.page-about {
  --rail-w: 176px;
  --rail-gap: clamp(24px, 3vw, 46px);
  background: var(--karst-ink);
  color: var(--mist-stone);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumbs {
  padding-top: clamp(14px, 3vw, 26px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(26px, 5vw, 58px) 0 clamp(28px, 4vw, 48px);
  isolation: isolate;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -30% 25% 8% -12%;
  background:
    radial-gradient(58% 66% at 22% 34%, rgba(20, 160, 165, .30), transparent 70%),
    radial-gradient(46% 56% at 82% 8%, rgba(255, 106, 26, .16), transparent 72%);
  pointer-events: none;
  z-index: -1;
}

.page-about .about-hero__inner {
  position: relative;
}

.page-about .about-hero__eyebrow {
  color: var(--waterfall-teal);
  margin: 0 0 clamp(14px, 2vw, 22px);
}

.page-about .about-hero__title {
  margin: 0 0 clamp(18px, 2.6vw, 28px);
  font-size: var(--step-5);
  line-height: .98;
  letter-spacing: -.035em;
  color: var(--mist-stone);
  max-width: 20ch;
  text-wrap: balance;
}

.page-about .about-hero__lead {
  max-width: 60ch;
  margin: 0;
  font-size: var(--step-1);
  line-height: 1.75;
  color: var(--mist-stone);
  opacity: .86;
}

.page-about .about-hero__facts {
  list-style: none;
  margin: clamp(26px, 4vw, 44px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--fog-line);
  border: 1px solid var(--fog-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
}

.page-about .about-hero__facts li {
  background: var(--slate-rock);
  padding: 14px 16px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .about-fact__value {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.35rem, 2.4vw, 1.95rem);
  line-height: 1.05;
  letter-spacing: -.02em;
  color: var(--turf-lime);
}

.page-about .about-fact__label {
  font-size: var(--step--1);
  color: var(--dim);
}

/* ---------- 通栏主视觉 ---------- */
.page-about .about-banner {
  padding-bottom: clamp(30px, 5vw, 60px);
}

.page-about .about-banner__frame {
  border: 1px solid var(--fog-line);
}

/* ---------- 两栏骨架 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 40px);
  padding-bottom: clamp(48px, 7vw, 96px);
}

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

.page-about .about-rail__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--fog-line);
}

.page-about .about-rail__nav {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding-bottom: 6px;
  scrollbar-width: thin;
}

.page-about .about-rail__nav .index-rail__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 9px 12px;
  font-size: var(--step--1);
  color: var(--dim);
  text-decoration: none;
  white-space: nowrap;
  border-left: 2px solid transparent;
  transition: color .25s var(--ease), background-color .25s var(--ease), border-color .25s var(--ease);
}

.page-about .about-rail__nav .index-rail__link::before {
  content: attr(data-ord);
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--fog-line);
  transition: color .25s var(--ease);
}

.page-about .about-rail__nav .index-rail__link:hover,
.page-about .about-rail__nav .index-rail__link:focus-visible {
  color: var(--mist-stone);
  background: var(--slate-rock);
}

.page-about .about-rail__nav .index-rail__link:hover::before,
.page-about .about-rail__nav .index-rail__link:focus-visible::before {
  color: var(--waterfall-teal);
}

.page-about .about-rail__nav .index-rail__link.is-current {
  color: var(--turf-lime);
  border-left-color: var(--turf-lime);
}

.page-about .about-rail__nav .index-rail__link.is-current::before {
  color: var(--turf-lime);
}

.page-about .about-flow {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  position: relative;
  padding-top: 0;
  padding-bottom: clamp(44px, 6vw, 80px);
  scroll-margin-top: 110px;
}

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

.page-about .about-chapter:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 0;
  right: 22%;
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--teal-deep), rgba(20, 160, 165, 0) 88%);
}

.page-about .about-chapter__head {
  position: relative;
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .section-num {
  display: block;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(3rem, 8vw, 5.6rem);
  line-height: .82;
  letter-spacing: -.05em;
  color: transparent;
  -webkit-text-stroke: 1px var(--fog-line);
  margin-bottom: 10px;
}

