/* ===== 1. 设计变量 ===== */
:root {
  --color-navy: #0F1F4B;
  --color-navy-soft: #1B3A7A;
  --color-yellow: #FFD200;
  --color-cyan: #00E5FF;
  --color-purple: #7B61FF;
  --color-ink: #1E293B;
  --color-slate: #64748B;
  --color-mist: #F8FAFC;
  --color-white: #FFFFFF;
  --color-line: #E2E8F0;
  --color-success: #22C55E;
  --color-danger: #EF4444;
  --font-display: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-data: "Roboto Mono", "SFMono-Regular", "Consolas", monospace;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.25rem;
  --text-xl: 1.75rem;
  --text-2xl: 2.5rem;
  --text-3xl: 3.5rem;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 1rem;
  --space-4: 2rem;
  --space-5: 3rem;
  --space-6: 5rem;
  --container: 1200px;
  --container-narrow: 960px;
  --radius: 12px;
  --radius-sm: 6px;
  --radius-lg: 20px;
  --shadow: 0 4px 20px rgba(15, 31, 75, 0.08);
  --shadow-hover: 0 12px 32px rgba(15, 31, 75, 0.16);
  --transition: 0.25s ease;
  --header-z: 100;
  --footer-z: 10;
}

/* ===== 2. Reset 与基础 ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

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

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.75;
  color: var(--color-ink);
  background-color: var(--color-white);
  min-width: 320px;
  overflow-x: hidden;
}

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

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

a {
  color: var(--color-navy);
  text-underline-offset: 4px;
}

ul,
ol {
  list-style: none;
}

:focus-visible {
  outline: 3px solid var(--color-cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

::selection {
  background: var(--color-yellow);
  color: var(--color-navy);
}

/* ===== 3. 排版 ===== */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-display);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--color-navy);
}

h1 {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  color: var(--color-navy);
}

h2 {
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
}

h3 {
  font-size: 1.75rem;
}

h4 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--space-3);
  max-width: 65ch;
}

.small-note {
  font-size: var(--text-sm);
  color: var(--color-slate);
}

/* ===== 4. 容器与主内容 ===== */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 4vw, 2.5rem);
}

.container--narrow {
  max-width: var(--container-narrow);
}

.main-content {
  min-height: 70vh;
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===== 5. 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8em 1.5em;
  border: 2px solid transparent;
  border-radius: 8px;
  font-family: var(--font-display);
  font-size: 0.9375rem;
  font-weight: 700;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), border-color var(--transition), box-shadow var(--transition), transform 0.15s ease;
  white-space: nowrap;
}

.btn--primary {
  background: var(--color-yellow);
  border-color: var(--color-yellow);
  color: var(--color-navy);
}

.btn--primary:hover {
  background: #ffdd33;
  border-color: #ffdd33;
  box-shadow: 0 8px 24px rgba(255, 210, 0, 0.35);
  transform: translateY(-1px);
}

.btn--ghost {
  background: transparent;
  border-color: var(--color-cyan);
  color: #0097b8;
}

.btn--ghost:hover {
  background: rgba(0, 229, 255, 0.1);
  border-color: var(--color-cyan);
}

.btn--purple {
  background: var(--color-purple);
  border-color: var(--color-purple);
  color: var(--color-white);
}

.btn--purple:hover {
  background: #8a6cff;
  box-shadow: 0 8px 24px rgba(123, 97, 255, 0.3);
  transform: translateY(-1px);
}

/* ===== 6. 面包屑 ===== */
.breadcrumb {
  margin-bottom: 2rem;
  font-size: var(--text-sm);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding: 0.4rem 0;
  border-bottom: 1px solid var(--color-line);
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.breadcrumb li + li::before {
  content: "/";
  color: var(--color-slate);
  font-family: var(--font-data);
}

.breadcrumb a {
  color: var(--color-slate);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

.breadcrumb [aria-current="page"] {
  color: var(--color-ink);
  font-weight: 700;
}

