@import url('https://fonts.googleapis.com/css2?family=Crimson+Text:wght@400;600;700&family=EB+Garamond:wght@400;500;600;700;800&display=swap');

:root {
  --paper: #f5f5f5;
  --sheet: #ffffff;
  --ink: #1f1f1f;
  --ink-soft: #4d4d4d;
  --ink-mute: #6d6d6d;
  --r: 18px;
  --e1: 0 1px 2px rgba(31, 31, 31, .10);
  --e2: 0 5px 14px rgba(31, 31, 31, .10);
  --e3: 0 14px 32px rgba(31, 31, 31, .13);
  --e4: 0 26px 58px rgba(31, 31, 31, .18);
  --bar-h: 132px;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: 'EB Garamond', 'Crimson Text', Georgia, 'Songti SC', 'Noto Serif SC', 'SimSun', serif;
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: .01em;
}

a { color: var(--ink); }

img { max-width: 100%; }

/* ---------- 顶栏（aside > nav > ul > li > a） ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(255, 255, 255, .84);
  -webkit-backdrop-filter: blur(16px) saturate(130%);
  backdrop-filter: blur(16px) saturate(130%);
  border-bottom: 1px solid var(--ink);
  box-shadow: var(--e2);
  transition: box-shadow .25s ease, background .25s ease;
}

.topbar.scrolled {
  box-shadow: var(--e3);
  background: rgba(255, 255, 255, .94);
}

.bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 10px clamp(14px, 3.4vw, 44px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  min-height: 44px;
  padding: 0 16px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  background: var(--sheet);
  text-decoration: none;
  box-shadow: var(--e1);
  z-index: 3;
}

.brand-logo {
  display: block;
  width: 26px;
  height: 26px;
  object-fit: contain;
  border-radius: 50%;
}

.brand-word {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .18em;
}

.search {
  flex: 0 1 auto;
}

.search-input {
  display: block;
  width: min(268px, 44vw);
  min-height: 42px;
  padding: 0 18px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  background: var(--sheet);
  font-family: inherit;
  font-size: 16px;
  color: var(--ink);
  box-shadow: var(--e1);
}

.search-input::placeholder { color: var(--ink-mute); }
.search-input:focus { outline: 2px solid var(--ink); outline-offset: 2px; }

.caps {
  border-top: 1px solid rgba(31, 31, 31, .18);
  background: rgba(255, 255, 255, .62);
}

.caps ul {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 8px clamp(14px, 3.4vw, 44px);
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.caps a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 15px;
  border: 1px solid rgba(31, 31, 31, .34);
  border-radius: 999px;
  background: var(--sheet);
  text-decoration: none;
  font-size: 16px;
  white-space: nowrap;
  box-shadow: var(--e1);
  transition: background .2s ease, color .2s ease, border-color .2s ease, transform .2s ease;
}

.caps a:hover,
.caps a:focus-visible {
  background: var(--ink);
  color: var(--sheet);
  border-color: var(--ink);
  transform: translateY(-1px);
}

/* ---------- 首屏 ---------- */
.hero {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-rows: 1fr auto;
  min-height: 100vh;
  min-height: 100svh;
  padding: clamp(24px, 5vw, 70px) clamp(16px, 4vw, 56px) 0;
}

.hero-text {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-end;
  text-align: right;
  position: relative;
  z-index: 3;
  max-width: min(780px, 100%);
  margin: 0 0 clamp(-28px, -3vw, -14px) auto;
  padding: clamp(18px, 3vw, 38px);
  background: rgba(255, 255, 255, .88);
  -webkit-backdrop-filter: blur(9px);
  backdrop-filter: blur(9px);
  border: 1px solid var(--ink);
  border-radius: var(--r);
  box-shadow: var(--e4);
}

h1 {
  margin: 0;
  font-size: clamp(29px, 6.4vw, 62px);
  line-height: 1.14;
  font-weight: 700;
  letter-spacing: .01em;
  max-width: 20ch;
}

.hero-kw {
  margin: 14px 0 0;
  font-size: clamp(14px, 1.7vw, 18px);
  letter-spacing: .18em;
  color: var(--ink-soft);
}

.hero-media {
  position: relative;
  z-index: 1;
  margin: 0 calc(-1 * clamp(16px, 4vw, 56px));
  border-top: 1px solid var(--ink);
  overflow: hidden;
  height: clamp(200px, 40vh, 420px);
}

.hero-media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-media-flat { background: var(--sheet); }

/* ---------- 主体骨架 ---------- */
main { position: relative; z-index: 5; }

.wrap {
  display: grid;
  grid-template-columns: minmax(0, 258px) minmax(0, 1fr);
  gap: clamp(20px, 3vw, 46px);
  max-width: 1180px;
  margin: 0 auto;
  padding: clamp(38px, 6vw, 84px) clamp(16px, 4vw, 40px) 0;
}

.toc {
  position: sticky;
  top: calc(var(--bar-h) + 16px);
  align-self: start;
  z-index: 6;
  padding: 18px 16px 14px;
  background: var(--sheet);
  border: 1px solid var(--ink);
  border-radius: var(--r);
  box-shadow: var(--e3);
}

