/* =============================================================
   华体登 · 共享样式 /assets/site.css
   底色：高原暮色  主色：深松绿  重音：暖琥珀  点睛：荧光橙
   ============================================================= */

/* ── 1. Reset ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body, h1, h2, h3, h4, h5, p, ul, ol, figure, blockquote, dl, dd { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
a { color: inherit; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
table { border-collapse: collapse; width: 100%; }
[hidden] { display: none !important; }

/* ── 2. 变量 ──────────────────────────────────────────────── */
:root {
  --ink:        #101614;
  --pine:       #17453A;
  --moss:       #3F6B4E;
  --amber:      #D89A3C;
  --flare:      #FF6A1F;
  --clay:       #B4694A;
  --paper:      #F4EFE6;
  --paper-soft: #D9D3C6;
  --stone:      #7C847C;
  --mist:       #A9B7B0;
  --deep:       #0A0F0D;

  --line:        rgba(216, 154, 60, 0.24);
  --line-soft:   rgba(244, 239, 230, 0.10);
  --line-strong: rgba(216, 154, 60, 0.52);

  --font-head: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --shell: 1240px;
  --gut: 20px;
  --r: 2px;
  --shadow-paper: 0 12px 0 -8px rgba(10, 15, 13, 0.65);

  --ease: cubic-bezier(0.22, 0.8, 0.28, 1);
}

/* ── 3. 基础排版 ─────────────────────────────────────────── */
body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--paper-soft);
  background-color: var(--ink);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5 {
  font-family: var(--font-head);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.22;
  color: var(--paper);
}

.display       { font-size: clamp(30px, 3.6vw, 44px); line-height: 1.18; }
.section-title { font-size: clamp(22px, 2.4vw, 28px); line-height: 1.28; }
.sub-title     { font-size: 20px; line-height: 1.4; font-weight: 700; }

.mono-tag {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--amber);
}
.mono-index {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--stone);
}

::selection { background: var(--amber); color: var(--deep); }

:focus-visible {
  outline: 2px solid var(--flare);
  outline-offset: 3px;
  border-radius: var(--r);
}

/* ── 4. 通用工具 ─────────────────────────────────────────── */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gut);
}

.grid { display: grid; gap: 22px; }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.breadcrumb {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--stone);
  margin-bottom: 22px;
}
.breadcrumb ol { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.breadcrumb li { display: inline-flex; align-items: center; }
.breadcrumb li::after { content: "/"; margin-left: 6px; color: var(--moss); }
.breadcrumb li:last-child::after { content: ""; margin: 0; }
.breadcrumb a { color: var(--mist); text-decoration: none; transition: color .18s var(--ease); }
.breadcrumb a:hover { color: var(--amber); }

.prose { max-width: 64ch; color: var(--paper-soft); }
.prose p { margin-bottom: 1.1em; }
.prose p:last-child { margin-bottom: 0; }
.prose a {
  color: var(--amber);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: color .18s var(--ease);
}
.prose a:hover { color: var(--flare); }
.prose strong { color: var(--paper); font-weight: 700; }
.prose ul, .prose ol { margin: 0 0 1.1em 0; padding-left: 1.2em; }
.prose ul { list-style: none; }
.prose ul li { position: relative; padding-left: 14px; }
.prose ul li::before {
  content: ""; position: absolute; left: 0; top: 0.72em;
  width: 5px; height: 5px; background: var(--clay); transform: rotate(45deg);
}
.prose ol { list-style: decimal; }
.prose ol li { padding-left: 4px; }

/* 章节头 */
.section-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  flex-wrap: wrap;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 26px;
}
.section-head__title { font-size: clamp(22px, 2.4vw, 28px); }
.section-head__aside {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--stone);
}

/* 展览标签牌 */
.label-tag {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 4px 10px;
  background: var(--paper);
  color: var(--ink);
  border-left: 3px solid var(--clay);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.05em;
}
.label-tag__num { color: var(--clay); font-weight: 700; }

