.page-about {
  --about-gap: clamp(28px, 5vw, 56px);
  --about-gap-lg: clamp(48px, 8vw, 104px);
  --about-line: #17466F;
  color: var(--mist);
  background: var(--night);
}

.page-about .about-crumb-wrap {
  padding-top: 20px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(24px, 4vw, 44px) 0 clamp(48px, 8vw, 92px);
  position: relative;
}

.page-about .about-hero__grid {
  display: grid;
  gap: var(--about-gap);
  grid-template-columns: 1fr;
}

.page-about .about-hero__main h1 {
  font-size: clamp(34px, 7vw, 66px);
  line-height: 1.12;
  letter-spacing: 0.04em;
  font-weight: 900;
  color: var(--white);
  margin: 14px 0 22px;
  max-width: 15em;
}

.page-about .about-hero__main .lead {
  max-width: 36em;
  color: var(--mist);
  font-size: 16px;
  line-height: 1.8;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .fact {
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  padding: 14px 12px;
  background: rgba(14, 42, 71, 0.55);
}

.page-about .fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 3.4vw, 30px);
  font-weight: 700;
  color: var(--lime);
  line-height: 1.1;
  letter-spacing: 0.02em;
}

.page-about .fact__num em {
  font-style: normal;
  font-size: 0.6em;
  vertical-align: super;
}

.page-about .fact__label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

.page-about .about-hero__rail {
  border-top: 1px solid var(--about-line);
  padding-top: 18px;
}

.page-about .about-hero__rail-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--orange);
  margin-bottom: 12px;
}

.page-about .about-rail {
  display: grid;
  gap: 2px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-rail a {
  display: flex;
  gap: 12px;
  align-items: baseline;
  padding: 9px 0;
  color: var(--mist);
  text-decoration: none;
  font-size: 14px;
  border-bottom: 1px dashed rgba(23, 70, 111, 0.7);
  transition: color 0.22s var(--ease), transform 0.22s var(--ease);
}

.page-about .about-rail a .num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--about-line);
  transition: color 0.22s var(--ease);
}

.page-about .about-rail a:hover,
.page-about .about-rail a:focus-visible {
  color: var(--lime);
  transform: translateX(4px);
}

.page-about .about-rail a:hover .num,
.page-about .about-rail a:focus-visible .num {
  color: var(--lime);
}

/* ---------- 通用章节 ---------- */
.page-about .section {
  padding: var(--about-gap-lg) 0;
}

.page-about .section-head {
  max-width: 44em;
  margin-bottom: var(--about-gap);
}

.page-about .section-head h2 {
  font-size: clamp(24px, 4.4vw, 40px);
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--white);
  margin: 12px 0 16px;
  line-height: 1.2;
}

.page-about .section-head .lead {
  color: var(--mist);
  font-size: 15px;
  line-height: 1.8;
}

.page-about .band--lake {
  background: linear-gradient(180deg, rgba(14, 42, 71, 0.9) 0%, rgba(6, 20, 27, 0.9) 100%);
}

.page-about .band--paper {
  background: var(--paper);
  color: var(--graphite);
}

.page-about .band--paper .section-head h2,
.page-about .band--paper h2 {
  color: var(--graphite);
}

.page-about .band--paper .eyebrow {
  color: #7a6b2f;
}

.page-about .band--paper .about-account__lead {
  color: var(--graphite);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
}

.page-about .tl-list {
  position: relative;
  padding-left: 26px;
}

.page-about .tl-list::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg, var(--lime) 0%, var(--about-line) 60%, rgba(23, 70, 111, 0.15) 100%);
}

.page-about .tl-node {
  position: relative;
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  background: rgba(14, 42, 71, 0.6);
  box-shadow: var(--shadow-card);
  margin-bottom: 20px;
  transition: border-color 0.24s var(--ease), transform 0.24s var(--ease);
}

