.page-about {
  --about-rule: rgba(42, 51, 49, .14);
  --about-measure: 66ch;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-top: clamp(26px, 4.6vw, 52px);
  padding-bottom: clamp(44px, 8vw, 92px);
}

.page-about .about-hero .crumbs {
  margin: 0 0 clamp(30px, 5vw, 58px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--silver-dim);
}

.page-about .about-hero .crumbs a {
  color: var(--silver-dim);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.page-about .about-hero .crumbs a:hover,
.page-about .about-hero .crumbs a:focus-visible {
  color: var(--cyan);
}

.page-about .about-hero .crumbs__sep {
  margin-inline: 8px;
  color: var(--silver-dim);
  opacity: .5;
}

.page-about .about-hero__kicker {
  margin: 0 0 clamp(16px, 2.4vw, 26px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .about-hero__title {
  margin: 0 0 clamp(20px, 3vw, 34px);
  max-width: 18ch;
  font-family: var(--font-title);
  font-weight: 900;
  font-size: clamp(34px, 6.4vw, 78px);
  line-height: 1.05;
  letter-spacing: -.02em;
  color: var(--mist);
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 52ch;
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 1.78;
  color: var(--silver);
}

/* ---------- 正文骨架 ---------- */

.page-about .about-body {
  padding-top: clamp(48px, 8vw, 96px);
  padding-bottom: clamp(56px, 9vw, 112px);
}

.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(32px, 6vw, 60px);
}

.page-about .about-rail-wrap {
  display: none;
}

@media (min-width: 960px) {
  .page-about .about-layout {
    grid-template-columns: 168px minmax(0, 1fr);
    gap: clamp(36px, 5vw, 76px);
    align-items: start;
  }

  .page-about .about-rail-wrap {
    display: block;
    position: sticky;
    top: 108px;
  }
}

.page-about .about-main {
  min-width: 0;
}

/* ---------- 左侧年份刻度 ---------- */

.page-about .about-rail {
  position: relative;
  display: grid;
  gap: 2px;
  padding-left: 16px;
  border-left: 1px solid var(--about-rule);
}

.page-about .about-rail::after {
  content: "";
  position: absolute;
  left: -1px;
  top: 4px;
  bottom: 4px;
  width: 8px;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    to bottom,
    var(--about-rule) 0 1px,
    transparent 1px 13px
  );
}

.page-about .about-rail .rail__item {
  position: relative;
  display: grid;
  grid-template-columns: 24px minmax(0, 1fr);
  gap: 8px;
  align-items: baseline;
  padding: 9px 0;
  font-size: 13px;
  line-height: 1.5;
  color: var(--silver-dim);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.page-about .about-rail .rail__item::before {
  content: "";
  position: absolute;
  left: -16px;
  top: 50%;
  width: 3px;
  height: 5px;
  margin-top: -2.5px;
  background: var(--silver);
  transition:
    height var(--dur) var(--ease),
    margin-top var(--dur) var(--ease),
    background-color var(--dur) var(--ease);
}

.page-about .about-rail .rail__item:hover,
.page-about .about-rail .rail__item:focus-visible {
  color: var(--ink-deep);
}

.page-about .about-rail .rail__item.is-active {
  color: var(--ink-deep);
}

.page-about .about-rail .rail__item.is-active::before {
  height: 20px;
  margin-top: -10px;
  background: var(--ink-mid);
}

.page-about .about-rail__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--silver-dim);
  transition: color var(--dur) var(--ease);
}

.page-about .about-rail .rail__item.is-active .about-rail__no {
  color: var(--amber-deep);
}

.page-about .about-rail__label {
  font-family: var(--font-body);
}

/* ---------- 章节通用 ---------- */

.page-about .about-sec {
  padding-top: clamp(40px, 6vw, 68px);
  scroll-margin-top: 96px;
}

.page-about .about-main > .about-sec:first-child {
  padding-top: 0;
}

.page-about .about-sec + .about-sec {
  margin-top: clamp(40px, 6vw, 68px);
  border-top: 1px solid var(--about-rule);
}

.page-about .about-sec .section-head {
  margin: 0 0 clamp(20px, 3vw, 32px);
}

.page-about .about-sec__no {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--amber-deep);
}

.page-about .about-sec .section-head__title {
  margin: 0 0 8px;
  font-family: var(--font-title);
  font-weight: 900;
  font-size: clamp(22px, 3vw, 34px);
  line-height: 1.24;
  letter-spacing: -.01em;
  color: var(--ink-deep);
}

.page-about .about-sec .section-head__note {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: .04em;
  color: var(--silver-dim);
}

.page-about .about-sec__body p {
  max-width: var(--about-measure);
  margin: 0 0 1.05em;
  font-size: 17px;
  line-height: 1.78;
  color: var(--graphite);
}

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

/* ---------- 02 内容从哪来 ---------- */

.page-about .about-flow {
  display: grid;
  gap: clamp(28px, 4vw, 44px);
  align-items: start;
}

@media (min-width: 1040px) {
  .page-about .about-flow {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 52px);
  }
}

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

.page-about .about-step {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: clamp(12px, 2vw, 22px);
  padding: clamp(16px, 2.4vw, 24px) 0;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-step__idx {
  padding-top: 4px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--ink-mid);
}

