.page-about {
  --about-gap: clamp(18px, 3vw, 32px);
  --about-line: rgba(108, 122, 156, 0.22);
  --about-card: #1B263B;
  display: block;
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumbs {
  padding-top: clamp(14px, 2.2vw, 24px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-block: clamp(26px, 4vw, 52px) clamp(32px, 5vw, 66px);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(90deg, rgba(108, 122, 156, 0.14) 0 1px, transparent 1px 84px),
    repeating-linear-gradient(0deg, rgba(108, 122, 156, 0.1) 0 1px, transparent 1px 84px);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 82%);
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 82%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 52px);
  align-items: center;
}

.page-about .about-hero__copy h1 {
  margin: 12px 0 18px;
  font-family: var(--font-head);
  font-size: var(--fs-h1);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.01em;
  color: var(--c-paper);
  max-width: 18ch;
}

.page-about .about-hero__copy .lede {
  max-width: 62ch;
  color: #C8D4EA;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__visual {
  position: relative;
  width: 100%;
  max-width: 460px;
  margin-inline: auto;
  aspect-ratio: 1 / 1;
  border: var(--hair);
  clip-path: polygon(0 0, 100% 0, 100% 88%, 88% 100%, 0 100%);
  background:
    radial-gradient(circle at 72% 18%, rgba(0, 229, 255, 0.2), transparent 58%),
    linear-gradient(158deg, #1B263B 0%, #0A1128 72%);
  overflow: hidden;
}

.page-about .about-visual__pitch {
  position: absolute;
  inset: 6%;
  width: 88%;
  height: 88%;
}

.page-about .about-visual__stamp {
  position: absolute;
  right: 14px;
  bottom: 14px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  letter-spacing: 0.14em;
  color: var(--c-cyan-soft);
  text-transform: uppercase;
}

/* ---------- 首屏数据条 ---------- */
.page-about .about-hero__stats {
  position: relative;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(30px, 4vw, 48px);
  background: var(--about-line);
  border: var(--hair);
}

.page-about .about-hero__stats .stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 18px;
  background: var(--c-deep);
}

.page-about .about-hero__stats .stat__value {
  font-family: var(--font-mono);
  font-size: clamp(22px, 3.2vw, 30px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--c-cyan);
  line-height: 1.1;
}

.page-about .about-hero__stats .stat:nth-child(2) .stat__value {
  color: var(--c-orange);
}

.page-about .about-hero__stats .stat:nth-child(3) .stat__value {
  color: var(--c-lime);
}

.page-about .about-hero__stats .stat:nth-child(4) .stat__value {
  color: var(--c-cyan-soft);
}

.page-about .about-hero__stats .stat__label {
  font-size: var(--fs-micro);
  letter-spacing: 0.14em;
  color: var(--c-muted);
}

/* ---------- 主体：侧边导览 + 内容泳道 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 52px);
  padding-bottom: clamp(40px, 6vw, 88px);
}

.page-about .about-toc {
  position: static;
  border-left: 0;
  padding-left: 0;
}

.page-about .about-toc__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  letter-spacing: 0.16em;
  color: var(--c-muted);
  text-transform: uppercase;
}

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

.page-about .about-toc__link {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 7px 12px;
  border: 1px solid var(--about-line);
  color: var(--c-muted);
  font-size: var(--fs-micro);
  text-decoration: none;
  transition: color var(--speed), border-color var(--speed), background-color var(--speed);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  color: var(--c-deep);
  background: var(--c-cyan);
  border-color: var(--c-cyan);
}

.page-about .about-toc__num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--c-orange);
}

.page-about .about-toc__link:hover .about-toc__num,
.page-about .about-toc__link:focus-visible .about-toc__num {
  color: var(--c-orange-deep);
}

/* ---------- 区块通用 ---------- */
.page-about .about-block {
  padding-block: clamp(26px, 4vw, 44px);
  border-top: var(--hair);
  scroll-margin-top: 96px;
}