.page-about .tl-node[open] {
  border-color: rgba(183, 241, 58, 0.45);
}

.page-about .tl-node > summary {
  list-style: none;
  cursor: pointer;
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-areas:
    "year head toggle"
    "year brief toggle";
  align-items: center;
  gap: 4px 14px;
  padding: 16px 16px 16px 18px;
}

.page-about .tl-node > summary::-webkit-details-marker {
  display: none;
}

.page-about .tl-node__marker {
  position: absolute;
  left: -26px;
  top: 26px;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--night);
  border: 2px solid var(--lime);
  box-shadow: 0 0 0 4px rgba(6, 20, 27, 0.9);
}

.page-about .tl-node__year {
  grid-area: year;
  font-family: var(--font-mono);
  font-size: clamp(26px, 5vw, 44px);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--lime);
  line-height: 1;
}

.page-about .tl-node__head {
  grid-area: head;
  display: contents;
}

.page-about .tl-node__title {
  grid-area: head;
  font-size: 17px;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.02em;
}

.page-about .tl-node__brief {
  grid-area: brief;
  font-size: 13px;
  color: var(--mist);
  line-height: 1.6;
}

.page-about .tl-node__toggle {
  grid-area: toggle;
  width: 26px;
  height: 26px;
  border: 1px solid var(--about-line);
  border-radius: 50%;
  position: relative;
  transition: border-color 0.24s var(--ease), background 0.24s var(--ease);
}

.page-about .tl-node__toggle::before,
.page-about .tl-node__toggle::after {
  content: "";
  position: absolute;
  background: var(--lime);
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  transition: opacity 0.24s var(--ease);
}

.page-about .tl-node__toggle::before {
  width: 11px;
  height: 1.5px;
}

.page-about .tl-node__toggle::after {
  width: 1.5px;
  height: 11px;
}

.page-about .tl-node[open] .tl-node__toggle {
  border-color: var(--lime);
  background: rgba(183, 241, 58, 0.12);
}

.page-about .tl-node[open] .tl-node__toggle::after {
  opacity: 0;
}

.page-about .tl-node__body {
  padding: 0 18px 18px;
  border-top: 1px dashed rgba(23, 70, 111, 0.85);
  margin: 0 16px 0 18px;
  padding-top: 14px;
}

.page-about .tl-node__body p {
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
  max-width: 40em;
}

.page-about .tl-node__body p + p {
  margin-top: 10px;
}

.page-about .tl-node__note {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--orange);
  letter-spacing: 0.02em;
}

.page-about .about-timeline__side {
  display: grid;
  gap: 16px;
  align-content: start;
}

.page-about .side-card {
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  padding: 18px;
  background: var(--lake);
}

.page-about .side-card--lime {
  background: transparent;
  border-left: 3px solid var(--lime);
}

.page-about .side-card__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--orange);
  margin-bottom: 10px;
}

.page-about .side-card__num {
  font-family: var(--font-mono);
  font-size: 52px;
  font-weight: 700;
  line-height: 1;
  color: var(--lime);
}

.page-about .side-card__text {
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--mist);
  margin-top: 10px;
}

/* ---------- 团队 ---------- */
.page-about .about-team__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
}

.page-about .about-team__hint {
  font-size: 13px;
  color: var(--mist);
  margin-bottom: 14px;
}

.page-about .role {
  border-top: 1px solid var(--about-line);
}

.page-about .role:last-child {
  border-bottom: 1px solid var(--about-line);
}

.page-about .role > summary {
  list-style: none;
  cursor: pointer;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 14px;
  padding: 16px 4px;
  transition: background 0.22s var(--ease);
}

.page-about .role > summary::-webkit-details-marker {
  display: none;
}

.page-about .role > summary:hover,
.page-about .role > summary:focus-visible {
  background: rgba(183, 241, 58, 0.06);
}

.page-about .role__idx {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--lime);
  min-width: 2.6em;
}

.page-about .role__name {
  font-size: 17px;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.03em;
}

