@import url('https://fonts.googleapis.com/css2?family=Inter:ital,wght@0,400;0,500;0,600;0,700;0,800;1,400&family=JetBrains+Mono:wght@400&family=Playfair+Display:ital@1&display=swap');

/* ── 基础变量 ── */
:root {
  --paper: #fdfbf7;
  --paper-alt: #f5f5f5;
  --ink: #1a1a1a;
  --ink-mid: #3a3a3a;
  --ink-light: #6a6a6a;
  --ink-faint: #a0a0a0;
  --rule: #d8d4ce;
  --rule-strong: #b0aca6;
  --accent: #1a1a1a;
  --accent-hover: #3a3a3a;
  --font-serif: 'Playfair Display', 'Noto Serif SC', Georgia, serif;
  --font-sans: 'Inter', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --nav-width: 240px;
  --content-max: 780px;
  --gap: 2rem;
  --gap-sm: 1rem;
  --gap-xs: 0.5rem;
  --radius: 4px;
  --transition: none;
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: auto; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.75;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  /* paper grain texture */
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='200' height='200' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }
a:hover { color: var(--ink-mid); }
ul, ol { list-style: none; }

/* ── 左侧固定竖排导航 ── */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-width);
  height: 100vh;
  background: var(--paper);
  border-right: 1px solid var(--rule);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow-y: auto;
}

.site-nav {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 2rem 1.5rem;
  gap: 0;
}

.site-nav__brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding-bottom: 1.5rem;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 2rem;
}

.nav-logo {
  width: 32px;
  height: 32px;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
}

.nav-brand-name {
  font-family: var(--font-serif);
  font-size: 0.9rem;
  font-style: italic;
  line-height: 1.3;
  color: var(--ink);
  font-weight: 400;
}

.site-nav__links {
  display: flex;
  flex-direction: column;
  gap: 0;
  flex: 1;
}

.nav-link {
  display: block;
  padding: 0.65rem 0;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--ink-mid);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  line-height: 1.4;
  transition: var(--transition);
  min-height: 40px;
  display: flex;
  align-items: center;
}

.nav-link:hover { color: var(--ink); }
.nav-link--active {
  color: var(--ink);
  font-weight: 700;
  border-left: 3px solid var(--ink);
  padding-left: 0.75rem;
}

.site-nav__contact {
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  margin-top: auto;
}

.nav-contact-link {
  display: block;
  padding: 0.6rem 0;
  font-size: 0.8rem;
  color: var(--ink-light);
  text-decoration: none;
  font-weight: 500;
  min-height: 40px;
  display: flex;
  align-items: center;
}
.nav-contact-link:hover { color: var(--ink); }

/* ── 主内容区（左移 nav-width） ── */
.page-main {
  margin-left: var(--nav-width);
  min-height: 100vh;
  padding: 3rem 3rem 3rem 3rem;
}

.wrap {
  max-width: var(--content-max);
  margin: 0 auto;
}

/* ── 面包屑 ── */
.breadcrumb {
  font-size: 0.8rem;
  color: var(--ink-light);
  margin-bottom: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem;
  align-items: center;
}
.breadcrumb a { color: var(--ink-light); text-decoration: none; }
.breadcrumb a:hover { color: var(--ink); text-decoration: underline; }

/* ── 眉题与标题 ── */
.section-eyebrow {
  display: block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 0.6rem;
  font-family: var(--font-sans);
}

.section-heading {
  font-family: var(--font-serif);
  font-size: 1.6rem;
  font-style: italic;
  font-weight: 400;
  color: var(--ink);
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 0.75rem;
}

/* ── Hero（首页） ── */
.hero-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  min-height: 70vh;
  align-items: center;
  margin-bottom: 4rem;
  padding: 2rem 0;
  position: relative;
}

.hero-media {
  position: relative;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--paper-alt);
}

.hero-grid-overlay {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--rule) 1px, transparent 1px),
    linear-gradient(90deg, var(--rule) 1px, transparent 1px);
  background-size: 32px 32px;
  opacity: 0.4;
  pointer-events: none;
}

.hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  position: relative;
  z-index: 1;
}

.hero-content {
  text-align: right;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 1.2rem;
}

.hero-eyebrow {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 3vw, 2.8rem);
  font-style: italic;
  font-weight: 400;
  line-height: 1.2;
  color: var(--ink);
}

.hero-desc {
  font-size: 1rem;
  color: var(--ink-mid);
  max-width: 40ch;
  line-height: 1.7;
}

.hero-cta {
  display: inline-block;
  padding: 0.8rem 2rem;
  background: var(--ink);
  color: var(--paper);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  border-radius: var(--radius);
  min-height: 44px;
  line-height: 1;
  display: inline-flex;
  align-items: center;
}
.hero-cta:hover { background: var(--ink-mid); color: var(--paper); }

/* ── 首页内容区块 ── */
.home-content-section,
.home-nav-section {
  margin-bottom: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--rule);
}

/* ── 子页卡片列表 ── */
.child-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.child-item {
  border-bottom: 1px solid var(--rule);
}
.child-item:first-child { border-top: 1px solid var(--rule); }