.page-about .about-chapter__head h2 {
  margin: 0;
  max-width: 24ch;
  font-size: var(--step-3);
  line-height: 1.12;
  letter-spacing: -.02em;
  color: var(--mist-stone);
}

.page-about .about-chapter__head::after {
  content: "";
  display: block;
  width: 64px;
  height: 2px;
  margin-top: 18px;
  background: linear-gradient(90deg, var(--waterfall-teal), var(--turf-lime));
}

.page-about .about-chapter > p {
  max-width: 68ch;
  margin: 0 0 4px;
  font-size: var(--step-0);
  line-height: 1.8;
  color: var(--mist-stone);
  opacity: .86;
}

.page-about .about-link-line {
  margin-top: clamp(20px, 3vw, 30px);
}

/* ---------- 01 赛事范围 ---------- */
.page-about .league-grid {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .league-grid .cut__body {
  height: 100%;
  padding: 20px 18px 22px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .league-card__num {
  font-size: var(--step-2);
  font-weight: 700;
  line-height: 1;
  color: var(--turf-lime);
  letter-spacing: -.02em;
}

.page-about .league-card__title {
  margin: 0;
  font-size: var(--step-1);
  line-height: 1.3;
  color: var(--mist-stone);
}

.page-about .league-grid .cut__body p {
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.7;
  color: var(--dim);
}

/* ---------- 02 数据链路 ---------- */
.page-about .pipe {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .pipe__step {
  position: relative;
  padding: 20px 18px 22px;
  background: var(--slate-rock);
  border-top: 2px solid var(--waterfall-teal);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
}

.page-about .pipe__no {
  display: block;
  font-size: var(--step-0);
  font-weight: 700;
  color: var(--waterfall-teal);
  margin-bottom: 8px;
}

.page-about .pipe__title {
  margin: 0 0 8px;
  font-size: var(--step-1);
  line-height: 1.3;
  color: var(--mist-stone);
}

.page-about .pipe__step p {
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.72;
  color: var(--dim);
}

.page-about .about-pipe__figure {
  margin: clamp(24px, 3vw, 34px) 0 0;
  border: 1px solid var(--fog-line);
}

/* ---------- 03 团队 ---------- */
.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3vw, 32px);
  margin-top: clamp(22px, 3vw, 32px);
}

.page-about .crew {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .crew__row {
  display: grid;
  grid-template-columns: 5.5em minmax(0, 1fr) 3em;
  align-items: center;
  gap: 12px;
  font-size: var(--step--1);
}

.page-about .crew__name {
  color: var(--mist-stone);
  white-space: nowrap;
}

.page-about .crew__bar {
  height: 8px;
  background: linear-gradient(90deg, var(--teal-deep), var(--waterfall-teal));
  clip-path: polygon(0 0, 100% 0, calc(100% - 6px) 100%, 0 100%);
}

.page-about .crew__row:nth-child(1) .crew__bar { width: 38%; }
.page-about .crew__row:nth-child(2) .crew__bar { width: 21%; }
.page-about .crew__row:nth-child(3) .crew__bar { width: 13%; }

.page-about .crew__val {
  text-align: right;
  font-weight: 700;
  color: var(--turf-lime);
}

.page-about .about-team__note {
  margin: clamp(18px, 3vw, 26px) 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--teal-deep);
  font-size: var(--step--1);
  line-height: 1.72;
  color: var(--dim);
}

.page-about .about-team__figure {
  margin: 0;
  border: 1px solid var(--fog-line);
}

/* ---------- 04 发展历程 ---------- */
.page-about .milestones {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
}

.page-about .milestones__item {
  position: relative;
  display: grid;
  grid-template-columns: minmax(4.6em, 5.8em) minmax(0, 1fr);
  gap: 16px;
  padding: 0 0 30px 22px;
}

.page-about .milestones__item::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 12px;
  bottom: 0;
  width: 1px;
  background: var(--fog-line);
}

