.page-about {
  --about-card-bg: rgba(233, 239, 243, .038);
  position: relative;
  background:
    radial-gradient(92% 56% at 92% -6%, rgba(43, 30, 74, .72), transparent 62%),
    radial-gradient(76% 46% at -12% 16%, rgba(14, 55, 48, .92), transparent 66%),
    var(--bx-navy);
  color: var(--bx-white);
  font-family: var(--bx-font-body);
  overflow-x: clip;
  padding-bottom: clamp(48px, 8vw, 104px);
}

/* ---------- 首屏 ---------- */
.page-about__hero {
  position: relative;
  isolation: isolate;
  padding: clamp(20px, 4vw, 38px) 0 clamp(28px, 5vw, 48px);
}

.page-about__hero::before {
  content: "";
  position: absolute;
  z-index: -2;
  top: -30px;
  left: 34%;
  right: -18%;
  height: 82%;
  background: linear-gradient(148deg, var(--bx-green-2) 0%, var(--bx-green) 44%, rgba(10, 26, 42, 0) 84%);
  clip-path: polygon(24% 0, 100% 0, 100% 70%, 0 100%);
  opacity: .88;
  pointer-events: none;
}

.page-about__hero::after {
  content: "";
  position: absolute;
  z-index: -1;
  left: -16%;
  bottom: 0;
  width: 58%;
  height: 44%;
  background: linear-gradient(118deg, rgba(226, 59, 52, .2), rgba(226, 59, 52, 0) 72%);
  clip-path: polygon(0 0, 100% 46%, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-about__hero-index {
  margin-top: clamp(18px, 4vw, 32px);
  color: var(--bx-cyan);
}

.page-about__title {
  margin: 14px 0 0;
  max-width: 21ch;
  font-size: clamp(1.95rem, 5.4vw, 3.9rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -.012em;
  text-wrap: balance;
}

.page-about__lead {
  margin: clamp(16px, 3vw, 24px) 0 0;
  max-width: 62ch;
  font-size: clamp(.98rem, 1.5vw, 1.12rem);
  line-height: 1.82;
  color: rgba(233, 239, 243, .84);
}

.page-about__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(26px, 5vw, 42px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--bx-line);
  border: 1px solid var(--bx-line);
  border-radius: var(--bx-radius);
  overflow: hidden;
}

.page-about__stat {
  display: grid;
  gap: 5px;
  padding: 15px 16px;
  background: rgba(10, 26, 42, .66);
}

.page-about__stat-num {
  font-family: var(--bx-font-data);
  font-size: clamp(1.4rem, 3.6vw, 2rem);
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.page-about__stat:nth-child(1) .page-about__stat-num { color: var(--bx-yellow); }
.page-about__stat:nth-child(2) .page-about__stat-num { color: var(--bx-cyan); }
.page-about__stat:nth-child(3) .page-about__stat-num { color: var(--bx-white); }
.page-about__stat:nth-child(4) .page-about__stat-num { color: var(--bx-red); }

.page-about__stat-label {
  font-size: 12.5px;
  letter-spacing: .1em;
  color: var(--bx-slate);
}

/* ---------- 主体骨架 ---------- */
.page-about__layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 4vw, 36px);
  padding-top: clamp(20px, 4vw, 34px);
}

.page-about__toc {
  padding: 14px 16px;
  border: 1px solid var(--bx-line);
  border-radius: var(--bx-radius-sm);
  background: linear-gradient(160deg, rgba(14, 55, 48, .5), rgba(10, 26, 42, .34));
}

.page-about__toc-title {
  margin: 0 0 10px;
  font-family: var(--bx-font-data);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--bx-slate);
}

.page-about__toc-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 4px 10px;
}

.page-about__toc-link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 8px;
  border-radius: 8px;
  font-size: 13.5px;
  line-height: 1.5;
  color: rgba(233, 239, 243, .74);
  text-decoration: none;
  transition: background-color .2s var(--bx-ease), color .2s var(--bx-ease);
}

.page-about__toc-num {
  font-family: var(--bx-font-data);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--bx-yellow);
}

.page-about__toc-link:hover,
.page-about__toc-link:focus-visible {
  background: rgba(79, 209, 197, .14);
  color: var(--bx-white);
  outline: none;
}

.page-about__content {
  min-width: 0;
}

.page-about__section {
  position: relative;
  scroll-margin-top: calc(var(--bx-head-h) + 26px);
}

.page-about__section + .page-about__section {
  margin-top: clamp(34px, 6vw, 62px);
  padding-top: clamp(34px, 6vw, 62px);
}

.page-about__section + .page-about__section::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: min(100%, 460px);
  height: 1px;
  background: linear-gradient(90deg, var(--bx-line-strong), rgba(79, 209, 197, 0));
}

.page-about__section-head {
  max-width: 66ch;
  margin-bottom: clamp(20px, 3.4vw, 32px);
}

.page-about__section-head .bx-index {
  color: var(--bx-yellow);
}

.page-about__h2 {
  margin: 10px 0 0;
  font-size: clamp(1.45rem, 3.4vw, 2.25rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -.006em;
}

