.page-about {
  --about-rail: 128px;
  --about-gap: clamp(18px, 3.4vw, 40px);
  --about-text: #b9c9d7;
  --about-text-dim: #8ca0b8;
  display: block;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(64px, 11vw, 148px) clamp(36px, 5vw, 64px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -30% -10% auto -10%;
  height: 150%;
  background:
    radial-gradient(52% 46% at 14% 6%, rgba(56, 232, 255, 0.16), transparent 70%),
    radial-gradient(46% 44% at 88% 20%, rgba(138, 107, 255, 0.18), transparent 72%),
    linear-gradient(180deg, rgba(6, 43, 51, 0.9), rgba(6, 11, 24, 0) 62%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(90deg, rgba(30, 42, 69, 0.55) 0 1px, transparent 1px 120px);
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.7), transparent 72%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.7), transparent 72%);
  pointer-events: none;
  z-index: 0;
}

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

.page-about .about-hero__eyebrow {
  margin-top: clamp(24px, 4vw, 48px);
  color: var(--cyan-400);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
  margin-top: clamp(18px, 2.6vw, 30px);
}

.page-about .about-hero__title {
  margin: 0;
  font-weight: 300;
  font-size: clamp(36px, 8.2vw, 104px);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--mist-050);
  max-width: 13em;
}

.page-about .about-hero__intro p {
  margin: 0 0 1.1em;
}

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

.page-about .about-hero__sub {
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text-dim);
}

.page-about .about-index {
  list-style: none;
  margin: clamp(36px, 6vw, 76px) 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line-700);
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
}

.page-about .about-index a {
  color: var(--slate-400);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-index a:hover,
.page-about .about-index a:focus-visible {
  color: var(--cyan-400);
  border-bottom-color: var(--cyan-400);
}

/* ---------- 通用区块骨架 ---------- */
.page-about .about-section {
  padding-block: clamp(48px, 8vw, 108px);
}

.page-about .about-section__inner {
  display: grid;
  gap: clamp(12px, 2vw, 22px);
}

.page-about .about-rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
}

.page-about .about-rail__num {
  color: var(--cyan-400);
}

.page-about .about-rail__label {
  color: var(--slate-400);
}

.page-about .about-title {
  margin: 0 0 clamp(18px, 2.6vw, 28px);
  font-weight: 300;
  font-size: clamp(27px, 4.6vw, 46px);
  line-height: 1.18;
  letter-spacing: -0.01em;
  color: var(--mist-050);
}

.page-about .about-body {
  max-width: 680px;
}

.page-about .about-body > p {
  margin: 0 0 1.35em;
  font-size: 17px;
  line-height: 1.85;
  color: var(--about-text);
}

.page-about .about-inline-link {
  color: var(--cyan-400);
  text-decoration: none;
  border-bottom: 1px solid rgba(56, 232, 255, 0.4);
  transition: border-color 0.25s var(--ease), color 0.25s var(--ease);
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  color: var(--mist-050);
  border-bottom-color: var(--mist-050);
}

.page-about .about-note {
  position: relative;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 4px 0 4px 26px;
  border-left: 1px solid var(--line-700);
}

.page-about .about-note__mark {
  position: absolute;
  left: -4px;
  top: 12px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--violet-500);
}

.page-about .about-note p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--slate-400);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  position: relative;
  padding-block: clamp(52px, 9vw, 124px);
  background:
    radial-gradient(64% 46% at 82% 0%, rgba(138, 107, 255, 0.15), transparent 68%),
    linear-gradient(180deg, rgba(11, 18, 38, 0.95), rgba(6, 11, 24, 0));
}

.page-about .about-timeline__head {
  max-width: 720px;
}

.page-about .about-timeline__head .about-rail {
  margin-bottom: clamp(14px, 2vw, 22px);
}

.page-about .about-timeline__head .about-title {
  margin-bottom: 14px;
}

.page-about .about-timeline__lede {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text-dim);
  max-width: 34em;
}

.page-about .about-banner {
  margin: clamp(30px, 5vw, 56px) 0 clamp(36px, 5vw, 68px);
}

.page-about .about-banner img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: clamp(160px, 26vw, 320px);
  object-fit: cover;
  border-radius: 6px;
  border: 1px solid var(--line-700);
  opacity: 0.82;
}

.page-about .about-banner figcaption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--slate-400);
}

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

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 24px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan-700), rgba(30, 42, 69, 0.5) 62%, transparent);
}

.page-about .tl__item {
  position: relative;
  padding: 0 0 clamp(30px, 4.6vw, 52px) 34px;
}

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

.page-about .tl__item::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 6px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  border: 1px solid var(--cyan-700);
  background: var(--ink-900);
  transition: border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.page-about .tl__item:nth-child(3n + 2)::before {
  border-color: rgba(138, 107, 255, 0.8);
}

.page-about .tl__item:hover::before,
.page-about .tl__item:focus-within::before {
  border-color: var(--cyan-400);
  box-shadow: 0 0 0 4px rgba(56, 232, 255, 0.12);
}

.page-about .tl__mark {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--cyan-400);
  margin-bottom: 8px;
}

.page-about .tl__item:nth-child(3n + 2) .tl__mark {
  color: var(--violet-500);
}

.page-about .tl__title {
  margin: 0 0 10px;
  font-weight: 400;
  font-size: clamp(19px, 2.4vw, 25px);
  line-height: 1.35;
  color: var(--mist-050);
}

.page-about .tl__text {
  margin: 0;
  max-width: 620px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text);
}

