/* ========== 1. RESET ========== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  min-height: 100vh;
  overflow-x: hidden;
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: #E5E9F0;
  background: #0B1B3D;
}

img, svg, picture, video {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: #D4AF37;
  text-decoration: none;
  transition: color 0.25s ease, border-color 0.25s ease, background 0.25s ease;
}

a:hover {
  color: #F0D878;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  cursor: pointer;
}

ul, ol {
  list-style: none;
}

::selection {
  background: rgba(212, 175, 55, 0.3);
  color: #FFFFFF;
}

/* ========== 2. CSS VARIABLES ========== */
:root {
  --color-bg-deep: #050B18;
  --color-bg-primary: #0B1B3D;
  --color-bg-secondary: #1A3A6B;
  --color-gold: #D4AF37;
  --color-gold-light: #F0D878;
  --color-neon-purple: #7B2FF7;
  --color-neon-cyan: #00C2FF;
  --color-text-primary: #E5E9F0;
  --color-text-secondary: #A0B0C0;
  --color-border: #2A3B55;

  --font-display: "Poppins", "Montserrat", "Arial Black", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Courier Prime", "Courier New", "Consolas", "Liberation Mono", monospace;

  --container-max: 1280px;
  --container-pad: 32px;
  --header-height: 72px;
  --header-top-height: 36px;
  --header-scrolled-height: 56px;
  --section-gap: 96px;

  --glass-bg: rgba(11, 27, 61, 0.82);
  --glass-blur: 18px;
  --gold-glow: 0 0 24px rgba(212, 175, 55, 0.25);

  --transition-fast: 0.2s ease;
  --transition-normal: 0.35s ease;
  --transition-slow: 0.6s ease;

  --z-header: 1000;
  --z-skip: 2000;
  --z-back-top: 900;
}

/* ========== 3. BASE TYPOGRAPHY ========== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: 0.02em;
  color: var(--color-text-primary);
  margin-bottom: 0.5em;
}

p {
  margin-bottom: 1em;
}

:focus-visible {
  outline: 2px solid var(--color-gold);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ========== 4. LAYOUT UTILITIES ========== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}

.section {
  padding: var(--section-gap) 0;
}

.section-tight {
  padding: 48px 0;
}

.split-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  gap: 64px;
  align-items: start;
}

.grid-cols-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 32px;
}

.grid-cols-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 32px;
}

.content-stack {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.section-header {
  margin-bottom: 48px;
}

.section-title {
  display: flex;
  align-items: center;
  gap: 16px;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 2.5vw, 2.2rem);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--color-text-primary);
}

.section-title::before {
  content: "";
  flex: 0 0 auto;
  width: 36px;
  height: 3px;
  background: linear-gradient(90deg, var(--color-gold), transparent);
}

.section-subtitle {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-top: 10px;
  padding-left: 52px;
}

/* ========== 5. INDEX LABELS & MONO ========== */
.mono-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-gold);
}

.index-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-gold);
}

.index-label::before {
  content: "";
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
  background-image:
    linear-gradient(45deg, currentColor 25%, transparent 25%, transparent 75%, currentColor 75%),
    linear-gradient(45deg, currentColor 25%, transparent 25%, transparent 75%, currentColor 75%);
  background-size: 6px 6px;
  background-position: 0 0, 3px 3px;
}

/* ========== 6. BUTTONS ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 4px;
  border: 1px solid transparent;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: all var(--transition-normal);
  text-decoration: none;
  white-space: nowrap;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-gold) 0%, var(--color-gold-light) 100%);
  color: var(--color-bg-deep);
  border-color: var(--color-gold);
}

.btn-primary:hover {
  box-shadow: var(--gold-glow);
  color: var(--color-bg-deep);
  transform: translateY(-2px);
}

.btn-primary:active {
  box-shadow: none;
  transform: translateY(0);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-primary);
  border-color: rgba(212, 175, 55, 0.35);
}

.btn-ghost:hover {
  border-color: var(--color-gold);
  color: var(--color-gold-light);
  background: rgba(212, 175, 55, 0.06);
  transform: translateY(-2px);
}

.btn-compact {
  padding: 8px 18px;
  font-size: 13px;
}

/* ========== 7. SKIP LINK ========== */
.skip-link {
  position: fixed;
  top: -100%;
  left: 20px;
  z-index: var(--z-skip);
  padding: 10px 22px;
  background: var(--color-gold);
  color: var(--color-bg-deep);
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  border-radius: 0 0 6px 6px;
  text-decoration: none;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  transition: top 0.25s ease;
}

.skip-link:focus {
  top: 0;
  color: var(--color-bg-deep);
}

/* ========== 8. HEADER ========== */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition-normal);
}

.site-header[data-scrolled] {
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
  border-bottom-color: rgba(212, 175, 55, 0.2);
}

