/* ===========================================================
   千亿指南 · 共享样式 /assets/site.css
   墨色基底 + 鎏金导视 + 青瓷引导 + 朱砂信号
   =========================================================== */

/* ---------- 1. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 24px);
}
body, h1, h2, h3, h4, h5, p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; padding: 0; }
ul, ol { list-style: none; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
img, svg, video { display: block; max-width: 100%; }
i, em { font-style: normal; }
table { border-collapse: collapse; width: 100%; }

/* ---------- 2. 变量 ---------- */
:root {
  --ink-900: #121212;
  --ink-850: #161616;
  --ink-800: #1C1C1C;
  --ink-700: #2E2E2E;
  --ink-600: #3A3A3A;
  --gold: #C9A227;
  --gold-bright: #E3C766;
  --gold-deep: #8C6F14;
  --celadon: #3E7C6A;
  --celadon-soft: #6FA895;
  --cinnabar: #C0392B;
  --paper: #F2EDE3;
  --ash: #8A8579;

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

  --fs-12: 0.75rem;
  --fs-14: 0.875rem;
  --fs-16: 1rem;
  --fs-18: 1.125rem;
  --fs-22: 1.375rem;
  --fs-28: 1.75rem;
  --fs-40: 2.5rem;
  --fs-64: 4rem;

  --sp-1: 8px;
  --sp-2: 16px;
  --sp-3: 24px;
  --sp-4: 32px;
  --sp-5: 48px;
  --sp-6: 64px;
  --sp-7: 96px;
  --sp-8: 128px;

  --cut: 18px;
  --shell-max: 1360px;
  --shell-pad: clamp(16px, 3vw, 40px);
  --header-h: 64px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  background-color: var(--ink-900);
  background-image:
    linear-gradient(rgba(242, 237, 227, 0.022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(242, 237, 227, 0.022) 1px, transparent 1px);
  background-size: 96px 96px, 96px 96px;
  background-position: -1px -1px, -1px -1px;
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--paper);
}
h1 { font-size: clamp(2rem, 5vw, var(--fs-64)); }
h2 { font-size: clamp(1.5rem, 3.4vw, var(--fs-40)); }
h3 { font-size: var(--fs-22); }
h4 { font-size: var(--fs-18); }
p { max-width: 62ch; }
p + p { margin-top: var(--sp-2); }
strong { font-weight: 700; color: var(--paper); }
::selection { background: var(--gold); color: var(--ink-900); }
:focus-visible { outline: 2px solid var(--gold-bright); outline-offset: 2px; }

/* ---------- 4. 布局容器 ---------- */
.container {
  width: min(var(--shell-max), 100%);
  margin-inline: auto;
  padding-inline: var(--shell-pad);
}
.site-main { display: block; padding-bottom: var(--sp-7); }

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-4);
  width: min(var(--shell-max), 100%);
  margin-inline: auto;
  padding-inline: var(--shell-pad);
}
@media (min-width: 1024px) {
  .layout {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: var(--sp-5);
    align-items: start;
  }
}

/* ---------- 5. 左锚点带 ---------- */
.rail { display: none; }
@media (min-width: 1024px) {
  .rail {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }
}
.rail__label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  color: var(--ash);
  padding-bottom: 10px;
}
.rail__list {
  position: relative;
  padding-left: 16px;
  border-left: 1px solid var(--ink-700);
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.rail__track {
  position: absolute;
  left: -1px;
  top: 0;
  width: 1px;
  height: var(--rail-progress, 0%);
  background: linear-gradient(180deg, var(--gold-deep), var(--gold), var(--gold-bright));
  transition: height 320ms var(--ease);
}
.rail__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 6px 0;
  font-size: var(--fs-14);
  color: var(--ash);
  transition: color 160ms var(--ease);
}
.rail__link:hover { color: var(--paper); }
.rail__link.is-active { color: var(--gold-bright); }
.rail__link.is-active .rail__idx { color: var(--gold); }
.rail__idx {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--ink-600);
}

/* ---------- 6. 章节 ---------- */
.section { padding-block: var(--sp-5); }
.section--wide { padding-block: var(--sp-6); }
.section--narrow { max-width: 760px; }
.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 14px;
  padding-bottom: var(--sp-2);
  border-bottom: 1px solid var(--ink-700);
  margin-bottom: var(--sp-4);
}
.section__idx {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--gold-deep);
}
.section__title { font-size: clamp(1.4rem, 3vw, 2rem); letter-spacing: 0.03em; }
.section__note { font-size: var(--fs-14); color: var(--ash); max-width: 46ch; }
@media (min-width: 768px) {
  .section__head .section__note { margin-left: auto; }
}