.child-card {
  padding: 1.5rem 0;
  display: block;
}

.child-card__title {
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}
.child-card__title a {
  text-decoration: none;
  color: var(--ink);
}
.child-card__title a:hover { text-decoration: underline; }

.child-card__desc {
  font-size: 0.9rem;
  color: var(--ink-mid);
  line-height: 1.6;
  margin-bottom: 0.4rem;
}

.card-date {
  font-size: 0.78rem;
  color: var(--ink-faint);
  font-family: var(--font-mono);
}

/* 带编号的卡片（topic页） */
.child-card--numbered {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
}

.child-card__num {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 400;
  color: var(--rule-strong);
  line-height: 1;
  padding-top: 0.2rem;
  flex-shrink: 0;
  min-width: 2.5rem;
}

.child-card__body { flex: 1; }

/* ── Topic 页 ── */
.topic-header {
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--ink);
}

.topic-title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 2.5vw, 2.4rem);
  font-style: italic;
  font-weight: 400;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.topic-desc {
  font-size: 1.05rem;
  color: var(--ink-mid);
  max-width: 65ch;
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.topic-date {
  font-size: 0.8rem;
  color: var(--ink-faint);
  font-family: var(--font-mono);
}

.topic-content-section,
.topic-children-section {
  margin-bottom: 3.5rem;
  padding-top: 2rem;
}

/* ── Article 页 ── */
.article-header {
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--ink);
}

.article-title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 2.5vw, 2.4rem);
  font-style: italic;
  font-weight: 400;
  line-height: 1.25;
  margin-bottom: 1rem;
}

.article-meta {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.article-date {
  font-size: 0.8rem;
  color: var(--ink-faint);
  font-family: var(--font-mono);
}
.article-date--modified::before { content: ''; }

.article-hero-figure {
  margin-bottom: 2.5rem;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  overflow: hidden;
}

.article-hero-img { width: 100%; display: block; }

.article-body-section { margin-bottom: 3.5rem; }

.article-related-section {
  margin-bottom: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--rule);
}

.article-nav-links {
  padding-top: 2rem;
  border-top: 1px solid var(--rule);
}

.back-link {
  font-size: 0.875rem;
  color: var(--ink-mid);
  text-decoration: none;
  font-weight: 500;
}
.back-link:hover { color: var(--ink); text-decoration: underline; }

/* ── Related cards ── */
.related-list { gap: 0; }

.related-item { border-bottom: 1px solid var(--rule); }
.related-item:first-child { border-top: 1px solid var(--rule); }

.related-card { padding: 1.2rem 0; }

.related-card__title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.3rem;
}
.related-card__title a { text-decoration: none; color: var(--ink); }
.related-card__title a:hover { text-decoration: underline; }

.related-card__desc {
  font-size: 0.875rem;
  color: var(--ink-mid);
  line-height: 1.5;
}

/* ── About 页 ── */
.about-header {
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--ink);
}

.about-title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 2.5vw, 2.4rem);
  font-style: italic;
  font-weight: 400;
  line-height: 1.25;
  margin-bottom: 0.75rem;
}

.about-date { font-size: 0.8rem; color: var(--ink-faint); font-family: var(--font-mono); }

.about-layout {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 3rem;
  align-items: start;
}

.about-sidebar-block {
  position: sticky;
  top: 2rem;
}

.about-info-panel {
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  padding: 1.5rem;
  background: var(--paper-alt);
}

.about-panel-heading {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-style: italic;
  font-weight: 400;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--rule);
}

.about-nav-dl dt {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-top: 1rem;
  margin-bottom: 0.4rem;
}
.about-nav-dl dd { margin-bottom: 0.4rem; }
.about-nav-dl dd a { font-size: 0.875rem; color: var(--ink-mid); }
.about-nav-dl dd a:hover { color: var(--ink); }

/* ── Privacy 页 ── */
.privacy-header {
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--ink);
}

.privacy-title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 2.5vw, 2.4rem);
  font-style: italic;
  font-weight: 400;
  line-height: 1.25;
  margin-bottom: 0.75rem;
}

.privacy-meta { display: flex; gap: 1.5rem; flex-wrap: wrap; }
.privacy-date { font-size: 0.8rem; color: var(--ink-faint); font-family: var(--font-mono); }

.privacy-body-section { margin-bottom: 3rem; }

.privacy-footer-links {
  display: flex;
  gap: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--rule);
  font-size: 0.875rem;
}
.privacy-footer-links a { color: var(--ink-mid); }
.privacy-footer-links a:hover { color: var(--ink); }

/* ── Prose（正文排版） ── */
.prose {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ink);
}

.prose h2 {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-style: italic;
  font-weight: 400;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--rule);
  color: var(--ink);
}

.prose h3 {
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 700;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  color: var(--ink);
}

.prose h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.prose p {
  margin-bottom: 1.2rem;
}

.prose ul, .prose ol {
  margin-bottom: 1.2rem;
  padding-left: 1.5rem;
}

.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }

.prose li { margin-bottom: 0.4rem; line-height: 1.7; }

.prose a { color: var(--ink); font-weight: 500; }
.prose a:hover { color: var(--ink-mid); }