.header-top {
  height: var(--header-top-height);
  overflow: hidden;
  background: rgba(5, 11, 24, 0.72);
  border-bottom: 1px solid rgba(42, 59, 85, 0.55);
  transition: height var(--transition-normal), opacity var(--transition-normal), border-color var(--transition-normal);
}

.site-header[data-scrolled] .header-top {
  height: 0;
  opacity: 0;
  border-bottom-color: transparent;
}

.header-top-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: 16px;
}

.header-top-tagline {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--color-text-secondary);
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.header-top-group {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.lang-toggle {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--color-text-secondary);
  padding: 4px 10px;
  border: 1px solid var(--color-border);
  border-radius: 20px;
  cursor: default;
  transition: border-color var(--transition-fast), color var(--transition-fast);
}

.lang-toggle:hover {
  border-color: var(--color-gold);
  color: var(--color-gold);
}

.header-divider {
  width: 1px;
  height: 12px;
  background: var(--color-border);
}

.history-entry {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--color-text-secondary);
  padding: 4px 6px;
  transition: color var(--transition-fast);
}

.history-entry:hover {
  color: var(--color-gold-light);
}

.header-main {
  border-bottom: 1px solid rgba(42, 59, 85, 0.35);
}

.header-main-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  height: var(--header-height);
  transition: height var(--transition-normal);
}

.site-header[data-scrolled] .header-main-inner {
  height: var(--header-scrolled-height);
}

/* Brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  position: relative;
  display: block;
  flex: 0 0 auto;
  width: 36px;
  height: 36px;
  border: 2px solid var(--color-gold);
  border-radius: 4px;
  background-color: var(--color-bg-deep);
  background-image:
    linear-gradient(45deg, var(--color-gold) 25%, transparent 25%, transparent 75%, var(--color-gold) 75%),
    linear-gradient(45deg, var(--color-gold) 25%, transparent 25%, transparent 75%, var(--color-gold) 75%);
  background-size: 10px 10px;
  background-position: 0 0, 5px 5px;
  box-shadow: 0 0 12px rgba(212, 175, 55, 0.2);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.brand:hover .brand-mark {
  transform: rotate(8deg) scale(1.05);
  box-shadow: 0 0 20px rgba(212, 175, 55, 0.4);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-cn {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--color-text-primary);
  white-space: nowrap;
}

.brand-en {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  color: var(--color-gold);
  text-transform: uppercase;
  margin-top: 2px;
}

/* Primary Navigation */
.site-nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-item {
  position: relative;
}

.nav-link {
  position: relative;
  display: block;
  padding: 10px 16px;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--color-text-primary);
  border-bottom: 2px solid transparent;
  border-radius: 2px;
  transition: color var(--transition-fast), border-color var(--transition-fast), background var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-gold-light);
  background: rgba(212, 175, 55, 0.05);
}

.nav-link[aria-current="page"] {
  color: var(--color-gold);
  border-bottom-color: var(--color-gold);
}

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 16px;
  right: 16px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-gold), transparent);
}

/* Header Tools */
.header-tools {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}

/* Hamburger Toggle */
.nav-toggle {
  display: none;
  position: relative;
  width: 44px;
  height: 44px;
  border-radius: 6px;
  border: 1px solid var(--color-border);
  background: rgba(5, 11, 24, 0.5);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.nav-toggle:hover {
  border-color: var(--color-gold);
  background: rgba(212, 175, 55, 0.08);
}

.nav-toggle-line {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-gold);
  border-radius: 2px;
  transition: transform var(--transition-normal), opacity var(--transition-normal);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(7px) 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(-7px) rotate(-45deg);
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--color-gold);
  outline-offset: 2px;
}

/* ========== 9. FOOTER ========== */
.site-footer {
  background-color: var(--color-bg-deep);
  background-image:
    linear-gradient(45deg, rgba(212, 175, 55, 0.025) 25%, transparent 25%, transparent 75%, rgba(212, 175, 55, 0.025) 75%),
    linear-gradient(45deg, rgba(212, 175, 55, 0.025) 25%, transparent 25%, transparent 75%, rgba(212, 175, 55, 0.025) 75%);
  background-size: 28px 28px;
  background-position: 0 0, 14px 14px;
  border-top: none;
  padding-bottom: 0;
}

.footer-gold-line {
  height: 2px;
  background: linear-gradient(90deg, transparent 0%, var(--color-gold) 25%, var(--color-gold-light) 50%, var(--color-gold) 75%, transparent 100%);
  margin: 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr) minmax(0, 1fr) minmax(0, 1fr);
  gap: 48px;
  padding: 64px 0 48px;
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.footer-brand:hover {
  text-decoration: none;
}

