.page-about {
  --about-side: 236px;
  --about-fade: rgba(143, 163, 184, 0.1);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding-block: clamp(40px, 6vw, 84px) clamp(40px, 5vw, 72px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 100% at 8% 0%, rgba(15, 163, 107, 0.16) 0%, rgba(15, 163, 107, 0) 55%),
    var(--ink);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0 0 0 auto;
  width: 34%;
  background: linear-gradient(155deg, rgba(255, 106, 26, 0.14), rgba(255, 106, 26, 0) 62%);
  clip-path: polygon(30% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-about .about-hero .breadcrumb {
  position: relative;
  z-index: 1;
  margin: 0 0 clamp(22px, 3vw, 36px);
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(30px, 4vw, 48px);
  align-items: end;
}

.page-about .about-hero__intro .eyebrow {
  margin: 0 0 14px;
}

.page-about .about-hero__intro h1 {
  margin: 0 0 clamp(16px, 2vw, 24px);
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(2.3rem, 6.6vw, 4.6rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 34em;
  font-size: clamp(15.5px, 1.6vw, 17px);
  line-height: 1.78;
  color: var(--paper);
  opacity: 0.86;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 32px);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 0;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
  background: rgba(6, 10, 18, 0.5);
}

.page-about .about-fact {
  padding: 16px 18px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-fact dt {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--mist);
  margin-bottom: 8px;
}

.page-about .about-fact dd {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-fact dd .mono {
  font-family: var(--font-mono);
  font-size: 22px;
  color: var(--pitch);
  margin-right: 4px;
}

/* ---------- 主体双栏 + 粘性目录 ---------- */

.page-about [data-section] {
  scroll-margin-top: 132px;
}

.page-about .about-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 56px);
  padding-block: clamp(44px, 6vw, 84px) clamp(64px, 8vw, 120px);
}

.page-about .about-toc {
  border-top: 2px solid var(--signal);
  padding-top: 14px;
}

.page-about .about-toc__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 20px;
}

.page-about .about-toc__list li {
  min-width: 0;
}

.page-about .about-toc__list a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 0;
  font-size: 14px;
  color: var(--mist);
  text-decoration: none;
  transition: color 0.24s var(--ease);
}

.page-about .about-toc__list a .mono {
  display: inline-block;
  width: 24px;
  height: 22px;
  line-height: 22px;
  text-align: center;
  font-size: 11px;
  letter-spacing: 0.04em;
  background: var(--ink-soft);
  color: var(--mist);
  transition: background 0.24s var(--ease), color 0.24s var(--ease);
}

.page-about .about-toc__list a:hover,
.page-about .about-toc__list a.is-active {
  color: var(--paper);
}

.page-about .about-toc__list a:hover .mono,
.page-about .about-toc__list a.is-active .mono {
  background: var(--signal);
  color: var(--ink-deep);
}

/* ---------- 章节骨架 ---------- */

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

.page-about .about-section {
  padding-block: clamp(38px, 5vw, 60px);
  border-top: 1px solid var(--line);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-section__head {
  display: flex;
  align-items: baseline;
  gap: clamp(14px, 2vw, 22px);
  padding-bottom: 16px;
  margin-bottom: clamp(20px, 3vw, 30px);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-section__num {
  flex: none;
  font-size: clamp(26px, 4vw, 40px);
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--signal);
}

.page-about .about-section__title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(1.4rem, 3vw, 2rem);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-prose p {
  margin: 0 0 1.05em;
  color: var(--paper);
  opacity: 0.88;
}

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

.page-about .about-prose strong {
  color: var(--signal);
  font-weight: 700;
  opacity: 1;
}

/* ---------- 团队与角色 ---------- */

.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3vw, 40px);
}

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

.page-about .about-roles {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  margin-top: clamp(22px, 3vw, 32px);
}

.page-about .about-role {
  border-left: 3px solid var(--pitch);
  padding: 2px 0 2px 16px;
}

.page-about .about-role h3 {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-role p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-split__media {
  margin: 0;
  min-width: 0;
}

.page-about .about-split__media .media__tag {
  margin-top: 10px;
}

/* ---------- 核对步骤 ---------- */

.page-about .about-steps {
  list-style: none;
  margin: clamp(22px, 3vw, 30px) 0 0;
  padding: 0;
}

.page-about .about-step {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: clamp(14px, 2vw, 26px);
  padding-block: clamp(16px, 2vw, 22px);
  border-top: 1px solid var(--line-soft);
}

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

.page-about .about-step__num {
  font-size: clamp(22px, 3.2vw, 32px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--signal);
}

