/* =============================================================
   优乐在线 · 共享样式表 /assets/site.css
   装帧语言：江南地方志 · 纸白墨黑 · 朱砂锚点 · 等宽索引
   ============================================================= */

/* ---------- reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, dl, dt, dd, figure, figcaption, blockquote { margin: 0; }

ul, ol { padding: 0; list-style: none; }

button { font: inherit; color: inherit; }

a { color: inherit; }

/* ---------- tokens ---------- */
:root {
  --paper: #F7F4EC;
  --paper-warm: #EFE9DB;
  --ink: #1E1C1A;
  --slate: #3E4A4F;
  --slate-100: #C7CCC6;
  --bamboo: #5B7A5E;
  --cinnabar: #B23A2E;
  --cinnabar-soft: #F0DAD4;
  --deep: #22333A;
  --muted: #5F6E73;
  --index-yellow: #E6DCC6;

  --serif: "Source Han Serif SC", "Noto Serif SC", "Songti SC", STSong, SimSun, serif;
  --sans: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --mono: "IBM Plex Mono", "JetBrains Mono", ui-monospace, SFMono-Regular, Consolas, monospace;

  --rail: 180px;
  --gutter: 48px;
  --maxw: 1120px;

  --line: 1px solid var(--slate-100);
  --line-ink: 1px solid var(--slate);
  --shade: 0 1px 0 rgba(30, 28, 26, .05), 0 14px 26px -20px rgba(30, 28, 26, .42);
  --shade-lift: 0 2px 0 rgba(30, 28, 26, .06), 0 20px 34px -22px rgba(30, 28, 26, .5);
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- base ---------- */
html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.85;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(180deg, rgba(230, 220, 198, .55) 0, rgba(247, 244, 236, 0) 360px),
    repeating-linear-gradient(90deg, rgba(62, 74, 79, .028) 0 1px, transparent 1px 3px);
  background-repeat: no-repeat, repeat;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: -0.01em;
  text-shadow: 0 .5px 0 rgba(30, 28, 26, .18);
}

h1 { font-size: clamp(30px, 4vw, 44px); }
h2 { font-size: clamp(24px, 3vw, 32px); }
h3 { font-size: 24px; }
h4 { font-size: 19px; font-weight: 700; }

p { line-height: 1.85; }

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

:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 2px;
}

.mono {
  font-family: var(--mono);
  font-size: .92em;
  letter-spacing: .04em;
}

/* ---------- layout ---------- */
.shell {
  width: min(100% - 32px, var(--maxw));
  margin-inline: auto;
}

.page-frame {
  display: grid;
  grid-template-columns: var(--rail) minmax(0, 1fr);
  gap: var(--gutter);
  align-items: start;
}

/* 竖排索引栏（页面阶段使用，id="rail-index" 供头部开关引用） */
.rail-index {
  position: sticky;
  top: 148px;
  align-self: start;
  padding-top: 14px;
  border-top: 2px solid var(--ink);
  transition: opacity .18s var(--ease);
}

.rail-title {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--muted);
  margin-bottom: 12px;
}

.rail-list li { border-bottom: 1px dashed var(--slate-100); }

.rail-list a {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 7px 0;
  font-size: 14px;
  color: var(--slate);
  text-decoration: none;
  transition: color .12s var(--ease), transform .12s var(--ease);
}

.rail-list a:hover { color: var(--cinnabar); transform: translateX(3px); }

.rail-num {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .04em;
  color: var(--muted);
}

html[data-index="off"] .rail-index { display: none; }
html[data-index="off"] .page-frame { grid-template-columns: minmax(0, 1fr); }

/* 页面容器 */
.page-main { padding-bottom: 40px; }

.page-title { margin-bottom: 12px; }

.page-sub {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--muted);
  margin-bottom: 22px;
}

.lede {
  font-size: 19px;
  line-height: 1.8;
  color: var(--slate);
  max-width: 30em;
}

.prose { color: var(--slate); }

.prose p { max-width: 34em; margin-bottom: 1.2em; }
.prose p:last-child { margin-bottom: 0; }
.prose h3 { color: var(--ink); margin: 28px 0 10px; }
.prose h4 { color: var(--ink); margin: 22px 0 8px; }
.prose ul, .prose ol { max-width: 34em; margin-bottom: 1.2em; padding-left: 1.2em; }
.prose ul { list-style: square; }
.prose ol { list-style: decimal; }
.prose li { margin-bottom: .4em; }
.prose a { color: var(--cinnabar); text-decoration: none; border-bottom: 1px solid var(--cinnabar-soft); }
.prose a:hover { border-bottom-color: var(--cinnabar); }
.prose blockquote {
  border-left: 2px solid var(--cinnabar);
  padding-left: 16px;
  color: var(--slate);
  font-family: var(--serif);
  max-width: 32em;
}

