/* joycema.ai — 白纸、铅笔灰、一处哑光暖金（与公众号配图同一套气质） */
:root {
  --paper: #ffffff;
  --ink: #262626;
  --graphite: #5f5f5f;
  --pencil: #9b9b9b;
  --rule: #e8e8e6;
  --gold: #a6834e;
  --serif: "Noto Serif SC", "Songti SC", "STSong", "SimSun", Georgia, serif;
  --sans: -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --measure: 36em;
  --wide: 68rem;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 17px/1.9 var(--serif);
  text-rendering: optimizeLegibility;
}
a { color: inherit; }
img { max-width: 100%; height: auto; display: block; }
:focus-visible { outline: 2px solid var(--gold); outline-offset: 3px; }

/* 页眉 */
.top {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 28px 24px 0;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.name { font-weight: 700; font-size: 1.15rem; letter-spacing: .02em; text-decoration: none; }
.top nav { display: flex; gap: 22px; font: 15px/1 var(--sans); }
.top nav a { color: var(--graphite); text-decoration: none; padding: 6px 0; }
.top nav a:hover, .top nav a[aria-current] { color: var(--ink); box-shadow: inset 0 -1px 0 var(--ink); }

main { max-width: var(--wide); margin: 0 auto; padding: 0 24px; }

/* 首页 */
.intro { max-width: var(--measure); margin: 56px 0 36px; color: var(--graphite); font-size: 1.05rem; }
.intro p { margin: 0; }
.lead { display: block; text-decoration: none; margin-bottom: 72px; }
.lead figure { margin: 0; border-bottom: 1px solid var(--rule); }
.lead img { width: 100%; aspect-ratio: 2.35 / 1; object-fit: cover; }
.lead-text { max-width: 44rem; padding-top: 28px; }
.lead h1, .lead-title { font-size: clamp(2rem, 4.6vw, 3.4rem); line-height: 1.25; margin: 6px 0 8px; font-weight: 700; letter-spacing: -.01em; }
.lead .subtitle { font-size: clamp(1.2rem, 2.4vw, 1.6rem); margin: 0 0 14px; color: var(--graphite); line-height: 1.5; }
.lead .ex { color: var(--graphite); margin: 0; max-width: var(--measure); }
.lead:hover .lead-title { text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 8px; }

.kicker { font: 14px/1.4 var(--sans); color: var(--pencil); margin: 0; }

.block, .group { margin: 0 0 64px; display: grid; grid-template-columns: 12rem 1fr; gap: 8px 32px; }
.block h2, .group h2 { font: 600 1rem/1.9 var(--serif); margin: 0; padding-top: 14px; position: sticky; top: 16px; align-self: start; }
.block .more { grid-column: 2; margin: 8px 0 0; font: 15px/1.6 var(--sans); }
.block .more a { color: var(--graphite); }

/* 文章列表 */
.list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--rule); }
.list li { border-bottom: 1px solid var(--rule); }
.list a { display: grid; grid-template-columns: 5.5em 1fr; gap: 16px; padding: 14px 0; text-decoration: none; }
.list a:hover .h { text-decoration: underline; text-underline-offset: 5px; text-decoration-thickness: 1px; }
.list time { font: 14px/1.9 var(--sans); color: var(--pencil); font-variant-numeric: tabular-nums; }
.list .t { display: block; line-height: 1.65; }
.list .kind { font: 13px/1 var(--sans); color: var(--gold); margin-right: 10px; vertical-align: 2px; }
.list .h { font-weight: 600; }
.list .sub { display: block; color: var(--graphite); font-size: .95rem; }
.list.skills a { grid-template-columns: 1fr; }

/* 栏目页 */
.pagehead { max-width: var(--measure); margin: 56px 0 48px; }
.pagehead h1 { font-size: clamp(2rem, 4vw, 2.8rem); line-height: 1.3; margin: 0 0 12px; }
.lede { color: var(--graphite); margin: 0; }