/* ---------- 7. 栅格 ---------- */
.grid { display: grid; gap: var(--sp-2); }
.grid--2, .grid--3 { grid-template-columns: minmax(0, 1fr); }
.grid--auto { grid-template-columns: repeat(auto-fit, minmax(min(260px, 100%), 1fr)); }
@media (min-width: 640px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (min-width: 1024px) {
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

/* ---------- 8. 切角面板 ---------- */
.panel {
  position: relative;
  isolation: isolate;
  padding: var(--sp-3);
}
.panel::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  border: 1px solid var(--ink-700);
  background: linear-gradient(160deg, #1C1C1C, #141414 72%);
  clip-path: polygon(
    var(--cut) 0,
    100% 0,
    100% calc(100% - var(--cut)),
    calc(100% - var(--cut)) 100%,
    0 100%,
    0 var(--cut)
  );
  transition: border-color 200ms var(--ease), background 200ms var(--ease);
}
.panel::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: var(--cut);
  height: var(--cut);
  background: linear-gradient(to top right, transparent calc(50% - 0.5px), var(--gold) 50%, transparent calc(50% + 0.5px));
  opacity: 0;
  pointer-events: none;
  transition: opacity 200ms var(--ease);
}
.panel:hover::before { border-color: rgba(201, 162, 39, 0.45); }
.panel:hover::after { opacity: 1; }
.panel__head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 12px;
}
.panel__idx {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--gold-deep);
}
.panel__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-22);
  letter-spacing: 0.02em;
  color: var(--paper);
}
.panel__text { font-size: var(--fs-16); color: var(--ash); line-height: 1.8; }
.panel__foot {
  margin-top: var(--sp-2);
  padding-top: 12px;
  border-top: 1px solid var(--ink-700);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  font-size: var(--fs-14);
}
.panel__link {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--gold);
}
.panel__link:hover { color: var(--gold-bright); }

/* ---------- 9. 图片容器 ---------- */
.figure { display: flex; flex-direction: column; gap: 8px; }
.media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--ink-700);
  background:
    linear-gradient(140deg, #1C1C1C, #121212 58%, #171717),
    var(--ink-900);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
}
.media--square { aspect-ratio: 1 / 1; }
.media--tall { aspect-ratio: 4 / 5; }
.media--band { aspect-ratio: 21 / 9; }
.media > img, .media > video, .media > svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media__grid {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(242, 237, 227, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(242, 237, 227, 0.05) 1px, transparent 1px);
  background-size: 32px 32px, 32px 32px;
}
.media__caption {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.04em;
  color: var(--ash);
}

/* ---------- 10. 按钮与筛选 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 20px;
  font-size: var(--fs-14);
  letter-spacing: 0.06em;
  color: var(--paper);
  border: 1px solid var(--ink-700);
  background: linear-gradient(180deg, #1C1C1C, #151515);
  transition: color 160ms var(--ease), border-color 160ms var(--ease), background 200ms var(--ease);
}
.btn:hover {
  color: var(--gold-bright);
  border-color: rgba(201, 162, 39, 0.55);
  background: linear-gradient(180deg, #221F14, #151515);
}
.btn--gold {
  font-weight: 700;
  color: var(--ink-900);
  border-color: transparent;
  background: linear-gradient(135deg, var(--gold-bright), var(--gold) 55%, var(--gold-deep));
}
.btn--gold:hover { color: var(--ink-900); filter: brightness(1.06); border-color: transparent; }
.btn--ghost { color: var(--ash); background: transparent; }
.btn--ghost:hover { color: var(--paper); background: rgba(242, 237, 227, 0.03); }
.btn--guide {
  color: var(--celadon-soft);
  border-color: rgba(62, 124, 106, 0.55);
  background: linear-gradient(180deg, rgba(62, 124, 106, 0.16), rgba(62, 124, 106, 0.04));
}
.btn--guide:hover { color: var(--paper); border-color: var(--celadon-soft); }
.btn__mark { font-family: var(--font-mono); letter-spacing: 0; }