.page-about__sub {
  margin: 12px 0 0;
  font-size: clamp(.96rem, 1.4vw, 1.05rem);
  line-height: 1.8;
  color: rgba(233, 239, 243, .74);
}

/* ---------- 图片 ---------- */
.page-about__figure {
  margin: 0 0 clamp(22px, 3.5vw, 32px);
  border: 1px solid var(--bx-line);
  border-radius: var(--bx-radius);
  background: linear-gradient(150deg, rgba(21, 80, 69, .42), rgba(10, 26, 42, .5));
  overflow: hidden;
}

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

.page-about__figure figcaption {
  padding: 12px 16px;
  border-top: 1px solid var(--bx-line);
  font-size: 12.5px;
  line-height: 1.65;
  letter-spacing: .07em;
  color: var(--bx-slate);
}

.page-about__figure--center {
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.page-about__figure--side {
  margin-bottom: 0;
}

/* ---------- 编年时间轴 ---------- */
.page-about__timeline {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: clamp(15px, 2.6vw, 22px);
}

.page-about__timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 12px;
  bottom: 12px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--bx-red) 0%, var(--bx-yellow) 40%, var(--bx-cyan) 100%);
  opacity: .66;
}

.page-about__stage {
  position: relative;
  padding-left: 34px;
}

.page-about__stage::before {
  content: "";
  position: absolute;
  left: 0;
  top: 20px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--bx-navy);
  border: 3px solid var(--bx-cyan);
  box-shadow: 0 0 0 4px rgba(79, 209, 197, .12);
}

.page-about__stage:nth-child(2)::before {
  border-color: var(--bx-yellow);
  box-shadow: 0 0 0 4px rgba(242, 194, 48, .14);
}

.page-about__stage:nth-child(3)::before {
  border-color: var(--bx-red);
  box-shadow: 0 0 0 4px rgba(226, 59, 52, .14);
}

.page-about__stage:nth-child(4)::before {
  border-color: var(--bx-yellow);
  box-shadow: 0 0 0 4px rgba(242, 194, 48, .14);
}

.page-about__stage-body {
  padding: 17px 19px 19px;
  border: 1px solid var(--bx-line);
  border-radius: var(--bx-radius-sm);
  background: linear-gradient(150deg, rgba(233, 239, 243, .055), rgba(233, 239, 243, .014));
}

.page-about__stage:nth-child(2) .page-about__stage-body {
  background: linear-gradient(150deg, rgba(74, 28, 44, .44), rgba(10, 26, 42, .34));
}

.page-about__stage:nth-child(3) .page-about__stage-body {
  background: linear-gradient(150deg, rgba(43, 30, 74, .48), rgba(10, 26, 42, .34));
}

.page-about__stage:nth-child(5) .page-about__stage-body {
  background: linear-gradient(150deg, rgba(21, 80, 69, .46), rgba(10, 26, 42, .34));
}

.page-about__era {
  margin: 0;
  font-family: var(--bx-font-data);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--bx-cyan);
  font-variant-numeric: tabular-nums;
}

.page-about__stage-title {
  margin: 8px 0 0;
  font-size: clamp(1.02rem, 2vw, 1.2rem);
  font-weight: 700;
  line-height: 1.42;
}

.page-about__stage-text {
  margin: 8px 0 0;
  font-size: .96rem;
  line-height: 1.82;
  color: rgba(233, 239, 243, .78);
}

/* ---------- 正文链接 ---------- */
.page-about__stage-text a,
.page-about__note a,
.page-about__closing a {
  color: var(--bx-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(79, 209, 197, .4);
  transition: color .2s var(--bx-ease), border-color .2s var(--bx-ease);
}

.page-about__stage-text a:hover,
.page-about__note a:hover,
.page-about__closing a:hover,
.page-about__stage-text a:focus-visible,
.page-about__note a:focus-visible,
.page-about__closing a:focus-visible {
  color: var(--bx-yellow);
  border-bottom-color: rgba(242, 194, 48, .65);
  outline: none;
}

/* ---------- 团队分工 ---------- */
.page-about__split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3.5vw, 30px);
}

.page-about__lanes {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about__lane {
  padding: 18px 19px 20px;
  border: 1px solid var(--bx-line);
  border-radius: var(--bx-radius-sm);
  background: linear-gradient(142deg, rgba(21, 80, 69, .52), rgba(10, 26, 42, .38));
}

.page-about__lane:nth-child(2) {
  background: linear-gradient(142deg, rgba(43, 30, 74, .56), rgba(10, 26, 42, .38));
}

.page-about__lane:nth-child(3) {
  background: linear-gradient(142deg, rgba(74, 28, 44, .5), rgba(10, 26, 42, .38));
}

.page-about__lane-num {
  margin: 0;
  font-family: var(--bx-font-data);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--bx-yellow);
}

.page-about__lane-title {
  margin: 8px 0 0;
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.44;
}

.page-about__lane-text {
  margin: 8px 0 0;
  font-size: .95rem;
  line-height: 1.8;
  color: rgba(233, 239, 243, .78);
}

