/* ============================================
   东升国际CN — Site Kit 共享样式
   基调：深蓝墨 · 香槟金 · 川蜀红
   ============================================ */

/* ---------- 设计令牌 ---------- */
:root {
  /* 色彩 Hex */
  --color-ink: #0A1628;
  --color-ink-soft: #102F4F;
  --color-blue: #1C4E80;
  --color-blue-soft: #A9C6E0;
  --color-gold: #C9A227;
  --color-gold-light: #E4C465;
  --color-silver: #7E96B0;
  --color-crimson: #B2493C;
  --color-crimson-soft: #E08A7C;
  --color-text: #F3F5F7;
  --color-text-bright: #FFFFFF;
  --color-paper: #F5F0E1;

  /* 色彩 RGB（用于 rgba 引用） */
  --color-ink-rgb: 10, 22, 40;
  --color-ink-soft-rgb: 16, 48, 79;
  --color-blue-rgb: 28, 78, 128;
  --color-gold-rgb: 201, 162, 39;
  --color-silver-rgb: 126, 150, 176;
  --color-crimson-rgb: 178, 73, 60;
  --color-text-rgb: 243, 245, 247;

  /* 字体 */
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", monospace;

  /* 动效 */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);

  /* 布局与圆角 */
  --container-max: 1440px;
  --radius-pill: 999px;
}

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 110px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background:
    radial-gradient(1000px 700px at 88% -5%, rgba(var(--color-blue-rgb), 0.22), transparent 60%),
    radial-gradient(700px 500px at -8% 25%, rgba(var(--color-ink-soft-rgb), 0.28), transparent 55%),
    var(--color-ink);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

ul,
ol {
  list-style: none;
}

a {
  color: var(--color-gold-light);
  text-decoration: none;
}

a:hover {
  color: var(--color-gold);
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-serif);
  line-height: 1.15;
  font-weight: 600;
  color: var(--color-text-bright);
}

h1 {
  font-size: clamp(30px, 4vw, 40px);
}

h2 {
  font-size: clamp(22px, 2.6vw, 26px);
  letter-spacing: 0.04em;
}

h3 {
  font-size: 18px;
  letter-spacing: 0.02em;
}

p {
  color: var(--color-text);
}

::selection {
  background: rgba(var(--color-gold-rgb), 0.35);
  color: var(--color-text-bright);
}

:focus-visible {
  outline: 2px double var(--color-gold-light);
  outline-offset: 3px;
}

::-webkit-scrollbar {
  width: 12px;
}

::-webkit-scrollbar-track {
  background: var(--color-ink);
}

::-webkit-scrollbar-thumb {
  background: var(--color-blue);
  border-radius: var(--radius-pill);
  border: 3px solid var(--color-ink);
}

/* ---------- 顶部悬浮胶囊导航 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1100;
  padding: 20px 48px 0;
  pointer-events: none;
  transition: padding 400ms var(--ease-out);
}

.site-header[data-scrolled] {
  padding-top: 12px;
}

.skip-link {
  position: fixed;
  top: 16px;
  left: 50%;
  transform: translateX(-50%) translateY(-220px);
  z-index: 2000;
  background: linear-gradient(120deg, var(--color-gold), var(--color-gold-light));
  color: var(--color-ink);
  font-size: 14px;
  font-weight: 600;
  padding: 10px 22px;
  border-radius: var(--radius-pill);
  text-decoration: none;
  pointer-events: auto;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
  transition: transform 400ms var(--ease-out);
}

.skip-link:focus {
  transform: translateX(-50%) translateY(0);
}

.nav-capsule {
  position: relative;
  pointer-events: auto;
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 8px 8px 8px 26px;
  background: linear-gradient(135deg, rgba(var(--color-ink-rgb), 0.96), rgba(var(--color-ink-soft-rgb), 0.9));
  border: 1px solid rgba(var(--color-gold-rgb), 0.28);
  border-radius: var(--radius-pill);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
  transition: background 500ms var(--ease-out), border-color 500ms var(--ease-out), box-shadow 500ms var(--ease-out);
}

.site-header[data-scrolled] .nav-capsule {
  background: linear-gradient(135deg, rgba(var(--color-ink-rgb), 0.78), rgba(var(--color-ink-soft-rgb), 0.66));
  border-color: rgba(var(--color-gold-rgb), 0.4);
  border-bottom-color: var(--color-gold);
  box-shadow: 0 14px 48px rgba(0, 0, 0, 0.38);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.nav-brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
  flex-shrink: 0;
}