/* 文章页 */
.post { max-width: var(--measure); margin: 56px auto 0; }
.post header { margin-bottom: 40px; }
.post h1 { font-size: clamp(1.8rem, 4vw, 2.5rem); line-height: 1.35; margin: 8px 0 10px; letter-spacing: -.005em; }
.post .subtitle { font-size: 1.3rem; color: var(--graphite); margin: 0 0 16px; line-height: 1.55; }
.post .meta { font: 14px/1.4 var(--sans); color: var(--pencil); margin: 0; }
.prose { font-size: 1.06rem; line-height: 2; }
.prose p { margin: 0 0 1.1em; }
.prose h2 { font-size: 1.35rem; line-height: 1.5; margin: 2.4em 0 .8em; }
.prose h3 { font-size: 1.12rem; line-height: 1.6; margin: 2em 0 .6em; }
.prose strong { font-weight: 700; }
.prose a { text-decoration-color: var(--pencil); text-underline-offset: 4px; }
.prose img { margin: 2em auto; }
.prose blockquote { margin: 1.5em 0; padding-left: 1.2em; border-left: 2px solid var(--rule); color: var(--graphite); }
.prose ul, .prose ol { padding-left: 1.4em; margin: 0 0 1.1em; }
.prose li { margin: .3em 0; }
.prose hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5em 0; }
.prose table { width: 100%; border-collapse: collapse; font: 15px/1.6 var(--sans); margin: 1.5em 0; display: block; overflow-x: auto; }
.prose th, .prose td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--rule); vertical-align: top; }
.prose th { font-weight: 600; }
.prose code { font-size: .9em; background: #f5f5f3; padding: .1em .35em; border-radius: 3px; }
.prose pre { background: #f7f7f5; padding: 14px 16px; overflow-x: auto; font-size: 14px; line-height: 1.6; border-radius: 4px; }
.prose pre code { background: none; padding: 0; }
.post > footer { margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--rule); }
.src { font: 14px/1.7 var(--sans); color: var(--pencil); margin: 0; }
.src a { color: var(--graphite); }

.pager { max-width: var(--measure); margin: 40px auto 0; display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.pager a { text-decoration: none; line-height: 1.6; font-weight: 600; }
.pager a:hover { text-decoration: underline; text-underline-offset: 5px; }
.pager small { display: block; font: 13px/1.6 var(--sans); color: var(--pencil); font-weight: 400; }
.pager .older { grid-column: 2; text-align: right; }

/* 技能 */
.skill { max-width: var(--measure); margin: 0 0 64px; padding-top: 24px; border-top: 1px solid var(--rule); }
.skill h2 { font-size: 1.5rem; margin: 0 0 12px; }
.actions { margin: 24px 0; }
.btn { display: inline-block; font: 600 15px/1 var(--sans); padding: 13px 20px; border: 1px solid var(--ink); border-radius: 2px; text-decoration: none; }
.btn:hover { background: var(--ink); color: var(--paper); }
.skillmd summary { cursor: pointer; font: 15px/1.6 var(--sans); color: var(--graphite); }
.skillmd[open] summary { margin-bottom: 16px; }
.skillmd .prose { font-size: .95rem; }

.foot { max-width: var(--wide); margin: 96px auto 0; padding: 24px 24px 48px; border-top: 1px solid var(--rule); font: 14px/1.7 var(--sans); color: var(--pencil); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.foot p { margin: 0; }
.foot a { color: var(--graphite); }

@media (max-width: 760px) {
  body { font-size: 16px; }
  .top { padding: 20px 16px 0; }
  .top nav { gap: 16px; }
  main { padding: 0 16px; }
  .intro { margin: 36px 0 28px; }
  .lead { margin-bottom: 48px; }
  .block, .group { grid-template-columns: 1fr; margin-bottom: 48px; }
  .block h2, .group h2 { position: static; padding-top: 0; }
  .block .more { grid-column: 1; }
  .list a { grid-template-columns: 3.6em 1fr; gap: 12px; }
  .post { margin-top: 36px; }
  .foot { padding: 20px 16px 40px; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }
@media print { .top, .foot, .pager { display: none; } }
.post .hero { margin: 0 0 40px; }

/* 文章 / Skills 横向切换 */
.tabs { display: flex; gap: 36px; border-bottom: 1px solid var(--rule); margin: 0 0 20px; }
.tabs a { font: 700 1.5rem/1 var(--serif); color: var(--pencil); text-decoration: none; padding: 0 0 14px; margin-bottom: -1px; border-bottom: 2px solid transparent; }
.tabs a:hover { color: var(--graphite); }
.tabs a[aria-current] { color: var(--ink); border-bottom-color: var(--ink); }

/* 合集筛选 */
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 16px; }
.chips a { font: 15px/1 var(--sans); color: var(--graphite); text-decoration: none; padding: 9px 14px; border: 1px solid var(--rule); border-radius: 999px; white-space: nowrap; }
.chips a:hover { border-color: var(--pencil); color: var(--ink); }
.chips a[aria-current] { background: var(--ink); border-color: var(--ink); color: var(--paper); }
.chips span { margin-left: 6px; font-size: 12px; color: var(--pencil); font-variant-numeric: tabular-nums; }
.chips a[aria-current] span { color: #c9c9c9; }
.tabs-lede { font: 14px/1.7 var(--sans); color: var(--pencil); margin: 0 0 40px; max-width: var(--measure); }
.kicker a { color: inherit; text-decoration: none; }
.kicker a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }
.group h2 { font-variant-numeric: tabular-nums; }
.list .kind { white-space: nowrap; }

