.page-about {
  --ab-rail: 200px;
  --ab-cut: 18px;
  --ab-gap: 28px;
  color: var(--yk-ink);
  overflow-x: clip;
}

/* ---------- 通用文本 ---------- */
.page-about .ab-hero__lead,
.page-about .ab-stage__text,
.page-about .ab-produce__text,
.page-about .ab-reach__text,
.page-about .ab-partner__text,
.page-about .ab-vision__text {
  font-family: var(--yk-font-body);
  font-size: 16px;
  line-height: 1.78;
  color: var(--yk-ink-70);
}

.page-about .yk-num {
  font-family: var(--yk-font-num);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding: 20px 0 56px;
}

.page-about .ab-hero__grid {
  display: grid;
  gap: var(--ab-gap);
  align-items: end;
}

.page-about .ab-hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 16px;
  padding: 6px 14px;
  border: 1px solid var(--yk-gray);
  border-radius: 999px;
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--yk-teal);
  background: var(--yk-mist);
}

.page-about .ab-hero__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--yk-gold);
}

.page-about .ab-hero__title {
  margin: 0 0 20px;
  font-family: var(--yk-font-head);
  font-weight: 900;
  font-size: clamp(30px, 6.4vw, 58px);
  line-height: 1.06;
  letter-spacing: -0.01em;
  color: var(--yk-ink);
  max-width: 16em;
}

.page-about .ab-hero__lead {
  margin: 0 0 16px;
  max-width: 36em;
  font-size: 17px;
  color: var(--yk-ink-70);
}

.page-about .ab-hero__note {
  margin: 0;
  padding-left: 14px;
  border-left: 2px solid var(--yk-teal);
  max-width: 34em;
  font-size: 14px;
  line-height: 1.7;
  color: var(--yk-ink-55);
}

.page-about .ab-hero__aside {
  position: relative;
  padding: 24px 22px 20px;
  background:
    linear-gradient(140deg, rgba(14, 124, 134, .10), rgba(242, 183, 5, .10) 62%, rgba(14, 124, 134, 0) 100%),
    var(--yk-mist);
  border: 1px solid var(--yk-gray);
  clip-path: polygon(0 0, calc(100% - var(--ab-cut)) 0, 100% var(--ab-cut), 100% 100%, 0 100%);
}

.page-about .ab-hero__aside-title {
  margin: 0 0 16px;
  font-family: var(--yk-font-head);
  font-size: 13px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--yk-teal);
}

.page-about .ab-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
  margin: 0;
}

.page-about .ab-hero__fact dt {
  margin: 0 0 4px;
  font-size: 12.5px;
  letter-spacing: .02em;
  color: var(--yk-ink-55);
}

.page-about .ab-hero__fact dd {
  margin: 0;
  font-size: 26px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--yk-ink);
}

.page-about .ab-hero__fact dd span {
  font-size: 13px;
  font-weight: 500;
  color: var(--yk-ink-55);
  margin-left: 2px;
}

.page-about .ab-hero__media {
  margin: 40px 0 0;
}

.page-about .ab-hero__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 2 / 1;
  object-fit: cover;
  clip-path: polygon(0 0, calc(100% - var(--ab-cut)) 0, 100% var(--ab-cut), 100% 100%, 0 100%);
}

.page-about .ab-hero__caption,
.page-about .ab-produce__caption,
.page-about .ab-partner__caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--yk-ink-55);
}

/* ---------- 年份刻度 + 阶段 ---------- */
.page-about .ab-timeline__grid {
  display: grid;
  gap: var(--ab-gap);
  margin-top: 32px;
}

.page-about .ab-scale__head {
  margin: 0 0 14px;
  font-family: var(--yk-font-head);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--yk-ink-55);
}

.page-about .ab-scale__list {
  display: flex;
  gap: 10px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-scale__item {
  flex: 0 0 auto;
}