.brand-mark {
  width: 12px;
  height: 12px;
  background: linear-gradient(135deg, var(--color-gold), var(--color-gold-light));
  transform: rotate(45deg);
  border-radius: 2px;
  position: relative;
  flex-shrink: 0;
}

.brand-mark::after {
  content: "";
  position: absolute;
  inset: 3px;
  background: var(--color-crimson);
  border-radius: 50%;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1;
}

.brand-cn {
  font-family: var(--font-serif);
  font-size: 18px;
  font-weight: 600;
  color: var(--color-text-bright);
  letter-spacing: 0.08em;
  line-height: 1.2;
}

.brand-cn-en {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  color: var(--color-gold-light);
  margin-left: 2px;
}

.brand-en {
  margin-top: 5px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--color-silver);
  text-transform: uppercase;
  white-space: nowrap;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav-links a {
  display: inline-flex;
  align-items: center;
  padding: 10px 14px;
  border-radius: var(--radius-pill);
  font-size: 14px;
  letter-spacing: 0.05em;
  color: var(--color-text);
  text-decoration: none;
  white-space: nowrap;
  transition: background 300ms var(--ease-out), color 300ms var(--ease-out);
}

.nav-links a:hover {
  color: var(--color-gold-light);
  background: rgba(var(--color-gold-rgb), 0.12);
}

.nav-links a[aria-current="page"] {
  color: var(--color-gold-light);
  background: rgba(var(--color-gold-rgb), 0.16);
  box-shadow: inset 0 0 0 1px rgba(var(--color-gold-rgb), 0.4);
}

.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid rgba(var(--color-gold-rgb), 0.35);
  border-radius: var(--radius-pill);
  cursor: pointer;
  padding: 0;
  flex-shrink: 0;
}

.nav-toggle-line {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--color-gold-light);
  border-radius: 2px;
  transition: transform 350ms var(--ease-out), opacity 200ms;
}

/* ---------- 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: 80px;
  padding: 80px 48px 28px;
  background: var(--color-ink);
  border-top: 1px solid rgba(var(--color-gold-rgb), 0.22);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -160px;
  right: -120px;
  width: 420px;
  height: 420px;
  background: radial-gradient(circle, rgba(var(--color-blue-rgb), 0.45), rgba(var(--color-ink-rgb), 0) 70%);
  pointer-events: none;
}

.site-footer::after {
  content: "东升";
  position: absolute;
  bottom: -40px;
  left: 0;
  font-family: var(--font-serif);
  font-size: 220px;
  font-weight: 600;
  line-height: 1;
  color: rgba(var(--color-ink-soft-rgb), 0.32);
  writing-mode: vertical-rl;
  letter-spacing: 0.05em;
  user-select: none;
  pointer-events: none;
}

.footer-frame {
  position: relative;
  z-index: 1;
  max-width: var(--container-max);
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: clamp(32px, 5vw, 72px);
}

.footer-col {
  min-width: 0;
}

.footer-brand-cn {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 600;
  color: var(--color-text-bright);
  letter-spacing: 0.1em;
}

.footer-brand-en {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  color: var(--color-silver);
  margin-top: 6px;
  text-transform: uppercase;
}

.footer-trust {
  margin-top: 24px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--color-silver);
  max-width: 44ch;
}

.footer-region {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 20px;
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--color-gold-light);
  border: 1px solid rgba(var(--color-crimson-rgb), 0.5);
  background: rgba(var(--color-crimson-rgb), 0.12);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
}

.dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-crimson);
  display: inline-block;
  box-shadow: 0 0 0 3px rgba(var(--color-crimson-rgb), 0.22);
}

.footer-heading {
  font-family: var(--font-serif);
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--color-gold-light);
  margin-bottom: 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(var(--color-gold-rgb), 0.25);
  display: inline-block;
}

.footer-nav {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-nav a {
  color: var(--color-text);
  font-size: 14px;
  text-decoration: none;
  position: relative;
  padding-left: 0;
  transition: color 200ms, padding-left 300ms var(--ease-out);
}

.footer-nav a::before {
  content: "›";
  color: var(--color-gold);
  margin-right: 8px;
  font-family: var(--font-mono);
}

.footer-nav a:hover {
  color: var(--color-gold-light);
  padding-left: 10px;
}

.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.footer-contact-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer-contact-label {
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--color-gold);
  text-transform: uppercase;
}

