .nf, :root[data-theme="dark"] .chroma .nb { color: #e3b06a; }
:root[data-theme="dark"] .chroma .o, :root[data-theme="dark"] .chroma .ow { color: #c4a2e8; }
:root[data-theme="dark"] .chroma .err { color: #e08a9c; }
:root[data-theme="dark"] .chroma .gd { color: #f2857c; }
:root[data-theme="dark"] .chroma .gi { color: #8fce9f; }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .chroma .k, :root:not([data-theme="light"]) .chroma .kc, :root:not([data-theme="light"]) .chroma .kd, :root:not([data-theme="light"]) .chroma .kn, :root:not([data-theme="light"]) .chroma .kp, :root:not([data-theme="light"]) .chroma .kr { color: #e48fb1; }
  :root:not([data-theme="light"]) .chroma .s, :root:not([data-theme="light"]) .chroma .s1, :root:not([data-theme="light"]) .chroma .s2, :root:not([data-theme="light"]) .chroma .sb, :root:not([data-theme="light"]) .chroma .sc, :root:not([data-theme="light"]) .chroma .sd, :root:not([data-theme="light"]) .chroma .se, :root:not([data-theme="light"]) .chroma .sh, :root:not([data-theme="light"]) .chroma .si, :root:not([data-theme="light"]) .chroma .sx, :root:not([data-theme="light"]) .chroma .sr, :root:not([data-theme="light"]) .chroma .ss { color: #8fce9f; }
  :root:not([data-theme="light"]) .chroma .m, :root:not([data-theme="light"]) .chroma .mb, :root:not([data-theme="light"]) .chroma .mf, :root:not([data-theme="light"]) .chroma .mh, :root:not([data-theme="light"]) .chroma .mi, :root:not([data-theme="light"]) .chroma .il, :root:not([data-theme="light"]) .chroma .mo { color: #86b8e8; }
  :root:not([data-theme="light"]) .chroma .c, :root:not([data-theme="light"]) .chroma .c1, :root:not([data-theme="light"]) .chroma .cm, :root:not([data-theme="light"]) .chroma .cp, :root:not([data-theme="light"]) .chroma .cs { color: #7f848c; font-style: italic; }
  :root:not([data-theme="light"]) .chroma .n, :root:not([data-theme="light"]) .chroma .nn, :root:not([data-theme="light"]) .chroma .py { color: var(--ink); }
  :root:not([data-theme="light"]) .chroma .nt { color: #86b8e8; }
  :root:not([data-theme="light"]) .chroma .p { color: var(--ink-2); }
  :root:not([data-theme="light"]) .chroma .nx { color: var(--ink); }
  :root:not([data-theme="light"]) .chroma .nf, :root:not([data-theme="light"]) .chroma .nb { color: #e3b06a; }
  :root:not([data-theme="light"]) .chroma .o, :root:not([data-theme="light"]) .chroma .ow { color: #c4a2e8; }
  :root:not([data-theme="light"]) .chroma .err { color: #e08a9c; }
  :root:not([data-theme="light"]) .chroma .gd { color: #f2857c; }
  :root:not([data-theme="light"]) .chroma .gi { color: #8fce9f; }
}

/* 复制按钮 */
.copy-btn {
  position: absolute;
  top: 10px; right: 10px;
  padding: 3px 10px;
  font-size: 11.5px;
  font-family: var(--sans);
  color: var(--ink-3);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  cursor: pointer;
  opacity: 0;
  transition: opacity .18s var(--ease), color .18s var(--ease), border-color .18s var(--ease);
}
.content pre:hover .copy-btn, .copy-btn:focus-visible { opacity: 1; }
.copy-btn:hover { color: var(--accent); border-color: var(--accent); }
.copy-btn.done { color: var(--accent); border-color: var(--accent); opacity: 1; }

/* 标签 */
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
}
.tags span, .tag {
  display: inline-block;
  background: var(--accent-wash);
  color: var(--accent-ink);
  font-size: 12.5px;
  padding: 3px 11px;
  border-radius: 999px;
  border: 1px solid color-mix(in srgb, var(--accent) 22%, transparent);
}
.tag { font-size: 12px; padding: 2px 9px; }