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

.page-about .about-block .section-title {
  color: var(--c-paper);
}

.page-about .about-figure {
  margin: clamp(20px, 3vw, 30px) 0;
}

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

/* ---------- 时间线 ---------- */
.page-about .tl {
  position: relative;
  margin: 26px 0 0;
  padding: 0 0 0 24px;
  list-style: none;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--c-cyan), var(--c-orange));
  opacity: 0.6;
}

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

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

.page-about .tl__dot {
  position: absolute;
  left: -24px;
  top: 18px;
  width: 12px;
  height: 12px;
  background: var(--c-deep);
  border: 2px solid var(--c-cyan);
  transform: rotate(45deg);
  transition: background-color var(--speed), border-color var(--speed);
}

.page-about .tl__item:hover .tl__dot,
.page-about .tl__item:focus-within .tl__dot {
  background: var(--c-cyan);
}

.page-about .tl__card {
  padding: 16px 18px 18px;
  background: var(--about-card);
  border: 1px solid var(--about-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
  transition: border-color var(--speed), transform var(--speed);
}

.page-about .tl__item:hover .tl__card {
  border-color: rgba(0, 229, 255, 0.55);
  transform: translateX(4px);
}

.page-about .tl__stage {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  letter-spacing: 0.12em;
  color: var(--c-orange);
}

.page-about .tl__title {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--c-paper);
}

.page-about .tl__text {
  margin: 0;
  font-size: var(--fs-small);
  line-height: 1.75;
  color: #B9C6DE;
}

/* ---------- 数据能力 ---------- */
.page-about .about-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(14px, 2.4vw, 22px);
  margin: 24px 0 30px;
}

.page-about .about-metrics .stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-left: 14px;
  border-left: 2px solid var(--c-cyan);
}

.page-about .about-metrics .stat--orange {
  border-left-color: var(--c-orange);
}

.page-about .about-metrics .stat--lime {
  border-left-color: var(--c-lime);
}

.page-about .about-metrics .stat__value {
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.6vw, 36px);
  font-weight: 700;
  line-height: 1.05;
  color: var(--c-cyan);
}

.page-about .about-metrics .stat--orange .stat__value {
  color: var(--c-orange);
}

.page-about .about-metrics .stat--lime .stat__value {
  color: var(--c-lime);
}

.page-about .about-metrics .stat__label {
  font-size: var(--fs-micro);
  letter-spacing: 0.12em;
  color: var(--c-muted);
}

.page-about .about-tabs .tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  border-bottom: var(--hair);
}

.page-about .about-tabs .tab {
  padding: 10px 16px;
  background: transparent;
  border: 1px solid var(--about-line);
  border-bottom: 0;
  color: var(--c-muted);
  font-family: var(--font-head);
  font-size: var(--fs-small);
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: color var(--speed), background-color var(--speed), border-color var(--speed);
}

.page-about .about-tabs .tab:hover {
  color: var(--c-cyan);
  border-color: rgba(0, 229, 255, 0.5);
}

.page-about .about-tabs .tab[aria-selected="true"] {
  color: var(--c-deep);
  background: var(--c-cyan);
  border-color: var(--c-cyan);
}

.page-about .about-tabs .tabpanel {
  padding: 20px 0 4px;
}

.page-about .about-tabs .tabpanel + .tabpanel {
  border-top: var(--hair);
}

.page-about .about-panel__title {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 600;
  color: var(--c-paper);
}

.page-about .about-tabs .tabpanel p {
  margin: 0;
  max-width: 68ch;
  color: #B9C6DE;
}

/* ---------- 本地合作卡片 ---------- */
.page-about .about-coop {
  margin-top: 26px;
}

.page-about .coop-card {
  border-top: 3px solid var(--c-cyan);
}

.page-about .about-coop .coop-card:nth-child(2) {
  border-top-color: var(--c-orange);
}

.page-about .about-coop .coop-card:nth-child(3) {
  border-top-color: var(--c-lime);
}

.page-about .coop-card .card__label {
  font-family: var(--font-mono);
  font-size: var(--fs-micro);
  letter-spacing: 0.14em;
  color: var(--c-cyan-soft);
}