.footer-contact-value {
  font-size: 14px;
  color: var(--color-text);
  line-height: 1.5;
  word-break: break-all;
}

.footer-contact-note {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--color-silver);
  border-left: 2px solid var(--color-gold);
  padding-left: 12px;
}

.footer-bottom {
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid rgba(var(--color-silver-rgb), 0.18);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px 28px;
  font-size: 13px;
  color: var(--color-silver);
}

.footer-copy {
  margin: 0;
  color: var(--color-silver);
  font-size: 13px;
}

.footer-icp {
  color: var(--color-silver);
  font-size: 13px;
}

.footer-legal {
  display: flex;
  gap: 20px;
  margin-left: auto;
}

.footer-legal a {
  color: var(--color-silver);
  text-decoration: none;
  font-size: 13px;
  transition: color 200ms;
}

.footer-legal a:hover {
  color: var(--color-gold-light);
}

/* ---------- 正文容器与网格 ---------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: 48px;
  padding-right: 48px;
}

#main-content,
.main-content {
  display: block;
  width: 100%;
  min-height: 60vh;
  position: relative;
  z-index: 1;
}

.section {
  padding: 96px 0;
}

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 24px;
}

.split-layout {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: 64px;
  align-items: start;
}

.split-layout--inverted {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: 64px;
  align-items: start;
}

/* ---------- 排版阶梯 ---------- */
.overline-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-gold);
}

.display-title {
  font-family: var(--font-serif);
  font-size: clamp(40px, 7vw, 80px);
  line-height: 1.15;
  font-weight: 600;
  color: var(--color-text-bright);
  letter-spacing: 0.03em;
  text-wrap: balance;
}

.page-title {
  font-family: var(--font-serif);
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.2;
  font-weight: 600;
  color: var(--color-text-bright);
  letter-spacing: 0.04em;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(22px, 2.6vw, 26px);
  line-height: 1.25;
  font-weight: 600;
  color: var(--color-text);
  letter-spacing: 0.06em;
}

.card-title {
  font-family: var(--font-serif);
  font-size: 18px;
  line-height: 1.4;
  font-weight: 600;
  color: var(--color-text);
}

.note-text {
  font-size: 13px;
  line-height: 1.7;
  color: var(--color-silver);
}

.text-gold {
  color: var(--color-gold-light);
}

.text-gold-gradient {
  background: linear-gradient(120deg, var(--color-gold) 0%, var(--color-gold-light) 45%, var(--color-gold) 90%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.divider-gold {
  width: 56px;
  height: 2px;
  border: none;
  background: linear-gradient(90deg, var(--color-gold), rgba(var(--color-gold-rgb), 0));
  margin: 28px 0;
}

.side-note {
  writing-mode: vertical-rl;
  font-family: var(--font-serif);
  font-size: 13px;
  letter-spacing: 0.3em;
  color: var(--color-silver);
  border-right: 1px solid rgba(var(--color-gold-rgb), 0.45);
  padding-right: 14px;
  line-height: 1.8;
}

.side-note strong {
  color: var(--color-gold-light);
  font-weight: 600;
}

.prose {
  font-size: 16px;
  line-height: 1.8;
  color: rgba(var(--color-text-rgb), 0.85);
}

.prose p {
  margin-bottom: 18px;
}

.prose strong {
  color: var(--color-text-bright);
}

.prose a {
  color: var(--color-gold-light);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose h3 {
  margin-top: 32px;
  margin-bottom: 10px;
}

.list-deco {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.list-deco li {
  position: relative;
  padding-left: 22px;
  color: var(--color-text);
  font-size: 15px;
}

.list-deco li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.65em;
  width: 8px;
  height: 8px;
  border: 2px solid var(--color-gold);
  transform: rotate(45deg);
}

/* ---------- 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-decoration: none;
  cursor: pointer;
  line-height: 1.4;
  transition: transform 300ms var(--ease-out), box-shadow 300ms var(--ease-out), background 300ms var(--ease-out), color 300ms var(--ease-out), border-color 300ms var(--ease-out);
}

.btn--gold {
  background: linear-gradient(120deg, var(--color-gold), var(--color-gold-light));
  color: var(--color-ink);
  font-weight: 600;
}

.btn--gold:hover {
  color: var(--color-ink);
  box-shadow: 0 10px 30px rgba(var(--color-gold-rgb), 0.3);
  transform: translateY(-2px);
}

