.page-about {
  --about-rail-w: 208px;
  --about-gap: clamp(24px, 4vw, 56px);
  --about-pad: clamp(20px, 3vw, 40px);
  --about-rule: rgba(11, 20, 32, 0.08);
  background: var(--white);
  color: var(--ink);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(36px, 6vw, 76px) 0 clamp(22px, 3.4vw, 36px);
}

.page-about .about-hero__eyebrow {
  margin-top: 20px;
  color: var(--ublue);
  letter-spacing: 0.18em;
}

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

.page-about .about-hero__title {
  margin: 14px 0 0;
  max-width: 15em;
  font-size: clamp(29px, 6vw, 58px);
  line-height: 1.12;
  letter-spacing: -0.015em;
  font-weight: 900;
}

.page-about .about-hero__lede {
  margin-top: 18px;
  max-width: 40em;
  color: var(--steel);
}

.page-about .about-hero__note {
  color: var(--steel);
  opacity: 0.7;
  font-size: 12px;
  letter-spacing: 0.18em;
  transition: opacity var(--dur), color var(--dur), letter-spacing var(--dur);
}

.page-about .about-hero__note:hover {
  opacity: 1;
  color: var(--ublue);
  letter-spacing: 0.26em;
}

@media (min-width: 880px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 48px;
  }
}

@media (max-width: 879px) {
  .page-about .about-hero__note {
    display: none;
  }
}

/* ---------- 首屏数据带 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(28px, 4.4vw, 46px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--mist);
  border: 1px solid var(--mist);
  border-radius: var(--radius);
  overflow: hidden;
}

@media (min-width: 820px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-stats__item {
  background: var(--white);
  padding: 18px 16px 20px;
}

.page-about .about-stats__num {
  display: block;
  font-size: clamp(21px, 3.2vw, 30px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--ublue);
}

.page-about .about-stats__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--steel);
}

/* ---------- 主体栅格 ---------- */
.page-about .about-body {
  padding-bottom: clamp(32px, 5vw, 72px);
}

@media (min-width: 1000px) {
  .page-about .about-body {
    display: grid;
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }
}

/* ---------- 左侧时间轨道 ---------- */
.page-about .about-rail {
  position: sticky;
  top: 0;
  z-index: 6;
  margin: 0 calc(var(--gutter) * -1) 22px;
  padding: 10px var(--gutter);
  background: rgba(247, 249, 252, 0.94);
  border-bottom: 1px solid var(--mist);
  backdrop-filter: blur(10px);
}

.page-about .about-rail__head {
  margin: 0 0 8px;
  font-size: 10px;
  letter-spacing: 0.22em;
  color: var(--tint);
}

.page-about .about-rail__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 2px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  min-height: 44px;
  padding: 0 14px;
  border: 1px solid var(--mist);
  border-radius: 999px;
  background: var(--white);
  color: var(--steel);
  font-size: 13px;
  line-height: 1;
  white-space: nowrap;
  text-decoration: none;
  transition: color var(--dur), border-color var(--dur), background var(--dur);
}

.page-about .about-rail__num {
  font-size: 11px;
  color: var(--tint);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--ublue);
  border-color: var(--cyan);
}

@media (min-width: 1000px) {
  .page-about .about-rail {
    top: 32px;
    margin: 0;
    padding: 0;
    background: none;
    border-bottom: 0;
    backdrop-filter: none;
  }

  .page-about .about-rail__head {
    margin-bottom: 14px;
  }

  .page-about .about-rail__list {
    position: relative;
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-left: 0;
  }

  .page-about .about-rail__list::before {
    content: "";
    position: absolute;
    left: 3px;
    top: 14px;
    bottom: 14px;
    width: 1px;
    background: var(--mist);
  }

  .page-about .about-rail__link {
    position: relative;
    display: flex;
    min-height: 44px;
    padding: 10px 0 10px 22px;
    border: 0;
    border-radius: 0;
    background: none;
    white-space: normal;
  }

  .page-about .about-rail__link::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 7px;
    height: 7px;
    margin-top: -3.5px;
    border: 1px solid var(--tint);
    border-radius: 50%;
    background: var(--white);
    transition: background var(--dur), border-color var(--dur), box-shadow var(--dur);
  }