/* ---------- sections ---------- */
.section {
  position: relative;
  padding: 56px 0;
  border-top: var(--line);
}

.section:first-of-type { border-top: none; }

.section-head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 12px;
  margin-bottom: 26px;
  border-bottom: var(--line);
}

.folio {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--cinnabar);
}

/* ---------- breadcrumb ---------- */
.crumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0 8px;
  padding: 22px 0 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--muted);
}

.crumb li { display: flex; align-items: center; gap: 8px; }
.crumb li::after { content: "/"; color: var(--slate-100); }
.crumb li:last-child::after { content: ""; }
.crumb a { color: var(--slate); text-decoration: none; }
.crumb a:hover { color: var(--cinnabar); }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  font-size: 15px;
  font-family: var(--sans);
  line-height: 1.4;
  border: 1px solid var(--ink);
  background: transparent;
  color: var(--ink);
  text-decoration: none;
  cursor: pointer;
  transition: transform .12s var(--ease), box-shadow .12s var(--ease),
              background-color .12s var(--ease), border-color .12s var(--ease);
}

.btn:hover { transform: translateY(-2px); box-shadow: var(--shade-lift); }

.btn--primary {
  background: var(--cinnabar);
  border-color: var(--cinnabar);
  color: var(--paper);
}

.btn--primary:hover { background: #9B3026; border-color: #9B3026; }

.btn--ghost { border-color: var(--slate-100); color: var(--slate); }
.btn--ghost:hover { border-color: var(--cinnabar); color: var(--cinnabar); }

.btn-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 26px; }

/* ---------- panels ---------- */
.panel {
  border: var(--line);
  background: var(--paper-warm);
  margin-bottom: 12px;
  transition: box-shadow .18s var(--ease), transform .18s var(--ease);
}

.panel[open] { box-shadow: var(--shade); }

.panel > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 15px 18px;
  font-family: var(--serif);
  font-size: 17px;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
}

.panel > summary::-webkit-details-marker { display: none; }

.panel > summary::after {
  content: "＋";
  font-family: var(--mono);
  font-size: 13px;
  color: var(--cinnabar);
}

.panel[open] > summary::after { content: "－"; }

.panel > summary:hover { background: var(--paper); }

.panel-body {
  padding: 0 18px 18px;
  font-size: 15px;
  color: var(--slate);
}

.panel-body p { max-width: 34em; margin-bottom: .9em; }
.panel-body p:last-child { margin-bottom: 0; }

/* ---------- tags / stamp ---------- */
.tag {
  display: inline-block;
  padding: 2px 8px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  border: 1px solid var(--slate-100);
  background: var(--paper);
  color: var(--muted);
}

.tag--cinnabar { border-color: var(--cinnabar); color: var(--cinnabar); }
.tag--bamboo { border-color: var(--bamboo); color: var(--bamboo); }

.stamp {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 54px;
  height: 54px;
  padding: 4px;
  border: 2px solid var(--cinnabar);
  color: var(--cinnabar);
  font-family: var(--serif);
  font-size: 15px;
  line-height: 1.15;
  letter-spacing: .08em;
  text-align: center;
}

/* ---------- cards ---------- */
.card {
  background: var(--paper-warm);
  border: var(--line);
  padding: 22px 20px;
  box-shadow: var(--shade);
  transition: transform .14s var(--ease), box-shadow .14s var(--ease);
}

.card:hover { transform: translateY(-2px); box-shadow: var(--shade-lift); }

.card-title {
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 600;
  margin-bottom: 8px;
}

.card-meta {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--muted);
  margin-bottom: 12px;
}

.card p { font-size: 15px; color: var(--slate); }

/* ---------- spec list ---------- */
.spec-list { border-top: var(--line-ink); }

.spec-list > div {
  display: grid;
  grid-template-columns: 168px minmax(0, 1fr);
  gap: 16px;
  padding: 11px 0;
  border-bottom: var(--line);
  font-size: 15px;
  color: var(--slate);
}

.spec-list dt {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
}

/* ---------- plates ---------- */
.plate {
  background: var(--paper-warm);
  border: var(--line);
  padding: 10px;
  box-shadow: var(--shade);
}