.page-about .ab-scale__link {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 128px;
  padding: 10px 14px;
  border: 1px solid var(--yk-gray);
  border-left: 3px solid var(--yk-teal);
  background: var(--yk-mist);
  text-decoration: none;
  transition: background-color .16s var(--yk-ease), transform .16s var(--yk-ease);
}

.page-about .ab-scale__link:hover {
  background: #eef6f7;
  transform: translateY(-2px);
}

.page-about .ab-scale__year {
  font-size: 15px;
  font-weight: 700;
  color: var(--yk-teal);
}

.page-about .ab-scale__name {
  font-size: 13px;
  color: var(--yk-ink-70);
}

.page-about .ab-scale__foot {
  margin: 12px 0 0;
  font-size: 12.5px;
  color: var(--yk-ink-55);
}

.page-about .ab-stages {
  display: grid;
  gap: 22px;
}

.page-about .ab-stage {
  position: relative;
  padding: 26px 22px 24px;
  background: #fff;
  border: 1px solid var(--yk-gray);
  clip-path: polygon(0 0, calc(100% - var(--ab-cut)) 0, 100% var(--ab-cut), 100% 100%, 0 100%);
  transition: transform .18s var(--yk-ease), box-shadow .18s var(--yk-ease);
}

.page-about .ab-stage:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 30px -22px rgba(16, 42, 67, .5);
}

.page-about .ab-stage::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.page-about .ab-stage--grow::before {
  background-image: repeating-linear-gradient(112deg, rgba(14, 124, 134, .08) 0 1px, transparent 1px 9px);
}

.page-about .ab-stage--v2::before {
  background-image: linear-gradient(100deg, rgba(242, 183, 5, .22), rgba(14, 124, 134, 0) 58%);
}

.page-about .ab-stage--v1 {
  border-left: 4px solid var(--yk-gray);
}

.page-about .ab-stage--grow {
  border-left: 4px solid var(--yk-teal);
}

.page-about .ab-stage--v2 {
  border-left: 4px solid var(--yk-gold);
}

.page-about .ab-stage:target {
  border-color: var(--yk-gold);
  box-shadow: 0 16px 32px -24px rgba(16, 42, 67, .55);
}

.page-about .ab-stage__tag {
  position: relative;
  margin: 0 0 10px;
  font-family: var(--yk-font-num);
  font-size: 12px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--yk-teal);
}

.page-about .ab-stage--v2 .ab-stage__tag {
  color: #a97e00;
}

.page-about .ab-stage__title {
  position: relative;
  margin: 0 0 12px;
  font-family: var(--yk-font-head);
  font-weight: 800;
  font-size: clamp(20px, 4.2vw, 25px);
  line-height: 1.28;
  color: var(--yk-ink);
}

.page-about .ab-stage__list {
  position: relative;
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 9px;
}

.page-about .ab-stage__list li {
  position: relative;
  padding-left: 20px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--yk-ink-70);
}

.page-about .ab-stage__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 10px;
  height: 2px;
  background: var(--yk-teal);
}

.page-about .ab-stage--v2 .ab-stage__list li::before {
  background: var(--yk-gold);
}

/* ---------- 版本对照标签页 ---------- */
.page-about .ab-compare__tabs {
  margin-top: 26px;
}

.page-about .ab-compare__tablist {
  display: flex;
  gap: 8px;
  overflow-x: auto;
}

.page-about .ab-compare__tab {
  flex: 0 0 auto;
  padding: 11px 18px;
  border: 1px solid var(--yk-gray);
  background: #fff;
  font-family: var(--yk-font-body);
  font-size: 14px;
  font-weight: 600;
  color: var(--yk-ink-70);
  cursor: pointer;
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 0 100%);
  transition: background-color .16s var(--yk-ease), color .16s var(--yk-ease);
}

.page-about .ab-compare__tab[aria-selected="true"] {
  background: var(--yk-teal);
  border-color: var(--yk-teal);
  color: #fff;
}