@media (max-width: 760px) {
  .tabs { gap: 28px; }
  .tabs a { font-size: 1.3rem; }
  .chips { flex-wrap: nowrap; overflow-x: auto; margin: 0 -16px 16px; padding: 0 16px 4px; scrollbar-width: none; }
  .chips::-webkit-scrollbar { display: none; }
  .tabs-lede { margin-bottom: 28px; }
}

.group { margin-bottom: 36px; }

.intro p + p { margin-top: .2em; }
.intro .note { margin-top: 14px; font: 14px/1.7 var(--sans); color: var(--pencil); }

/* 哈佛案例预习：日历 */
.calnote { font: 14px/1.7 var(--sans); color: var(--pencil); margin: 6px 0 28px; }
.cal { border-top: 1px solid var(--ink); }
.cal-head, .week { display: grid; grid-template-columns: repeat(7, minmax(0, 1fr)); }
.cal-head span { font: 13px/1 var(--sans); color: var(--pencil); padding: 12px 8px; }
.week { border-top: 1px solid var(--rule); }
.day { padding: 10px 8px 16px; border-left: 1px solid var(--rule); min-height: 9rem; scroll-margin-top: 24px; }
.day:first-child { border-left: 0; }
.day h3 { display: flex; align-items: baseline; gap: 6px; margin: 0 0 8px; font: 600 1.05rem/1.2 var(--serif); }
.day .wd { display: none; font: 13px/1 var(--sans); color: var(--pencil); font-weight: 400; }
.day .cnt { margin-left: auto; font: 12px/1 var(--sans); color: var(--gold); font-weight: 400; }
.day .now { font: 600 12px/1 var(--sans); color: var(--paper); background: var(--gold); padding: 3px 6px; border-radius: 2px; }
.day.today { background: #faf7f1; }
.day.empty .dn { color: var(--pencil); font-weight: 400; }
.day .off { font: 13px/1.4 var(--sans); color: var(--pencil); margin: 0; }
.slots { list-style: none; margin: 0; padding: 0; }
.slot { font: 12.5px/1.45 var(--sans); color: var(--pencil); padding: 6px 0; border-top: 1px dotted var(--rule); }
.slot:first-child { border-top: 0; padding-top: 0; }
.slot time { display: block; font-variant-numeric: tabular-nums; }
.slot .c { display: block; font-size: 11.5px; letter-spacing: .02em; }
.slot .n { display: block; color: var(--graphite); }
.slot .h, .slot .tag { display: none; }
.slot.has .go { display: block; text-decoration: none; color: var(--ink); margin: 0 -4px; padding: 4px; border-radius: 2px; }
.slot.has .go:hover { background: #f6f2ea; }
.slot.has time, .slot.has .c { color: var(--gold); }
.slot.has .n { color: var(--ink); font-weight: 600; font-family: var(--serif); font-size: 13.5px; line-height: 1.4; }
.slot.has .tag { display: block; font-size: 11.5px; color: var(--gold); margin-top: 2px; }
.slot .also { display: inline-block; font-size: 11.5px; color: var(--graphite); margin: 2px 0 0 0; }
.undated { margin: 48px 0 0; }
.undated h2 { font: 600 1rem/1.9 var(--serif); margin: 0 0 8px; }
.undated .list a { grid-template-columns: 1fr; }
.classtime { font: 14px/1.8 var(--sans); color: var(--graphite); margin: 14px 0 0; padding: 10px 14px; background: #faf7f1; border-left: 2px solid var(--gold); }
.classtime span { color: var(--gold); margin-right: 10px; }
.classtime a { color: var(--ink); text-underline-offset: 3px; }

