.page-about {
  --about-axis-x: 9px;
  --about-dot: 10px;
  --about-sticky-top: 84px;
  --about-scale-w: 168px;
  --about-gap: 36px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding-block: clamp(20px, 3vw, 32px) clamp(36px, 5.5vw, 68px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  z-index: 0;
  top: -180px;
  right: -140px;
  width: min(680px, 84vw);
  height: 470px;
  background:
    radial-gradient(circle at 32% 34%, var(--tb-gilt-100), transparent 60%),
    linear-gradient(138deg, var(--tb-patina-200), var(--tb-patina-050) 72%);
  border-radius: 46px 150px 60px 34px;
  transform: rotate(-9deg);
  opacity: 0.85;
  pointer-events: none;
}

.page-about .about-hero > .tb-container {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__grid {
  margin-top: clamp(20px, 3vw, 34px);
  align-items: start;
}

.page-about .about-hero__title {
  margin: 10px 0 0;
  font-family: var(--tb-font-serif);
  font-weight: 900;
  font-size: clamp(30px, 5.2vw, 52px);
  line-height: 1.18;
  letter-spacing: 0.02em;
  color: var(--tb-indigo-900);
  max-width: 15em;
}

.page-about .about-hero__intro {
  margin: 18px 0 0;
  max-width: 34em;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--tb-ink-800);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-facts {
  margin: 0;
  padding: clamp(18px, 2.6vw, 28px);
  background: var(--tb-card-000);
  border: 1px solid var(--tb-line-300);
  border-radius: var(--tb-radius-lg);
  box-shadow: var(--tb-shadow);
  display: grid;
  gap: 14px;
}

.page-about .about-facts__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--tb-line-300);
}

.page-about .about-facts__row:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.page-about .about-facts__row dt {
  margin: 0;
  font-size: 13.5px;
  letter-spacing: 0.04em;
  color: var(--tb-indigo-500);
}

.page-about .about-facts__row dd {
  margin: 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: 20px;
  color: var(--tb-indigo-900);
  white-space: nowrap;
}

.page-about .about-facts__row dd .tb-mono {
  font-family: var(--tb-font-mono);
  font-size: 19px;
  color: var(--tb-patina-600);
}

/* ---------- 编年区 ---------- */
.page-about .about-chron__heading {
  margin: 10px 0 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.28;
  letter-spacing: 0.02em;
  color: var(--tb-indigo-900);
}

.page-about .about-chron__lead {
  margin: 14px 0 0;
  max-width: 44em;
  font-size: 16px;
  line-height: 1.78;
  color: var(--tb-ink-800);
}

.page-about .about-chron__banner {
  margin: clamp(22px, 3.4vw, 34px) 0 0;
}

.page-about .about-chron__banner .tb-figure__frame {
  border-radius: var(--tb-radius-lg);
  overflow: hidden;
  border: 1px solid var(--tb-line-300);
}

.page-about .about-chron__nav {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: clamp(20px, 3vw, 30px);
  padding: 10px 14px;
  background: var(--tb-patina-050);
  border: 1px solid var(--tb-patina-200);
  border-radius: 999px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-chron-nav__label {
  flex: none;
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--tb-patina-600);
  text-transform: uppercase;
}

.page-about .about-chron-nav__list {
  display: flex;
  align-items: center;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-chron-nav__link {
  display: inline-block;
  flex: none;
  padding: 5px 12px;
  border-radius: 999px;
  font-family: var(--tb-font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--tb-indigo-500);
  text-decoration: none;
  border: 1px solid transparent;
  transition: background 0.25s ease, color 0.25s ease, border-color 0.25s ease;
}

.page-about .about-chron-nav__link:hover,
.page-about .about-chron-nav__link:focus-visible {
  background: var(--tb-gilt-100);
  border-color: var(--tb-gilt-500);
  color: var(--tb-indigo-900);
}

/* 竖向编年轴 */
.page-about .about-axis {
  position: relative;
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0 0 0 30px;
  list-style: none;
}

.page-about .about-axis::before {
  content: "";
  position: absolute;
  left: var(--about-axis-x);
  top: 8px;
  bottom: 42px;
  width: 1px;
  background: linear-gradient(
    180deg,
    var(--tb-patina-200) 0%,
    var(--tb-patina-600) 22%,
    var(--tb-patina-600) 55%,
    var(--tb-gilt-500) 100%
  );
}

.page-about .about-axis__item {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding: 0 0 32px;
}

.page-about .about-axis__item:last-child {
  padding-bottom: 0;
}

.page-about .about-axis__item::before {
  content: "";
  position: absolute;
  left: calc(var(--about-axis-x) - (var(--about-dot) / 2));
  top: 10px;
  width: var(--about-dot);
  height: var(--about-dot);
  border-radius: 50%;
  background: var(--tb-patina-200);
  box-shadow: 0 0 0 4px var(--tb-paper-000), 0 0 0 5px var(--tb-line-300);
  transition: background 0.3s ease, box-shadow 0.3s ease;
}

