.page-about {
  background: var(--night);
  color: var(--text);
  --about-pad-x: clamp(18px, 3vw, 40px);
  --about-pad-y: clamp(40px, 5.5vw, 72px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero__frame {
  position: absolute;
  inset: 0;
  z-index: -2;
}

.page-about .about-hero__img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 50% 42%;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(180deg,
      rgba(11, 16, 22, 0.82) 0%,
      rgba(11, 16, 22, 0.58) 32%,
      rgba(11, 16, 22, 0.90) 80%,
      var(--night) 100%);
}

.page-about .about-hero__inner {
  display: flex;
  flex-direction: column;
  min-height: clamp(460px, 64vh, 660px);
  padding-top: 22px;
  padding-bottom: clamp(44px, 6vw, 84px);
}

.page-about .about-hero .breadcrumb__link,
.page-about .about-hero .breadcrumb__current,
.page-about .about-hero .breadcrumb__sep {
  color: var(--text-dim);
}

.page-about .about-hero .breadcrumb__link:hover,
.page-about .about-hero .breadcrumb__link:focus-visible {
  color: var(--snow);
}

.page-about .about-hero__main {
  margin-top: auto;
  padding-top: crack;
  padding-top: clamp(40px, 8vw, 120px);
}

.page-about .about-hero__eyebrow {
  color: var(--lake-lift);
}

.page-about .about-hero__title {
  margin: 16px 0 0;
  max-width: 18ch;
  font-size: clamp(30px, 5.6vw, 60px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  font-weight: 800;
  color: var(--snow);
}

.page-about .about-hero__lead {
  margin: 22px 0 0;
  max-width: 44ch;
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 34px 0 0;
  max-width: 620px;
  border: 1px solid var(--line-strong);
  background: rgba(11, 16, 22, 0.52);
}

.page-about .about-fact {
  padding: 14px 16px;
  border-right: 1px solid var(--line);
  min-width: 0;
}

.page-about .about-fact:last-child {
  border-right: 0;
}

.page-about .about-fact__key {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--lake-lift);
}

.page-about .about-fact__val {
  margin: 6px 0 0;
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 650;
  color: var(--snow);
  white-space: nowrap;
}

/* ---------- 主体骨架 ---------- */

.page-about .about-body {
  padding: clamp(44px, 6vw, 88px) 0 clamp(56px, 7vw, 110px);
}

.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 36px;
  align-items: start;
}

.page-about .about-index__head {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-dim);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
}

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

.page-about .about-index__link {
  display: grid;
  grid-template-columns: 26px minmax(0, 1fr);
  align-items: baseline;
  gap: 10px;
  padding: 13px 10px 13px 12px;
  border-left: 2px solid transparent;
  color: var(--text-dim);
  font-size: 14px;
  line-height: 1.5;
  text-decoration: none;
  transition: color var(--t) var(--ease), border-color var(--t) var(--ease), background var(--t) var(--ease);
}

.page-about .about-index__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  transition: color var(--t) var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--snow);
  border-left-color: var(--lake-lift);
  background: rgba(28, 111, 180, 0.12);
}

.page-about .about-index__item.is-active .about-index__link {
  color: var(--snow);
  border-left-color: var(--score);
  background: rgba(61, 240, 140, 0.08);
}

.page-about .about-index__item.is-active .about-index__num {
  color: var(--score);
}

.page-about .about-flow {
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* ---------- 章节通用 ---------- */

.page-about .chapter {
  padding: var(--about-pad-y) 0;
  border-bottom: 1px solid var(--line);
}

.page-about .chapter:last-of-type {
  border-bottom: 0;
}

.page-about .chapter__eyebrow {
  color: var(--lake-lift);
}

.page-about .chapter__title {
  margin: 14px 0 0;
  max-width: 22ch;
  font-size: clamp(23px, 2.9vw, 38px);
  line-height: 1.18;
  letter-spacing: -0.01em;
  font-weight: 780;
  color: var(--snow);
}

.page-about .chapter__body {
  margin-top: 20px;
  display: grid;
  gap: 16px;
}

.page-about .chapter__body p {
  margin: 0;
  max-width: 38em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text);
}

