.page-about {
  --about-rail-w: 232px;
  --about-shell-gap: clamp(32px, 5vw, 76px);
  --about-chip: #A9C9BE;
  padding-bottom: clamp(48px, 8vw, 110px);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: flex-end;
  min-height: clamp(380px, 60vw, 640px);
  border-bottom: 2px solid var(--yf-line);
  background: linear-gradient(165deg, var(--yf-deep) 0%, var(--yf-bg) 68%);
}

.page-about .about-hero__img {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  max-width: none;
  object-fit: cover;
  object-position: center 40%;
  opacity: .42;
  filter: saturate(.7) contrast(1.08);
}

.page-about .about-hero__veil {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(5, 19, 15, .4) 0%, rgba(5, 19, 15, .74) 52%, var(--yf-bg) 100%),
    radial-gradient(120% 82% at 12% 100%, rgba(47, 232, 198, .18), transparent 62%),
    radial-gradient(88% 68% at 92% 8%, rgba(255, 78, 43, .14), transparent 66%);
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 2;
  width: 100%;
  max-width: var(--yf-wrap);
  margin: 0 auto;
  padding: clamp(48px, 8vw, 96px) var(--yf-gutter) clamp(30px, 5vw, 62px);
}

.page-about .about-hero .yf-breadcrumb {
  margin-bottom: clamp(18px, 3vw, 34px);
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--yf-cond);
  font-weight: 200;
  font-size: clamp(34px, 7.4vw, 100px);
  line-height: 1.02;
  letter-spacing: -.6px;
  color: var(--yf-ink);
  text-shadow: 0 20px 46px rgba(0, 0, 0, .55);
}

.page-about .about-hero__lead {
  margin: clamp(18px, 2.6vw, 28px) 0 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.8;
  color: var(--about-chip);
}

/* ---------- 外壳：左索引 + 右长卷 ---------- */
.page-about .about-shell {
  max-width: var(--yf-wrap);
  margin: clamp(34px, 6vw, 84px) auto 0;
  padding: 0 var(--yf-gutter);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--about-shell-gap);
}

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

.page-about .about-rail__block + .about-rail__block {
  margin-top: clamp(22px, 3vw, 34px);
  padding-top: clamp(18px, 2.4vw, 26px);
  border-top: 2px solid var(--yf-line);
}

.page-about .about-rail__label {
  margin: 0 0 14px;
  font-family: var(--yf-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--yf-muted);
}

.page-about .about-rail__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px 18px;
}

.page-about .about-rail__stats li {
  padding-left: 12px;
  border-left: 2px solid var(--yf-line);
}

.page-about .about-rail__num {
  display: block;
  font-family: var(--yf-mono);
  font-weight: 700;
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1;
  letter-spacing: -1px;
  color: var(--yf-cyan);
  border-bottom: 1px solid rgba(47, 232, 198, .28);
  padding-bottom: 4px;
  margin-bottom: 6px;
}

.page-about .about-rail__num em {
  font-style: normal;
  color: var(--yf-orange);
}

.page-about .about-rail__cap {
  display: block;
  font-size: 12px;
  line-height: 1.5;
  color: var(--yf-muted);
}

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

.page-about .about-rail__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 0;
  border-bottom: 1px solid var(--yf-line);
  font-size: 14px;
  color: var(--yf-muted);
  text-decoration: none;
  transition: color .24s var(--yf-ease), border-color .24s var(--yf-ease), padding-left .24s var(--yf-ease);
}

.page-about .about-rail__link span {
  font-family: var(--yf-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--yf-line);
  transition: color .24s var(--yf-ease);
}

.page-about .about-rail__link:hover {
  color: var(--yf-ink);
}

.page-about .about-rail__link[aria-current="true"] {
  color: var(--yf-cyan);
  border-bottom-color: var(--yf-cyan);
  padding-left: 6px;
}

.page-about .about-rail__link[aria-current="true"] span {
  color: var(--yf-cyan);
}

/* ---------- 右列长卷 ---------- */
.page-about .about-flow {
  min-width: 0;
}

.page-about .about-chapter {
  margin-bottom: clamp(44px, 7vw, 92px);
}

.page-about .about-chapter:last-of-type {
  margin-bottom: 0;
}

.page-about .about-chapter__head {
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: flex-end;
  min-height: clamp(146px, 17vw, 208px);
  padding: clamp(18px, 2.8vw, 32px);
  border: 2px solid var(--yf-line);
  background: linear-gradient(132deg, rgba(18, 70, 58, .92) 0%, var(--yf-panel) 52%, var(--yf-bg) 100%);
  box-shadow: var(--yf-hard-shadow);
}