/* ===== 7. 跳过链接 ===== */
.skip-link {
  position: fixed;
  top: -100%;
  left: 1rem;
  z-index: 2000;
  background: var(--color-yellow);
  color: var(--color-navy);
  padding: 0.75rem 1.5rem;
  border-radius: 0 0 8px 8px;
  font-family: var(--font-display);
  font-weight: 700;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0;
}

/* ===== 8. 页头 ===== */
.site-header {
  position: relative;
  z-index: var(--header-z);
  background: var(--color-white);
}

.header-topbar {
  background: var(--color-navy);
  color: rgba(248, 250, 252, 0.9);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  border-bottom: 2px solid rgba(0, 229, 255, 0.35);
}

.header-topbar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 2.5rem;
}

.header-topbar__brand {
  margin: 0;
  font-weight: 700;
  color: var(--color-white);
}

.header-topbar__brand::before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: 0.6rem;
  background: var(--color-yellow);
  border-radius: 2px;
  vertical-align: middle;
}

.header-topbar__slogan {
  margin: 0;
  font-size: var(--text-xs);
  color: rgba(248, 250, 252, 0.75);
  letter-spacing: 0.12em;
}

.header-topbar__slogan::after {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-left: 0.6rem;
  background: var(--color-cyan);
  border-radius: 50%;
  vertical-align: middle;
}

.header-navbar {
  position: relative;
  background: var(--color-white);
  border-bottom: 1px solid var(--color-line);
}

.header-navbar__inner {
  display: flex;
  align-items: center;
  min-height: 4.5rem;
  gap: 1rem;
}

.header-logo {
  display: inline-flex;
  align-items: baseline;
  gap: 0.55rem;
  text-decoration: none;
  flex-shrink: 0;
}

.header-logo__cn {
  font-family: var(--font-display);
  font-size: 1.375rem;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--color-navy);
  line-height: 1;
}

.header-logo__en {
  font-family: var(--font-data);
  font-size: 0.625rem;
  color: var(--color-slate);
  letter-spacing: 0.22em;
  line-height: 1;
  text-transform: uppercase;
}

.header-logo:hover .header-logo__cn {
  color: #152b5e;
}

.main-nav {
  margin-left: 1.75rem;
}

.main-nav__list {
  display: flex;
  gap: clamp(1rem, 2vw, 2.25rem);
}

.main-nav__item {
  display: block;
}

.main-nav__link {
  position: relative;
  display: inline-block;
  padding: 1.2rem 0 1.1rem;
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-ink);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s ease;
}

.main-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0.75rem;
  height: 2px;
  background: var(--color-cyan);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}

.main-nav__link:hover {
  color: var(--color-navy);
}

.main-nav__link:hover::after {
  transform: scaleX(1);
}

.main-nav__link[aria-current="page"] {
  color: var(--color-navy);
}

.main-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--color-yellow);
}

.header-login {
  margin-left: auto;
  flex-shrink: 0;
}

.nav-toggle {
  display: none;
  position: relative;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 4px;
  width: 44px;
  height: 44px;
  background: var(--color-white);
  border: 1px solid var(--color-line);
  border-radius: 8px;
  cursor: pointer;
  transition: border-color 0.2s ease, background 0.2s ease;
  flex-shrink: 0;
}

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

.nav-toggle__line {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-navy);
  border-radius: 2px;
  transition: transform var(--transition), opacity 0.2s ease;
}

.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);
}

/* ===== 9. 页脚 ===== */
.site-footer {
  position: relative;
  background: var(--color-navy);
  color: rgba(248, 250, 252, 0.85);
  z-index: var(--footer-z);
}

.site-footer__topline {
  height: 6px;
  background: linear-gradient(90deg, var(--color-yellow) 0 20%, var(--color-cyan) 20% 50%, var(--color-purple) 50% 78%, var(--color-yellow) 78% 100%);
}