.footer-trust {
  font-size: 14px;
  line-height: 1.8;
  color: var(--color-text-secondary);
  margin: 0;
  border-left: 2px solid rgba(212, 175, 55, 0.35);
  padding-left: 16px;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-col-title {
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-gold);
  margin: 0;
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(42, 59, 85, 0.6);
}

.footer-link-list,
.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-link-list a,
.footer-contact-list a {
  font-family: var(--font-body);
  font-size: 14px;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.footer-link-list a:hover,
.footer-contact-list a:hover {
  color: var(--color-gold-light);
  padding-left: 4px;
}

.footer-contact-list li {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  padding: 24px 0 36px;
  border-top: 1px solid rgba(42, 59, 85, 0.5);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--color-text-secondary);
}

.footer-copyright,
.footer-icp {
  margin: 0;
}

/* Back to Top */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: var(--z-back-top);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--color-gold);
  background: rgba(11, 27, 61, 0.9);
  color: var(--color-gold);
  font-size: 20px;
  font-family: var(--font-display);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: opacity var(--transition-normal), transform var(--transition-normal), visibility var(--transition-normal), background var(--transition-normal), color var(--transition-normal), box-shadow var(--transition-normal);
}

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

.back-to-top:hover {
  background: var(--color-gold);
  color: var(--color-bg-deep);
  box-shadow: var(--gold-glow);
}

.back-to-top:focus-visible {
  outline: 2px solid var(--color-gold-light);
  outline-offset: 2px;
}

/* ========== 10. CONTENT COMPONENTS ========== */

/* Breadcrumb */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--color-text-secondary);
  margin-bottom: 24px;
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb li:not(:last-child)::after {
  content: "→";
  color: var(--color-gold);
  font-size: 11px;
}

.breadcrumb a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

/* Page Head */
.page-head {
  padding: 56px 0 40px;
  margin-bottom: 40px;
  border-bottom: 1px solid var(--color-border);
  position: relative;
}

.page-head::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-gold) 0%, transparent 60%);
  opacity: 0.5;
}

.page-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  letter-spacing: 0.03em;
  line-height: 1.15;
  margin: 12px 0 8px;
  color: var(--color-text-primary);
}

.page-subtitle {
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text-secondary);
  max-width: 560px;
  margin: 0;
}

/* Cards */
.card {
  padding: 28px;
  border-radius: 10px;
  border: 1px solid var(--color-border);
  background: linear-gradient(145deg, var(--color-bg-secondary) 0%, var(--color-bg-primary) 100%);
  transition: border-color var(--transition-normal), box-shadow var(--transition-normal), transform var(--transition-normal);
}

.card:hover {
  border-color: rgba(212, 175, 55, 0.4);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.25);
}

.glass-card {
  position: relative;
  padding: 32px;
  border-radius: 12px;
  border: 1px solid rgba(212, 175, 55, 0.15);
  background: linear-gradient(135deg, rgba(26, 58, 107, 0.55) 0%, rgba(11, 27, 61, 0.75) 100%);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  transition: border-color var(--transition-normal), box-shadow var(--transition-normal), transform var(--transition-normal);
}

.glass-card:hover {
  border-color: rgba(212, 175, 55, 0.4);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.35), var(--gold-glow);
  transform: translateY(-3px);
}

/* Tag */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border: 1px solid rgba(212, 175, 55, 0.3);
  border-radius: 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--color-gold);
  background: rgba(212, 175, 55, 0.04);
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.tag:hover {
  border-color: var(--color-gold);
  background: rgba(212, 175, 55, 0.1);
}

/* Media Frame */
.media-frame {
  position: relative;
  aspect-ratio: 16 / 9;
  border-radius: 10px;
  overflow: hidden;
  background: linear-gradient(145deg, var(--color-bg-secondary), var(--color-bg-deep));
  border: 1px solid var(--color-border);
}

.media-frame > * {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame img {
  transition: transform var(--transition-slow);
}

.media-frame:hover img {
  transform: scale(1.04);
}

.media-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  background-image:
    linear-gradient(45deg, rgba(212, 175, 55, 0.06) 25%, transparent 25%, transparent 75%, rgba(212, 175, 55, 0.06) 75%),
    linear-gradient(45deg, rgba(212, 175, 55, 0.06) 25%, transparent 25%, transparent 75%, rgba(212, 175, 55, 0.06) 75%);
  background-size: 20px 20px;
  background-position: 0 0, 10px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
}

/* Gold Line Decorative */
.gold-line {
  position: relative;
  display: block;
  height: 2px;
  background: linear-gradient(90deg, var(--color-gold), transparent);
  border: none;
  margin: 16px 0;
}

/* Chessboard Pattern Utility */
.chessboard-pattern {
  position: relative;
  background-image:
    linear-gradient(45deg, rgba(212, 175, 55, 0.05) 25%, transparent 25%, transparent 75%, rgba(212, 175, 55, 0.05) 75%),
    linear-gradient(45deg, rgba(212, 175, 55, 0.05) 25%, transparent 25%, transparent 75%, rgba(212, 175, 55, 0.05) 75%);
  background-size: 24px 24px;
  background-position: 0 0, 12px 12px;
}