/* 纸张叠层卡片 */
.paper-card {
  position: relative;
  padding: 24px;
  background: var(--pine);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-paper);
}
.paper-card--light { background: var(--paper); color: var(--ink); border-color: transparent; }
.paper-card--light h1, .paper-card--light h2, .paper-card--light h3, .paper-card--light h4 { color: var(--ink); }
.paper-card--light .prose, .paper-card--light p { color: #3A3D38; }
.paper-card--flat {
  background: rgba(244, 239, 230, 0.03);
  box-shadow: none;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid var(--clay);
  border-radius: var(--r);
  color: var(--paper);
  font-size: 15px;
  font-weight: 700;
  text-decoration: none;
  transition: transform .2s var(--ease), border-color .2s var(--ease), color .2s var(--ease), background-color .2s var(--ease);
}
.btn:hover { transform: translateY(-2px); border-color: var(--flare); color: var(--flare); }
.btn--flare {
  background: var(--flare);
  border-color: var(--flare);
  color: #1A0C03;
}
.btn--flare:hover { background: #FF7E3B; border-color: #FF7E3B; color: #1A0C03; }
.btn--ghost { border-color: var(--line-soft); color: var(--mist); }
.btn--ghost:hover { border-color: var(--flare); color: var(--paper); }
.btn--clay { border-color: var(--clay); color: var(--clay); }
.btn--clay:hover { border-color: var(--flare); color: var(--flare); }

/* 图片占位框 */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  overflow: hidden;
  border: 1px solid var(--line);
  background: linear-gradient(148deg, var(--pine) 0%, #14211C 48%, var(--deep) 100%);
}
.media-frame > img,
.media-frame > picture > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame__cap {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  max-width: 100%;
  padding: 8px 13px;
  background: rgba(10, 15, 13, 0.78);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.05em;
  color: var(--paper-soft);
}
.media-frame--wide   { aspect-ratio: 16 / 9; }
.media-frame--tall   { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }

/* 横向刻度轨道 */
.rail {
  display: flex;
  gap: 14px;
  padding: 18px 4px 22px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  scrollbar-color: var(--moss) transparent;
  scrollbar-width: thin;
}
.rail > * { flex: 0 0 auto; scroll-snap-align: start; }
.rail::-webkit-scrollbar { height: 6px; }
.rail::-webkit-scrollbar-track { background: rgba(244, 239, 230, 0.06); }
.rail::-webkit-scrollbar-thumb { background: var(--moss); }

/* 显现 */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(6px);
  transition: opacity .22s var(--ease), transform .22s var(--ease);
}
.js [data-reveal].is-visible { opacity: 1; transform: none; }

/* ── 5. 页头 ────────────────────────────────────────────── */
.skip-link {
  position: absolute;
  left: 50%;
  top: 0;
  z-index: 200;
  transform: translate(-50%, -140%);
  padding: 10px 20px;
  background: var(--flare);
  color: #180A02;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-decoration: none;
  transition: transform .2s var(--ease);
}
.skip-link:focus { transform: translate(-50%, 0); }

.site-header {
  position: relative;
  z-index: 80;
  background: var(--ink);
  border-bottom: 1px solid var(--line);
}

.header-strip { background: var(--pine); border-bottom: 1px solid var(--line-soft); }
.header-strip__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding-block: 7px;
}
.header-strip__brand { color: var(--amber); }
.header-strip__note {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--mist);
}

.masthead { padding: 20px 0 16px; }
.masthead__inner {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 20px;
}
.masthead__side { display: flex; align-items: center; gap: 14px; }
.masthead__side--start { justify-content: flex-start; }
.masthead__side--end { justify-content: flex-end; }
.masthead__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--stone);
  padding-left: 14px;
  border-left: 1px solid var(--line-soft);
}

.masthead__brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding-inline: 26px;
  text-decoration: none;
  position: relative;
}
.masthead__brand::before,
.masthead__brand::after {
  content: "";
  position: absolute;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: var(--line);
}
.masthead__brand::before { left: 0; }
.masthead__brand::after { right: 0; }

