.page-about {
  --about-rail: 220px;
  --about-rail-gap: clamp(26px, 4vw, 62px);
  --about-tilt: -.9deg;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: calc(var(--header-h) + 42px) clamp(44px, 6vw, 74px);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(168deg, var(--blue-900) 0%, var(--blue-900) 52%, var(--blue-800) 100%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(38, 52, 74, .5) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(38, 52, 74, .5) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: linear-gradient(160deg, #000 0%, transparent 74%);
  mask-image: linear-gradient(160deg, #000 0%, transparent 74%);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -8%;
  top: -22%;
  width: 44%;
  height: 140%;
  transform: skewX(-9deg);
  background: linear-gradient(200deg, rgba(45, 226, 230, .18), rgba(45, 226, 230, 0) 64%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(34px, 5vw, 58px);
}

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

.page-about .crumbs {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
  margin-bottom: 24px;
}

.page-about .about-kicker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--cyan-500);
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(34px, 7.4vw, 74px);
  line-height: 1.03;
  letter-spacing: -.018em;
  color: var(--ink);
}

.page-about .about-hero__accent {
  color: var(--cyan-500);
}

.page-about .about-hero__lede {
  max-width: 58ch;
  margin: 20px 0 0;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.9;
  color: var(--ink-dim);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .about-hero__stats {
  display: grid;
  gap: 10px;
  min-width: 0;
}

.page-about .about-hero__stat {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 15px 18px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan-500);
  transform: rotate(var(--tilt, 0deg)) translateX(var(--shift, 0px));
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-hero__stat:nth-child(1) { --tilt: -1.1deg; --shift: -6px; }
.page-about .about-hero__stat:nth-child(2) { --tilt: .8deg; --shift: 10px; border-left-color: var(--orange-500); }
.page-about .about-hero__stat:nth-child(3) { --tilt: -.6deg; --shift: -2px; }

.page-about .about-hero__stat:hover {
  background: var(--blue-800);
  border-color: var(--cyan-300);
}

.page-about .about-hero__stat-num {
  flex: none;
  min-width: 2.6em;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(22px, 3vw, 30px);
  line-height: 1;
  color: var(--cyan-300);
}

.page-about .about-hero__stat-body {
  display: grid;
  gap: 3px;
  min-width: 0;
}

.page-about .about-hero__stat-body strong {
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.45;
}

.page-about .about-hero__stat-body em {
  font-style: normal;
  font-size: 12.5px;
  color: var(--muted);
  line-height: 1.5;
}

/* ---------- 主体双栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: var(--about-rail-gap);
  padding-block: clamp(34px, 5vw, 68px) clamp(52px, 7vw, 100px);
}

.page-about .about-index {
  min-width: 0;
  border-top: 2px solid var(--cyan-500);
  padding-top: 14px;
}

.page-about .about-index__title {
  margin: 0 0 12px;
  font-family: var(--font-serif);
  font-size: 12px;
  letter-spacing: .26em;
  color: var(--muted);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-index__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 11px;
  font-size: 13px;
  line-height: 1.4;
  white-space: nowrap;
  color: var(--ink-dim);
  text-decoration: none;
  border: 1px solid var(--line);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--ink);
  border-color: var(--cyan-500);
  background: rgba(45, 226, 230, .08);
}

.page-about .about-index__no {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--cyan-500);
}

.page-about .about-flow {
  display: grid;
  gap: clamp(34px, 4.5vw, 62px);
  min-width: 0;
}

.page-about .about-chapter {
  min-width: 0;
  scroll-margin-top: calc(var(--header-h) + 20px);
}

.page-about .about-chapter__head { margin-bottom: 20px; }

.page-about .about-chapter h2 {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(25px, 3.6vw, 38px);
  line-height: 1.16;
  letter-spacing: -.01em;
  color: var(--ink);
}

.page-about .about-prose p {
  max-width: 70ch;
  margin: 0 0 14px;
  font-size: clamp(15px, 1.5vw, 16.5px);
  line-height: 1.9;
  color: var(--ink-dim);
}

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

.page-about .about-inline-link {
  color: var(--cyan-300);
  text-decoration: none;
  border-bottom: 1px solid rgba(138, 245, 247, .42);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  color: var(--cyan-500);
  border-bottom-color: var(--cyan-500);
}

.page-about .about-note {
  max-width: 66ch;
  margin: 20px 0 0;
  padding: 4px 0 4px 16px;
  border-left: 2px solid var(--line);
  font-family: var(--font-serif);
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
}

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

.page-about .about-figure--narrow { max-width: 640px; }

/* ---------- 时间轴 ---------- */
.page-about .about-tl {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  position: relative;
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan-500), var(--line) 78%);
}

.page-about .about-tl__item {
  position: relative;
  padding: 0 0 22px 30px;
  outline: none;
}

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

.page-about .about-tl__item::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 6px;
  width: 11px;
  height: 11px;
  background: var(--bg);
  border: 1px solid var(--cyan-500);
  transform: rotate(45deg);
  transition: background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-tl__item:hover::before,
.page-about .about-tl__item:focus-within::before {
  background: var(--cyan-500);
  box-shadow: 0 0 0 4px rgba(45, 226, 230, .16);
}

.page-about .about-tl__item:focus-visible {
  outline: 2px solid var(--cyan-300);
  outline-offset: 4px;
}

.page-about .about-tl__year {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--muted);
  transition: color var(--dur) var(--ease);
}

.page-about .about-tl__item:hover .about-tl__year,
.page-about .about-tl__item:focus-within .about-tl__year {
  color: var(--cyan-500);
}

.page-about .about-tl__title {
  margin: 5px 0 6px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--ink);
}