.page-about .ab-compare__tab:focus-visible {
  outline: 3px solid var(--yk-gold);
  outline-offset: 2px;
}

.page-about .ab-compare__panel {
  margin-top: 18px;
  padding: 6px 0 0;
  border-top: 2px solid var(--yk-gray);
}

.page-about .ab-compare__panel:focus-visible {
  outline: 3px solid var(--yk-gold);
  outline-offset: 4px;
}

.page-about .ab-compare__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}

.page-about .ab-compare__list li {
  display: grid;
  gap: 4px;
  padding: 14px 2px;
  border-bottom: 1px solid var(--yk-gray);
}

.page-about .ab-compare__key {
  font-size: 12.5px;
  letter-spacing: .08em;
  color: var(--yk-teal);
  font-family: var(--yk-font-num);
}

.page-about .ab-compare__val {
  font-size: 15px;
  line-height: 1.7;
  color: var(--yk-ink-70);
}

/* ---------- 数据生产 ---------- */
.page-about .ab-produce__panel {
  padding: 30px 22px 28px;
  background:
    repeating-linear-gradient(104deg, rgba(95, 201, 214, .07) 0 1px, transparent 1px 11px),
    linear-gradient(150deg, #0E7C86 0%, #0A5A62 46%, #102A43 100%);
  color: var(--yk-mist);
  clip-path: polygon(0 0, calc(100% - 26px) 0, 100% 26px, 100% 100%, 0 100%);
}

.page-about .ab-produce__label .yk-label__name,
.page-about .ab-produce__label .yk-label__no {
  color: var(--yk-mist);
}

.page-about .ab-produce__label .yk-label__desc {
  color: rgba(247, 250, 251, .72);
}

.page-about .ab-produce__grid {
  display: grid;
  gap: 26px;
  margin-top: 22px;
}

.page-about .ab-produce__text {
  margin: 0 0 14px;
  color: rgba(247, 250, 251, .82);
}

.page-about .ab-produce__metrics {
  display: grid;
  gap: 10px;
  margin: 22px 0 24px;
}

.page-about .ab-produce__metric {
  padding: 12px 14px;
  border: 1px solid rgba(95, 201, 214, .34);
  border-left: 3px solid var(--yk-gold);
  background: rgba(16, 42, 67, .38);
}

.page-about .ab-produce__metric dt {
  font-size: 12.5px;
  letter-spacing: .06em;
  color: rgba(247, 250, 251, .62);
  margin-bottom: 4px;
}

.page-about .ab-produce__metric dd {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  color: var(--yk-mist);
}

.page-about .ab-produce__metric dd .yk-num {
  color: var(--yk-gold);
  font-weight: 700;
  font-size: 19px;
}

.page-about .ab-flow {
  display: block;
  width: 100%;
  max-width: 520px;
  height: auto;
}

.page-about .ab-flow__node {
  fill: rgba(95, 201, 214, .14);
  stroke: #5FC9D6;
  stroke-width: 1.4;
}

.page-about .ab-flow__label {
  fill: #F7FAFB;
  font-family: var(--yk-font-body);
  font-size: 14px;
  font-weight: 600;
  text-anchor: middle;
}

.page-about .ab-flow__link {
  fill: none;
  stroke: #5FC9D6;
  stroke-width: 1.6;
  stroke-dasharray: 5 4;
}

.page-about .ab-produce__media {
  margin: 0;
}

.page-about .ab-produce__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 9 / 7;
  object-fit: cover;
  border: 1px solid rgba(95, 201, 214, .3);
  clip-path: polygon(0 0, calc(100% - var(--ab-cut)) 0, 100% var(--ab-cut), 100% 100%, 0 100%);
}