.plate-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  background:
    repeating-linear-gradient(0deg, rgba(62, 74, 79, .06) 0 1px, transparent 1px 8px),
    var(--index-yellow);
}

.plate-frame > img,
.plate-frame > svg {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.plate--tall .plate-frame { aspect-ratio: 4 / 5; }
.plate--wide .plate-frame { aspect-ratio: 21 / 9; }

.plate-caption {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--muted);
}

.grid { display: grid; gap: 24px; }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(228px, 1fr)); }

/* ---------- skip link ---------- */
.skip-link {
  position: absolute;
  left: 12px;
  top: -60px;
  z-index: 60;
  padding: 9px 16px;
  background: var(--cinnabar);
  color: var(--paper);
  font-size: 14px;
  text-decoration: none;
  transition: top .15s var(--ease);
}

.skip-link:focus { top: 12px; }

/* =============================================================
   header
   ============================================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(247, 244, 236, .95);
  backdrop-filter: blur(3px);
  border-bottom: var(--line);
  transition: box-shadow .18s var(--ease);
}

.site-header[data-condensed] { box-shadow: 0 10px 20px -18px rgba(30, 28, 26, .5); }

.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: var(--cinnabar);
  transform: scaleX(var(--p, 0));
  transform-origin: 0 50%;
  pointer-events: none;
  will-change: transform;
}

.header-shell { position: relative; }

.header-top {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 14px;
  padding: 15px 0 10px;
  transition: padding .18s var(--ease);
}

/* 刊头 */
.masthead {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  text-decoration: none;
  color: var(--ink);
  padding: 0 6px;
}

.masthead-title {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 30px;
  line-height: 1.1;
  letter-spacing: .02em;
  text-shadow: 0 .5px 0 rgba(30, 28, 26, .3);
  white-space: nowrap;
  transition: font-size .18s var(--ease);
}

.masthead-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--muted);
  white-space: nowrap;
}

.masthead-brand { letter-spacing: .14em; }

.version-badge {
  display: inline-block;
  padding: 1px 6px;
  border: 1px solid var(--cinnabar);
  color: var(--cinnabar);
  border-radius: 2px;
  line-height: 1.5;
}

/* 右上工具区 */
.header-utility {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
  min-width: 0;
}

.utility-link,
.utility-toggle {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--slate);
  background: var(--paper);
  border: 1px solid var(--slate-100);
  padding: 5px 10px;
  line-height: 1.5;
  text-decoration: none;
  cursor: pointer;
  white-space: nowrap;
  transition: border-color .12s var(--ease), color .12s var(--ease),
              background-color .12s var(--ease);
}

.utility-link:hover,
.utility-toggle:hover { border-color: var(--cinnabar); color: var(--cinnabar); }

.utility-toggle[aria-pressed="true"] {
  background: var(--cinnabar);
  border-color: var(--cinnabar);
  color: var(--paper);
}

/* 移动端按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  background: transparent;
  border: 1px solid var(--slate-100);
  color: var(--slate);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  cursor: pointer;
  justify-self: start;
}

.nav-toggle:hover { border-color: var(--cinnabar); color: var(--cinnabar); }

.nav-toggle-bars,
.nav-toggle-bars::before,
.nav-toggle-bars::after {
  display: block;
  width: 14px;
  height: 1.5px;
  background: currentColor;
  content: "";
  position: relative;
}

.nav-toggle-bars::before { position: absolute; top: -4.5px; }
.nav-toggle-bars::after { position: absolute; top: 4.5px; }

/* 导航 */
.site-nav { padding-bottom: 12px; }

.nav-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 26px;
}

.nav-link {
  position: relative;
  display: inline-block;
  padding: 6px 2px;
  font-size: 15px;
  color: var(--slate);
  text-decoration: none;
  transition: color .12s var(--ease);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--cinnabar);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform .12s var(--ease);
}

.nav-link:hover { color: var(--ink); }
.nav-link:hover::after { transform: scaleX(1); }

.nav-link[aria-current="page"] { color: var(--cinnabar); font-weight: 600; }
.nav-link[aria-current="page"]::after { transform: scaleX(1); }

.nav-note {
  margin-top: 8px;
  text-align: center;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--muted);
}

/* 收窄态 */
.site-header[data-condensed] .header-top { padding: 8px 0 6px; }
.site-header[data-condensed] .masthead-title { font-size: 21px; }
.site-header[data-condensed] .masthead-meta { display: none; }
.site-header[data-condensed] .nav-note { display: none; }
.site-header[data-condensed] .site-nav { padding-bottom: 8px; }