@media (max-width: 900px) {
  .cal { border-top: 0; }
  .cal-head { display: none; }
  .week { display: block; border-top: 0; }
  .day { border-left: 0; border-top: 1px solid var(--rule); min-height: 0; padding: 16px 0 18px; }
  .day.empty { display: none; }
  .day.today { background: none; }
  .day h3 { font-size: 1.15rem; margin-bottom: 10px; }
  .day .wd { display: inline; }
  .slot { display: grid; grid-template-columns: 3.4em 1fr; gap: 2px 12px; font-size: 14px; padding: 10px 0; }
  .slot time { grid-row: span 3; }
  .slot .c, .slot .n, .slot .also { grid-column: 2; }
  .slot.has { display: block; }
  .slot.has .also { margin-left: 60px; }
  .slot.has .go { display: grid; grid-template-columns: 3.4em 1fr; gap: 2px 12px; margin: 0; padding: 0; }
  .slot.has .go:hover { background: none; }
  .slot.has .n { font-size: 1rem; }
  .slot.has .h { display: block; grid-column: 2; color: var(--graphite); font-family: var(--serif); font-size: .95rem; }
  .slot.has .tag { grid-column: 2; }
}
.material .actions { margin: 18px 0 0; display: flex; gap: 10px; flex-wrap: wrap; }
.material .prose h2 { font-size: 1.25rem; margin-top: 2em; padding-top: .9em; border-top: 1px solid var(--rule); }
.material .prose h2:first-child { margin-top: 0; }
.slot .also { margin-right: 10px; }

/* 中 / EN 切换 */
.top nav a.lang { margin-left: 6px; padding: 5px 9px; border: 1px solid var(--rule); border-radius: 999px; font-size: 13px; letter-spacing: .04em; }
.top nav a.lang:hover { color: var(--ink); border-color: var(--ink); box-shadow: none; }
.langnote { font: 14px/1.5 var(--sans); color: var(--graphite); margin: 0 0 12px; }

/* 内页导航：← 返回 · 首页 / 上一层（顶部）与 返回 + 回到首页（底部） */
.crumbs { max-width: calc(36 * 17px); margin: 40px auto -28px; display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; font: 14px/1.6 var(--sans); color: var(--pencil); }
.crumbs a { color: var(--graphite); text-decoration: none; }
.crumbs a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }
.crumbs .back { color: var(--ink); font-weight: 600; padding: 4px 12px 4px 10px; margin-left: -10px; border-radius: 999px; }
.crumbs .back:hover { background: #f6f2ea; text-decoration: none; }
.crumbs .trail { display: inline-flex; gap: 8px; align-items: baseline; }
.crumbs i { font-style: normal; color: var(--rule); }
.upnav { max-width: calc(36 * 17px); margin: 48px auto 0; padding-top: 20px; border-top: 1px solid var(--rule); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font: 15px/1.6 var(--sans); }
.upnav a { color: var(--graphite); text-decoration: none; }
.upnav a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 4px; }
.upnav a:only-child { margin-left: auto; }

/* 回到顶部 */
.totop { position: fixed; right: 22px; bottom: 26px; width: 42px; height: 42px; border-radius: 50%; border: 1px solid var(--rule); background: rgba(255,255,255,.94); color: var(--graphite); font: 18px/1 var(--sans); cursor: pointer; box-shadow: 0 2px 10px rgba(0,0,0,.06); opacity: 0; visibility: hidden; transform: translateY(8px); transition: opacity .2s, transform .2s, visibility .2s; z-index: 20; }
.totop.on { opacity: 1; visibility: visible; transform: none; }
.totop:hover { color: var(--ink); border-color: var(--pencil); }

/* 文章阅读进度 */
.progress { position: fixed; top: 0; left: 0; right: 0; height: 2px; z-index: 30; pointer-events: none; }
.progress i { display: block; height: 100%; background: var(--gold); transform: scaleX(0); transform-origin: 0 50%; }

@media (max-width: 760px) {
  .crumbs { margin: 24px auto -16px; }
  .totop { right: 14px; bottom: 18px; }
}
@media print { .crumbs, .upnav, .totop, .progress { display: none; } }

/* 页眉：搜索图标 */
.top nav { align-items: center; }
.top nav a.searchlink { display: inline-flex; align-items: center; padding: 6px 2px; }
.top nav a.searchlink:hover, .top nav a.searchlink[aria-current] { box-shadow: none; color: var(--ink); }

/* 分享 / 复制链接 */
.share { display: inline-flex; align-items: center; gap: 5px; margin-left: 12px; padding: 3px 10px; font: 13px/1.4 var(--sans); color: var(--graphite); background: none; border: 1px solid var(--rule); border-radius: 999px; cursor: pointer; vertical-align: 1px; }
.share:hover { color: var(--ink); border-color: var(--pencil); }
.share.ok { color: var(--gold); border-color: var(--gold); }