/* ---------- 时间分段控件 ---------- */

.page-about .seg {
  margin-top: 30px;
}

.page-about .seg__list {
  display: flex;
  flex-wrap: wrap;
  border: 1px solid var(--line-strong);
}

.page-about .seg__btn {
  flex: 1 1 130px;
  min-width: 0;
  margin: 0;
  padding: 14px 12px;
  appearance: none;
  background: transparent;
  border: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  line-height: 1.3;
  cursor: pointer;
  transition: background var(--t) var(--ease), color var(--t) var(--ease);
}

.page-about .seg__btn:hover {
  background: var(--rock);
  color: var(--snow);
}

.page-about .seg__btn[aria-selected="true"] {
  background: var(--lake);
  border-bottom-color: var(--lake);
  color: var(--snow);
}

.page-about .seg__btn:focus-visible {
  outline: 2px solid var(--lake-lift);
  outline-offset: -2px;
}

.page-about .panel {
  padding: 22px var(--about-pad-x);
  border: 1px solid var(--line-strong);
  border-top: 0;
  background: rgba(26, 35, 44, 0.55);
}

.page-about .panel + .panel {
  border-top: 0;
}

.page-about .panel__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.page-about .panel__mark {
  flex: 0 0 auto;
  width: 10px;
  height: 10px;
  background: var(--lake);
  transform: rotate(45deg);
}

.page-about .panel__era {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--snow);
}

.page-about .panel__body {
  margin-top: 14px;
}

.page-about .panel__body p {
  margin: 0;
  max-width: 38em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

/* ---------- 团队 ---------- */

.page-about .team-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  margin-top: 30px;
}

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

.page-about .about-figure__frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line-strong);
  background: var(--rock);
}

.page-about .about-figure__frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .about-figure--portrait .about-figure__frame {
  aspect-ratio: 3 / 4;
}

.page-about .about-figure--wide .about-figure__frame {
  aspect-ratio: 16 / 9;
}

.page-about .about-figure__cap {
  display: block;
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text-dim);
}

.page-about .team-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .team-list__item {
  padding: 20px 12px 20px 0;
  border-bottom: 1px solid var(--line);
  transition: background var(--t) var(--ease), padding-left var(--t) var(--ease);
}

.page-about .team-list__item:hover {
  background: rgba(28, 111, 180, 0.1);
  padding-left: 10px;
}

.page-about .team-list__top {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
}

.page-about .team-list__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--lake-lift);
}

.page-about .team-list__name {
  margin: 0;
  font-size: 18px;
  font-weight: 680;
  color: var(--snow);
}

.page-about .team-list__count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--score);
  white-space: nowrap;
}

.page-about .team-list__desc {
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text);
}

.page-about .team-list__meta {
  margin: 10px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--line-strong);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  line-height: 1.7;
  color: var(--text-dim);
}

/* ---------- 流程 ---------- */

.page-about .flow-list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .flow-list__item {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 14px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .flow-list__num {
  padding-top: 5px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .flow-list__title {
  margin: 0;
  font-size: 17px;
  font-weight: 660;
  color: var(--snow);
}

.page-about .flow-list__text {
  margin: 7px 0 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.82;
  color: var(--text);
}

/* ---------- 青海（明暗反转） ---------- */

.page-about .chapter--snow {
  background: var(--snow);
  border-bottom-color: transparent;
  padding-left: var(--about-pad-x);
  padding-right: var(--about-pad-x);
}

.page-about .chapter--snow .chapter__eyebrow {
  color: var(--moss);
}

.page-about .chapter--snow .chapter__title {
  color: var(--ink);
}

.page-about .chapter--snow .chapter__body p {
  color: #2a3238;
  line-height: 1.95;
  font-size: 16.5px;
}

.page-about .chapter--snow .about-figure__frame {
  border-color: rgba(20, 24, 28, 0.2);
  margin-top: 30px;
}

.page-about .chapter--snow .about-figure__cap {
  color: rgba(20, 24, 28, 0.62);
}

.page-about .alt-bars {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin-top: 26px;
}

.page-about .alt-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  background: var(--night);
  color: var(--snow);
  clip-path: polygon(0 0, 100% 0, calc(100% - 18px) 100%, 0 100%);
}