/* ---------- 分工 ---------- */
.page-about .about-roles {
  margin: clamp(26px, 4vw, 44px) 0 0;
  border-top: 1px solid var(--line-700);
}

.page-about .about-roles__row {
  display: grid;
  gap: 8px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line-700);
  transition: background-color 0.3s var(--ease);
}

.page-about .about-roles__row:hover {
  background: linear-gradient(90deg, rgba(56, 232, 255, 0.05), rgba(56, 232, 255, 0) 70%);
}

.page-about .about-roles dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.15em;
  color: var(--cyan-400);
}

.page-about .about-roles dd {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--about-text);
}

.page-about .about-figure {
  margin: clamp(26px, 4vw, 44px) 0 0;
}

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

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: 6px;
  border: 1px solid var(--line-700);
}

.page-about .about-figure figcaption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--slate-400);
}

/* ---------- 互校 ---------- */
.page-about .about-section--cross {
  position: relative;
  background: linear-gradient(180deg, rgba(6, 43, 51, 0.42), rgba(6, 11, 24, 0));
}

.page-about .about-split {
  display: grid;
  gap: clamp(20px, 4vw, 38px);
  margin-bottom: 1.4em;
}

.page-about .about-split__text p {
  margin: 0 0 1.2em;
  font-size: 17px;
  line-height: 1.85;
  color: var(--about-text);
}

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

/* ---------- 整理规矩 ---------- */
.page-about .rules {
  list-style: none;
  margin: clamp(26px, 4vw, 46px) 0 0;
  padding: 0;
  border-top: 1px solid var(--line-700);
}

.page-about .rules__item {
  display: grid;
  gap: 10px;
  padding: clamp(20px, 3vw, 32px) 0;
  border-bottom: 1px solid var(--line-700);
  transition: background-color 0.3s var(--ease);
}

.page-about .rules__item:hover {
  background: linear-gradient(90deg, rgba(245, 196, 107, 0.06), rgba(245, 196, 107, 0) 68%);
}

.page-about .rules__num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--gold-400);
}

.page-about .rules__title {
  margin: 0 0 8px;
  font-weight: 400;
  font-size: clamp(18px, 2.2vw, 23px);
  line-height: 1.35;
  color: var(--mist-050);
}

.page-about .rules__text {
  margin: 0;
  max-width: 640px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text);
}

/* ---------- 收尾 ---------- */
.page-about .about-reach {
  padding-block: clamp(20px, 4vw, 48px) clamp(64px, 10vw, 132px);
}

.page-about .about-reach__panel {
  position: relative;
  overflow: hidden;
  padding: clamp(30px, 5.5vw, 68px) clamp(22px, 4.5vw, 60px);
  border: 1px solid var(--line-700);
  border-radius: 8px;
  background:
    radial-gradient(76% 118% at 100% 0%, rgba(56, 232, 255, 0.15), transparent 62%),
    radial-gradient(58% 96% at 0% 100%, rgba(138, 107, 255, 0.17), transparent 66%),
    linear-gradient(180deg, rgba(11, 18, 38, 0.92), rgba(6, 43, 51, 0.6));
}

.page-about .about-rail--light {
  margin-bottom: clamp(12px, 2vw, 20px);
}

.page-about .about-title--reach {
  max-width: 18em;
}

.page-about .about-reach__lede {
  margin: 0 0 clamp(22px, 3vw, 34px);
  max-width: 40em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--about-text);
}

.page-about .about-links {
  list-style: none;
  margin: 0 0 clamp(26px, 3.6vw, 38px);
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
}

.page-about .about-links a {
  color: var(--cyan-400);
  text-decoration: none;
  border-bottom: 1px solid rgba(56, 232, 255, 0.34);
  padding-bottom: 2px;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-links a:hover,
.page-about .about-links a:focus-visible {
  color: var(--mist-050);
  border-bottom-color: var(--mist-050);
}

.page-about .about-reach__cta {
  display: inline-block;
}

/* ---------- 响应式 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    column-gap: clamp(32px, 5vw, 80px);
    align-items: end;
  }

  .page-about .about-section__inner {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    column-gap: clamp(28px, 5vw, 72px);
  }

  .page-about .about-rail {
    flex-direction: column;
    gap: 10px;
    align-self: start;
    position: sticky;
    top: 108px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    column-gap: clamp(28px, 4.5vw, 56px);
    align-items: start;
  }

  .page-about .about-roles__row {
    grid-template-columns: 168px minmax(0, 1fr);
    column-gap: clamp(20px, 3vw, 36px);
    align-items: baseline;
  }

  .page-about .rules__item {
    grid-template-columns: 68px minmax(0, 1fr);
    column-gap: clamp(18px, 3vw, 34px);
    align-items: baseline;
  }
}

@media (min-width: 820px) {
  .page-about .tl::before {
    left: 92px;
  }

  .page-about .tl__item {
    display: grid;
    grid-template-columns: 84px minmax(0, 1fr);
    column-gap: clamp(22px, 4vw, 44px);
    padding-left: 0;
    padding-bottom: clamp(34px, 4.6vw, 58px);
  }

  .page-about .tl__item::before {
    left: 86px;
  }

  .page-about .tl__mark {
    padding-top: 6px;
  }
}

@media (min-width: 640px) {
  .page-about .about-body > p,
  .page-about .about-split__text p {
    font-size: 17px;
  }
}

@media (max-width: 639px) {
  .page-about .about-hero__title {
    letter-spacing: -0.01em;
  }

  .page-about .about-banner figcaption,
  .page-about .about-figure figcaption {
    font-size: 12px;
  }

  .page-about .about-links {
    flex-direction: column;
    gap: 12px;
  }
}