.page-about {
  --ab-rail: 156px;
  --ab-dot: 9px;
  background: var(--paper);
  color: var(--graphite);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  background: var(--ink);
  color: var(--white);
  overflow: hidden;
}
.page-about .ab-hero__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.34;
  display: block;
}
.page-about .ab-hero__veil {
  position: absolute;
  inset: 0;
  background: linear-gradient(172deg, rgba(11, 18, 32, 0.7), rgba(11, 18, 32, 0.96) 74%);
}
.page-about .ab-hero__inner {
  position: relative;
  padding-top: 20px;
  padding-bottom: 44px;
}
.page-about .ab-hero__crumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}
.page-about .ab-hero__crumb a {
  color: var(--mist);
  text-decoration: none;
}
.page-about .ab-hero__crumb a:hover {
  color: var(--cyan);
}
.page-about .ab-hero__crumb .breadcrumb__sep {
  color: rgba(169, 192, 255, 0.45);
}
.page-about .ab-hero__crumb .breadcrumb__here {
  color: var(--white);
}
.page-about .ab-hero__eyebrow {
  margin: 22px 0 0;
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
}
.page-about .ab-hero__title {
  margin: 14px 0 0;
  max-width: 20em;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 7vw, 54px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--white);
}
.page-about .ab-hero__lead {
  margin: 18px 0 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(232, 238, 255, 0.82);
}
.page-about .ab-figures {
  margin: 30px 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--hair-invert);
  border: 1px solid var(--hair-invert);
}
.page-about .ab-figure {
  display: flex;
  flex-direction: column-reverse;
  gap: 6px;
  padding: 14px 14px 16px;
  background: rgba(16, 27, 51, 0.92);
}
.page-about .ab-figure dt,
.page-about .ab-figure dd {
  margin: 0;
}
.page-about .ab-figure__label {
  font-size: 12px;
  line-height: 1.5;
  color: var(--mist);
  letter-spacing: 0.02em;
}
.page-about .ab-figure__num {
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 600;
  line-height: 1;
  color: var(--white);
  letter-spacing: 0.02em;
}
.page-about .ab-figure__num span {
  font-size: 15px;
  color: var(--cyan);
  margin-left: 2px;
}

/* ---------- 章节头 ---------- */
.page-about .ab-sec-head {
  margin: 0 0 28px;
}
.page-about .ab-sec-head__no {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--blue);
  text-transform: uppercase;
}
.page-about .ab-sec-head__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 4.6vw, 34px);
  line-height: 1.3;
  color: var(--black);
  letter-spacing: -0.01em;
}
.page-about .ab-sec-head__note {
  margin: 12px 0 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--slate);
}
.page-about .ab-sec-head--invert .ab-sec-head__no {
  color: var(--cyan);
}
.page-about .ab-sec-head--invert .ab-sec-head__title {
  color: var(--white);
}
.page-about .ab-sec-head--invert .ab-sec-head__note {
  color: var(--mist);
}

/* ---------- 编年史 ---------- */
.page-about .ab-chron {
  padding: 48px 0 44px;
  border-top: 1px solid var(--hair);
}
.page-about .ab-chron__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}
.page-about .ab-years {
  margin: 0 0 22px;
}
.page-about .ab-years__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--slate);
}
.page-about .ab-years__list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
}
.page-about .ab-years__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 6px 10px;
  border: 1px solid var(--hair);
  background: var(--white);
  text-decoration: none;
  white-space: nowrap;
}
.page-about .ab-years__link:hover {
  border-color: var(--blue);
}
.page-about .ab-years__no {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--slate);
  letter-spacing: 0.02em;
}
.page-about .ab-years__tag {
  font-size: 11px;
  color: var(--slate);
}
.page-about .ab-years__link[aria-current="true"] .ab-years__no {
  color: var(--blue);
}
.page-about .ab-years__link[aria-current="true"] .ab-years__tag {
  color: var(--black);
}

.page-about .ab-track {
  position: relative;
}
.page-about .ab-track::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 12px;
  bottom: 14px;
  width: 1px;
  background: var(--hair);
}
.page-about .ab-era {
  position: relative;
  padding: 0 0 34px 30px;
}
.page-about .ab-era:last-child {
  padding-bottom: 0;
}
.page-about .ab-era::before {
  content: "";
  position: absolute;
  left: 0;
  top: 7px;
  width: var(--ab-dot);
  height: var(--ab-dot);
  border-radius: 50%;
  background: var(--paper);
  border: 1px solid var(--blue);
  box-sizing: border-box;
}
.page-about .ab-era--flag::before {
  background: var(--orange);
  border-color: var(--orange);
}
.page-about .ab-era__year {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.04em;
  color: var(--blue);
}
.page-about .ab-era__title {
  margin: 0 0 8px;
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: 19px;
  line-height: 1.45;
  color: var(--black);
}
.page-about .ab-era__body {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--graphite);
}
.page-about .ab-era__tip {
  max-height: 0;
  overflow: hidden;
  margin: 0;
  padding: 0 12px;
  border-left: 2px solid var(--blue);
  background: var(--paper-mist);
  font-size: 13px;
  line-height: 1.7;
  color: var(--slate);
  transition: max-height var(--dur) var(--ease), padding var(--dur) var(--ease),
    margin var(--dur) var(--ease);
}
.page-about .ab-era:hover .ab-era__tip,
.page-about .ab-era:focus-within .ab-era__tip {
  max-height: 160px;
  margin: 12px 0 0;
  padding: 9px 12px;
}