.page-about .alt-bar__key {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--lake-lift);
}

.page-about .alt-bar__val {
  font-size: 14px;
  line-height: 1.55;
}

/* ---------- 里程碑 ---------- */

.page-about .chapter--moss {
  background: var(--moss);
  border-bottom-color: transparent;
  padding-left: var(--about-pad-x);
  padding-right: var(--about-pad-x);
  color: var(--snow);
}

.page-about .chapter--moss .chapter__eyebrow {
  color: rgba(244, 241, 232, 0.72);
}

.page-about .chapter--moss .chapter__title {
  color: var(--snow);
}

.page-about .chapter--moss .chapter__body p {
  color: rgba(244, 241, 232, 0.92);
}

.page-about .mile-list {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border-top: 1px solid rgba(244, 241, 232, 0.26);
}

.page-about .mile-list__item {
  padding: 18px 0;
  border-bottom: 1px solid rgba(244, 241, 232, 0.26);
}

.page-about .mile-list__key {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: rgba(244, 241, 232, 0.7);
}

.page-about .mile-list__text {
  margin: 9px 0 0;
  max-width: 32em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--snow);
}

.page-about .stat-strip {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 30px;
  background: rgba(244, 241, 232, 0.24);
  border: 1px solid rgba(244, 241, 232, 0.24);
}

.page-about .stat-strip .stat {
  background: var(--moss);
  padding: 18px 16px;
  min-width: 0;
}

.page-about .stat-strip .stat__value {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.4vw, 40px);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--snow);
}

.page-about .stat-strip .stat__label {
  display: block;
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(244, 241, 232, 0.82);
}

/* ---------- 结尾 ---------- */

.page-about .about-cta {
  padding: var(--about-pad-y) 0 0;
}

.page-about .about-cta__title {
  margin: 0;
  font-size: clamp(22px, 2.6vw, 32px);
  line-height: 1.2;
  font-weight: 780;
  color: var(--snow);
}

.page-about .about-cta__text {
  margin: 16px 0 0;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

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

/* ---------- 响应式 ---------- */

@media (max-width: 1039px) {
  .page-about .about-index__list {
    display: flex;
    overflow-x: auto;
    border-bottom: 1px solid var(--line-strong);
    scrollbar-width: none;
    -webkit-overflow-scrolling: touch;
  }

  .page-about .about-index__list::-webkit-scrollbar {
    display: none;
  }

  .page-about .about-index__item {
    flex: 0 0 auto;
    border-bottom: 0;
    border-right: 1px solid var(--line);
  }

  .page-about .about-index__item:last-child {
    border-right: 0;
  }

  .page-about .about-index__link {
    grid-template-columns: 22px auto;
    border-left: 0;
    border-bottom: 2px solid transparent;
    padding: 12px 16px;
    white-space: nowrap;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    border-left-color: transparent;
    border-bottom-color: var(--lake-lift);
  }

  .page-about .about-index__item.is-active .about-index__link {
    border-left-color: transparent;
    border-bottom-color: var(--score);
  }
}

@media (max-width: 560px) {
  .page-about .about-hero__facts {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .about-fact {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

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

  .page-about .team-list__count {
    margin-left: 0;
  }
}

@media (min-width: 661px) {
  .page-about .alt-bars {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .stat-strip {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 761px) {
  .page-about .team-layout {
    grid-template-columns: minmax(0, 5fr) minmax(0, 9fr);
    gap: 36px;
  }

  .page-about .mile-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .mile-list__item:nth-child(odd) {
    padding-right: 26px;
    border-right: 1px solid rgba(244, 241, 232, 0.26);
  }

  .page-about .mile-list__item:nth-child(even) {
    padding-left: 26px;
  }
}

@media (min-width: 1040px) {
  .page-about .about-layout {
    grid-template-columns: minmax(0, 5fr) minmax(0, 15fr);
    gap: 56px;
  }

  .page-about .about-index {
    position: sticky;
    top: 96px;
    align-self: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__link,
  .page-about .seg__btn,
  .page-about .team-list__item,
  .page-about .about-index__num {
    transition: none;
  }
}