.page-about {
  --about-rail: 128px;
  --about-rail-gap: clamp(20px, 2.8vw, 44px);
  background: var(--c-frost);
  color: var(--c-navy);
  overflow-x: clip;
}

/* ---------- 章节锚点索引 ---------- */
.page-about .about-index {
  display: none;
}

@media (min-width: 1600px) {
  .page-about .about-index {
    display: flex;
    flex-direction: column;
    gap: 10px;
    position: fixed;
    top: 50%;
    right: 26px;
    z-index: 30;
    width: 132px;
    transform: translateY(-50%);
    padding: 16px 0 16px 14px;
    border-left: 1px solid var(--c-line-soft);
  }
}

.page-about .about-index .anchor-index__link {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.06em;
  color: var(--c-slate);
  text-decoration: none;
  padding: 2px 0;
  border-left: 2px solid transparent;
  padding-left: 8px;
  margin-left: -1px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-index .anchor-index__link:hover,
.page-about .about-index .anchor-index__link[aria-current] {
  color: var(--c-violet);
  border-left-color: var(--c-violet);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(24px, 3.4vw, 44px) 0 clamp(56px, 7.5vw, 104px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: 12%;
  right: -12%;
  width: min(720px, 78vw);
  height: min(520px, 60vw);
  border-radius: 48% 52% 40% 60% / 55% 45% 60% 40%;
  background:
    radial-gradient(circle at 42% 46%, rgba(108, 75, 255, 0.2), transparent 62%),
    radial-gradient(circle at 68% 64%, rgba(33, 216, 206, 0.18), transparent 58%);
  filter: blur(4px);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero .container {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(26px, 3.8vw, 48px);
}

.page-about .about-hero__grid {
  align-items: end;
}

.page-about .about-hero__lead .label-en {
  color: var(--c-glacier);
  margin: 0;
}

.page-about .about-hero__title {
  margin: 16px 0 0;
  font-size: clamp(34px, 5.6vw, 72px);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--c-navy);
}

.page-about .about-hero__lede {
  margin: clamp(20px, 2.4vw, 28px) 0 0;
  max-width: 46ch;
  font-size: clamp(16px, 1.5vw, 18px);
  line-height: 1.9;
  color: var(--c-slate);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: clamp(26px, 3.4vw, 40px) 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: clamp(18px, 3vw, 44px);
}

.page-about .about-hero__fact {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .about-hero__fact b {
  font-family: var(--font-mono);
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--c-navy);
  line-height: 1;
}

.page-about .about-hero__fact:nth-child(2) b {
  color: var(--c-violet);
}

.page-about .about-hero__fact:nth-child(3) b {
  color: var(--c-amber);
}

.page-about .about-hero__fact span {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-slate);
}

.page-about .about-hero__visual {
  margin-top: clamp(30px, 4vw, 0px);
}

.page-about .about-hero__frame {
  border-radius: var(--r-lg) var(--r-lg) var(--r-sm) var(--r-lg);
}

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

/* ---------- 分裂分隔 ---------- */
.page-about .about-sep {
  padding: clamp(6px, 1vw, 14px) 0;
}

/* ---------- 章节基本骨架 ---------- */
.page-about .about-zone {
  padding: clamp(46px, 6vw, 84px) 0;
}

.page-about .about-zone__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .about-zone__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .about-zone__num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.4vw, 40px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--c-glacier);
}

.page-about .about-zone__note {
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--c-slate);
}

.page-about .about-zone__title {
  margin: 0;
  font-size: clamp(25px, 3.2vw, 42px);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--c-navy);
}

.page-about .about-zone__intro {
  margin: clamp(16px, 2vw, 24px) 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--c-slate);
}

.page-about .about-zone__body .prose {
  margin-top: clamp(18px, 2.2vw, 26px);
}

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

  .page-about .about-zone__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 18px;
  }

  .page-about .about-zone__note {
    writing-mode: vertical-rl;
    letter-spacing: 0.3em;
    max-height: 170px;
    padding-top: 4px;
  }
}

/* ---------- 02 选题标准 ---------- */
.page-about .about-standards {
  margin-top: clamp(28px, 3.4vw, 44px);
  display: grid;
  gap: 0;
  border-top: 1px solid var(--c-line-soft);
}

.page-about .about-standards__item {
  display: grid;
  gap: 8px;
  padding: 20px 0;
  border-bottom: 1px solid var(--c-line-soft);
}

.page-about .about-standards__tag {
  display: inline-flex;
  align-items: center;
  align-self: start;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--c-deep-ice);
  background: var(--c-mist);
  border-left: 3px solid var(--c-glacier);
  border-radius: var(--r-sm);
  padding: 4px 10px;
}