.page-about .about-chapter__head--media {
  min-height: clamp(220px, 30vw, 360px);
}

.page-about .about-chapter__head::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: .34;
  background-image:
    linear-gradient(rgba(28, 58, 49, .85) 1px, transparent 1px),
    linear-gradient(90deg, rgba(28, 58, 49, .85) 1px, transparent 1px);
  background-size: 46px 46px;
}

.page-about .about-chapter__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  max-width: none;
  object-fit: cover;
  opacity: .52;
  filter: saturate(.72) contrast(1.06);
}

.page-about .about-chapter__head--media::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(5, 19, 15, .35) 0%, rgba(5, 19, 15, .78) 100%);
}

.page-about .about-chapter__num {
  position: absolute;
  top: clamp(12px, 2vw, 22px);
  right: clamp(16px, 2.4vw, 30px);
  z-index: 2;
  font-family: var(--yf-mono);
  font-weight: 700;
  font-size: clamp(34px, 5.8vw, 72px);
  line-height: 1;
  letter-spacing: -.04em;
  color: rgba(47, 232, 198, .1);
  -webkit-text-stroke: 1.4px rgba(47, 232, 198, .45);
}

.page-about .about-chapter__title {
  position: relative;
  z-index: 2;
  margin: 0;
  max-width: 24ch;
  font-family: var(--yf-cond);
  font-weight: 200;
  font-size: clamp(25px, 4.2vw, 52px);
  line-height: 1.08;
  letter-spacing: -.4px;
  color: var(--yf-ink);
}

.page-about .about-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-top: clamp(20px, 2.6vw, 30px);
}

.page-about .about-cols p {
  margin: 0;
  max-width: 78ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--about-chip);
}

.page-about .about-note {
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  padding: 14px 16px;
  border-left: 3px solid var(--yf-amber);
  background: rgba(11, 31, 25, .7);
  font-size: 14px;
  line-height: 1.72;
  color: var(--yf-muted);
}

/* ---------- 覆盖范围数据条 ---------- */
.page-about .about-meters {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px 28px;
  margin-top: clamp(22px, 3vw, 34px);
}

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

.page-about .about-meter__top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 9px;
}

.page-about .about-meter__k {
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--yf-muted);
}

.page-about .about-meter__v {
  font-family: var(--yf-mono);
  font-weight: 700;
  font-size: clamp(19px, 2vw, 24px);
  line-height: 1;
  color: var(--yf-ink);
}

.page-about .about-meter__v em {
  font-style: normal;
  color: var(--yf-orange);
}

/* ---------- 团队 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-top: clamp(20px, 2.8vw, 32px);
}

.page-about .about-media {
  position: relative;
  margin: 0;
  overflow: hidden;
  border: 2px solid var(--yf-line);
  background: var(--yf-panel);
  box-shadow: var(--yf-hard-shadow);
}

.page-about .about-media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(.8) contrast(1.04);
}

.page-about .about-media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(5, 19, 15, .18) 0%, rgba(5, 19, 15, .62) 100%);
}

.page-about .about-media__cap {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 2;
  padding: 12px 14px;
  font-size: 12px;
  line-height: 1.55;
  letter-spacing: .03em;
  color: var(--yf-cyan-soft);
}

.page-about .about-split__body p {
  margin: 0 0 16px;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--about-chip);
}

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

.page-about .about-crew {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .about-crew__card {
  padding: 20px 18px 24px;
  border: 2px solid var(--yf-line);
  background: var(--yf-panel);
  box-shadow: var(--yf-hard-shadow);
  transition: border-color .26s var(--yf-ease), transform .26s var(--yf-ease), box-shadow .26s var(--yf-ease);
}

.page-about .about-crew__card:hover {
  border-color: var(--yf-cyan);
  transform: translateY(-4px);
  box-shadow: var(--yf-hard-shadow-lg);
}

.page-about .about-crew__tag {
  margin: 0 0 10px;
  font-family: var(--yf-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--yf-cyan);
}

.page-about .about-crew__title {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--yf-ink);
}

.page-about .about-crew__card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--yf-muted);
}

/* ---------- 呼吸带 ---------- */
.page-about .about-breath {
  position: relative;
  height: clamp(30px, 4.5vw, 78px);
}