.masthead__name {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-head);
  font-size: clamp(26px, 3.4vw, 40px);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--paper);
}
.masthead__mark {
  width: 10px;
  height: 10px;
  flex: 0 0 auto;
  background: var(--amber);
  transform: rotate(45deg);
  box-shadow: 0 0 0 4px rgba(216, 154, 60, 0.14);
}
.masthead__sub {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--stone);
  text-transform: uppercase;
}
.masthead__brand:hover .masthead__name { color: var(--amber); }

.cta-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  background: var(--flare);
  border: 1px solid rgba(255, 106, 31, 0.55);
  border-radius: var(--r);
  color: #1A0C03;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  box-shadow: 0 6px 0 -3px rgba(255, 106, 31, 0.24);
  transition: transform .2s var(--ease), background-color .2s var(--ease);
}
.cta-tag:hover { transform: translateY(-2px); background: #FF7E3B; }

.quick-rail { border-top: 1px solid var(--line-soft); }
.quick-rail__inner {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  padding-block: 9px;
}
.quick-rail__label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--stone);
  padding-right: 14px;
  border-right: 1px solid var(--line-soft);
}
.quick-rail__list { display: flex; gap: 10px; flex-wrap: wrap; }
.quick-rail__list a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 3px 11px;
  border: 1px solid var(--line-soft);
  border-radius: var(--r);
  color: var(--mist);
  font-size: 13px;
  text-decoration: none;
  transition: color .18s var(--ease), border-color .18s var(--ease), transform .18s var(--ease);
}
.quick-rail__list a::before {
  content: "";
  width: 5px;
  height: 5px;
  background: var(--clay);
  transform: rotate(45deg);
  transition: background-color .18s var(--ease);
}
.quick-rail__list a:hover { color: var(--paper); border-color: var(--flare); transform: translateY(-2px); }
.quick-rail__list a:hover::before { background: var(--flare); }

.site-nav {
  position: relative;
  background: rgba(10, 15, 13, 0.55);
  border-top: 1px solid var(--line);
}
.site-nav__inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  min-height: 48px;
}
.site-nav__eyebrow { display: none; }
.site-nav__list { display: flex; align-items: center; flex-wrap: wrap; gap: 2px; }
.site-nav__list a {
  display: block;
  padding: 12px 15px;
  color: var(--mist);
  font-size: 15px;
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}
.site-nav__list a:hover { color: var(--paper); border-bottom-color: var(--amber); }
.site-nav__list a[aria-current="page"] { color: var(--flare); border-bottom-color: var(--flare); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: rgba(244, 239, 230, 0.03);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.10em;
}
.nav-toggle__bars { display: inline-flex; flex-direction: column; gap: 3px; }
.nav-toggle__bars i { display: block; width: 16px; height: 1.5px; background: var(--amber); transition: background-color .18s var(--ease); }
.nav-toggle[aria-expanded="true"] { border-color: var(--flare); color: var(--flare); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i { background: var(--flare); }

/* ── 6. 页脚 ────────────────────────────────────────────── */
.site-footer {
  position: relative;
  margin-top: 80px;
  background: var(--deep);
  border-top: 1px solid var(--line);
  color: var(--mist);
  font-size: 14px;
}
.site-footer__track {
  height: 6px;
  border-bottom: 1px solid rgba(0, 0, 0, 0.55);
  background: repeating-linear-gradient(90deg, var(--moss) 0 1px, transparent 1px 24px);
  opacity: 0.6;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 36px;
  padding: 54px 0 38px;
}
.footer-brand__name {
  font-family: var(--font-head);
  font-size: 26px;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--paper);
}
.footer-brand__line { margin-top: 8px; color: var(--mist); max-width: 26ch; }
.footer-brand__tag { display: inline-block; margin-top: 14px; color: var(--stone); }

.footer-col__title {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--clay);
  margin-bottom: 14px;
}
.footer-col__list li { margin-bottom: 2px; }
.footer-col__list a {
  display: inline-block;
  padding: 4px 0;
  color: var(--mist);
  text-decoration: none;
  transition: color .18s var(--ease), transform .18s var(--ease);
}
.footer-col__list a:hover { color: var(--flare); transform: translateX(3px); }