.page-about .role__swatch {
  width: 22px;
  height: 5px;
  border-radius: 3px;
  background: var(--about-line);
  transition: background 0.24s var(--ease), width 0.24s var(--ease);
}

.page-about .role[open] .role__swatch {
  background: var(--orange);
  width: 34px;
}

.page-about .role__body {
  padding: 0 4px 18px 4px;
}

.page-about .role__body p {
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
  max-width: 38em;
}

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

/* ---------- 资料库 ---------- */
.page-about .about-archive__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
}

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

.page-about .about-archive__body .prose {
  color: var(--mist);
  font-size: 15px;
  line-height: 1.85;
  max-width: 36em;
}

.page-about .about-archive__body .prose + .prose {
  margin-top: 16px;
}

.page-about .archive-facts {
  display: grid;
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 26px 0 20px;
}

.page-about .archive-facts > div {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  background: var(--lake);
  padding: 14px 16px;
}

.page-about .archive-facts dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .archive-facts dd {
  font-size: 14px;
  color: var(--white);
  letter-spacing: 0.02em;
}

.page-about .about-archive__link {
  font-size: 14px;
  color: var(--mist);
}

.page-about .about-archive__link a,
.page-about .about-account__link a {
  color: var(--lime);
  text-decoration: none;
  border-bottom: 1px solid rgba(183, 241, 58, 0.4);
  padding-bottom: 1px;
  transition: border-color 0.22s var(--ease), color 0.22s var(--ease);
}

.page-about .about-archive__link a:hover,
.page-about .about-archive__link a:focus-visible {
  border-color: var(--lime);
}

/* ---------- 账号 ---------- */
.page-about .about-account__head {
  margin-bottom: var(--about-gap);
}

.page-about .about-account__head h2 {
  font-size: clamp(24px, 4.4vw, 40px);
  font-weight: 800;
  letter-spacing: 0.04em;
  line-height: 1.2;
  margin: 12px 0 0;
}

.page-about .about-account__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
}

.page-about .about-account__lead {
  font-size: 16px;
  line-height: 1.85;
  max-width: 34em;
  font-weight: 500;
}

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

.page-about .account-list li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  align-items: baseline;
  padding: 14px 16px;
  background: rgba(255, 255, 255, 0.62);
  border: 1px solid rgba(42, 50, 56, 0.16);
  border-radius: var(--radius);
  box-shadow: var(--shadow-paper);
}

.page-about .account-list__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: #7a6b2f;
}

.page-about .account-list__text {
  font-size: 14px;
  line-height: 1.75;
}

.page-about .account-list__text strong {
  color: #0E2A47;
  letter-spacing: 0.02em;
}

.page-about .account-card {
  background: var(--night);
  color: var(--mist);
  border-radius: var(--radius);
  padding: 22px 20px;
  border-left: 4px solid var(--orange);
}

.page-about .account-card__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--orange);
  margin-bottom: 10px;
}

.page-about .account-card__text {
  font-size: 15px;
  line-height: 1.8;
  color: var(--white);
}

.page-about .account-card__link {
  margin-top: 14px;
  font-size: 14px;
}

/* ---------- 西宁 ---------- */
.page-about .about-xining__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-xining__map svg {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  background: var(--lake);
}

.page-about .contact-block {
  display: grid;
  gap: 14px;
  margin-bottom: 22px;
}

.page-about .contact-block > div {
  border-left: 2px solid var(--about-line);
  padding-left: 14px;
}

.page-about .contact-block dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--orange);
  margin-bottom: 5px;
}

.page-about .contact-block dd {
  font-size: 15px;
  color: var(--white);
  letter-spacing: 0.02em;
  line-height: 1.6;
}

.page-about .contact-block dd a {
  color: var(--white);
  text-decoration: none;
  border-bottom: 1px solid rgba(183, 241, 58, 0.5);
  transition: color 0.22s var(--ease);
}