/* ---------- 满幅条带：六条产品线 ---------- */
.page-about .ab-lines {
  position: relative;
  padding: 52px 0 46px;
  background: var(--ink);
  color: var(--white);
  overflow: hidden;
}
.page-about .ab-lines::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(
    90deg,
    var(--hair-invert) 0 1px,
    transparent 1px 96px
  );
  opacity: 0.55;
  pointer-events: none;
}
.page-about .ab-lines .shell {
  position: relative;
  z-index: 1;
}
.page-about .ab-lines__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border-top: 1px solid var(--hair-invert);
}
.page-about .ab-line {
  padding: 20px 16px 22px;
  border-bottom: 1px solid var(--hair-invert);
  transition: background var(--dur) var(--ease);
}
.page-about .ab-line:focus {
  outline: 2px solid var(--blue-2);
  outline-offset: -2px;
}
.page-about .ab-line:hover,
.page-about .ab-line:focus-within {
  background: var(--ink-2);
}
.page-about .ab-line__no {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}
.page-about .ab-line__name {
  margin: 0 0 8px;
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: 18px;
  line-height: 1.4;
  color: var(--white);
}
.page-about .ab-line__solve {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(232, 238, 255, 0.74);
}
.page-about .ab-line__apps {
  margin: 12px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  color: var(--blue-2);
  opacity: 0;
  transform: translateY(-4px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.page-about .ab-line:hover .ab-line__apps,
.page-about .ab-line:focus-within .ab-line__apps {
  opacity: 1;
  transform: none;
}

.page-about .ab-services {
  margin: 26px 0 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border: 1px solid var(--hair-invert);
}
.page-about .ab-service {
  padding: 18px 16px 20px;
  border-bottom: 1px solid var(--hair-invert);
}
.page-about .ab-service:last-child {
  border-bottom: 0;
}
.page-about .ab-service__name {
  margin: 0 0 8px;
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: 16px;
  color: var(--white);
}
.page-about .ab-service__text {
  margin: 0 0 12px;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(232, 238, 255, 0.72);
}
.page-about .ab-service__link {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid rgba(169, 192, 255, 0.4);
  padding-bottom: 2px;
}
.page-about .ab-service__link:hover {
  color: var(--white);
  border-bottom-color: var(--white);
}

/* ---------- 技术支持 ---------- */
.page-about .ab-support {
  padding: 52px 0;
  border-top: 1px solid var(--hair);
}
.page-about .ab-support__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  align-items: start;
}
.page-about .ab-steps {
  list-style: none;
  margin: 0;
  padding: 0;
}
.page-about .ab-step {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 14px;
  padding: 18px 0;
  border-top: 1px solid var(--hair);
}
.page-about .ab-step:last-child {
  border-bottom: 1px solid var(--hair);
}
.page-about .ab-step__no {
  margin: 0;
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--blue);
}
.page-about .ab-step h3 {
  margin: 0 0 6px;
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: 17px;
  color: var(--black);
}
.page-about .ab-step p {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: var(--graphite);
}
.page-about .ab-support__main .note {
  margin: 20px 0 0;
  font-size: 14px;
  line-height: 1.8;
}
.page-about .ab-support__fig {
  margin: 0;
}
.page-about .ab-support__fig .media__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 资质 ---------- */
.page-about .ab-cert {
  padding: 52px 0;
  background: var(--paper-mist);
}
.page-about .ab-cert__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  align-items: center;
}
.page-about .ab-cert__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}
.page-about .ab-badge {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  padding: 16px;
  background: var(--paper);
}
.page-about .ab-badge svg {
  display: block;
  width: 42px;
  height: 42px;
  color: var(--blue);
}
.page-about .ab-badge h3 {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--black);
}
.page-about .ab-badge p {
  margin: 0;
  font-size: 13px;
  line-height: 1.72;
  color: var(--graphite);
}
.page-about .ab-cert__fig {
  margin: 0;
  background: var(--paper);
}
.page-about .ab-cert__fig .media__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 行业 ---------- */
.page-about .ab-industry {
  padding: 52px 0;
}
.page-about .ab-ind__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}
.page-about .ab-ind {
  padding: 18px 16px 20px;
  background: var(--paper);
}
.page-about .ab-ind__name {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 8px;
  font-family: var(--font-ui);
  font-weight: 600;
  font-size: 16px;
  color: var(--black);
}
.page-about .ab-ind__no {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.06em;
  color: var(--blue);
}
.page-about .ab-ind__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--graphite);
}