.site-footer__main {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr;
  gap: clamp(2rem, 5vw, 4rem);
  padding-top: 4rem;
  padding-bottom: 3.5rem;
  background-image:
    linear-gradient(rgba(0, 229, 255, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 229, 255, 0.045) 1px, transparent 1px);
  background-size: 44px 44px;
}

.site-footer__brand-name {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--color-white);
  line-height: 1;
}

.site-footer__brand-dot {
  color: var(--color-cyan);
  margin-left: 0.1rem;
}

.site-footer__brand-desc {
  font-size: var(--text-sm);
  color: rgba(248, 250, 252, 0.7);
  line-height: 1.8;
  margin-bottom: 1.25rem;
  max-width: 55ch;
}

.site-footer__ticker {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
  font-family: var(--font-data);
  font-size: 0.675rem;
  letter-spacing: 0.18em;
  color: rgba(248, 250, 252, 0.4);
  border-top: 1px solid rgba(248, 250, 252, 0.12);
  padding-top: 0.75rem;
}

.site-footer__ticker span:first-child {
  color: var(--color-yellow);
}

.site-footer__col {
  font-size: var(--text-sm);
}

.site-footer__heading {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-cyan);
  margin-bottom: 1.25rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid rgba(0, 229, 255, 0.2);
}

.site-footer__links {
  font-size: var(--text-sm);
  line-height: 1.9;
}

.site-footer__links li {
  margin-bottom: 0.4rem;
}

.site-footer__links a {
  color: rgba(248, 250, 252, 0.75);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.site-footer__links a:hover {
  color: var(--color-cyan);
  border-bottom-color: var(--color-cyan);
}

.site-footer__contact {
  color: rgba(248, 250, 252, 0.75);
}

.site-footer__icp {
  margin-top: 1.5rem;
  font-family: var(--font-data);
  font-size: var(--text-xs);
  color: rgba(248, 250, 252, 0.45);
  letter-spacing: 0.06em;
}

.site-footer__bottom {
  border-top: 1px solid rgba(248, 250, 252, 0.1);
  padding-block: 1.25rem;
}

.site-footer__bottom-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 1.5rem;
  font-size: var(--text-xs);
}

.site-footer__copyright {
  margin: 0;
  color: rgba(248, 250, 252, 0.5);
  font-family: var(--font-display);
}

.site-footer__legal {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  margin-left: auto;
}

.site-footer__legal a {
  color: rgba(248, 250, 252, 0.5);
  text-decoration: none;
  transition: color 0.2s ease;
}

.site-footer__legal a:hover {
  color: var(--color-yellow);
}

.site-footer__sep {
  opacity: 0.3;
}

.footer-backtop {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: rgba(248, 250, 252, 0.08);
  border: 1px solid rgba(248, 250, 252, 0.18);
  color: rgba(248, 250, 252, 0.75);
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 700;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.footer-backtop:hover {
  background: var(--color-yellow);
  border-color: var(--color-yellow);
  color: var(--color-navy);
}

/* ===== 10. 页面标题区 ===== */
.page-banner {
  background: var(--color-mist);
  border-bottom: 1px solid var(--color-line);
  padding-block: clamp(2.5rem, 6vw, 4rem);
}

.page-banner__inner {
  position: relative;
}

.page-banner__title {
  margin: 0 0 0.75rem;
  font-size: clamp(2rem, 4.5vw, 3.5rem);
  line-height: 1.1;
}

.page-banner__lead {
  margin: 0;
  max-width: 48em;
  font-family: var(--font-body);
  font-size: var(--text-lg);
  color: var(--color-slate);
  line-height: 1.8;
}

/* ===== 11. 展览章节结构 ===== */
.exhibit {
  display: grid;
  grid-template-columns: clamp(4.5rem, 8vw, 7rem) minmax(0, 1fr);
  column-gap: clamp(1.5rem, 4vw, 4rem);
  padding-block: clamp(3.5rem, 8vw, 6rem);
  border-bottom: 1px solid var(--color-line);
  position: relative;
}