.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px;
  font-size: var(--fs-14);
  color: var(--ash);
  border: 1px solid var(--ink-700);
  background: #151515;
  transition: color 160ms var(--ease), border-color 160ms var(--ease), background 160ms var(--ease);
}
.chip:hover { color: var(--paper); border-color: var(--ink-600); }
.chip[aria-pressed="true"], .chip.is-active {
  color: var(--ink-900);
  font-weight: 700;
  border-color: transparent;
  background: linear-gradient(135deg, var(--gold-bright), var(--gold));
}
.chip__count { font-family: var(--font-mono); font-size: 11px; opacity: 0.75; }

/* ---------- 11. 面包屑 ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.04em;
  color: var(--ash);
}
.crumbs__item { display: inline-flex; align-items: center; gap: 8px; }
.crumbs__item a:hover { color: var(--gold-bright); }
.crumbs__item[aria-current="page"] { color: var(--paper); }
.crumbs__sep { color: var(--ink-600); }

/* ---------- 12. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: linear-gradient(180deg, rgba(22, 22, 22, 0.98), rgba(18, 18, 18, 0.94));
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--ink-700);
  transition: box-shadow 240ms var(--ease), border-color 240ms var(--ease);
}
.site-header::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  transform: scaleX(var(--progress, 0));
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--gold-deep), var(--gold), var(--gold-bright));
  opacity: 0.9;
}
.site-header.is-scrolled {
  border-bottom-color: #262626;
  box-shadow: 0 16px 32px -26px rgba(0, 0, 0, 0.95);
}
.header-bar {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  width: min(var(--shell-max), 100%);
  margin-inline: auto;
  padding-inline: var(--shell-pad);
  min-height: var(--header-h);
}

.skip-link {
  position: absolute;
  left: var(--shell-pad);
  top: 8px;
  z-index: 80;
  transform: translateY(-200%);
  padding: 10px 16px;
  font-size: var(--fs-14);
  font-weight: 700;
  color: var(--ink-900);
  background: var(--gold);
  transition: transform 180ms var(--ease);
}
.skip-link:focus { transform: translateY(0); }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding: 6px 0;
}
.brand__glyph {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--ink-900);
  padding: 5px 7px;
  background: linear-gradient(135deg, var(--gold-bright), var(--gold) 55%, var(--gold-deep));
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%);
}
.brand__text { display: flex; flex-direction: column; line-height: 1.12; }
.brand__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-18);
  letter-spacing: 0.12em;
  color: var(--paper);
  white-space: nowrap;
}
.brand__sub {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--ash);
  white-space: nowrap;
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
}

.version-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 9px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--paper);
  border: 1px solid rgba(192, 57, 43, 0.5);
  background: linear-gradient(180deg, rgba(192, 57, 43, 0.22), rgba(192, 57, 43, 0.06));
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 7px), calc(100% - 7px) 100%, 0 100%);
}
.version-badge__dot {
  width: 5px;
  height: 5px;
  background: var(--cinnabar);
  box-shadow: 0 0 8px rgba(192, 57, 43, 0.9);
  animation: qyPulse 2.4s var(--ease) infinite;
}
.version-badge__label { font-size: 10px; letter-spacing: 0.14em; color: var(--ash); }
.version-badge__num { font-weight: 700; }
@keyframes qyPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.32; }
}

.back-anchor {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 10px;
  font-size: var(--fs-14);
  color: var(--ash);
  border: 1px solid transparent;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}
.back-anchor:hover { color: var(--gold-bright); border-color: rgba(201, 162, 39, 0.35); }
.back-anchor__mark { font-family: var(--font-mono); color: var(--gold); }
.back-anchor__label { white-space: nowrap; }