.prose strong { font-weight: 700; }
.prose em { font-style: italic; }

.prose blockquote {
  border-left: 3px solid var(--ink);
  margin: 1.5rem 0;
  padding: 0.75rem 1.5rem;
  background: var(--paper-alt);
  font-style: italic;
  color: var(--ink-mid);
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
}
.prose table th, .prose table td {
  border: 1px solid var(--rule);
  padding: 0.6rem 0.8rem;
  text-align: left;
}
.prose table th {
  background: var(--paper-alt);
  font-weight: 700;
}

.prose code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--paper-alt);
  border: 1px solid var(--rule);
  padding: 0.1em 0.4em;
  border-radius: var(--radius);
}

.prose pre {
  background: var(--ink);
  color: var(--paper);
  padding: 1.5rem;
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 1.5rem;
}
.prose pre code { background: none; border: none; padding: 0; color: inherit; }

.prose img {
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  margin: 1.5rem 0;
}

.prose time { font-family: var(--font-mono); font-size: 0.875em; color: var(--ink-faint); }

/* ── Footer ── */
.site-footer {
  margin-left: var(--nav-width);
  background: var(--ink);
  color: var(--paper);
  padding: 3rem;
}

.footer-cta-block {
  text-align: center;
  padding: 2.5rem;
  border: 1px solid rgba(253,251,247,0.15);
  border-radius: var(--radius);
  margin-bottom: 3rem;
  background: rgba(253,251,247,0.04);
}

.footer-cta-text {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-style: italic;
  font-weight: 400;
  color: var(--paper);
  margin-bottom: 1.2rem;
  opacity: 0.9;
}

.footer-cta-btn {
  display: inline-block;
  padding: 0.8rem 2rem;
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius);
  min-height: 44px;
  line-height: 1;
  display: inline-flex;
  align-items: center;
}
.footer-cta-btn:hover { background: var(--paper-alt); color: var(--ink); }

.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin-bottom: 2.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid rgba(253,251,247,0.15);
}

.footer-dl dt {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(253,251,247,0.5);
  margin-bottom: 1rem;
}

.footer-dl dd {
  margin-bottom: 0.6rem;
}

.footer-dl dd a {
  color: rgba(253,251,247,0.75);
  text-decoration: none;
  font-size: 0.875rem;
  line-height: 1.5;
}
.footer-dl dd a:hover { color: var(--paper); text-decoration: underline; }
.footer-dl dd span { color: rgba(253,251,247,0.5); font-size: 0.875rem; }

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-copyright {
  font-size: 0.8rem;
  color: rgba(253,251,247,0.5);
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}
.footer-links a {
  font-size: 0.8rem;
  color: rgba(253,251,247,0.5);
  text-decoration: none;
}
.footer-links a:hover { color: var(--paper); }

/* ── Scroll Reveal（原生 JS 配合） ── */
.reveal {
  opacity: 0;
  transform: translateY(16px);
}
.reveal.is-visible {
  opacity: 1;
  transform: none;
  transition: opacity 0.4s ease, transform 0.4s ease;
}

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; }
  .reveal.is-visible { transition: none; }
}

/* ── 响应式：移动端 ── */
@media (max-width: 900px) {
  :root { --nav-width: 0px; }

  .site-header {
    position: static;
    width: 100%;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--rule);
  }

  .site-nav {
    flex-direction: row;
    flex-wrap: wrap;
    padding: 1rem;
    gap: 0;
    align-items: center;
  }

  .site-nav__brand {
    padding-bottom: 0;
    border-bottom: none;
    margin-bottom: 0;
    margin-right: auto;
    padding-right: 1rem;
    border-right: 1px solid var(--rule);
    flex-shrink: 0;
  }

  .site-nav__links {
    flex-direction: row;
    flex-wrap: wrap;
    flex: none;
    padding: 0 1rem;
    gap: 0;
  }

  .nav-link {
    border-bottom: none;
    border-right: 1px solid var(--rule);
    padding: 0.4rem 0.75rem;
    font-size: 0.8rem;
    min-height: 40px;
  }
  .nav-link--active { border-left: none; padding-left: 0.75rem; border-bottom: 2px solid var(--ink); }

  .site-nav__contact {
    padding-top: 0;
    border-top: none;
    margin-top: 0;
    margin-left: auto;
    padding-left: 1rem;
  }

  .page-main {
    margin-left: 0;
    padding: 1.5rem 1rem;
  }

  .site-footer {
    margin-left: 0;
    padding: 2rem 1rem;
  }

  .hero-section {
    grid-template-columns: 1fr;
    min-height: auto;
    gap: 1.5rem;
  }

  .hero-content {
    text-align: left;
    align-items: flex-start;
  }

  .footer-cols {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .about-layout {
    grid-template-columns: 1fr;
  }

  .about-sidebar-block { position: static; }
}

@media (max-width: 480px) {
  .site-nav__links { display: none; }

  .page-main { padding: 1rem; }

  .hero-title { font-size: 1.5rem; }

  .article-title,
  .topic-title,
  .about-title,
  .privacy-title { font-size: 1.4rem; }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}