.exhibit + .exhibit {
  border-top: 0;
}

.exhibit__number {
  position: sticky;
  top: 1.5rem;
  align-self: start;
  font-family: var(--font-data);
  font-size: clamp(2.5rem, 6vw, 4.75rem);
  font-weight: 800;
  letter-spacing: -0.05em;
  color: var(--color-cyan);
  line-height: 0.9;
  opacity: 0.85;
}

.exhibit__body {
  min-width: 0;
}

.exhibit__title {
  margin: 0 0 1rem;
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  line-height: 1.2;
}

.exhibit__desc {
  margin: 0 0 1.5rem;
  max-width: 55ch;
  color: var(--color-slate);
  font-size: 1rem;
}

.exhibit__more {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-navy);
  text-decoration: none;
  border-bottom: 2px solid var(--color-cyan);
  padding-bottom: 0.25rem;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.exhibit__more:hover {
  color: #0097b8;
  border-color: var(--color-yellow);
}

/* ===== 12. 展区色带与纹理 ===== */
.section-band {
  display: block;
  width: 100%;
  height: 0.75rem;
  border: 0;
  background: linear-gradient(90deg, var(--color-navy) 0%, var(--color-navy) 55%, var(--color-yellow) 55%, var(--color-yellow) 65%, var(--color-cyan) 65%, var(--color-cyan) 100%);
}

.section-band--alt {
  background: linear-gradient(90deg, var(--color-yellow) 0%, var(--color-yellow) 20%, var(--color-purple) 20%, var(--color-purple) 55%, var(--color-cyan) 55%, var(--color-cyan) 78%, var(--color-navy) 78%, var(--color-navy) 100%);
}

.geo-texture {
  background-color: var(--color-mist);
  background-image:
    radial-gradient(ellipse 120% 80% at 85% 20%, rgba(0, 229, 255, 0.12) 0%, transparent 60%),
    radial-gradient(ellipse 60% 40% at 10% 80%, rgba(123, 97, 255, 0.1) 0%, transparent 70%);
}

.geo-texture--dark {
  background-color: var(--color-navy);
  background-image:
    radial-gradient(ellipse 100% 60% at 70% 10%, rgba(0, 229, 255, 0.12) 0%, transparent 60%),
    linear-gradient(150deg, transparent 30%, rgba(255, 210, 0, 0.05) 50%, transparent 70%);
}

.glass-panel {
  background: rgba(255, 255, 255, 0.72);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: var(--radius);
  padding: 1.5rem;
}

/* ===== 13. 目录网格 ===== */
.index-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.25rem;
}

.index-card {
  display: block;
  padding: 2rem 1.5rem 1.5rem;
  background: var(--color-mist);
  border-left: 4px solid var(--color-cyan);
  text-decoration: none;
  color: var(--color-ink);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  transition: background 0.3s ease, box-shadow 0.3s ease, transform 0.2s ease;
  height: 100%;
}

.index-card:hover {
  background: var(--color-white);
  box-shadow: var(--shadow-hover);
  transform: translateY(-3px);
}

.index-card__no {
  font-family: var(--font-data);
  font-size: var(--text-xs);
  color: #0097b8;
  letter-spacing: 0.12em;
  margin-bottom: 0.75rem;
}

.index-card:nth-child(2) .index-card__no {
  color: var(--color-purple);
}

.index-card:nth-child(3) .index-card__no {
  color: #b8860b;
}

.index-card__title {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 900;
  color: var(--color-navy);
  margin-bottom: 0.5rem;
  line-height: 1.3;
}

.index-card__desc {
  font-size: var(--text-sm);
  color: var(--color-slate);
  margin-bottom: 0.75rem;
  line-height: 1.7;
}

/* ===== 14. 数据组件 ===== */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 1.25rem;
  margin-block: 2rem;
}

