.page-about {
  --about-rail-w: 84px;
  --about-gap: clamp(18px, 2.6vw, 40px);
  --about-panel: rgba(22, 56, 47, .5);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  margin: clamp(18px, 3vw, 34px) 0 clamp(30px, 5vw, 62px);
}

.page-about .about-hero img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--jt-line-hair);
  filter: saturate(.72) brightness(.86);
}

/* ---------- 章节目录 ---------- */
.page-about .about-toc {
  margin: 0 auto clamp(34px, 5.5vw, 70px);
}

.page-about .about-toc .jt-toc__title {
  margin: 0 0 10px;
  font-family: var(--jt-font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--jt-mist);
}

.page-about .about-toc .jt-toc__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--jt-line-hair);
  padding-top: 12px;
}

.page-about .about-toc .jt-toc__link {
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--jt-mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .28s var(--jt-ease), border-color .28s var(--jt-ease);
}

.page-about .about-toc .jt-toc__link:hover,
.page-about .about-toc .jt-toc__link:focus-visible {
  color: var(--jt-accent);
  border-bottom-color: var(--jt-accent);
}

/* ---------- 通用栅格骨架：左轴 + 正文 ---------- */
.page-about .about-section {
  padding-block: clamp(42px, 6.5vw, 92px);
}

.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(16px, 3vw, 34px);
}

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

.page-about .about-body {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
  align-content: start;
  min-width: 0;
}

.page-about .about-rail__tick {
  display: block;
  width: 1px;
  height: 46px;
  background: linear-gradient(180deg, var(--jt-accent), transparent);
}

.page-about .about-rail__line {
  display: block;
  width: 1px;
  flex: 1 1 auto;
  min-height: 90px;
  background: var(--jt-line-hair);
}

@media (min-width: 900px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
  }

  .page-about .about-rail {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
    padding-top: 4px;
  }

  .page-about .about-rail--axis {
    position: sticky;
    top: calc(var(--jt-header-h) + 34px);
    align-self: start;
    height: 230px;
    justify-content: space-between;
  }
}

/* ---------- 01 定位 ---------- */
.page-about .about-copy p {
  margin: 0 0 14px;
}

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

.page-about .about-ledger {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--jt-line-hair);
  border: 1px solid var(--jt-line-hair);
}

.page-about .about-ledger__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 16px;
  background: var(--about-panel);
}

.page-about .about-ledger__value {
  font-family: var(--jt-font-mono);
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 600;
  line-height: 1;
  color: var(--jt-fog);
  font-variant-numeric: tabular-nums;
}

.page-about .about-ledger__item:first-child .about-ledger__value {
  color: var(--jt-accent);
}

.page-about .about-ledger__label {
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--jt-mist);
}

@media (min-width: 720px) {
  .page-about .about-ledger {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 02 三阶段 ---------- */
.page-about .about-stages {
  display: grid;
  gap: clamp(22px, 3.4vw, 42px);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-stage {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  padding-bottom: clamp(22px, 3.4vw, 40px);
  border-bottom: 1px solid var(--jt-line-hair);
}

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

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

.page-about .about-stage__index {
  font-family: var(--jt-font-mono);
  font-size: 14px;
  letter-spacing: .16em;
  color: var(--jt-sand);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stage__dot {
  display: block;
  width: 8px;
  height: 8px;
  border: 1px solid var(--jt-lake);
  border-radius: 50%;
  background: var(--jt-ink);
}

.page-about .about-stage:hover .about-stage__dot {
  background: var(--jt-accent);
  border-color: var(--jt-accent);
}

.page-about .about-stage__ver {
  margin: 0 0 6px;
  font-family: var(--jt-font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--jt-accent);
}

.page-about .about-stage__title {
  margin: 0 0 10px;
  font-size: clamp(19px, 2.4vw, 24px);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: -.01em;
  color: var(--jt-fog);
}

.page-about .about-stage__desc {
  margin: 0 0 16px;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--jt-mist);
}

.page-about .about-stage__facts {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  margin: 0;
  padding: 14px 0 0;
  border-top: 1px dashed var(--jt-line-hair);
}

.page-about .about-stage__fact {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  gap: 12px;
}

.page-about .about-stage__fact dt {
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--jt-mist);
}

.page-about .about-stage__fact dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--jt-fog);
}

@media (min-width: 720px) {
  .page-about .about-stage {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 30px;
  }

  .page-about .about-stage__axis {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    padding-top: 4px;
  }

  .page-about .about-stage__facts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
  }
}

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

.page-about .about-strip img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 5;
  object-fit: cover;
  border: 1px solid var(--jt-line-hair);
  opacity: .78;
}

/* ---------- 03 团队 ---------- */
.page-about .about-team {
  align-items: start;
}

.page-about .about-tree {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-tree__node {
  position: relative;
  padding: 22px 18px 20px;
  border: 1px solid var(--jt-line-hair);
  border-top-color: var(--jt-line-soft);
  background: var(--about-panel);
  box-shadow: var(--jt-shadow);
  outline: none;
  transition: border-color .32s var(--jt-ease), background .32s var(--jt-ease);
}