.page-about .about-axis__item:hover::before {
  background: var(--tb-gilt-500);
  box-shadow: 0 0 0 4px var(--tb-gilt-100), 0 0 0 5px var(--tb-gilt-500);
}

.page-about .about-axis__years {
  display: block;
  font-family: var(--tb-font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--tb-patina-600);
}

.page-about .about-axis__tag {
  display: inline-block;
  margin-top: 6px;
  padding-bottom: 2px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--tb-indigo-500);
  border-bottom: 2px solid var(--tb-gilt-500);
}

.page-about .about-axis__body {
  background: var(--tb-card-000);
  border: 1px solid var(--tb-line-300);
  border-left: 3px solid var(--tb-patina-200);
  border-radius: var(--tb-radius-md);
  padding: clamp(18px, 2.4vw, 26px);
  box-shadow: var(--tb-shadow);
  transition: transform 0.3s ease, border-color 0.3s ease;
}

.page-about .about-axis__item:hover .about-axis__body {
  transform: translateY(-3px);
  border-left-color: var(--tb-gilt-500);
}

.page-about .about-axis__title {
  margin: 0 0 12px;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: clamp(19px, 2.4vw, 23px);
  line-height: 1.34;
  letter-spacing: 0.02em;
  color: var(--tb-indigo-900);
}

.page-about .about-axis__body p {
  margin: 0 0 10px;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--tb-ink-800);
}

.page-about .about-axis__body p:last-child {
  margin-bottom: 0;
}

.page-about .about-axis__more {
  padding-left: 14px;
  border-left: 2px solid var(--tb-patina-200);
  color: var(--tb-indigo-500) !important;
  font-size: 14.5px !important;
}

/* ---------- 团队 ---------- */
.page-about .about-team__grid {
  align-items: center;
}

.page-about .about-team__heading {
  margin: 10px 0 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.28;
  letter-spacing: 0.02em;
  color: var(--tb-indigo-900);
}

.page-about .about-team__lead {
  margin: 14px 0 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--tb-ink-800);
}

.page-about .about-team__stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 14px;
  margin: 24px 0 0;
  padding: 18px 20px;
  background: var(--tb-patina-050);
  border-radius: var(--tb-radius-md);
  border: 1px solid var(--tb-patina-200);
}

.page-about .about-team__stat dt {
  margin: 0;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--tb-indigo-500);
}

.page-about .about-team__stat dd {
  margin: 6px 0 0;
  display: flex;
  align-items: baseline;
  gap: 5px;
  color: var(--tb-indigo-900);
}

.page-about .about-num {
  font-family: var(--tb-font-serif);
  font-weight: 900;
  font-size: 30px;
  line-height: 1;
  color: var(--tb-patina-900);
}

.page-about .about-unit {
  font-size: 13.5px;
  color: var(--tb-indigo-500);
}

.page-about .about-team__hours {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.page-about .about-team__hours li {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 8px;
  border-bottom: 1px dashed var(--tb-line-300);
  font-size: 14.5px;
  color: var(--tb-ink-800);
}

.page-about .about-team__hours li:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.page-about .about-team__hours .tb-mono {
  font-family: var(--tb-font-mono);
  font-size: 13.5px;
  color: var(--tb-patina-600);
}

.page-about .about-team__figure {
  margin: 0;
}

.page-about .about-team__figure .tb-figure__frame {
  border-radius: var(--tb-radius-lg);
  overflow: hidden;
  border: 1px solid var(--tb-line-300);
}

/* ---------- 资质与分级 ---------- */
.page-about .about-assurance__heading {
  margin: 10px 0 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.28;
  letter-spacing: 0.02em;
  color: var(--tb-indigo-900);
}

.page-about .about-assurance__lead {
  margin: 14px 0 0;
  max-width: 44em;
  font-size: 16px;
  line-height: 1.78;
  color: var(--tb-ink-800);
}

.page-about .about-assurance__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 16px;
  margin-top: clamp(22px, 3.2vw, 32px);
}

.page-about .about-assurance__card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 3px solid var(--tb-patina-200);
  transition: border-color 0.28s ease, transform 0.28s ease;
}

.page-about .about-assurance__card:hover {
  border-top-color: var(--tb-gilt-500);
  transform: translateY(-3px);
}

.page-about .about-assurance__index {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--tb-gilt-500);
}

.page-about .about-assurance__card .tb-card__title {
  margin: 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: 19px;
  color: var(--tb-indigo-900);
}

.page-about .about-assurance__card .tb-card__meta {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--tb-ink-800);
}

