:root {
  --color-snow: #F6F8FB;
  --color-blue: #1B5E9E;
  --color-night: #1F2937;
  --color-red: #A93226;
  --color-gold: #E0B86C;
  --color-ash: #A0AAB5;
  --color-slate: #2D4A5A;
  --color-mist: #DCE3EB;
  --font-head: "Songti SC", "Noto Serif SC", "STSong", SimSun, Georgia, "Times New Roman", serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", system-ui, -apple-system, sans-serif;
  --max-width: 1240px;
  --header-h: 4.25rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--color-snow);
  color: var(--color-night);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

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

h1,
h2,
h3 {
  font-family: var(--font-head);
  line-height: 1.22;
  margin: 0 0 .75em;
}

a {
  color: inherit;
}

:focus-visible {
  outline: 3px solid var(--color-blue);
  outline-offset: 2px;
}

#main-content {
  flex: 1 0 auto;
  width: 100%;
  outline: none;
}

.skip-link {
  position: fixed;
  top: .75rem;
  left: .75rem;
  z-index: 999;
  padding: .5rem 1rem;
  background: var(--color-blue);
  color: var(--color-snow);
  font-size: .9rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: 4px;
  opacity: 0;
  transform: translateY(-.5rem);
  pointer-events: none;
  transition: opacity .2s ease, transform .2s ease;
}

.skip-link:focus-visible {
  outline: 3px solid var(--color-gold);
  outline-offset: 3px;
  opacity: 1;
  transform: none;
  pointer-events: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(246, 248, 251, 0.94);
  border-bottom: 1px solid var(--color-mist);
}

.site-header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-blue) 0%, var(--color-gold) 55%, var(--color-red) 100%);
  z-index: 2;
}

.site-header__inner {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: clamp(1rem, 3vw, 2rem);
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: .75rem;
  text-decoration: none;
  color: var(--color-night);
}

.brand__seal {
  width: 2.5rem;
  height: 2.5rem;
  display: grid;
  place-items: center;
  font-family: var(--font-head);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-snow);
  background: linear-gradient(135deg, var(--color-blue) 0%, var(--color-slate) 100%);
  border-radius: .25rem 1rem .25rem 1rem;
  box-shadow: inset 0 0 0 1px rgba(224, 184, 108, 0.65), 0 2px 8px rgba(27, 94, 158, 0.25);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand__name {
  font-family: var(--font-head);
  font-size: 1.06rem;
  font-weight: 800;
  letter-spacing: .08em;
}

.brand__tagline {
  margin-top: .2rem;
  padding-left: .45rem;
  border-left: 2px solid var(--color-gold);
  font-size: .65rem;
  font-weight: 600;
  letter-spacing: .28em;
  text-transform: uppercase;
  color: var(--color-blue);
}

.site-nav {
  margin-left: auto;
}

.site-nav__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  align-items: center;
  gap: .25rem;
}

.site-nav__link {
  position: relative;
  display: block;
  padding: .45rem .75rem;
  border-radius: 4px;
  color: var(--color-slate);
  text-decoration: none;
  font-size: .88rem;
  font-weight: 500;
  transition: background-color .2s ease, color .2s ease;
}

.site-nav__link:hover {
  background: rgba(27, 94, 158, 0.08);
  color: var(--color-blue);
}

.site-nav__link[aria-current="page"] {
  background: var(--color-blue);
  color: var(--color-snow);
  box-shadow: 0 2px 10px rgba(27, 94, 158, 0.28);
}

.site-nav__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: .75rem;
  right: .75rem;
  bottom: .12rem;
  height: 2px;
  background: var(--color-gold);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: .55rem;
  margin-left: auto;
  padding: .4rem .8rem;
  border: 1px solid var(--color-mist);
  border-radius: 4px;
  background: var(--color-snow);
  color: var(--color-night);
  font-size: .85rem;
  font-weight: 600;
  font-family: var(--font-body);
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  transition: border-color .2s ease, color .2s ease;
}

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

.nav-toggle__text {
  font-size: .8rem;
  letter-spacing: .12em;
}

.nav-toggle__icon {
  width: 18px;
  height: 14px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.nav-toggle__icon span {
  display: block;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform .2s ease, opacity .2s ease;
}

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

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

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

.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--color-blue) 0%, var(--color-gold) 55%, var(--color-red) 100%);
  pointer-events: none;
  z-index: 5;
  transition: width .12s linear;
}