.stat-tile {
  background: var(--color-mist);
  border-radius: var(--radius-sm);
  border-top: 3px solid var(--color-cyan);
  padding: 1.5rem 1.25rem;
  transition: box-shadow 0.25s ease, transform 0.25s ease;
}

.stat-tile:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

.stat-tile--yellow {
  border-top-color: var(--color-yellow);
  background: rgba(255, 210, 0, 0.08);
}

.stat-tile--purple {
  border-top-color: var(--color-purple);
}

.stat-tile__value {
  font-family: var(--font-data);
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--color-navy);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 0.25rem;
}

.stat-tile__label {
  font-size: var(--text-sm);
  color: var(--color-slate);
}

.data-track {
  position: relative;
  height: 0.5rem;
  background: var(--color-line);
  border-radius: 999px;
  overflow: hidden;
  width: 100%;
}

.data-track__fill {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--color-navy) 10%, var(--color-cyan) 90%);
  border-radius: 999px;
  transition: width 0.85s cubic-bezier(0.22, 1, 0.36, 1);
}

.data-track__fill.is-animated {
  width: var(--value);
}

.data-track-wrap {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 0.75rem 1.5rem;
  margin-bottom: 1.25rem;
}

.data-track-wrap .data-track-label {
  grid-column: 1 / -1;
}

.data-track-wrap .data-track-value {
  font-family: var(--font-data);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-navy);
}

@media (prefers-reduced-motion: reduce) {
  .data-track__fill {
    width: var(--value);
    transition: none;
  }
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-data);
  font-size: var(--text-sm);
  margin-block: 1.5rem;
}

.data-table caption {
  text-align: left;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-slate);
  padding-bottom: 0.5rem;
}

.data-table th {
  text-align: left;
  padding: 0.8rem 1rem;
  background: var(--color-navy);
  color: var(--color-white);
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: 0.04em;
}

.data-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-line);
  color: var(--color-ink);
}

.data-table tbody tr {
  transition: background 0.2s ease;
}

.data-table tbody tr:hover {
  background: rgba(0, 229, 255, 0.08);
}

.data-table--striped tbody tr:nth-child(even) {
  background: var(--color-mist);
}

/* ===== 15. 说明牌与标签 ===== */
.placard {
  display: inline-flex;
  align-items: baseline;
  gap: 0.6rem;
  padding: 0.55rem 0.85rem;
  background: var(--color-mist);
  border-left: 3px solid var(--color-purple);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  color: var(--color-slate);
  margin-bottom: 1rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.placard__label {
  font-weight: 700;
  color: var(--color-navy);
  font-family: var(--font-display);
}

.placard__data {
  font-family: var(--font-data);
  color: var(--color-purple);
  font-weight: 700;
}

.tag {
  display: inline-block;
  padding: 0.25em 0.8em;
  border-radius: 999px;
  background: rgba(123, 97, 255, 0.12);
  color: #6a4fe0;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 700;
  line-height: 1.5;
  white-space: nowrap;
}

.tag--cyan {
  background: rgba(0, 229, 255, 0.15);
  color: #0097b8;
}

.tag--yellow {
  background: rgba(255, 210, 0, 0.2);
  color: #8c5c00;
}

.tag--navy {
  background: rgba(15, 31, 75, 0.1);
  color: var(--color-navy);
}

/* ===== 16. 媒体容器基础 ===== */
.media-frame {
  position: relative;
  display: block;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--color-line);
  aspect-ratio: 16 / 9;
  min-height: 0;
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.media-frame--screenshot {
  aspect-ratio: 4 / 3;
}

.media-frame--contain {
  background: var(--color-mist);
}

.media-frame--contain img {
  object-fit: contain;
}

.media-frame__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 0.5rem 1rem;
  background: rgba(15, 31, 75, 0.8);
  color: var(--color-white);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
}

/* ===== 17. 垂直注释 ===== */
.vertical-note {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  color: var(--color-slate);
  letter-spacing: 0.24em;
  white-space: nowrap;
  line-height: 1.6;
}