.page-about .ab-produce__caption {
  color: rgba(247, 250, 251, .58);
}

/* ---------- 覆盖范围 ---------- */
.page-about .ab-reach__grid {
  display: grid;
  gap: 26px;
  margin-top: 30px;
}

.page-about .ab-reach__board {
  padding: 24px 20px;
  background:
    radial-gradient(rgba(95, 201, 214, .30) 1.4px, transparent 1.4px) 0 0 / 18px 18px,
    linear-gradient(160deg, #102A43 0%, #0A5A62 100%);
  color: var(--yk-mist);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
}

.page-about .ab-reach__board-title {
  margin: 0 0 18px;
  font-family: var(--yk-font-head);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--yk-glow);
}

.page-about .ab-reach__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px 16px;
  margin: 0;
}

.page-about .ab-reach__stat {
  padding: 12px 13px;
  background: rgba(247, 250, 251, .07);
  border-top: 2px solid var(--yk-teal);
}

.page-about .ab-reach__stat dt {
  margin: 0 0 6px;
  font-size: 12.5px;
  color: rgba(247, 250, 251, .66);
}

.page-about .ab-reach__stat dd {
  margin: 0;
  font-size: 24px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--yk-mist);
}

.page-about .ab-reach__stat dd span {
  font-size: 13px;
  font-weight: 500;
  color: rgba(247, 250, 251, .68);
  margin-left: 2px;
}

.page-about .ab-reach__subtitle {
  margin: 0 0 14px;
  font-family: var(--yk-font-head);
  font-weight: 800;
  font-size: clamp(19px, 4vw, 23px);
  color: var(--yk-ink);
}

.page-about .ab-reach__text {
  margin: 0 0 14px;
}

.page-about .ab-reach__text:last-child {
  margin-bottom: 0;
}

/* ---------- 合作与认可 ---------- */
.page-about .ab-partner__media {
  margin: 26px 0 34px;
}

.page-about .ab-partner__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 8 / 3;
  object-fit: cover;
  clip-path: polygon(0 0, calc(100% - var(--ab-cut)) 0, 100% var(--ab-cut), 100% 100%, 0 100%);
}

.page-about .ab-partner__grid {
  display: grid;
  gap: 18px;
}

.page-about .ab-partner__block {
  padding: 22px 20px;
  border: 1px solid var(--yk-gray);
  border-top: 3px solid var(--yk-teal);
  background: var(--yk-mist);
}

.page-about .ab-partner__block:nth-child(3) {
  border-top-color: var(--yk-gold);
}

.page-about .ab-partner__num {
  margin: 0 0 6px;
  font-size: 34px;
  font-weight: 700;
  line-height: 1;
  color: var(--yk-ink);
}

.page-about .ab-partner__name {
  margin: 0 0 10px;
  font-family: var(--yk-font-head);
  font-weight: 700;
  font-size: 17px;
  color: var(--yk-teal);
}

.page-about .ab-partner__text {
  margin: 0;
  font-size: 15px;
}

/* ---------- 观赛判断 ---------- */
.page-about .ab-vision__panel {
  padding: 30px 22px 28px;
  background:
    linear-gradient(180deg, rgba(242, 183, 5, .12), rgba(14, 124, 134, 0) 42%),
    var(--yk-mist);
  border: 1px solid var(--yk-gray);
  clip-path: polygon(0 0, calc(100% - 24px) 0, 100% 24px, 100% 100%, 0 100%);
}

.page-about .ab-vision__grid {
  display: grid;
  gap: 16px;
  margin-top: 26px;
}

.page-about .ab-vision__item {
  padding: 20px 18px;
  background: #fff;
  border-left: 3px solid var(--yk-teal);
  box-shadow: 0 12px 26px -24px rgba(16, 42, 67, .6);
}

.page-about .ab-vision__item:nth-child(2) {
  border-left-color: var(--yk-glow);
}

.page-about .ab-vision__item:nth-child(3) {
  border-left-color: var(--yk-gold);
}