.site-footer {
  margin-top: auto;
  background: var(--color-slate);
  color: rgba(220, 227, 235, 0.9);
  border-top: 3px solid var(--color-gold);
}

.site-footer__inner {
  max-width: var(--max-width);
  margin-inline: auto;
  padding: clamp(2.75rem, 6vw, 3.75rem) clamp(1rem, 3vw, 2rem) 2.5rem;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: clamp(1.75rem, 4vw, 2.75rem);
}

.site-footer__brand-wrap {
  display: flex;
  flex-direction: column;
  gap: .35rem;
  min-width: 0;
  max-width: 31rem;
}

.site-footer__brand {
  font-family: var(--font-head);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--color-snow);
  margin-bottom: .2rem;
}

.site-footer__slogan {
  font-size: .8rem;
  font-weight: 500;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--color-gold);
}

.site-footer__note {
  margin-top: .5rem;
  font-size: .82rem;
  line-height: 1.7;
  color: rgba(220, 227, 235, 0.72);
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  min-width: 0;
}

.footer-col__title {
  font-family: var(--font-head);
  font-size: .88rem;
  font-weight: 600;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--color-gold);
  border-left: 3px solid var(--color-gold);
  padding-left: .7rem;
  margin-bottom: .25rem;
}

.footer-contact,
.footer-links {
  display: flex;
  flex-direction: column;
  gap: .55rem;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: .86rem;
}

.footer-contact li {
  display: flex;
  align-items: flex-start;
  gap: .5rem;
}

.footer-contact li::before {
  content: "";
  flex: 0 0 auto;
  width: 4px;
  height: 4px;
  margin-top: .65em;
  background: var(--color-gold);
}

.footer-links a {
  color: rgba(220, 227, 235, 0.88);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-bottom-color .2s ease;
}

.footer-links a:hover {
  color: var(--color-snow);
  border-bottom-color: var(--color-gold);
}

.site-footer__meta {
  padding: 1.25rem clamp(1rem, 3vw, 2rem);
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  text-align: center;
  font-size: .76rem;
  color: rgba(220, 227, 235, 0.68);
}

.site-footer__meta p {
  margin: 0;
}

.container {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: clamp(1rem, 3vw, 2rem);
}

.section {
  padding-block: clamp(3.5rem, 7vw, 6.5rem);
}

.section--tight {
  padding-block: clamp(2.25rem, 4vw, 3.5rem);
}

.grid {
  display: grid;
  gap: clamp(1rem, 2vw, 1.5rem);
}

.grid--12 {
  grid-template-columns: repeat(12, 1fr);
}

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

.grid--4 {
  grid-template-columns: repeat(4, 1fr);
}

.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-6 { grid-column: span 6; }
.span-8 { grid-column: span 8; }
.span-9 { grid-column: span 9; }
.span-12 { grid-column: span 12; }

.index-label {
  display: inline-flex;
  align-items: center;
  gap: .55rem;
  margin-bottom: 1rem;
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--color-red);
}

.index-label::before {
  content: "";
  width: 1.75rem;
  height: 2px;
  background: var(--color-gold);
}

.display-title {
  margin: 0 0 1rem;
  font-family: var(--font-head);
  font-size: clamp(2.75rem, 7vw, 6rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.04;
}

.display-title--light {
  font-weight: 300;
}

.section-title {
  margin: 0 0 1rem;
  font-family: var(--font-head);
  font-size: clamp(1.75rem, 4vw, 3rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.2;
}

.lede {
  max-width: 46rem;
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--color-slate);
}

.paper-card {
  position: relative;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--color-mist);
  border-radius: 2px 14px 2px 14px;
  padding: clamp(1.25rem, 2vw, 1.75rem);
  box-shadow: 0 1px 0 rgba(27, 94, 158, 0.04), 0 18px 36px -22px rgba(27, 94, 158, 0.22);
  transition: transform .25s ease, box-shadow .25s ease;
}

.paper-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 2px 0 rgba(27, 94, 158, 0.04), 0 28px 48px -24px rgba(27, 94, 158, 0.32);
}

.chapter-card {
  display: flex;
  flex-direction: column;
  gap: .65rem;
  min-height: 220px;
  color: inherit;
  text-decoration: none;
}

.chapter-card:hover .chapter-card__title {
  color: var(--color-blue);
}

.chapter-card__index {
  font-size: .75rem;
  font-weight: 500;
  letter-spacing: .3em;
  color: var(--color-ash);
}