.btn--outline {
  border-color: rgba(var(--color-gold-rgb), 0.5);
  background: transparent;
  color: var(--color-gold-light);
}

.btn--outline:hover {
  border-color: var(--color-gold-light);
  background: rgba(var(--color-gold-rgb), 0.1);
  color: var(--color-gold-light);
  transform: translateY(-2px);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 9px;
  padding: 20px 0;
  font-size: 13px;
  color: var(--color-silver);
}

.breadcrumb li {
  display: inline-flex;
  align-items: center;
  gap: 9px;
}

.breadcrumb li:not(:last-child)::after {
  content: "/";
  color: rgba(var(--color-silver-rgb), 0.5);
  font-family: var(--font-mono);
}

.breadcrumb a {
  color: var(--color-silver);
  text-decoration: none;
  transition: color 200ms;
}

.breadcrumb a:hover {
  color: var(--color-gold-light);
}

.breadcrumb [aria-current="page"] {
  color: var(--color-gold-light);
}

/* ---------- 分类标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(var(--color-gold-rgb), 0.35);
  background: rgba(var(--color-gold-rgb), 0.08);
  color: var(--color-gold-light);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  line-height: 1.5;
}

.tag::before {
  content: "";
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: currentColor;
  flex-shrink: 0;
}

.tag--red {
  border-color: rgba(var(--color-crimson-rgb), 0.45);
  background: rgba(var(--color-crimson-rgb), 0.1);
  color: var(--color-crimson-soft);
}

.tag--blue {
  border-color: rgba(var(--color-silver-rgb), 0.45);
  background: rgba(var(--color-blue-rgb), 0.2);
  color: var(--color-blue-soft);
}

.tag-cluster {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 档案夹与资料卡 ---------- */
.archive-card {
  position: relative;
  padding: 30px 28px 28px;
  background: linear-gradient(150deg, rgba(var(--color-ink-soft-rgb), 0.9), rgba(var(--color-ink-rgb), 0.85));
  border: 1px solid rgba(var(--color-silver-rgb), 0.22);
  border-radius: 4px 16px 16px 16px;
  transition: border-color 350ms var(--ease-out), transform 350ms var(--ease-out);
}

.archive-card::before {
  content: "";
  position: absolute;
  top: -13px;
  left: 20px;
  width: 58px;
  height: 13px;
  background: linear-gradient(120deg, var(--color-gold), var(--color-gold-light));
  border-radius: 7px 7px 0 0;
  opacity: 0.85;
}

.archive-card:hover {
  border-color: rgba(var(--color-gold-rgb), 0.4);
  transform: translateY(-3px);
}

.info-card {
  position: relative;
  padding: 24px;
  background: linear-gradient(150deg, rgba(var(--color-blue-rgb), 0.25), rgba(var(--color-ink-soft-rgb), 0.1));
  border: 1px solid rgba(var(--color-silver-rgb), 0.2);
  border-radius: 16px 4px 16px 4px;
}

.panel-light {
  background: var(--color-paper);
  color: var(--color-ink);
  border-radius: 24px 8px 24px 8px;
  padding: 32px;
}

.panel-light h1,
.panel-light h2,
.panel-light h3,
.panel-light .display-title,
.panel-light .page-title,
.panel-light .section-title,
.panel-light .card-title {
  color: var(--color-ink);
}

.panel-light p {
  color: rgba(var(--color-ink-rgb), 0.82);
}

.panel-light a {
  color: var(--color-blue);
}

.panel-light a:hover {
  color: var(--color-crimson);
}

/* ---------- 框景与媒体占位 ---------- */
.frame-window {
  position: relative;
  padding: 40px;
  background: linear-gradient(150deg, rgba(var(--color-ink-soft-rgb), 0.55), rgba(var(--color-ink-rgb), 0.35));
  border: 1px solid rgba(var(--color-gold-rgb), 0.2);
  border-radius: 4px 24px 4px 24px;
  box-shadow: inset 0 0 0 4px var(--color-ink), inset 0 0 0 5px rgba(var(--color-gold-rgb), 0.2);
}

.frame-window::before,
.frame-window::after {
  content: "";
  position: absolute;
  width: 24px;
  height: 24px;
  pointer-events: none;
}

.frame-window::before {
  top: 12px;
  left: 12px;
  border-top: 2px solid var(--color-gold);
  border-left: 2px solid var(--color-gold);
}