/* ---------- 覆盖范围 ---------- */
.page-about__coverage {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about__cov {
  display: grid;
  align-content: start;
  gap: 6px;
  padding: 19px 20px 21px;
  border: 1px solid var(--bx-line);
  border-radius: var(--bx-radius-sm);
  background: var(--about-card-bg);
}

.page-about__cov-num {
  margin: 0;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--bx-line-strong);
  font-family: var(--bx-font-data);
  font-size: clamp(1.7rem, 4vw, 2.2rem);
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--bx-cyan);
}

.page-about__cov-title {
  margin: 4px 0 0;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: .02em;
}

.page-about__cov-text {
  margin: 0;
  font-size: .94rem;
  line-height: 1.78;
  color: rgba(233, 239, 243, .76);
}

/* ---------- 服务承诺 ---------- */
.page-about__pledges {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about__pledge {
  padding: 20px 20px 22px;
  border: 1px solid var(--bx-line);
  border-top-width: 3px;
  border-radius: var(--bx-radius-sm);
  background: var(--about-card-bg);
}

.page-about__pledge--red { border-top-color: var(--bx-red); }
.page-about__pledge--yellow { border-top-color: var(--bx-yellow); }
.page-about__pledge--cyan { border-top-color: var(--bx-cyan); }

.page-about__pledge-num {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin: 0;
  font-family: var(--bx-font-data);
  font-size: clamp(1.8rem, 4.4vw, 2.5rem);
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.page-about__pledge-num span {
  font-size: .85rem;
  font-weight: 500;
  letter-spacing: .05em;
  color: var(--bx-slate);
}

.page-about__pledge--red .page-about__pledge-num { color: var(--bx-red); }
.page-about__pledge--yellow .page-about__pledge-num { color: var(--bx-yellow); }
.page-about__pledge--cyan .page-about__pledge-num { color: var(--bx-cyan); }

.page-about__pledge h3 {
  margin: 14px 0 0;
  font-size: 1.02rem;
  font-weight: 700;
}

.page-about__pledge p:not(.page-about__pledge-num) {
  margin: 8px 0 0;
  font-size: .94rem;
  line-height: 1.78;
  color: rgba(233, 239, 243, .76);
}

/* ---------- 提示与结尾 ---------- */
.page-about__note {
  max-width: 72ch;
  margin: clamp(18px, 3vw, 26px) 0 0;
  padding: 14px 18px;
  border-left: 3px solid var(--bx-yellow);
  border-radius: 0 var(--bx-radius-sm) var(--bx-radius-sm) 0;
  background: rgba(242, 194, 48, .075);
  font-size: .94rem;
  line-height: 1.78;
  color: rgba(233, 239, 243, .84);
}

.page-about__closing {
  max-width: 68ch;
  margin: clamp(20px, 3vw, 28px) 0 0;
  font-size: .97rem;
  line-height: 1.85;
  color: rgba(233, 239, 243, .78);
}

/* ---------- 备案与联系 ---------- */
.page-about__contact {
  margin: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border: 1px solid var(--bx-line);
  border-radius: var(--bx-radius);
  overflow: hidden;
  background: rgba(233, 239, 243, .04);
}

.page-about__contact-row {
  display: grid;
  gap: 6px;
  padding: 15px 18px;
  background: rgba(10, 26, 42, .42);
}

.page-about__contact-row + .page-about__contact-row {
  border-top: 1px solid var(--bx-line);
}

.page-about__contact-row dt {
  font-size: 12.5px;
  letter-spacing: .12em;
  color: var(--bx-slate);
}

.page-about__contact-row dd {
  margin: 0;
  font-size: 1rem;
  line-height: 1.7;
  overflow-wrap: anywhere;
}

.page-about__contact-row dd .bx-num {
  font-family: var(--bx-font-data);
  font-variant-numeric: tabular-nums;
  letter-spacing: .01em;
}

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

  .page-about__stat {
    padding: 18px 18px;
  }

  .page-about__contact-row {
    grid-template-columns: 148px minmax(0, 1fr);
    align-items: baseline;
    gap: 24px;
    padding: 17px 20px;
  }
}

@media (min-width: 720px) {
  .page-about__coverage {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 880px) {
  .page-about__split {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    align-items: start;
  }

  .page-about__figure--side {
    position: sticky;
    top: calc(var(--bx-head-h) + 24px);
  }
}

@media (min-width: 1000px) {
  .page-about__layout {
    grid-template-columns: 212px minmax(0, 1fr);
    gap: clamp(38px, 5vw, 68px);
    align-items: start;
    padding-top: clamp(26px, 4vw, 40px);
  }

  .page-about__toc {
    position: sticky;
    top: calc(var(--bx-head-h) + 22px);
    padding: 18px 16px 20px;
  }

  .page-about__toc-list {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px;
  }

  .page-about__toc-link {
    padding: 8px 10px;
    font-size: 14px;
  }

  .page-about__stage-body {
    padding: 20px 24px 22px;
  }

  .page-about__timeline {
    gap: 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about__toc-link,
  .page-about__stage-text a,
  .page-about__note a,
  .page-about__closing a {
    transition: none;
  }
}