.toc-h {
  display: flex;
  align-items: center;
  margin: 0 0 8px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: .24em;
}

.toc-h span {
  display: inline-flex;
  align-items: center;
  gap: 9px;
}

.toc-h span::before {
  content: "";
  width: 20px;
  height: 1px;
  background: var(--ink);
}

.toc-list {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: toc;
}

.toc-list li { counter-increment: toc; }
.toc-list li[hidden] { display: none; }

.toc-list a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  min-height: 42px;
  padding: 9px 9px;
  border: 1px solid transparent;
  border-radius: 12px;
  text-decoration: none;
  font-size: 16px;
  line-height: 1.4;
}

.toc-list a::before {
  content: counter(toc, decimal-leading-zero);
  flex: 0 0 auto;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--ink-mute);
}

.toc-list a:hover,
.toc-list a:focus-visible {
  border-color: var(--ink);
  background: var(--paper);
}

.toc-back {
  margin: 12px 0 0;
  padding-top: 10px;
  border-top: 1px solid rgba(31, 31, 31, .18);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .16em;
}

.toc-back a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  text-decoration: none;
}

.content { min-width: 0; position: relative; z-index: 2; }

/* ---------- 正文 ---------- */
.prose {
  font-size: 17px;
  line-height: 1.85;
}

.prose > div {
  position: relative;
  z-index: 2;
  scroll-margin-top: calc(var(--bar-h) + 20px);
  margin: 0 0 clamp(22px, 3vw, 38px);
  padding: clamp(20px, 3.4vw, 46px);
  background: var(--sheet);
  border: 1px solid var(--ink);
  border-radius: var(--r);
}

.prose > div:nth-child(even) { z-index: 1; }

.prose h2 {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin: 0 0 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--ink);
  font-size: clamp(21px, 2.6vw, 29px);
  line-height: 1.34;
}

.prose h3 {
  margin: 26px 0 10px;
  font-size: clamp(18px, 2vw, 21px);
  line-height: 1.4;
}

.prose h2 > span,
.prose h3 > span { display: inline-block; }

.prose p { margin: 0 0 15px; }

.prose ul,
.prose ol {
  margin: 0 0 16px;
  padding-left: 1.3em;
}

.prose li { margin: 0 0 8px; }

.prose a {
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.prose blockquote {
  margin: 18px 0;
  padding: 4px 0 4px 18px;
  border-left: 2px solid var(--ink);
  color: var(--ink-soft);
  font-style: italic;
}

.prose img {
  height: auto;
  border: 1px solid var(--ink);
  border-radius: 12px;
}

.prose > div > :last-child { margin-bottom: 0; }

/* ---------- 页脚（仅 p + small） ---------- */
.foot {
  position: relative;
  z-index: 8;
  margin-top: clamp(34px, 6vw, 84px);
  padding: clamp(28px, 5vw, 62px) clamp(16px, 4vw, 56px) 22px;
  background: var(--sheet);
  border-top: 1px solid var(--ink);
  box-shadow: var(--e4);
}

.foot-cta {
  display: grid;
  grid-template-columns: 1fr 1fr auto;
  gap: 16px 24px;
  align-items: end;
  margin: 0 0 26px;
  font-size: clamp(21px, 3.4vw, 38px);
  line-height: 1.16;
  font-weight: 700;
}

.fc-brand { letter-spacing: .04em; }

.fc-kw {
  font-size: clamp(14px, 1.5vw, 17px);
  font-weight: 400;
  letter-spacing: .12em;
  color: var(--ink-soft);
}

.fc-top { font-size: clamp(15px, 1.5vw, 17px); font-weight: 400; }

.fc-top a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  text-decoration: none;
  box-shadow: var(--e2);
}

.fc-top a:hover { background: var(--ink); color: var(--sheet); }

.foot small {
  display: block;
  padding-top: 14px;
  border-top: 1px solid rgba(31, 31, 31, .2);
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--ink-mute);
}

/* ---------- 动效 ---------- */
.js .prose > div.rv {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .6s ease, transform .6s ease;
}

.js .prose > div.rv.in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .prose > div.rv { opacity: 1; transform: none; transition: none; }
  .caps a { transition: none; }
}

/* ---------- 宽屏轻微层叠 ---------- */
@media (min-width: 961px) {
  .prose > div:nth-child(even) { margin-left: clamp(8px, 1.6vw, 26px); }
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  :root { --bar-h: 150px; }

  .wrap {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .toc {
    position: static;
    box-shadow: var(--e1);
  }

  .toc-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4px;
  }

  .toc-list a { padding: 7px 8px; }

  .hero-text {
    align-items: flex-start;
    text-align: right;
    margin-bottom: -18px;
  }

  .hero-text h1 { margin-left: auto; }

  .foot-cta {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .fc-top { justify-self: start; }
}

@media (max-width: 560px) {
  body { font-size: 16px; }

  .search-input { width: 100%; }

  .bar {
    flex-wrap: wrap;
    row-gap: 8px;
  }

  .search { flex: 1 1 100%; }

  .caps ul { padding-left: 12px; padding-right: 12px; }
}

button[aria-expanded]{min-width:44px;min-height:44px}