.frame-window::after {
  bottom: 12px;
  right: 12px;
  border-bottom: 2px solid var(--color-gold);
  border-right: 2px solid var(--color-gold);
}

.media-frame {
  position: relative;
  overflow: hidden;
  border-radius: 16px 4px 16px 4px;
  background: linear-gradient(140deg, rgba(var(--color-blue-rgb), 0.3), rgba(var(--color-ink-soft-rgb), 0.15));
  border: 1px solid rgba(var(--color-silver-rgb), 0.25);
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 600ms var(--ease-out);
}

.media-frame:hover img {
  transform: scale(1.02);
}

.media-frame--square {
  aspect-ratio: 1 / 1;
}

.media-frame--wide {
  aspect-ratio: 16 / 9;
}

.media-frame--portrait {
  aspect-ratio: 4 / 5;
}

/* ---------- 折叠面板 ---------- */
.fold details {
  border-bottom: 1px solid rgba(var(--color-silver-rgb), 0.2);
}

.fold details:first-child {
  border-top: 1px solid rgba(var(--color-silver-rgb), 0.2);
}

.fold summary {
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 20px 4px;
  cursor: pointer;
  font-family: var(--font-serif);
  font-size: 18px;
  color: var(--color-text);
  user-select: none;
  transition: color 250ms;
}

.fold summary:hover {
  color: var(--color-gold-light);
}

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

.fold summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--color-gold);
  transition: transform 400ms var(--ease-out);
  flex-shrink: 0;
}

.fold details[open] summary::after {
  transform: rotate(45deg);
}

.fold details :not(summary) {
  padding: 0 4px 24px;
  color: var(--color-text);
  font-size: 15px;
  line-height: 1.7;
}

/* ---------- 滚动进度与返回顶部 ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0;
  background: linear-gradient(90deg, var(--color-crimson) 0%, var(--color-gold) 40%, var(--color-gold-light) 100%);
  z-index: 1500;
  pointer-events: none;
  transition: width 120ms linear;
}

.back-to-top {
  position: fixed;
  right: 32px;
  bottom: 32px;
  z-index: 1400;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 1px solid rgba(var(--color-gold-rgb), 0.6);
  background: linear-gradient(145deg, rgba(var(--color-ink-soft-rgb), 0.92), rgba(var(--color-ink-rgb), 0.94));
  color: var(--color-gold-light);
  font-size: 18px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  transition: opacity 300ms var(--ease-out), transform 300ms var(--ease-out), visibility 300ms;
}

.back-to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  color: var(--color-ink);
  background: linear-gradient(145deg, var(--color-gold), var(--color-gold-light));
}

.back-to-top-icon {
  display: block;
  line-height: 1;
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  html {
    scroll-padding-top: 90px;
  }

  .site-header {
    padding: 14px 20px 0;
  }

  .nav-capsule {
    padding: 8px 8px 8px 18px;
    gap: 12px;
  }

  .nav-links {
    position: absolute;
    top: calc(100% + 14px);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 6px;
    padding: 16px;
    background: rgba(var(--color-ink-rgb), 0.97);
    border: 1px solid rgba(var(--color-gold-rgb), 0.35);
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px) scale(0.98);
    transition: opacity 350ms var(--ease-out), transform 350ms var(--ease-out), visibility 350ms;
  }

  .nav-capsule[data-open] .nav-links {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
  }

  .nav-links a {
    display: block;
    padding: 14px 18px;
    font-size: 15px;
  }

  .nav-toggle {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    width: 46px;
    height: 46px;
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }

  .site-footer {
    padding: 56px 20px 24px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 44px;
  }

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

  .footer-legal {
    margin-left: 0;
  }

  .container {
    padding-left: 20px;
    padding-right: 20px;
  }

  .section {
    padding: 64px 0;
  }

  .split-layout,
  .split-layout--inverted {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .side-note {
    writing-mode: horizontal-tb;
    border-right: none;
    border-left: 2px solid rgba(var(--color-gold-rgb), 0.45);
    padding-left: 12px;
    padding-right: 0;
  }

  .frame-window {
    padding: 28px;
  }

  .back-to-top {
    right: 20px;
    bottom: 20px;
  }
}

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

  .nav-capsule {
    padding-left: 16px;
  }

  .brand-cn {
    font-size: 17px;
  }

  .footer-brand-cn {
    font-size: 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}