.page-about .contact-block dd a:hover,
.page-about .contact-block dd a:focus-visible {
  color: var(--lime);
}

.page-about .about-xining__info .prose {
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--mist);
  max-width: 36em;
}

.page-about .about-xining__link {
  margin-top: 16px;
  font-size: 14px;
  color: var(--mist);
}

.page-about .about-xining__link a {
  color: var(--lime);
  text-decoration: none;
  border-bottom: 1px solid rgba(183, 241, 58, 0.4);
}

.page-about .about-xining__figure {
  margin: var(--about-gap) 0 0;
}

/* ---------- 三件事 ---------- */
.page-about .principle-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .principle {
  position: relative;
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  background: rgba(14, 42, 71, 0.5);
  padding: 22px 20px 24px;
  box-shadow: var(--shadow-card);
}

.page-about .principle__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--orange);
  margin-bottom: 10px;
}

.page-about .principle__title {
  font-size: clamp(22px, 3.6vw, 30px);
  font-weight: 800;
  letter-spacing: 0.08em;
  color: var(--white);
  margin-bottom: 12px;
}

.page-about .principle__text {
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--mist);
  max-width: 32em;
}

.page-about .about-close {
  margin-top: var(--about-gap);
  padding-top: 28px;
  border-top: 1px solid var(--about-line);
  display: grid;
  gap: 18px;
}

.page-about .about-close__text {
  font-size: 16px;
  line-height: 1.8;
  color: var(--white);
  max-width: 30em;
}

.page-about .about-close__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero__facts {
    gap: 18px;
  }

  .page-about .tl-node > summary {
    grid-template-columns: auto 1fr auto;
    grid-template-areas: "year head toggle";
    padding: 20px 22px;
    gap: 20px;
  }

  .page-about .tl-node__year {
    font-size: clamp(34px, 5vw, 52px);
    min-width: 3.4em;
  }

  .page-about .tl-node__head {
    display: grid;
    gap: 6px;
  }

  .page-about .tl-node__brief {
    font-size: 13.5px;
  }

  .page-about .archive-facts > div {
    grid-template-columns: 132px 1fr;
    align-items: baseline;
    gap: 16px;
  }

  .page-about .about-account__grid {
    grid-template-columns: 1fr 1fr;
    align-items: start;
    gap: 32px 48px;
  }

  .page-about .about-account__lead {
    grid-column: 1 / -1;
  }

  .page-about .about-xining__layout {
    grid-template-columns: minmax(0, 3fr) minmax(0, 4fr);
    gap: 48px;
  }

  .page-about .about-xining__figure {
    margin-top: var(--about-gap);
  }

  .page-about .principle-list {
    grid-template-columns: repeat(3, 1fr);
    gap: 0;
  }

  .page-about .principle {
    border-radius: 0;
    border-right: none;
    box-shadow: none;
    background: transparent;
    padding: 26px 24px 30px 0;
    border-top: 2px solid var(--about-line);
    border-left: none;
    border-bottom: none;
  }

  .page-about .principle:last-child {
    border-right: none;
  }

  .page-about .principle + .principle {
    border-left: 1px solid var(--about-line);
    padding-left: 24px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 3fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .about-hero__rail {
    padding-top: 42px;
  }

  .page-about .about-timeline__layout {
    grid-template-columns: minmax(0, 7fr) minmax(0, 3fr);
    gap: 56px;
  }

  .page-about .about-team__layout {
    grid-template-columns: minmax(0, 4fr) minmax(0, 3fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .about-archive__layout {
    grid-template-columns: minmax(0, 4fr) minmax(0, 4fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .tl-list {
    padding-left: 34px;
  }

  .page-about .tl-node__marker {
    left: -34px;
  }
}

@media (max-width: 420px) {
  .page-about .about-hero__facts {
    grid-template-columns: 1fr;
  }

  .page-about .tl-node__year {
    font-size: 24px;
  }
}