.footer-contact {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px 30px;
  padding: 24px 0;
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}
.footer-contact__item { display: flex; flex-direction: column; gap: 4px; }
.footer-contact__key {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--stone);
}
.footer-contact__val {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  color: var(--paper-soft);
  word-break: break-word;
}
.footer-contact__note {
  grid-column: 1 / -1;
  font-size: 13px;
  color: var(--mist);
  padding-top: 4px;
}

.footer-base {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  padding: 18px 0 34px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--stone);
}
.footer-base__sign { color: var(--moss); }

/* ── 7. 返回顶部 ────────────────────────────────────────── */
.to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  z-index: 90;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1px;
  width: 56px;
  height: 56px;
  background: var(--amber);
  border: 1px solid rgba(10, 15, 13, 0.45);
  border-radius: var(--r);
  color: #1A1002;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  box-shadow: 0 10px 22px -8px rgba(0, 0, 0, 0.8);
  transition: transform .2s var(--ease), background-color .2s var(--ease);
}
.to-top:hover { background: var(--flare); transform: translateY(-3px); }
.to-top__glyph { font-size: 16px; line-height: 1; }

/* ── 8. 响应式 ──────────────────────────────────────────── */
@media (max-width: 1080px) {
  .footer-grid { grid-template-columns: 1.4fr 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 1000px) {
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 900px) {
  .site-nav__inner {
    justify-content: space-between;
    min-height: 54px;
  }
  .site-nav__eyebrow { display: inline-block; color: var(--stone); }
  .nav-toggle { display: inline-flex; }
  .site-nav__list {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    z-index: 70;
    display: grid;
    grid-template-columns: 1fr;
    gap: 0;
    padding: 8px;
    background: var(--deep);
    border: 1px solid var(--line);
    border-top: 2px solid var(--flare);
    box-shadow: 0 20px 40px -16px rgba(0, 0, 0, 0.85);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-6px);
    transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s linear;
  }
  .site-nav[data-open] .site-nav__list {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  .site-nav__list a {
    padding: 14px 16px;
    border-bottom: 1px solid var(--line-soft);
    border-left: 2px solid transparent;
  }
  .site-nav__list a:hover,
  .site-nav__list a[aria-current="page"] {
    border-bottom-color: var(--line-soft);
    border-left-color: var(--flare);
    background: rgba(255, 106, 31, 0.06);
  }
}

@media (max-width: 760px) {
  :root { --gut: 16px; }
  body { font-size: 15px; }
  .grid--2, .grid--3, .grid--4 { grid-template-columns: minmax(0, 1fr); }
  .header-strip__note { display: none; }
  .quick-rail__label { display: none; }
  .masthead { padding: 16px 0 14px; }
  .masthead__inner { grid-template-columns: 1fr; position: relative; }
  .masthead__side--start { display: none; }
  .masthead__side--end {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
  }
  .masthead__brand { padding-inline: 0; }
  .masthead__brand::before, .masthead__brand::after { display: none; }
  .cta-tag { padding: 8px 12px; font-size: 12px; }
  .footer-grid { grid-template-columns: 1fr; gap: 26px; padding: 38px 0 28px; }
  .footer-contact { grid-template-columns: 1fr; gap: 14px; }
  .footer-base { flex-direction: column; align-items: flex-start; gap: 6px; padding-bottom: 28px; }
  .paper-card { padding: 18px; }
  .to-top { right: 14px; bottom: 14px; width: 48px; height: 48px; }
}

@media (max-width: 420px) {
  .masthead__name { font-size: 24px; }
  .quick-rail__list { gap: 6px; }
  .quick-rail__list a { padding: 3px 8px; font-size: 12px; }
}

/* ── 9. 动效降级 ────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .js [data-reveal] { opacity: 1; transform: none; }
  .rail { scroll-snap-type: none; }
  .btn:hover, .cta-tag:hover, .to-top:hover,
  .quick-rail__list a:hover, .footer-col__list a:hover { transform: none; }
}