.page-about .about-standards__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-slate);
}

@media (min-width: 720px) {
  .page-about .about-standards__item {
    grid-template-columns: 168px minmax(0, 1fr);
    gap: clamp(16px, 3vw, 40px);
    align-items: start;
  }
}

/* ---------- 03 时间轴 ---------- */
.page-about .about-zone--timeline {
  position: relative;
}

.page-about .about-tl-wrap {
  margin-top: clamp(28px, 3.6vw, 44px);
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 48px);
}

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

.page-about .about-tl .timeline__item + .timeline__item {
  margin-top: clamp(14px, 2vw, 24px);
}

.page-about .about-tl__stage {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-glacier);
}

.page-about .about-tl__title {
  margin: 0 0 8px;
  font-size: clamp(17px, 1.6vw, 20px);
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: -0.005em;
  color: var(--c-navy);
}

.page-about .about-tl__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-slate);
  max-width: 54ch;
}

.page-about .about-tl__visual {
  margin: 0;
  border-radius: var(--r-md) var(--r-lg) var(--r-md) var(--r-sm);
}

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

@media (min-width: 900px) {
  .page-about .about-tl-wrap {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 0.8fr);
    align-items: start;
  }

  .page-about .about-tl__visual {
    position: sticky;
    top: calc(var(--header-h) + 32px);
  }
}

/* ---------- 04 团队 ---------- */
.page-about .about-split {
  margin-top: clamp(24px, 3vw, 36px);
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3.4vw, 40px);
  align-items: start;
}

.page-about .about-split__text .prose {
  margin-top: 0;
}

.page-about .about-split__media {
  margin: 0;
  border-radius: var(--r-lg) var(--r-sm) var(--r-lg) var(--r-md);
}

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

@media (min-width: 900px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  }
}

/* ---------- 05 合作方 ---------- */
.page-about .about-partners {
  list-style: none;
  margin: clamp(28px, 3.6vw, 44px) 0 0;
  padding: 0;
  border-top: 1px solid var(--c-line-soft);
}

.page-about .about-partners__row {
  display: grid;
  gap: 8px;
  padding: clamp(18px, 2.4vw, 26px) 0;
  border-bottom: 1px solid var(--c-line-soft);
}

.page-about .about-partners__key {
  position: relative;
  padding-left: 16px;
  font-size: 15px;
  font-weight: 700;
  color: var(--c-navy);
  letter-spacing: 0.01em;
}

.page-about .about-partners__key::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--c-cyan);
  box-shadow: 0 0 0 3px rgba(33, 216, 206, 0.18);
}

.page-about .about-partners__val {
  font-size: 15px;
  line-height: 1.82;
  color: var(--c-slate);
}

@media (min-width: 720px) {
  .page-about .about-partners__row {
    grid-template-columns: 176px minmax(0, 1fr);
    gap: clamp(16px, 3vw, 44px);
    align-items: baseline;
  }
}

.page-about .about-partners__foot {
  margin: clamp(22px, 3vw, 32px) 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-slate);
}

.page-about .about-partners__foot a {
  color: var(--c-violet);
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid rgba(108, 75, 255, 0.4);
}

.page-about .about-partners__foot a:hover {
  border-bottom-color: var(--c-violet);
}

/* ---------- 06 下一步与行动区 ---------- */
.page-about .about-cta {
  margin-top: clamp(32px, 4vw, 52px);
  padding: clamp(26px, 3.4vw, 44px);
  border-radius: var(--r-lg) var(--r-sm) var(--r-lg) var(--r-md);
  background:
    radial-gradient(circle at 88% 12%, rgba(108, 75, 255, 0.16), transparent 56%),
    linear-gradient(150deg, var(--c-mist), var(--c-frost) 68%);
  border-left: 4px solid var(--c-violet);
}

.page-about .about-cta__title {
  margin: 0 0 12px;
  font-size: clamp(19px, 2vw, 24px);
  font-weight: 800;
  line-height: 1.4;
  color: var(--c-navy);
}

.page-about .about-cta__text {
  margin: 0 0 clamp(20px, 2.6vw, 28px);
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-slate);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-cta__actions .btn {
  flex: 0 1 auto;
}

/* ---------- 窄屏收敛 ---------- */
@media (max-width: 520px) {
  .page-about .about-hero__facts {
    gap: 16px 24px;
  }

  .page-about .about-hero__fact b {
    font-size: 22px;
  }

  .page-about .about-cta__actions .btn {
    flex: 1 1 100%;
    text-align: center;
  }
}