.chapter-card__index::before {
  content: "◆";
  margin-right: .45rem;
  font-size: .6rem;
  color: var(--color-gold);
}

.chapter-card__title {
  font-family: var(--font-head);
  font-size: 1.35rem;
  font-weight: 700;
  transition: color .2s ease;
}

.chapter-card__body {
  flex: 1;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--color-slate);
}

.chapter-card__link {
  margin-top: .75rem;
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  font-size: .85rem;
  font-weight: 600;
  color: var(--color-blue);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin: .4rem 0 0;
  padding: 0;
  list-style: none;
}

.tag {
  display: inline-block;
  padding: .22rem .65rem;
  border: 1px solid var(--color-mist);
  border-radius: 999px;
  background: var(--color-snow);
  color: var(--color-slate);
  font-size: .76rem;
  letter-spacing: .02em;
}

.tag--red {
  border-color: rgba(169, 50, 38, 0.3);
  background: rgba(169, 50, 38, 0.06);
  color: var(--color-red);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .65rem 1.15rem;
  border: 1px solid transparent;
  border-radius: 4px;
  background: transparent;
  color: var(--color-night);
  font-family: var(--font-body);
  font-size: .9rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  transition: background-color .2s ease, color .2s ease, border-color .2s ease, transform .2s ease;
}

.btn--primary {
  background: var(--color-blue);
  color: var(--color-snow);
}

.btn--primary:hover {
  background: var(--color-slate);
  transform: translateY(-2px);
}

.btn--gold {
  background: var(--color-gold);
  color: var(--color-night);
}

.btn--gold:hover {
  background: #D8B05C;
  transform: translateY(-2px);
}

.btn--outline {
  background: transparent;
  border-color: var(--color-mist);
  color: var(--color-blue);
}

.btn--outline:hover {
  border-color: var(--color-blue);
  background: rgba(27, 94, 158, 0.06);
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: .25rem;
  margin: 0 0 2rem;
  padding: 0;
  list-style: none;
  font-size: .82rem;
  color: var(--color-ash);
}

.breadcrumbs li + li::before {
  content: "/";
  margin: 0 .55rem;
  color: var(--color-mist);
}

.breadcrumbs a {
  color: var(--color-blue);
  text-decoration: none;
}

.breadcrumbs a:hover {
  border-bottom: 1px solid var(--color-blue);
}

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

.figure {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #ECF1F6 0%, #F8FAFC 55%, #EFE3C8 170%);
  border: 1px solid var(--color-mist);
}

.figure--hero {
  height: clamp(260px, 48vh, 560px);
  border-radius: 0 2rem 0 2rem;
}

.figure--card {
  height: 220px;
  border-radius: 2px 12px 2px 12px;
}

.figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .45s ease;
}

.figure:hover img {
  transform: scale(1.02);
}

.figure::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(27, 94, 158, 0) 60%, rgba(27, 94, 158, 0.16));
  pointer-events: none;
}

.geo-divider {
  height: 2px;
  margin: 2rem 0;
  border: 0;
  background: linear-gradient(90deg, var(--color-blue) 0%, var(--color-gold) 55%, var(--color-red) 100%);
  opacity: .7;
}

.has-js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .7s ease, transform .7s ease;
}

.has-js [data-reveal].is-inview {
  opacity: 1;
  transform: none;
}

@media (max-width: 960px) {
  .grid--12 {
    grid-template-columns: repeat(6, 1fr);
  }

  .span-3,
  .span-4,
  .span-6,
  .span-8,
  .span-9,
  .span-12 {
    grid-column: span 6;
  }
}

@media (max-width: 860px) {
  .site-header__inner {
    flex-wrap: wrap;
    height: auto;
    padding-block: .65rem;
  }

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

  .site-nav {
    order: 3;
    flex: 1 0 100%;
    display: none;
    margin-left: 0;
    padding-bottom: .25rem;
  }

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

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
  }

  .site-nav__link {
    padding: .7rem .9rem;
    font-size: 1rem;
  }

  .site-footer__inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

@media (max-width: 600px) {
  .grid--12,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }

  .span-3,
  .span-4,
  .span-6,
  .span-8,
  .span-9,
  .span-12 {
    grid-column: span 1;
  }

  .brand__tagline {
    letter-spacing: .16em;
  }

  .site-footer__inner {
    padding-top: 2rem;
  }
}

@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;
  }

  .has-js [data-reveal],
  .has-js [data-reveal].is-inview {
    opacity: 1;
    transform: none;
    transition: none;
  }
}