.page-about .coop-card .card__text {
  color: #B9C6DE;
}

/* ---------- 青训 ---------- */
.page-about .age-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 22px 0 24px;
}

.page-about .age-chip {
  padding: 6px 14px;
  border: 1px solid var(--about-line);
  font-family: var(--font-mono);
  font-size: var(--fs-small);
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--c-cyan);
  border-color: rgba(0, 229, 255, 0.45);
}

.page-about .age-chip:nth-child(2) {
  color: var(--c-lime);
  border-color: rgba(57, 255, 20, 0.42);
}

.page-about .age-chip:nth-child(3) {
  color: var(--c-orange);
  border-color: rgba(255, 107, 53, 0.45);
}

.page-about .age-chip:nth-child(4) {
  color: var(--c-cyan-soft);
  border-color: rgba(138, 240, 255, 0.42);
}

.page-about .age-chip:nth-child(5) {
  color: var(--c-lime);
  border-color: rgba(57, 255, 20, 0.42);
}

.page-about .age-chip:nth-child(6) {
  color: var(--c-orange);
  border-color: rgba(255, 107, 53, 0.45);
}

.page-about .about-youth {
  margin-top: 4px;
}

.page-about .youth-card {
  padding: 20px 20px 22px;
  background: var(--about-card);
  border: 1px solid var(--about-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
  transition: border-color var(--speed), transform var(--speed);
}

.page-about .youth-card:hover {
  border-color: rgba(0, 229, 255, 0.5);
  transform: translateY(-4px);
}

.page-about .youth-card__num {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: clamp(30px, 4.4vw, 44px);
  font-weight: 700;
  line-height: 1;
  color: var(--c-orange);
}

.page-about .about-youth .youth-card:nth-child(2) .youth-card__num {
  color: var(--c-lime);
}

.page-about .youth-card__unit {
  margin-left: 4px;
  font-size: var(--fs-small);
  color: var(--c-muted);
}

.page-about .youth-card__title {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 600;
  color: var(--c-paper);
}

.page-about .youth-card__text {
  margin: 0;
  font-size: var(--fs-small);
  line-height: 1.75;
  color: #B9C6DE;
}

/* ---------- 下一步 ---------- */
.page-about .about-next__links {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 24px;
  background: var(--about-line);
  border: var(--hair);
}

.page-about .about-next__link {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 20px;
  background: var(--c-deep);
  text-decoration: none;
  transition: background-color var(--speed), padding-left var(--speed);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  background: var(--c-mid);
  padding-left: 26px;
}

.page-about .about-next__link-key {
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--c-cyan);
}

.page-about .about-next__link-desc {
  font-size: var(--fs-small);
  line-height: 1.7;
  color: #B9C6DE;
}

/* ---------- 中屏 ---------- */
@media (min-width: 700px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

/* ---------- 桌面：侧边导览与错位时间线 ---------- */
@media (min-width: 1000px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    gap: clamp(36px, 5vw, 72px);
  }

  .page-about .about-body {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: clamp(36px, 5vw, 72px);
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 96px;
    border-left: 2px solid var(--c-cyan);
    padding-left: 16px;
  }

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

  .page-about .about-toc__link {
    display: flex;
    width: 100%;
    padding: 10px 0;
    border: 0;
    border-bottom: var(--hair);
    font-size: var(--fs-small);
    background: transparent;
  }

  .page-about .about-toc__link:hover,
  .page-about .about-toc__link:focus-visible {
    color: var(--c-cyan);
    background: transparent;
    padding-left: 6px;
  }

  .page-about .about-toc__link:hover .about-toc__num,
  .page-about .about-toc__link:focus-visible .about-toc__num {
    color: var(--c-orange);
  }

  .page-about .tl {
    padding-left: 30px;
  }

  .page-about .tl__dot {
    left: -30px;
  }

  .page-about .tl__item:nth-child(even) {
    margin-left: clamp(24px, 6vw, 84px);
  }

  .page-about .tl__item:nth-child(even) .tl__dot {
    left: calc(-30px - clamp(24px, 6vw, 84px));
  }

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