.page-about .about-breath::before {
  content: "";
  position: absolute;
  inset: 50% 0 auto 0;
  height: 2px;
  background: linear-gradient(90deg, transparent 0%, var(--yf-orange) 32%, var(--yf-cyan) 68%, transparent 100%);
  opacity: .38;
}

/* ---------- 时间轴阶段 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0 0 0 26px;
  border-left: 2px solid var(--yf-line);
}

.page-about .about-timeline__node {
  position: relative;
  padding-bottom: 18px;
}

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

.page-about .about-timeline__node::before {
  content: "";
  position: absolute;
  top: 8px;
  left: -34px;
  width: 14px;
  height: 14px;
  background: var(--yf-bg);
  border: 2px solid var(--yf-cyan);
  box-shadow: 0 0 0 4px rgba(47, 232, 198, .12);
}

.page-about .about-stage {
  border: 2px solid var(--yf-line);
  background: rgba(11, 31, 25, .82);
  transition: border-color .26s var(--yf-ease);
}

.page-about .about-stage:hover {
  border-color: rgba(47, 232, 198, .55);
}

.page-about .about-stage[open] {
  border-color: var(--yf-line);
}

.page-about .about-stage__sum {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  cursor: pointer;
  list-style: none;
}

.page-about .about-stage__sum::-webkit-details-marker {
  display: none;
}

.page-about .about-stage__idx {
  font-family: var(--yf-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--yf-muted);
  white-space: nowrap;
}

.page-about .about-stage__name {
  flex: 1;
  font-size: 16px;
  font-weight: 600;
  color: var(--yf-ink);
}

.page-about .about-stage__sign {
  position: relative;
  flex: 0 0 auto;
  width: 14px;
  height: 14px;
}

.page-about .about-stage__sign::before,
.page-about .about-stage__sign::after {
  content: "";
  position: absolute;
  background: var(--yf-cyan);
  transition: transform .26s var(--yf-ease), opacity .26s var(--yf-ease);
}

.page-about .about-stage__sign::before {
  top: 6px;
  left: 0;
  width: 14px;
  height: 2px;
}

.page-about .about-stage__sign::after {
  top: 0;
  left: 6px;
  width: 2px;
  height: 14px;
}

.page-about .about-stage[open] .about-stage__sign::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .about-stage__body {
  margin: 0;
  padding: 0 18px 18px;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--about-chip);
}

/* ---------- 下一步 ---------- */
.page-about .about-next {
  margin-top: clamp(38px, 6vw, 76px);
  padding: clamp(26px, 4vw, 46px);
  border: 2px solid var(--yf-line);
  background:
    radial-gradient(110% 130% at 100% 0%, rgba(47, 232, 198, .12), transparent 58%),
    linear-gradient(150deg, var(--yf-panel) 0%, var(--yf-bg) 100%);
  box-shadow: var(--yf-hard-shadow);
}

.page-about .about-next__title {
  margin: 10px 0 0;
  font-family: var(--yf-cond);
  font-weight: 200;
  font-size: clamp(25px, 3.6vw, 44px);
  line-height: 1.1;
  color: var(--yf-ink);
}

.page-about .about-next__text {
  margin: 14px 0 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--about-chip);
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .about-rail__stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-cols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px 34px;
  }

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

@media (min-width: 780px) {
  .page-about .about-crew {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .about-crew__card:nth-child(2) {
    margin-top: 30px;
  }

  .page-about .about-crew__card:nth-child(3) {
    margin-top: 12px;
  }
}

@media (min-width: 880px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 0.88fr) minmax(0, 1.12fr);
    gap: clamp(26px, 3.5vw, 46px);
    align-items: start;
  }
}

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

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--yf-header-h) + 28px);
    align-self: start;
    max-height: calc(100vh - var(--yf-header-h) - 56px);
    overflow-y: auto;
    padding-right: 6px;
  }

  .page-about .about-rail__stats {
    grid-template-columns: minmax(0, 1fr);
    gap: 16px;
  }

  .page-about .about-rail__num {
    font-size: 30px;
  }

  .page-about .about-cols p {
    font-size: 15px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-crew__card,
  .page-about .about-rail__link,
  .page-about .about-stage__sign::before,
  .page-about .about-stage__sign::after {
    transition: none;
  }

  .page-about .about-crew__card:hover {
    transform: none;
  }
}