/* ---------- 合作与认可 ---------- */
.page-about .about-partners__panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  padding: clamp(24px, 4vw, 46px);
  background:
    linear-gradient(150deg, var(--tb-patina-900), var(--tb-patina-600) 78%);
  border-radius: var(--tb-radius-lg);
  color: var(--tb-paper-000);
}

.page-about .about-partners__copy .tb-eyebrow {
  color: var(--tb-gilt-100);
}

.page-about .about-partners__heading {
  margin: 10px 0 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.28;
  letter-spacing: 0.02em;
  color: var(--tb-paper-000);
}

.page-about .about-partners__copy p {
  margin: 14px 0 0;
  max-width: 40em;
  font-size: 15.5px;
  line-height: 1.8;
  color: rgba(251, 248, 241, 0.86);
}

.page-about .about-partners__copy .tb-btn {
  margin-top: 24px;
}

.page-about .about-partners__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.page-about .about-partners__list li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: 16px;
  padding: 14px 18px;
  background: rgba(251, 248, 241, 0.08);
  border: 1px solid rgba(243, 228, 180, 0.28);
  border-radius: var(--tb-radius-md);
}

.page-about .about-partners__num {
  font-family: var(--tb-font-serif);
  font-weight: 900;
  font-size: 34px;
  line-height: 1;
  color: var(--tb-gilt-100);
}

.page-about .about-partners__label {
  font-size: 14.5px;
  line-height: 1.65;
  color: rgba(251, 248, 241, 0.9);
}

/* ---------- 地域与覆盖 ---------- */
.page-about .about-region__panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  align-items: center;
}

.page-about .about-region__figure {
  margin: 0;
}

.page-about .about-region__figure .tb-figure__frame {
  border-radius: var(--tb-radius-lg);
  overflow: hidden;
  border: 1px solid var(--tb-line-300);
}

.page-about .about-region__heading {
  margin: 10px 0 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: clamp(23px, 3.2vw, 30px);
  line-height: 1.3;
  letter-spacing: 0.02em;
  color: var(--tb-indigo-900);
}

.page-about .about-region__copy p {
  margin: 14px 0 0;
  max-width: 38em;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--tb-ink-800);
}

.page-about .about-region__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

/* ---------- 下一步 ---------- */
.page-about .about-next__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  padding: clamp(24px, 4vw, 42px);
  background: var(--tb-orange-050);
  border: 1px solid var(--tb-line-300);
  border-radius: var(--tb-radius-lg);
}

.page-about .about-next__heading {
  margin: 10px 0 0;
  font-family: var(--tb-font-serif);
  font-weight: 700;
  font-size: clamp(22px, 3vw, 28px);
  line-height: 1.32;
  letter-spacing: 0.02em;
  color: var(--tb-indigo-900);
}

.page-about .about-next__copy p {
  margin: 14px 0 0;
  max-width: 42em;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--tb-ink-800);
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: start;
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-partners__panel {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    gap: 40px;
    align-items: center;
  }

  .page-about .about-region__panel {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 40px;
  }

  .page-about .about-next__inner {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    align-items: center;
    gap: 34px;
  }

  .page-about .about-next__links {
    justify-content: flex-end;
  }
}

@media (min-width: 900px) {
  .page-about .about-axis {
    padding-left: 0;
  }

  .page-about .about-axis::before {
    left: calc(var(--about-scale-w) + (var(--about-gap) / 2));
  }

  .page-about .about-axis__item {
    grid-template-columns: var(--about-scale-w) minmax(0, 1fr);
    gap: var(--about-gap);
    padding-left: 0;
    padding-bottom: 44px;
  }

  .page-about .about-axis__item::before {
    left: calc(var(--about-scale-w) + (var(--about-gap) / 2) - (var(--about-dot) / 2));
    top: 14px;
  }

  .page-about .about-axis__scale {
    position: sticky;
    top: var(--about-sticky-top);
    align-self: start;
    padding-top: 4px;
  }

  .page-about .about-axis__body {
    border-left-width: 1px;
    border-top: 3px solid var(--tb-patina-200);
  }

  .page-about .about-axis__item:hover .about-axis__body {
    border-top-color: var(--tb-gilt-500);
    border-left-color: var(--tb-line-300);
  }
}

@media (max-width: 639px) {
  .page-about .about-chron__nav {
    padding: 10px 12px;
  }

  .page-about .about-chron-nav__label {
    display: none;
  }

  .page-about .about-facts__row {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .about-facts__row dd {
    white-space: normal;
  }

  .page-about .about-team__hours li {
    flex-direction: column;
    gap: 4px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-axis__body,
  .page-about .about-axis__item::before,
  .page-about .about-assurance__card,
  .page-about .about-chron-nav__link {
    transition: none !important;
  }

  .page-about .about-axis__item:hover .about-axis__body,
  .page-about .about-assurance__card:hover {
    transform: none;
  }
}