  .page-about .about-rail__link:hover::before,
  .page-about .about-rail__link:focus-visible::before {
    border-color: var(--cyan);
    background: var(--cyan);
    box-shadow: 0 0 0 4px rgba(46, 230, 214, 0.18);
  }
}

/* ---------- 章节容器 ---------- */
.page-about .about-chapter {
  padding: var(--about-pad);
  background: var(--white);
  border: 1px solid var(--mist);
  border-radius: var(--radius);
  scroll-margin-top: 92px;
  transition: border-color var(--dur), box-shadow var(--dur);
}

.page-about .about-chapter + .about-chapter {
  margin-top: clamp(18px, 2.4vw, 28px);
}

.page-about .about-chapter--paper {
  background: var(--paper);
  border-color: var(--about-rule);
}

.page-about .about-chapter:target {
  border-color: var(--ublue);
  box-shadow: 0 0 0 3px rgba(29, 91, 214, 0.1);
}

.page-about .about-chapter__head {
  margin-bottom: clamp(18px, 2.8vw, 30px);
}

.page-about .about-chapter__no {
  display: inline-block;
  margin: 0;
  padding: 4px 11px;
  border: 1px solid var(--ublue);
  border-radius: 999px;
  color: var(--ublue);
  font-size: 11px;
  letter-spacing: 0.14em;
}

.page-about .about-chapter__title {
  margin: 14px 0 0;
  font-size: clamp(22px, 3.4vw, 33px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  font-weight: 800;
}

.page-about .about-chapter__lede {
  margin: 12px 0 0;
  max-width: 38em;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
  color: var(--steel);
}

/* ---------- 三条业务主线 ---------- */
.page-about .about-lines {
  display: grid;
  gap: 1px;
  background: var(--about-rule);
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  overflow: hidden;
}

@media (min-width: 780px) {
  .page-about .about-lines {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-line {
  background: var(--white);
  padding: clamp(18px, 2.4vw, 26px);
}

.page-about .about-line__tag {
  margin: 0;
  font-size: 10px;
  letter-spacing: 0.24em;
  color: var(--tint);
}

.page-about .about-line__title {
  margin: 10px 0 0;
  font-size: 19px;
  font-weight: 800;
  line-height: 1.35;
}

.page-about .about-line__text {
  margin: 12px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--steel);
}

.page-about .about-line__facts {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--mist);
  padding-top: 14px;
}

.page-about .about-line__facts li {
  position: relative;
  padding-left: 15px;
  font-size: 13px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-line__facts li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.82em;
  width: 6px;
  height: 1px;
  background: var(--ublue);
}

/* ---------- 蓝标认证 ---------- */
.page-about .about-check {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}

@media (min-width: 840px) {
  .page-about .about-check {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: start;
  }
}

.page-about .about-seal {
  float: left;
  width: 64px;
  height: 64px;
  margin: 4px 18px 6px 0;
  color: var(--ublue);
}

.page-about .about-check__text p {
  margin: 0 0 16px;
  font-size: 15.5px;
  line-height: 1.86;
  color: var(--steel);
}

.page-about .about-check__text p:last-child {
  margin-bottom: 0;
}

.page-about .about-check__figure {
  margin: 0;
  border-radius: var(--radius);
  overflow: hidden;
}

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

/* ---------- 发展历程 ---------- */
.page-about .about-history__figure {
  margin: 0 0 clamp(22px, 3vw, 34px);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--mist);
}

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

.page-about .about-timeline {
  position: relative;
  margin: 0;
  padding: 0 0 0 24px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 12px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--ublue) 0%, var(--tint) 45%, var(--mist) 100%);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: clamp(20px, 2.8vw, 30px);
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -24px;
  top: 7px;
  width: 11px;
  height: 11px;
  border: 2px solid var(--ublue);
  border-radius: 50%;
  background: var(--paper);
}

.page-about .about-timeline__item:last-child::before {
  border-color: var(--cyan);
  background: var(--cyan);
}

.page-about .about-timeline__tag {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ublue);
}

.page-about .about-timeline__title {
  margin: 8px 0 0;
  font-size: clamp(16px, 2vw, 19px);
  font-weight: 800;
  line-height: 1.4;
}

.page-about .about-timeline__text {
  margin: 8px 0 0;
  max-width: 40em;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--steel);
}