.page-about .about-step__title {
  margin: 0 0 6px;
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.4;
  color: var(--ink-deep);
}

.page-about .about-step p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

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

.page-about .about-flow__fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  filter: saturate(.55) contrast(1.03);
}

/* ---------- 03 发展历程 ---------- */

.page-about .about-era {
  display: grid;
  gap: clamp(28px, 4vw, 48px);
  align-items: start;
}

@media (min-width: 1040px) {
  .page-about .about-era {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
  }
}

.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 20px;
  bottom: 20px;
  width: 1px;
  background: var(--about-rule);
}

.page-about .about-timeline__item {
  position: relative;
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: clamp(12px, 2vw, 20px);
  padding-block: clamp(12px, 1.8vw, 18px);
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 26px;
  width: 7px;
  height: 7px;
  background: var(--ink-mid);
  transform: translateX(-3px);
  transition: background-color var(--dur) var(--ease);
}

.page-about .about-timeline__item:hover::before {
  background: var(--amber-deep);
}

.page-about .about-timeline__year {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.5;
  letter-spacing: .04em;
  color: var(--ink-deep);
}

.page-about .about-timeline__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

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

.page-about .about-era__fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 5 / 7;
  object-fit: cover;
  filter: saturate(.5) contrast(1.04);
}

/* ---------- 04 团队与分工 ---------- */

.page-about .about-roles {
  list-style: none;
  margin: clamp(20px, 3vw, 32px) 0 0;
  padding: 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-role {
  display: grid;
  grid-template-columns: clamp(58px, 8vw, 86px) minmax(0, 1fr);
  gap: clamp(14px, 2.4vw, 28px);
  padding: clamp(18px, 2.6vw, 26px) 0;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-role__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--ink-deep);
}

.page-about .about-role__num small {
  display: block;
  margin-top: 8px;
  font-family: var(--font-body);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: .1em;
  line-height: 1.4;
  color: var(--silver-dim);
}

.page-about .about-role__title {
  margin: 0 0 6px;
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.4;
  color: var(--ink-deep);
}

.page-about .about-role p {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

.page-about .about-team__fig {
  margin: clamp(24px, 4vw, 38px) 0 0;
}

.page-about .about-team__fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  filter: saturate(.5) contrast(1.03);
}

/* ---------- 05 覆盖范围与内容规模 ---------- */

.page-about .about-scope {
  list-style: none;
  margin: clamp(20px, 3vw, 32px) 0 0;
  padding: 0;
  max-width: 660px;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-scope__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 16px;
  padding: clamp(12px, 1.8vw, 18px) 0;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-scope__label {
  font-size: 15px;
  line-height: 1.62;
  color: var(--graphite);
}

.page-about .about-scope__val {
  font-family: var(--font-mono);
  font-size: clamp(18px, 2.2vw, 24px);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--ink-deep);
  white-space: nowrap;
}

.page-about .about-scope__val span {
  margin-left: 5px;
  font-size: .58em;
  font-weight: 400;
  letter-spacing: .04em;
  color: var(--silver-dim);
}

/* ---------- 06 资质与认可 ---------- */

.page-about .about-credit-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-credit-item {
  display: grid;
  grid-template-columns: 20px minmax(0, 1fr);
  gap: 14px;
  padding: clamp(14px, 2vw, 20px) 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-credit-item:last-child {
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-credit-item::before {
  content: "";
  display: block;
  width: 8px;
  height: 8px;
  margin-top: 9px;
  background: var(--amber);
  clip-path: polygon(0 0, 100% 0, 100% 72%, 72% 100%, 0 100%);
}

.page-about .about-credit__title {
  margin: 0 0 5px;
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 16px;
  line-height: 1.45;
  color: var(--ink-deep);
}

.page-about .about-credit-item p {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

/* ---------- 页尾联系 ---------- */

.page-about .about-contact {
  margin-top: clamp(44px, 6.5vw, 76px);
  padding-top: clamp(28px, 4vw, 44px);
  border-top: 2px solid var(--ink-deep);
  scroll-margin-top: 96px;
}

.page-about .about-contact__title {
  margin: 0 0 12px;
  font-family: var(--font-title);
  font-weight: 900;
  font-size: clamp(20px, 2.6vw, 28px);
  line-height: 1.28;
  letter-spacing: -.01em;
  color: var(--ink-deep);
}

.page-about .about-contact__lead {
  margin: 0 0 clamp(20px, 3vw, 30px);
  max-width: 54ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

.page-about .about-contact__list {
  margin: 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-contact__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: clamp(12px, 1.8vw, 16px) 0;
  border-bottom: 1px solid var(--about-rule);
}

@media (min-width: 720px) {
  .page-about .about-contact__item {
    grid-template-columns: 110px minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }
}

.page-about .about-contact__item dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--silver-dim);
}

.page-about .about-contact__item dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink-deep);
  word-break: break-word;
}

.page-about .about-contact__note {
  margin: 14px 0 0;
  max-width: 58ch;
  font-size: 13px;
  line-height: 1.72;
  color: var(--silver-dim);
}

.page-about .about-contact__more {
  margin: clamp(20px, 3vw, 28px) 0 0;
}

/* ---------- 动效降级 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail .rail__item::before,
  .page-about .about-timeline__item::before,
  .page-about .about-hero .crumbs a {
    transition: none;
  }
}