/* =============================================================
   footer
   ============================================================= */
.site-footer {
  margin-top: 96px;
  background: var(--deep);
  color: var(--paper);
  border-top: 3px double rgba(247, 244, 236, .35);
}

.footer-shell { padding: 54px 0 34px; }

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 20px 32px;
}

.footer-brand {
  font-family: var(--serif);
  font-size: 26px;
  font-weight: 600;
  letter-spacing: .02em;
  color: var(--paper);
}

.footer-sub {
  margin-top: 6px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: #9FB0AF;
}

.footer-closing {
  font-family: var(--serif);
  font-size: 16px;
  color: #DCD8CD;
  text-align: right;
  max-width: 24em;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 24px 28px;
  margin-top: 30px;
  padding: 28px 0;
  border-top: 1px solid rgba(247, 244, 236, .18);
  border-bottom: 1px solid rgba(247, 244, 236, .18);
}

.footer-col-title {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: #8FA3A2;
  margin-bottom: 8px;
}

.footer-col-body {
  font-size: 14px;
  line-height: 1.75;
  color: #DCD8CD;
}

.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 32px;
  padding: 24px 0;
  font-size: 14px;
  color: #DCD8CD;
}

.footer-contact li { display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px; }

.footer-k {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: #8FA3A2;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-top: 20px;
  border-top: 1px solid rgba(247, 244, 236, .18);
  font-size: 13px;
  color: #B9C2BF;
}

.footer-links { display: flex; flex-wrap: wrap; gap: 18px; }

.footer-links a {
  color: #DCD8CD;
  text-decoration: none;
  border-bottom: 1px solid rgba(247, 244, 236, .35);
  transition: color .12s var(--ease), border-color .12s var(--ease);
}

.footer-links a:hover { color: var(--paper); border-bottom-color: var(--cinnabar); }

/* =============================================================
   响应式
   ============================================================= */
@media (max-width: 1040px) {
  :root { --gutter: 32px; }
  .footer-closing { text-align: left; }
}

@media (max-width: 960px) {
  .page-frame { grid-template-columns: minmax(0, 1fr); gap: 24px; }

  .rail-index {
    position: static;
    border-top-width: 1px;
    border-top-color: var(--slate);
    padding-top: 10px;
  }

  .rail-list { display: flex; flex-wrap: wrap; gap: 0 18px; }
  .rail-list li { border-bottom: none; }
  .rail-list a { padding: 5px 0; }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 880px) {
  .nav-toggle { display: inline-flex; }

  .header-top { grid-template-columns: auto 1fr auto; padding: 10px 0 8px; }

  .masthead-title { font-size: 22px; }
  .masthead-meta { font-size: 10px; }

  .site-nav {
    display: none;
    padding-bottom: 0;
    border-top: var(--line);
    margin-top: 8px;
  }

  .site-nav[data-open] { display: block; padding: 10px 0 14px; }

  .nav-list { flex-direction: column; gap: 0; }

  .nav-link {
    display: block;
    padding: 13px 4px;
    font-size: 16px;
    border-bottom: 1px solid var(--slate-100);
  }

  .nav-link::after { display: none; }
  .nav-link[aria-current="page"] {
    border-left: 3px solid var(--cinnabar);
    padding-left: 12px;
    background: var(--cinnabar-soft);
  }

  .nav-note { text-align: left; padding: 12px 4px 0; }

  .site-header[data-condensed] .nav-note { display: block; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }

  .section { padding: 40px 0; }
  .lede { font-size: 17px; }

  .spec-list > div { grid-template-columns: minmax(0, 1fr); gap: 4px; }

  .utility-link { display: none; }

  .footer-shell { padding: 40px 0 28px; }
  .footer-top { grid-template-columns: minmax(0, 1fr); }
  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 20px; }
  .footer-contact { flex-direction: column; gap: 10px; }
  .footer-legal { flex-direction: column; align-items: flex-start; }
}

/* ---------- 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;
    scroll-behavior: auto !important;
  }

  .btn:hover,
  .card:hover { transform: none; }
  .rail-list a:hover { transform: none; }
}

/* ---------- 打印 ---------- */
@media print {
  .site-header,
  .site-footer,
  .skip-link { display: none; }

  body { background: #fff; color: #000; }
  .page-frame { grid-template-columns: minmax(0, 1fr); }
}