/* ---------- 合作方式 ---------- */
.page-about .ab-coop {
  padding: 52px 0;
  border-top: 1px solid var(--hair);
}
.page-about .ab-coop__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}
.page-about .ab-coop__card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 22px 20px;
  border: 1px solid var(--hair);
  background: var(--white);
}
.page-about .ab-coop__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--slate);
}
.page-about .ab-coop__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 21px;
  line-height: 1.35;
  color: var(--black);
}
.page-about .ab-coop__text {
  margin: 0 0 6px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--graphite);
}
.page-about .ab-coop__card--main {
  background: var(--ink);
  border-color: var(--ink);
}
.page-about .ab-coop__card--main .ab-coop__no {
  color: var(--mist);
}
.page-about .ab-coop__card--main .ab-coop__title {
  color: var(--white);
}
.page-about .ab-coop__card--main .ab-coop__text {
  color: rgba(232, 238, 255, 0.76);
}
.page-about .ab-link {
  margin-top: auto;
  display: inline-block;
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 600;
  color: var(--blue);
  text-decoration: none;
  border-bottom: 1px solid rgba(30, 90, 255, 0.35);
  padding-bottom: 3px;
  align-self: flex-start;
}
.page-about .ab-link:hover {
  border-bottom-color: var(--blue);
}
.page-about .ab-coop__card--main .ab-link {
  color: var(--mist);
  border-bottom-color: rgba(169, 192, 255, 0.4);
}
.page-about .ab-coop__card--main .ab-link:hover {
  color: var(--white);
  border-bottom-color: var(--white);
}

/* ---------- 收尾 ---------- */
.page-about .ab-tail {
  padding: 0 0 56px;
}
.page-about .ab-tail__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  align-items: center;
  justify-content: space-between;
  padding-top: 26px;
  border-top: 1px solid var(--hair);
}
.page-about .ab-tail__text {
  margin: 0;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--graphite);
}
.page-about .ab-tail__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .ab-figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .ab-lines__grid {
    grid-template-columns: 1.12fr 0.94fr 1.3fr;
  }
  .page-about .ab-line {
    border-right: 1px solid var(--hair-invert);
  }
  .page-about .ab-lines__grid .ab-line:nth-child(3n) {
    border-right: 0;
  }
  .page-about .ab-lines__grid .ab-line:nth-child(n + 4) {
    border-bottom: 0;
  }
  .page-about .ab-services {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }
  .page-about .ab-service {
    border-bottom: 0;
    border-right: 1px solid var(--hair-invert);
  }
  .page-about .ab-service:last-child {
    border-right: 0;
  }
  .page-about .ab-ind__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .ab-coop__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  }
  .page-about .ab-coop__card--main {
    grid-row: span 2;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero__inner {
    padding-top: 26px;
    padding-bottom: 56px;
  }
  .page-about .ab-hero__lead {
    font-size: 16px;
  }
  .page-about .ab-chron {
    padding: 60px 0 52px;
  }
  .page-about .ab-chron__grid {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 48px;
  }
  .page-about .ab-years {
    position: sticky;
    top: calc(var(--cmd-h) + 16px);
    align-self: start;
    margin: 0;
  }
  .page-about .ab-years__title {
    padding-bottom: 8px;
    border-bottom: 1px solid var(--hair);
  }
  .page-about .ab-years__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }
  .page-about .ab-years__link {
    position: relative;
    border: 0;
    background: transparent;
    padding: 8px 10px 8px 14px;
    white-space: normal;
  }
  .page-about .ab-years__link::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 2px;
    height: 0;
    background: var(--blue);
    transition: height var(--dur) var(--ease);
  }
  .page-about .ab-years__link:hover::before,
  .page-about .ab-years__link[aria-current="true"]::before {
    height: 18px;
  }
  .page-about .ab-era {
    padding-left: 34px;
  }
  .page-about .ab-era__title {
    font-size: 20px;
  }
  .page-about .ab-lines {
    padding: 62px 0 54px;
  }
  .page-about .ab-support {
    padding: 62px 0;
  }
  .page-about .ab-support__grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: 48px;
  }
  .page-about .ab-cert {
    padding: 62px 0;
  }
  .page-about .ab-cert__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    gap: 40px;
  }
  .page-about .ab-industry,
  .page-about .ab-coop {
    padding: 62px 0;
  }
  .page-about .ab-coop__grid {
    grid-template-columns: 1.25fr 1fr 1fr;
  }
  .page-about .ab-coop__card--main {
    grid-row: auto;
  }
}

@media (min-width: 1040px) {
  .page-about .ab-ind__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .ab-coop__title {
    font-size: 22px;
  }
}

@media (hover: none) {
  .page-about .ab-era__tip {
    max-height: 200px;
    margin: 12px 0 0;
    padding: 9px 12px;
  }
  .page-about .ab-line__apps {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-era__tip,
  .page-about .ab-line__apps,
  .page-about .ab-line,
  .page-about .ab-years__link::before {
    transition: none;
  }
  .page-about .ab-line__apps {
    opacity: 1;
    transform: none;
  }
}