/* ---------- 服务规模 ---------- */
.page-about .about-scale {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 14px;
}

.page-about .about-scale__item {
  padding: 20px 18px 22px;
  border: 1px solid var(--mist);
  border-left: 3px solid var(--ublue);
  border-radius: var(--radius-sm);
  background: linear-gradient(180deg, rgba(29, 91, 214, 0.055) 0%, rgba(29, 91, 214, 0) 72%);
}

.page-about .about-scale__num {
  margin: 0;
  font-size: clamp(22px, 3.2vw, 30px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--ublue);
  line-height: 1.1;
}

.page-about .about-scale__label {
  margin: 8px 0 0;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.5;
}

.page-about .about-scale__desc {
  margin: 8px 0 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--steel);
}

/* ---------- 团队分工 ---------- */
.page-about .about-teams {
  display: grid;
  gap: clamp(18px, 2.4vw, 28px);
}

@media (min-width: 780px) {
  .page-about .about-teams {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-team {
  padding-left: 16px;
  border-left: 2px solid var(--ublue);
}

.page-about .about-team__tag {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--ublue);
}

.page-about .about-team__title {
  margin: 9px 0 0;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.45;
}

.page-about .about-team__text {
  margin: 10px 0 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--steel);
}

.page-about .about-sla {
  display: grid;
  gap: 12px;
  margin: clamp(22px, 3vw, 32px) 0 0;
}

@media (min-width: 660px) {
  .page-about .about-sla {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-sla__item {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin: 0;
  padding: 15px 18px;
  background: var(--white);
  border: 1px solid var(--mist);
  border-radius: var(--radius-sm);
}

.page-about .about-sla__num {
  flex: none;
  font-size: 17px;
  font-weight: 700;
  color: var(--ublue);
}

.page-about .about-sla__text {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--steel);
}

/* ---------- 适配生态 ---------- */
.page-about .about-eco {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}

@media (min-width: 840px) {
  .page-about .about-eco {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.86fr);
    align-items: start;
  }
}

.page-about .about-eco__text p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.86;
  color: var(--steel);
}

.page-about .about-eco__list {
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--mist);
}

.page-about .about-eco__list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
  padding: 13px 0;
  border-bottom: 1px solid var(--mist);
}

.page-about .about-eco__key {
  flex: none;
  min-width: 76px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ublue);
}

.page-about .about-eco__val {
  font-size: 14px;
  line-height: 1.7;
}

.page-about .about-eco__figure {
  margin: 0;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--mist);
}

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

/* ---------- 收束 ---------- */
.page-about .about-close {
  margin-top: clamp(30px, 5vw, 60px);
  padding: clamp(38px, 6vw, 72px) 0;
  background: var(--steel);
  color: var(--white);
}

.page-about .about-close__eyebrow {
  margin: 0;
  color: var(--cyan);
  letter-spacing: 0.2em;
}

.page-about .about-close__title {
  margin: 14px 0 0;
  max-width: 18em;
  font-size: clamp(24px, 4vw, 40px);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .about-close__text {
  margin: 16px 0 0;
  max-width: 36em;
  font-size: 15.5px;
  line-height: 1.85;
  color: rgba(247, 249, 252, 0.78);
}

.page-about .about-close__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 32px);
}

.page-about .about-close .btn {
  min-height: 44px;
  background: transparent;
  border: 1px solid rgba(247, 249, 252, 0.34);
  color: var(--white);
  transition: color var(--dur), border-color var(--dur), background var(--dur);
}

.page-about .about-close .btn:hover,
.page-about .about-close .btn:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

.page-about .about-close .btn--primary {
  background: var(--ublue);
  border-color: var(--ublue);
  color: var(--white);
}

.page-about .about-close .btn--primary:hover,
.page-about .about-close .btn--primary:focus-visible {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
}

/* ---------- 小屏收尾 ---------- */
@media (max-width: 559px) {
  .page-about .about-chapter {
    border-radius: var(--radius-sm);
  }

  .page-about .about-seal {
    width: 52px;
    height: 52px;
    margin-right: 14px;
  }

  .page-about .about-close__actions .btn {
    flex: 1 1 45%;
    justify-content: center;
  }
}

.page-about img {
  max-width: 100%;
  height: auto;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-hero__note,
  .page-about .about-close .btn {
    transition: none;
  }
}