/* 文章目录 */
.toc { margin: 0 0 36px; padding: 14px 18px; background: #faf9f6; border: 1px solid var(--rule); border-radius: 3px; font: 15px/1.7 var(--sans); }
.toc summary { cursor: pointer; font-weight: 600; color: var(--ink); list-style-position: inside; }
.toc summary span { margin-left: 8px; font-weight: 400; font-size: 13px; color: var(--pencil); }
.toc ol { margin: 10px 0 2px; padding-left: 1.5em; color: var(--pencil); }
.toc li { margin: 3px 0; }
.toc a { color: var(--graphite); text-decoration: none; }
.toc a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }
.prose h2, .prose h3 { scroll-margin-top: 24px; }
html { scroll-behavior: smooth; }

/* 文末订阅 */
.subscribe { display: flex; gap: 20px; align-items: flex-start; margin-top: 28px; padding: 20px 22px; background: #faf7f1; border-left: 2px solid var(--gold); font: 15px/1.75 var(--sans); color: var(--graphite); }
.subscribe .qr { width: 104px; height: 104px; flex: none; background: #fff; }
.subscribe p { margin: 0; }
.subscribe .sub-h { font: 600 1.05rem/1.6 var(--serif); color: var(--ink); margin-bottom: 4px; }
.subscribe a { color: var(--ink); text-underline-offset: 3px; }
.sub-actions { margin-top: 12px !important; display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.sub-actions .share { margin-left: 0; background: #fff; }

/* 相关文章 */
.related { max-width: calc(36 * 17px); margin: 56px auto 0; }
.related h2 { font: 600 1.05rem/1.6 var(--serif); margin: 0 0 10px; }
.related .list a { grid-template-columns: 6.2em 1fr; }

/* 搜索 */
.vh { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.searchbox input { width: 100%; max-width: calc(36 * 17px); font: 18px/1.4 var(--sans); padding: 14px 16px; border: 1px solid var(--pencil); border-radius: 3px; background: #fff; color: var(--ink); }
.searchbox input:focus { outline: none; border-color: var(--ink); box-shadow: 0 0 0 3px #f1ece2; }
.sinfo { font: 14px/1.6 var(--sans); color: var(--pencil); margin: 14px 0 8px; min-height: 1.6em; }
.results { list-style: none; margin: 0; padding: 0; max-width: calc(36 * 17px); }
.results li { border-bottom: 1px solid var(--rule); }
.results li:first-child { border-top: 1px solid var(--rule); }
.results a { display: block; padding: 16px 0; text-decoration: none; }
.results .sk { display: block; font: 13px/1.6 var(--sans); color: var(--gold); }
.results .h { display: block; font-weight: 600; line-height: 1.55; }
.results a:hover .h { text-decoration: underline; text-underline-offset: 5px; text-decoration-thickness: 1px; }
.results .sub { display: block; color: var(--graphite); font-size: .95rem; }
.results .sx { display: block; margin-top: 4px; font: 14px/1.7 var(--sans); color: var(--pencil); }
.results mark { background: #f3e9d4; color: var(--ink); padding: 0 1px; border-radius: 2px; }

/* 联系我 */
.contact { max-width: calc(32 * 17px); }
.field { margin: 0 0 18px; }
.field label { display: block; font: 600 15px/1.6 var(--sans); margin-bottom: 6px; }
.field small { font-weight: 400; color: var(--pencil); margin-left: 8px; font-size: 13px; }
.field input, .field textarea { width: 100%; font: 16px/1.6 var(--sans); padding: 11px 13px; border: 1px solid #cfcfcc; border-radius: 3px; background: #fff; color: var(--ink); }
.field textarea { resize: vertical; min-height: 9rem; }
.field input:focus, .field textarea:focus { outline: none; border-color: var(--ink); box-shadow: 0 0 0 3px #f1ece2; }
.contact .btn { background: var(--ink); color: var(--paper); cursor: pointer; padding: 13px 28px; }
.contact .btn:hover { background: #000; }
.contact .btn:disabled { opacity: .5; cursor: wait; }
.cnote { font: 13px/1.7 var(--sans); color: var(--pencil); margin: 14px 0 0; }
.cstatus { max-width: calc(32 * 17px); font: 15px/1.7 var(--sans); margin: 8px 0 0; }
.cstatus.ok { padding: 18px 20px; background: #faf7f1; border-left: 2px solid var(--gold); color: var(--ink); font-size: 16px; }
.cstatus.err { color: #a33b2b; }

@media (max-width: 760px) {
  .top nav { gap: 14px; }
  .subscribe { flex-direction: column; gap: 12px; padding: 18px; }
  .related .list a { grid-template-columns: 5.6em 1fr; }
  .meta .share { margin-left: 8px; }
}
@media print { .share, .toc, .subscribe, .related { display: none; } }

/* 复制到公众号 */
.share.wx { margin-left: 8px; }
.share[hidden] { display: none !important; }
a.share { text-decoration: none; }