.page-about .about-tree__node:hover,
.page-about .about-tree__node:focus-visible {
  border-color: var(--jt-lake);
  background: rgba(46, 110, 126, .16);
}

.page-about .about-tree__count {
  display: block;
  font-family: var(--jt-font-mono);
  font-size: 30px;
  font-weight: 600;
  line-height: 1;
  color: var(--jt-accent);
  font-variant-numeric: tabular-nums;
}

.page-about .about-tree__role {
  margin: 12px 0 4px;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--jt-fog);
}

.page-about .about-tree__brief {
  margin: 0;
  font-size: 13px;
  color: var(--jt-sand);
}

.page-about .about-tree__note {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--jt-mist);
  opacity: .6;
  transition: opacity .32s var(--jt-ease), color .32s var(--jt-ease);
}

.page-about .about-tree__node:hover .about-tree__note,
.page-about .about-tree__node:focus-visible .about-tree__note {
  opacity: 1;
  color: var(--jt-fog);
}

@media (min-width: 820px) {
  .page-about .about-tree {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .about-tree__node::before {
    content: "";
    position: absolute;
    top: -16px;
    left: 26px;
    width: 1px;
    height: 16px;
    background: var(--jt-line-hair);
  }
}

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

.page-about .about-desk img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--jt-line-hair);
  filter: saturate(.68) brightness(.84);
}

/* ---------- 04 方法与校对（深色带） ---------- */
.page-about .about-section--band {
  background: var(--jt-moss);
  border-top: 1px solid var(--jt-line-hair);
  border-bottom: 1px solid var(--jt-line-hair);
}

.page-about .about-lead {
  max-width: 62ch;
  color: var(--jt-fog);
}

.page-about .about-methods {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--jt-line-hair);
}

.page-about .about-methods__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px 20px;
  padding: 20px 0 22px;
  border-bottom: 1px solid var(--jt-line-hair);
  transition: background .3s var(--jt-ease);
}

.page-about .about-methods__item:hover {
  background: rgba(76, 147, 168, .1);
}

.page-about .about-methods__index {
  font-family: var(--jt-font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--jt-accent);
  font-variant-numeric: tabular-nums;
}

.page-about .about-methods__title {
  margin: 0;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--jt-fog);
}

.page-about .about-methods__desc {
  margin: 0;
  max-width: 68ch;
  font-size: 14px;
  line-height: 1.78;
  color: var(--jt-mist);
}

@media (min-width: 780px) {
  .page-about .about-methods__item {
    grid-template-columns: 56px minmax(0, 210px) minmax(0, 1fr);
    align-items: baseline;
    padding: 22px 0;
  }
}

/* ---------- 05 合作生态 ---------- */
.page-about .about-eco {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-eco__item {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 22px 20px;
}

.page-about .about-eco__item:nth-child(2) {
  border-top-color: var(--jt-lake);
}

.page-about .about-eco__count {
  font-family: var(--jt-font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--jt-sand);
  font-variant-numeric: tabular-nums;
}

.page-about .about-eco__title {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--jt-fog);
}

.page-about .about-eco__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.76;
  color: var(--jt-mist);
}

@media (min-width: 760px) {
  .page-about .about-eco {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-note {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 12px;
  padding-top: 16px;
  border-top: 1px dashed var(--jt-line-hair);
}

.page-about .about-note p {
  margin: 0;
  max-width: 62ch;
  font-size: 13px;
  line-height: 1.72;
  color: var(--jt-mist);
}

/* ---------- 06 引用与收束 ---------- */
.page-about .about-honor {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--jt-line-hair);
  border: 1px solid var(--jt-line-hair);
}

.page-about .about-honor__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 8px 18px;
  padding: 20px 18px;
  background: var(--about-panel);
}

.page-about .about-honor__label {
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--jt-mist);
}

.page-about .about-honor__value {
  font-family: var(--jt-font-mono);
  font-size: 28px;
  font-weight: 600;
  line-height: 1;
  color: var(--jt-fog);
  font-variant-numeric: tabular-nums;
  justify-self: end;
}

.page-about .about-honor__note {
  grid-column: 1 / -1;
  font-size: 12px;
  line-height: 1.6;
  color: var(--jt-sand);
}

@media (min-width: 760px) {
  .page-about .about-honor {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .about-honor__value {
    justify-self: start;
    margin-top: 4px;
  }
}

.page-about .about-next {
  margin-top: clamp(8px, 2vw, 18px);
  padding: clamp(22px, 3.4vw, 34px) clamp(20px, 3vw, 32px);
  border: 1px solid var(--jt-line-hair);
  border-left: 2px solid var(--jt-accent);
  background: var(--about-panel);
}

.page-about .about-next__title {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--jt-fog);
}

.page-about .about-next__desc {
  margin: 0 0 18px;
  max-width: 62ch;
  font-size: 14px;
  line-height: 1.74;
  color: var(--jt-mist);
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

@media (max-width: 640px) {
  .page-about .about-next__links .jt-btn {
    width: 100%;
    text-align: center;
  }
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-tree__node,
  .page-about .about-tree__note,
  .page-about .about-methods__item,
  .page-about .about-stage__dot,
  .page-about .about-toc .jt-toc__link {
    transition: none;
  }
}