/* ===== 18. 基础表单（页面扩展使用） ===== */
.form-field {
  margin-bottom: 1.5rem;
}

.form-field label {
  display: block;
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 0.4rem;
}

.form-field input,
.form-field textarea,
.form-field select {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-white);
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-ink);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-field input:focus,
.form-field textarea:focus,
.form-field select:focus {
  outline: none;
  border-color: var(--color-cyan);
  box-shadow: 0 0 0 3px rgba(0, 229, 255, 0.15);
}

/* ===== 19. 入场动画（由JS添加js-ready时启用） ===== */
html.js-ready .exhibit:not(.is-visible) {
  opacity: 0;
  transform: translateY(26px);
}

html.js-ready .exhibit.is-visible {
  opacity: 1;
  transform: translateY(0);
  transition:
    opacity 0.7s ease,
    transform 0.7s ease;
}

@media (prefers-reduced-motion: reduce) {
  html.js-ready .exhibit:not(.is-visible) {
    opacity: 1;
    transform: none;
  }

  html.js-ready .exhibit.is-visible {
    transition: none;
  }

  body,
  a,
  button {
    transition: none !important;
  }
}

/* ===== 20. 响应式断点 ===== */
/* Tablet 与 Mobile */
@media (max-width: 1023.98px) {
  .main-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-white);
    border-top: 1px solid var(--color-line);
    border-bottom: 4px solid var(--color-navy);
    box-shadow: 0 20px 40px rgba(15, 31, 75, 0.12);
    display: none;
    margin-left: 0;
    z-index: 90;
  }

  .main-nav[data-open] {
    display: block;
  }

  .main-nav__list {
    flex-direction: column;
    gap: 0;
    padding: 0.5rem 0 1rem;
  }

  .main-nav__item {
    width: 100%;
  }

  .main-nav__link {
    display: block;
    padding: 0.9rem clamp(1.25rem, 4vw, 2rem);
    border-bottom: 1px solid var(--color-line);
    font-size: 1rem;
  }

  .main-nav__link::after {
    display: none;
  }

  .main-nav__link:hover {
    background: var(--color-mist);
  }

  .main-nav__link[aria-current="page"] {
    background: rgba(0, 229, 255, 0.08);
    border-left: 4px solid var(--color-yellow);
    padding-left: calc(clamp(1.25rem, 4vw, 2rem) - 4px);
  }

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

  .header-login {
    margin-left: auto;
    padding: 0.55em 1em;
    font-size: var(--text-sm);
  }
}

@media (max-width: 767.98px) {
  .header-topbar__slogan {
    display: none;
  }

  .header-logo__en {
    display: none;
  }

  .header-navbar__inner {
    min-height: 4rem;
    gap: 0.5rem;
  }

  .header-login {
    font-size: var(--text-xs);
    padding: 0.5em 0.8em;
  }

  .nav-toggle {
    width: 40px;
    height: 40px;
  }

  .site-footer__main {
    grid-template-columns: 1fr;
    gap: 2.5rem;
    padding-top: 3rem;
  }

  .site-footer__bottom-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .site-footer__legal {
    margin-left: 0;
  }

  .index-grid {
    grid-template-columns: 1fr;
  }

  .exhibit {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .exhibit__number {
    position: static;
    font-size: 2.75rem;
  }

  .data-table-wrap {
    overflow-x: auto;
  }
}

/* Tablet 中间态（768–1023px） */
@media (min-width: 768px) and (max-width: 1023.98px) {
  .site-footer__main {
    grid-template-columns: 1fr 1fr;
  }

  .site-footer__brand {
    grid-column: 1 / -1;
  }

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

  .header-topbar__slogan {
    display: inline;
  }
}

/* ===== 21. 打印与杂项 ===== */
@media print {
  .site-header,
  .site-footer,
  .nav-toggle,
  .footer-backtop,
  .skip-link {
    display: none !important;
  }

  body {
    background: var(--color-white);
  }
}