.page-about .about-tl__text {
  margin: 0;
  max-width: 62ch;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-dim);
}

.page-about .about-tl__more {
  display: grid;
  grid-template-rows: 0fr;
  margin: 0;
  transition: grid-template-rows var(--dur) var(--ease);
}

.page-about .about-tl__more > span {
  display: block;
  overflow: hidden;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-tl__item:hover .about-tl__more,
.page-about .about-tl__item:focus-within .about-tl__more {
  grid-template-rows: 1fr;
}

.page-about .about-tl__item:hover .about-tl__more > span,
.page-about .about-tl__item:focus-within .about-tl__more > span {
  padding-top: 8px;
}

/* ---------- 数据旅程步骤 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-steps__item {
  background: var(--blue-800);
  padding: 18px 18px 20px;
  transition: background var(--dur) var(--ease);
}

.page-about .about-steps__item:hover { background: var(--blue-700); }

.page-about .about-steps__no {
  display: block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: .14em;
  color: var(--cyan-500);
}

.page-about .about-steps__item h3 {
  margin: 8px 0 8px;
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-steps__item p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-dim);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-team__card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 2px solid var(--cyan-500);
  padding: 18px 18px 20px;
  transition: border-top-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-team__card:nth-child(2) { border-top-color: var(--orange-500); }
.page-about .about-team__card:nth-child(4) { border-top-color: var(--orange-500); }

.page-about .about-team__card:hover {
  background: var(--blue-800);
  border-top-color: var(--cyan-300);
}

.page-about .about-team__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--cyan-300);
}

.page-about .about-team__card h3 {
  margin: 10px 0 8px;
  font-family: var(--font-serif);
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-team__card p:last-child {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-dim);
}

/* ---------- 覆盖指标 ---------- */
.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 24px 0;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-facts__cell {
  background: var(--blue-800);
  padding: 16px 14px 18px;
  min-width: 0;
}

.page-about .about-facts__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--cyan-300);
}

.page-about .about-facts__unit {
  font-size: .55em;
  color: var(--orange-500);
  margin-left: 2px;
}

.page-about .about-facts__label {
  display: block;
  margin-top: 9px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

/* ---------- 校验清单 ---------- */
.page-about .about-checks {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-checks li {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-dim);
}

.page-about .about-checks__no {
  flex: none;
  width: 26px;
  height: 26px;
  display: grid;
  place-items: center;
  font-family: var(--font-serif);
  font-size: 13px;
  color: var(--blue-900);
  background: var(--cyan-500);
  transform: rotate(45deg);
}

.page-about .about-checks__no::first-letter { transform: rotate(-45deg); }

.page-about .about-creds {
  margin-top: 28px;
  padding: 20px;
  background: var(--blue-800);
  border: 1px solid var(--line);
  border-left: 3px solid var(--orange-500);
}

.page-about .about-creds__title {
  margin: 0 0 12px;
  font-family: var(--font-serif);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--ink);
}

.page-about .about-creds__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 9px;
}

.page-about .about-creds__list li {
  position: relative;
  padding-left: 20px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--ink-dim);
}

.page-about .about-creds__list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 9px;
  width: 7px;
  height: 7px;
  background: var(--green-500);
}

/* ---------- 生态 ---------- */
.page-about .about-eco {
  display: grid;
  gap: 1px;
  margin-top: 24px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-eco__col {
  background: var(--panel);
  padding: 18px;
}

.page-about .about-eco__label {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--cyan-500);
}

.page-about .about-eco__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-dim);
}

/* ---------- 引文与收束 ---------- */
.page-about .about-quote {
  margin: 24px 0;
  padding: 6px 0 6px 20px;
  border-left: 2px solid var(--orange-500);
  font-family: var(--font-serif);
  font-size: clamp(18px, 2.5vw, 25px);
  line-height: 1.7;
  color: var(--ink);
}

.page-about .about-cta {
  margin-top: 32px;
  padding: clamp(22px, 3.4vw, 36px);
  background: linear-gradient(150deg, var(--blue-800), var(--blue-700));
  border: 1px solid var(--line);
  border-top: 2px solid var(--orange-500);
}

.page-about .about-cta h2 {
  font-size: clamp(22px, 3vw, 31px);
  margin: 9px 0 0;
}

.page-about .about-cta > p:not(.about-kicker) {
  margin: 12px 0 0;
  max-width: 56ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-dim);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

/* ---------- 桌面 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    align-items: end;
  }

  .page-about .about-steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .about-team { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .about-facts { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .page-about .about-eco { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 26px);
    border-top: 1px solid var(--line);
    padding-top: 16px;
  }

  .page-about .about-index__list {
    flex-direction: column;
    overflow: visible;
    gap: 2px;
    padding-bottom: 0;
  }

  .page-about .about-index__link {
    border: 0;
    border-left: 2px solid var(--line);
    padding: 8px 10px;
    white-space: normal;
    font-size: 13.5px;
    line-height: 1.45;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    background: rgba(45, 226, 230, .07);
    border-left-color: var(--cyan-500);
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero__stats { gap: 12px; }
}

/* ---------- 窄屏收敛 ---------- */
@media (max-width: 719px) {
  .page-about .about-hero__stat { --tilt: 0deg; --shift: 0px; }
  .page-about .about-hero::after { width: 62%; right: -18%; opacity: .7; }
  .page-about .about-checks li { font-size: 14px; }
  .page-about .about-facts__label { font-size: 12.5px; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-hero__stat,
  .page-about .about-tl__more,
  .page-about .about-tl__item::before,
  .page-about .about-index__link {
    transition: none;
  }
}