.page-about .about-step__body h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-step__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-status-wrap {
  margin-top: clamp(22px, 3vw, 30px);
  padding: 18px 20px;
  background: var(--paper);
  border-left: 3px solid var(--signal);
}

.page-about .about-status-wrap__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--steel);
}

.page-about .about-status {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-figure {
  margin: clamp(24px, 3vw, 34px) 0 0;
}

.page-about .about-figure .media__tag {
  margin-top: 10px;
}

/* ---------- 数据来源 ---------- */

.page-about .about-sources {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin-top: clamp(24px, 3vw, 32px);
  border: 1px solid var(--line);
  background: var(--line-soft);
}

.page-about .about-source {
  padding: 20px 20px 22px;
  background: var(--ink);
}

.page-about .about-source__num {
  display: block;
  font-size: clamp(24px, 3.4vw, 34px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--pitch);
}

.page-about .about-source__name {
  margin: 12px 0 6px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1rem;
  color: var(--paper);
}

.page-about .about-source__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 时间线 ---------- */

.page-about .about-figure--wide .media {
  aspect-ratio: 16 / 6;
}

.page-about .about-timeline {
  list-style: none;
  margin: clamp(24px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .about-timeline__item {
  position: relative;
  padding: 18px 0 18px 22px;
  border-left: 1px solid var(--line-strong);
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 26px;
  width: 9px;
  height: 9px;
  background: var(--signal);
  transition: transform 0.24s var(--ease);
}

.page-about .about-timeline__item:last-child {
  border-left-color: transparent;
}

.page-about .about-timeline__year {
  display: block;
  font-size: 18px;
  letter-spacing: 0.02em;
  color: var(--signal);
}

.page-about .about-timeline__title {
  margin: 8px 0 6px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1rem;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-timeline__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-timeline__note {
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--line-soft);
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 规模数据 ---------- */

.page-about .about-metrics {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: clamp(24px, 3vw, 32px) 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--line-soft);
}

.page-about .about-metric {
  padding: 20px 18px;
  background: var(--ink);
}

.page-about .about-metric__num {
  display: block;
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--paper);
}

.page-about .about-metric__label {
  margin: 10px 0 0;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--mist);
}

/* ---------- 收口 ---------- */

.page-about .about-join__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 30px);
}

/* ---------- 720px 起 ---------- */

@media (min-width: 720px) {
  .page-about .about-roles {
    grid-template-columns: 1.1fr 1fr 0.9fr;
    gap: 22px;
  }

  .page-about .about-sources {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .about-timeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(18px, 3vw, 32px);
  }

  .page-about .about-timeline__item:nth-child(odd) {
    border-left-color: var(--line-strong);
  }
}

/* ---------- 1040px 起：双栏 → 三栏工作台 ---------- */

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

  .page-about .about-body {
    grid-template-columns: var(--about-side) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 122px;
    align-self: start;
  }

  .page-about .about-toc__list {
    display: block;
    gap: 0;
  }

  .page-about .about-toc__list a {
    padding: 9px 0 9px 12px;
    border-left: 2px solid transparent;
    transition: color 0.24s var(--ease), border-color 0.24s var(--ease), padding-left 0.24s var(--ease);
  }

  .page-about .about-toc__list a:hover,
  .page-about .about-toc__list a.is-active {
    border-left-color: var(--signal);
    padding-left: 18px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    align-items: start;
  }

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

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

@media (min-width: 880px) {
  .page-about .about-timeline {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    column-gap: 0;
    border-top: 1px solid var(--line-strong);
    padding-top: 0;
  }

  .page-about .about-timeline__item {
    padding: 26px 18px 8px 0;
    border-left: 0;
    border-right: 1px solid var(--line-soft);
  }

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

  .page-about .about-timeline__item::before {
    left: 0;
    top: -5px;
  }
}

@media (min-width: 880px) and (hover: hover) {
  .page-about .about-timeline__desc {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.3s var(--ease), opacity 0.3s var(--ease), margin-top 0.3s var(--ease);
  }

  .page-about .about-timeline__item:hover .about-timeline__desc {
    max-height: 9em;
    opacity: 1;
    margin-top: 6px;
  }

  .page-about .about-timeline__item:hover::before {
    transform: scale(1.5);
  }

  .page-about .about-timeline__item:hover .about-timeline__title {
    color: var(--signal);
  }
}

@media (max-width: 719px) {
  .page-about .about-hero::after {
    width: 52%;
    opacity: 0.7;
  }

  .page-about .about-hero__intro h1 br {
    display: none;
  }

  .page-about .about-status-wrap {
    padding: 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc__list a,
  .page-about .about-timeline__item::before,
  .page-about .about-timeline__desc,
  .page-about .about-timeline__title {
    transition: none;
  }
}