/* Accordion */
.accordion {
  border: 1px solid var(--color-border);
  border-radius: 10px;
  overflow: hidden;
  background: var(--color-bg-primary);
}

.accordion-item {
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition-fast);
}

.accordion-item:last-child {
  border-bottom: none;
}

.accordion-item[data-open] {
  background: rgba(212, 175, 55, 0.035);
}

.accordion-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 18px 24px;
  text-align: left;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--color-text-primary);
  cursor: pointer;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.accordion-trigger:hover {
  color: var(--color-gold-light);
  background: rgba(212, 175, 55, 0.04);
}

.accordion-trigger::after {
  content: "+";
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 400;
  color: var(--color-gold);
  transition: transform var(--transition-normal);
}

.accordion-item[data-open] .accordion-trigger::after {
  content: "−";
  transform: rotate(180deg);
}

.accordion-panel {
  max-height: 0;
  overflow: hidden;
  padding: 0 24px;
  color: var(--color-text-secondary);
  font-size: 15px;
  line-height: 1.75;
  transition: max-height 0.4s ease, padding 0.4s ease;
}

.accordion-item[data-open] .accordion-panel {
  max-height: 520px;
  padding: 0 24px 24px;
}

.accordion-trigger:focus-visible {
  outline: 2px solid var(--color-gold);
  outline-offset: -2px;
}

/* Scroll Reveal */
[data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

[data-reveal][data-revealed] {
  opacity: 1;
  transform: translateY(0);
}

/* ========== 11. RESPONSIVE ========== */

@media (max-width: 1024px) {
  :root {
    --container-pad: 24px;
    --section-gap: 72px;
  }

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

  .grid-cols-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .site-header {
    position: sticky;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: block;
    background: rgba(5, 11, 24, 0.97);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(212, 175, 55, 0.35);
    box-shadow: 0 24px 48px rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity var(--transition-normal), transform var(--transition-normal), visibility var(--transition-normal);
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
  }

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

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px 0;
  }

  .nav-item {
    border-bottom: 1px solid rgba(42, 59, 85, 0.5);
  }

  .nav-item:last-child {
    border-bottom: none;
  }

  .nav-link {
    padding: 16px 24px;
    border-radius: 0;
    border-left: 3px solid transparent;
    font-size: 16px;
  }

  .nav-link:hover {
    background: rgba(212, 175, 55, 0.06);
  }

  .nav-link[aria-current="page"] {
    border-left-color: var(--color-gold);
    background: rgba(212, 175, 55, 0.05);
    border-bottom-color: transparent;
  }

  .nav-link[aria-current="page"]::after {
    display: none;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    flex: 0 0 auto;
    justify-content: flex-start;
  }

  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 40px;
  }
}

@media (max-width: 768px) {
  :root {
    --container-pad: 20px;
    --section-gap: 56px;
    --header-height: 62px;
    --header-scrolled-height: 56px;
    --header-top-height: 0px;
  }

  .header-top {
    display: none;
  }

  .header-main-inner {
    gap: 8px;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
    background-size: 8px 8px;
    background-position: 0 0, 4px 4px;
  }

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

  .brand-en {
    font-size: 9px;
    letter-spacing: 0.16em;
  }

  .btn-compact {
    padding: 7px 14px;
    font-size: 12px;
  }

  .grid-cols-2,
  .grid-cols-3 {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .section-title {
    font-size: 1.3rem;
  }

  .section-subtitle {
    padding-left: 0;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
    padding: 48px 0 32px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    padding: 16px 0 28px;
  }

  .back-to-top {
    right: 16px;
    bottom: 16px;
    width: 40px;
    height: 40px;
    font-size: 18px;
  }

  .page-head {
    padding: 36px 0 28px;
    margin-bottom: 32px;
  }

  .breadcrumb {
    font-size: 12px;
  }

  .card,
  .glass-card {
    padding: 20px;
  }

  .accordion-trigger {
    padding: 14px 16px;
    font-size: 15px;
  }

  .accordion-panel {
    padding: 0 16px;
  }

  .accordion-item[data-open] .accordion-panel {
    padding: 0 16px 16px;
  }
}

/* ========== 12. ACCESSIBILITY ========== */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0ms !important;
  }

  .site-nav[data-open] {
    transform: none;
    transition: none;
  }

  .accordion-panel {
    max-height: 0;
    transition: none;
  }

  .accordion-item[data-open] .accordion-panel {
    max-height: none;
    transition: none;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .back-to-top {
    transition: none;
  }

  .skip-link {
    transition: none;
  }
}