/* 上一篇 / 下一篇 */
.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-top: 40px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}
.pager a {
  display: block;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  text-decoration: none;
  transition: border-color .2s var(--ease), transform .2s var(--ease);
}
.pager a:hover { border-color: var(--accent); transform: translateY(-2px); }
.pager .dir { font-size: 12px; color: var(--ink-3); letter-spacing: .1em; }
.pager .t { display: block; margin-top: 6px; font-family: var(--serif); font-size: 15.5px; color: var(--ink); line-height: 1.5; }
.pager .next { text-align: right; }

.back {
  margin: 34px 0 0;
  font-size: 14px;
}
.back a {
  color: var(--ink-3);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.back a:hover { color: var(--accent); }

/* ── 关于区 ── */
.about {
  max-width: var(--measure);
  color: var(--ink-2);
}
.about h2 {
  font-family: var(--serif);
  font-size: 22px;
  color: var(--ink);
  margin: 0 0 12px;
}
.about a { font-weight: 500; }

/* ── 空状态 ── */
.empty {
  color: var(--ink-3);
  font-style: italic;
  padding: 30px 0;
}

/* ── 页脚 ── */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--paper-2);
  padding: 40px 0 34px;
  color: var(--ink-3);
  font-size: 13.5px;
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 20px 40px;
  align-items: flex-start;
}
.footer-brand {
  font-family: var(--serif);
  font-size: 16px;
  color: var(--ink);
  margin: 0 0 6px;
}
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; }
.footer-links a { color: var(--ink-3); text-decoration: none; }
.footer-links a:hover { color: var(--accent); }
.footer-note { margin: 0; }
.footer-note .dot-sep { margin: 0 8px; opacity: .5; }

/* ── 回到顶部 ── */
.to-top {
  position: fixed;
  right: 22px; bottom: 22px;
  width: 40px; height: 40px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink-2);
  box-shadow: var(--shadow-md);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .25s var(--ease), transform .25s var(--ease), visibility .25s, color .18s;
  z-index: 40;
}
.to-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.to-top:hover { color: var(--accent); border-color: var(--accent); }
.to-top svg { width: 16px; height: 16px; }

/* ── 滚动揭示（仅在支持 scroll-driven animation 的浏览器） ── */
@supports (animation-timeline: view()) {
  @media (prefers-reduced-motion: no-preference) {
    .reveal {
      animation: reveal-up linear both;
      animation-timeline: view();
      animation-range: entry 5% entry 40%;
    }
    @keyframes reveal-up {
      from { opacity: .25; transform: translateY(14px); }
      to   { opacity: 1;   transform: none; }
    }
  }
}

/* ── 响应式 ── */
@media (max-width: 900px) {
  .bento { grid-template-columns: repeat(2, 1fr); }
  .bento > .tile, .bento > .tile-wide { grid-column: span 1; }
  .bento > .tile-wide { grid-column: span 2; }
}

@media (max-width: 640px) {
  :root { --header-h: 56px; }
  .container { padding: 0 18px; }
  .bento { grid-template-columns: 1fr; }
  .bento > .tile-wide { grid-column: span 1; }
  .nav a { padding: 6px 9px; font-size: 13.5px; }
  .brand { font-size: 17px; }
  .pager { grid-template-columns: 1fr; }
  .pager .next { text-align: left; }
  .content { font-size: 16px; }
  .to-top { right: 14px; bottom: 14px; }
}

/* 窄屏：头部改为两行，导航独占一行平铺，避免挤成一团 */
@media (max-width: 520px) {
  :root { --header-h: 100px; }
  .header-inner {
    flex-wrap: wrap;
    height: auto;
    padding: 10px 0 8px;
    row-gap: 6px;
  }
  .nav {
    order: 3;
    width: 100%;
    justify-content: space-between;
    gap: 2px;
    margin-left: 0;
  }
  .nav a { padding: 5px 6px; font-size: 13.5px; }
  .theme-toggle { order: 2; margin-left: auto; }
}

/* ── 打印 ── */
@media print {
  .site-header, .site-footer, .to-top, .progress, .copy-btn, .pager { display: none !important; }
  body { background: #fff; color: #000; font-size: 12pt; }
  .content a { color: #000; text-decoration: underline; }
  .article { max-width: none; }
}

/* ── 降低动效偏好 ── */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  .tile:hover, .post-card:hover, .pager a:hover { transform: none; }
}