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 8px 10px;
  border: 1px solid var(--ink-700);
  background: linear-gradient(180deg, #1C1C1C, #151515);
  transition: border-color 160ms var(--ease), color 160ms var(--ease);
}
.nav-toggle__bars { display: grid; gap: 4px; width: 18px; }
.nav-toggle__bars i {
  display: block;
  height: 1px;
  background: var(--paper);
  transition: transform 200ms var(--ease), opacity 160ms var(--ease);
}
.nav-toggle__bars i:nth-child(2) { width: 12px; }
.nav-toggle__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ash);
}
.nav-toggle[aria-expanded="true"] { border-color: rgba(201, 162, 39, 0.5); }
.nav-toggle[aria-expanded="true"] .nav-toggle__label { color: var(--gold-bright); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* 移动端导航抽屉 */
.site-nav {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  max-height: min(78vh, 620px);
  overflow-y: auto;
  padding: var(--sp-2) var(--shell-pad) var(--sp-3);
  background: linear-gradient(180deg, #171717, #121212);
  border-bottom: 1px solid var(--ink-700);
}
.site-nav[data-open] {
  display: block;
  animation: qyNavDrop 220ms var(--ease) both;
}
@keyframes qyNavDrop {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: none; }
}
.site-nav__list { display: flex; flex-direction: column; }
.site-nav__item { display: block; }
.site-nav__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 4px;
  font-size: var(--fs-16);
  color: var(--paper);
  border-bottom: 1px solid rgba(242, 237, 227, 0.06);
  transition: color 160ms var(--ease), background 160ms var(--ease);
}
.site-nav__idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--gold-deep);
}
.site-nav__label { letter-spacing: 0.04em; }
.site-nav__link:hover { color: var(--gold-bright); }
.site-nav__link[aria-current="page"] {
  color: var(--gold-bright);
  box-shadow: inset 2px 0 0 var(--gold);
  background: linear-gradient(90deg, rgba(201, 162, 39, 0.1), transparent 62%);
}
.site-nav__link[aria-current="page"] .site-nav__idx { color: var(--gold); }
.site-nav__link[aria-current="page"]::after {
  content: "当前";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--gold-bright);
  border: 1px solid rgba(201, 162, 39, 0.4);
  padding: 1px 6px;
}
.site-nav__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: var(--sp-2);
  padding-top: var(--sp-2);
  border-top: 1px solid var(--ink-700);
}
.nav-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 14px;
  font-size: var(--fs-14);
  color: var(--paper);
  border: 1px solid var(--ink-700);
  transition: border-color 160ms var(--ease), color 160ms var(--ease);
}
.nav-chip__mark { font-family: var(--font-mono); }
.nav-chip--guide {
  border-color: rgba(62, 124, 106, 0.55);
  background: linear-gradient(180deg, rgba(62, 124, 106, 0.16), rgba(62, 124, 106, 0.03));
}
.nav-chip--guide .nav-chip__mark { color: var(--celadon-soft); }
.nav-chip--gold {
  border-color: rgba(201, 162, 39, 0.45);
  background: linear-gradient(180deg, rgba(201, 162, 39, 0.14), rgba(201, 162, 39, 0.02));
}
.nav-chip--gold .nav-chip__mark { color: var(--gold-bright); }
.nav-chip:hover { color: var(--gold-bright); border-color: var(--gold); }

/* ---------- 13. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: var(--sp-8);
  color: var(--ash);
  background: linear-gradient(180deg, #101010, #171717 42%, #121212);
  border-top: 1px solid var(--ink-700);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: min(340px, 44%);
  height: 1px;
  background: linear-gradient(90deg, var(--gold), var(--gold-bright), transparent);
}
.footer-shell {
  display: grid;
  gap: var(--sp-4);
  width: min(var(--shell-max), 100%);
  margin-inline: auto;
  padding: var(--sp-5) var(--shell-pad) var(--sp-4);
}
@media (min-width: 900px) {
  .footer-shell {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.45fr);
    gap: var(--sp-6);
  }
}
.footer-brand { display: flex; flex-direction: column; gap: 12px; max-width: 36ch; }
.brand--footer { padding: 0; }
.brand--footer .brand__name { font-size: var(--fs-22); }
.footer-summary {
  font-family: var(--font-display);
  font-size: var(--fs-18);
  line-height: 1.6;
  letter-spacing: 0.02em;
  color: var(--paper);
  max-width: 26ch;
}
.footer-meta {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  align-self: flex-start;
  padding: 5px 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  border: 1px solid var(--ink-700);
}
.footer-meta__key { letter-spacing: 0.18em; color: var(--ash); }
.footer-meta__val { font-weight: 700; color: var(--gold); }
.footer-nav {
  display: grid;
  gap: var(--sp-3);
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}
.footer-col { min-width: 0; }
.footer-col__title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0.2em;
  color: var(--ash);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--ink-700);
}
.footer-col__list { display: flex; flex-direction: column; gap: 2px; margin-top: 10px; }
.footer-link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 5px 0;
  font-size: var(--fs-14);
  color: var(--paper);
  opacity: 0.78;
  transition: opacity 160ms var(--ease), color 160ms var(--ease);
}
.footer-link:hover { opacity: 1; color: var(--gold-bright); }
.footer-link__idx { font-family: var(--font-mono); font-size: 10px; color: var(--gold-deep); }