.page-about .milestones__item:last-child::before {
  display: none;
}

.page-about .milestones__item::after {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--karst-ink);
  box-shadow: 0 0 0 2px var(--fog-line);
  transition: background-color .3s var(--ease), box-shadow .3s var(--ease);
}

.page-about .milestones__item.is-visible::after {
  background: var(--turf-lime);
  box-shadow: 0 0 0 2px var(--turf-lime), 0 0 14px rgba(182, 255, 60, .55);
}

.page-about .milestones__year {
  display: block;
  padding-top: 4px;
  font-family: var(--font-mono);
  font-size: var(--step-0);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--dim);
  transition: color .3s var(--ease);
}

.page-about .milestones__item.is-visible .milestones__year {
  color: var(--waterfall-teal);
}

.page-about .milestones__body h3 {
  margin: 0 0 6px;
  font-size: var(--step-1);
  line-height: 1.3;
  color: var(--mist-stone);
}

.page-about .milestones__body p {
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.78;
  color: var(--mist-stone);
  opacity: .72;
}

/* ---------- 05 合作生态 ---------- */
.page-about .about-network {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3vw, 34px);
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .about-network__map {
  position: relative;
  padding: clamp(16px, 3vw, 26px);
  background: var(--slate-rock);
  border: 1px solid var(--fog-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
}

.page-about .dotmap {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .dotmap__base circle {
  fill: var(--fog-line);
}

.page-about .dotmap__hot circle {
  fill: var(--waterfall-teal);
}

.page-about .dotmap__hot circle:nth-child(2n) {
  fill: var(--turf-lime);
}

.page-about .dotmap__hot circle:nth-child(3n) {
  fill: var(--pulse-orange);
}

.page-about .about-network__tags {
  list-style: none;
  margin: clamp(16px, 2vw, 22px) 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-network__tag {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 7px 12px;
  font-size: var(--step--1);
  color: var(--mist-stone);
  background: rgba(20, 160, 165, .12);
  border: 1px solid var(--teal-deep);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 8px), calc(100% - 8px) 100%, 0 100%);
}

.page-about .about-network__tag b {
  color: var(--turf-lime);
}

.page-about .about-network__text p {
  margin: 0;
  font-size: var(--step-0);
  line-height: 1.8;
  color: var(--mist-stone);
  opacity: .86;
}

/* ---------- 06 服务标准 ---------- */
.page-about .standard-grid {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--fog-line);
  border: 1px solid var(--fog-line);
}

.page-about .standard-grid li {
  background: var(--slate-rock);
  padding: 18px 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .standard__val {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.25rem, 2.2vw, 1.7rem);
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--turf-lime);
}

.page-about .standard__label {
  font-size: var(--step--1);
  line-height: 1.6;
  color: var(--mist-stone);
  opacity: .78;
}

.page-about .about-standards__note {
  margin: clamp(22px, 3vw, 32px) 0 0;
  max-width: 66ch;
  font-size: var(--step-0);
  line-height: 1.8;
  color: var(--mist-stone);
  opacity: .82;
}

.page-about .about-next {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(20px, 3vw, 28px);
}

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

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

@media (min-width: 760px) {
  .page-about .about-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 280px);
    align-items: start;
  }

  .page-about .about-network {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    align-items: start;
  }

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

@media (min-width: 900px) {
  .page-about .pipe {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .pipe__step:not(:last-child)::after {
    content: "";
    position: absolute;
    top: 34px;
    right: -13px;
    width: 9px;
    height: 9px;
    border-top: 2px solid var(--turf-lime);
    border-right: 2px solid var(--turf-lime);
    transform: rotate(45deg);
    opacity: .85;
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: var(--rail-w) minmax(0, 1fr);
    gap: var(--rail-gap);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
  }

  .page-about .about-rail__nav {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail__nav .index-rail__link {
    padding: 10px 12px 10px 14px;
  }

  .page-about .about-chapter__head h2 {
    font-size: var(--step-4);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .milestones__item::after,
  .page-about .milestones__year,
  .page-about .about-rail__nav .index-rail__link {
    transition: none;
  }
}