.page-about .ab-vision__badge {
  display: inline-block;
  margin: 0 0 10px;
  padding: 4px 12px;
  background: rgba(14, 124, 134, .1);
  font-family: var(--yk-font-num);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--yk-deep);
}

.page-about .ab-vision__title {
  margin: 0 0 10px;
  font-family: var(--yk-font-head);
  font-weight: 800;
  font-size: 19px;
  color: var(--yk-ink);
}

.page-about .ab-vision__text {
  margin: 0;
  font-size: 15px;
}

.page-about .ab-vision__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .ab-vision__foot {
  margin: 20px 0 0;
  padding-top: 18px;
  border-top: 1px solid var(--yk-gray);
  font-size: 14px;
  line-height: 1.8;
  color: var(--yk-ink-55);
}

.page-about .ab-vision__link {
  color: var(--yk-teal);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .ab-vision__link:hover {
  color: var(--yk-deep);
}

.page-about .ab-vision__link:focus-visible {
  outline: 3px solid var(--yk-gold);
  outline-offset: 2px;
}

/* ---------- 显现动效 ---------- */
.page-about [data-reveal] {
  opacity: 1;
  transform: none;
}

.page-about [data-reveal].is-in {
  animation: ab-rise .46s var(--yk-ease) both;
}

@keyframes ab-rise {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- 中屏 ---------- */
@media (min-width: 720px) {
  .page-about .ab-produce__metrics {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

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

  .page-about .ab-compare__list li {
    grid-template-columns: 110px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }
}

/* ---------- 桌面端：窄栏 + 宽叙事 ---------- */
@media (min-width: 960px) {
  .page-about {
    --ab-cut: 20px;
  }

  .page-about .ab-hero {
    padding-top: 28px;
  }

  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(280px, .9fr);
    gap: 56px;
    align-items: end;
  }

  .page-about .ab-hero__media {
    margin-top: 52px;
  }

  .page-about .ab-timeline__grid {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 52px;
  }

  .page-about .ab-scale {
    position: sticky;
    top: calc(var(--yk-topbar-h) + 24px);
    align-self: start;
  }

  .page-about .ab-scale__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
  }

  .page-about .ab-scale__item {
    flex: initial;
  }

  .page-about .ab-scale__link {
    min-width: 0;
    padding: 12px 0 12px 16px;
    border: 0;
    border-left: 2px solid var(--yk-gray);
    background: transparent;
    position: relative;
  }

  .page-about .ab-scale__link::before {
    content: "";
    position: absolute;
    left: -5px;
    top: 50%;
    transform: translateY(-50%);
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--yk-gray);
    transition: background-color .16s var(--yk-ease);
  }

  .page-about .ab-scale__link:hover {
    background: transparent;
    transform: none;
  }

  .page-about .ab-scale__link:hover::before,
  .page-about .ab-scale__link:focus-visible::before {
    background: var(--yk-gold);
  }

  .page-about .ab-scale__link:focus-visible {
    outline: 3px solid var(--yk-gold);
    outline-offset: 4px;
  }

  .page-about .ab-stages {
    gap: 26px;
  }

  .page-about .ab-stage {
    padding: 32px 30px 30px;
  }

  .page-about .ab-produce__panel {
    padding: 46px 46px 42px;
  }

  .page-about .ab-produce__grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(280px, .85fr);
    gap: 46px;
    align-items: start;
  }

  .page-about .ab-reach__grid {
    grid-template-columns: minmax(0, .95fr) minmax(0, 1.05fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .ab-partner__grid {
    gap: 24px;
  }

  .page-about .ab-vision__panel {
    padding: 46px 46px 42px;
  }
}

/* ---------- 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal].is-in {
    animation: none;
  }

  .page-about .ab-stage,
  .page-about .ab-scale__link {
    transition: none;
  }

  .page-about .ab-stage:hover {
    transform: none;
  }
}