.footer-base {
  display: grid;
  gap: 10px;
  width: min(var(--shell-max), 100%);
  margin-inline: auto;
  padding: var(--sp-3) var(--shell-pad) var(--sp-5);
  border-top: 1px solid var(--ink-700);
}
.footer-contact {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
  font-size: var(--fs-14);
  color: var(--paper);
  max-width: none;
}
.footer-contact__item { display: inline-flex; align-items: center; gap: 8px; }
.footer-contact__key {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--ash);
}
.footer-contact__value { font-family: var(--font-mono); color: var(--paper); }
.footer-address { font-size: var(--fs-14); color: var(--ash); max-width: 52ch; }
.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.02em;
  color: var(--ash);
  max-width: none;
}
.footer-legal__item { display: inline-flex; align-items: center; gap: 6px; }

.copy-btn {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--ash);
  border: 1px solid var(--ink-700);
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}
.copy-btn:hover { color: var(--gold-bright); border-color: rgba(201, 162, 39, 0.4); }
.copy-btn[data-copied="true"] { color: var(--celadon-soft); border-color: rgba(111, 168, 149, 0.5); }

/* ---------- 14. 工具类 ---------- */
.mono { font-family: var(--font-mono); letter-spacing: 0.04em; }
.num { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
.text-ash { color: var(--ash); }
.text-gold { color: var(--gold); }
.text-paper { color: var(--paper); }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.22em;
  color: var(--gold-deep);
}
.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: linear-gradient(90deg, var(--gold), transparent);
}
.lede { font-size: var(--fs-18); line-height: 1.75; color: var(--ash); max-width: 60ch; }
.rule { height: 1px; border: 0; background: var(--ink-700); }
.rule--gold { background: linear-gradient(90deg, var(--gold), transparent); }
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ---------- 15. 显现动效 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 240ms var(--ease), transform 240ms var(--ease);
}
[data-reveal].is-visible { opacity: 1; transform: none; }
html:not(.js) [data-reveal] { opacity: 1; transform: none; }

/* ---------- 16. 桌面端命令栏 ---------- */
@media (min-width: 1080px) {
  :root { --header-h: 72px; }

  .header-bar { gap: var(--sp-3); }

  .site-nav {
    position: static;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    flex: 1 1 auto;
    margin-left: var(--sp-3);
    max-height: none;
    overflow: visible;
    padding: 0;
    background: none;
    border: 0;
  }
  .site-nav[data-open] { display: flex; animation: none; }
  .site-nav__list { flex-direction: row; align-items: center; gap: 2px; }
  .site-nav__link {
    padding: 7px 11px;
    font-size: var(--fs-14);
    letter-spacing: 0.02em;
    color: var(--ash);
    border: 1px solid transparent;
    border-bottom: 1px solid transparent;
  }
  .site-nav__link::after { display: none; }
  .site-nav__link:hover {
    color: var(--paper);
    border-color: var(--ink-700);
    background: linear-gradient(180deg, #1E1E1E, #161616);
  }
  .site-nav__link[aria-current="page"] {
    color: var(--gold-bright);
    box-shadow: none;
    border-color: rgba(201, 162, 39, 0.45);
    background: linear-gradient(180deg, rgba(201, 162, 39, 0.12), rgba(201, 162, 39, 0.02));
  }
  .site-nav__meta { display: none; }
  .nav-toggle { display: none; }
}

/* ---------- 17. 窄屏收敛 ---------- */
@media (max-width: 480px) {
  .back-anchor { display: none; }
}
@media (max-width: 400px) {
  .brand__sub { display: none; }
  .version-badge__label { display: none; }
  .nav-toggle__label { display: none; }
}

/* ---------- 18. 降级与无障碍 ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  html { scroll-behavior: auto; }
  [data-reveal] { opacity: 1; transform: none; }
  .version-badge__dot { animation: none; }
}
@media print {
  .site-header, .site-footer, .nav-toggle, .rail { display: none; }
  body { background: #fff; color: #000; }
}