.page-about {
  --about-hang: 72px;
  background: var(--ink);
  color: var(--paper);
  padding-bottom: 24px;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-top: 24px;
  padding-bottom: 4px;
  font-size: var(--fs-14);
  color: var(--mute);
}

.page-about .breadcrumbs a {
  color: var(--gold);
  text-decoration: none;
}

.page-about .breadcrumbs a:hover,
.page-about .breadcrumbs a:focus-visible {
  text-decoration: underline;
}

.page-about .breadcrumbs__sep {
  color: var(--grid);
}

/* ---------- 页首 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 8px 0 56px;
  background:
    radial-gradient(880px 400px at 8% -14%, rgba(201, 162, 74, 0.22), transparent 62%),
    radial-gradient(720px 360px at 94% 4%, rgba(123, 77, 255, 0.20), transparent 60%);
}

.page-about .about-hero__inner {
  max-width: 960px;
  padding-top: 16px;
  padding-bottom: 36px;
}

.page-about .about-hero__kicker {
  margin: 0 0 20px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--gold);
}

.page-about .about-hero__title {
  margin: 0 0 24px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 6.2vw, 72px);
  line-height: 1.08;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-hero__lede {
  max-width: 68ch;
  margin: 0 0 32px;
  font-size: clamp(16px, 2vw, 20px);
  line-height: 1.75;
  color: rgba(243, 236, 221, 0.82);
}

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

.page-about .about-hero__figure {
  margin-top: 8px;
}

.page-about .image-frame__media {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 主体两栏 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 40px;
  padding-top: 48px;
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: 216px minmax(0, 1fr);
    gap: 64px;
    padding-top: 72px;
  }
}

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

/* ---------- 左侧目录 ---------- */
.page-about .about-rail {
  border-top: 1px solid var(--gold);
  padding-top: 16px;
}

@media (min-width: 1024px) {
  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    align-self: start;
    border-top: 0;
    border-left: 1px solid var(--grid);
    padding: 4px 0 0 20px;
  }
}

.page-about .about-rail__label {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--mute);
}

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

.page-about .about-rail__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 0;
  font-size: var(--fs-14);
  color: var(--mute);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--gold);
}

.page-about .about-rail__num {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--gold);
}

.page-about .about-rail__note {
  margin: 20px 0 0;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--mute);
}

@media (min-width: 1024px) {
  .page-about .about-rail__note {
    margin-top: 28px;
  }
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  padding: 48px 0;
  border-top: 1px solid var(--grid);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec__head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  margin-bottom: 32px;
}

@media (min-width: 768px) {
  .page-about .about-sec__head {
    grid-template-columns: var(--about-hang) minmax(0, 1fr);
    gap: 24px;
  }
}

.page-about .about-sec__num {
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  line-height: 1;
  color: var(--gold);
}

.page-about .about-sec__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 3.4vw, 44px);
  line-height: 1.16;
  color: var(--paper);
}

.page-about .about-sec__lead {
  max-width: 68ch;
  margin: 0;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: rgba(243, 236, 221, 0.76);
}

/* ---------- 01 时间轴 ---------- */
.page-about .about-timeline {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(238px, 1fr);
  overflow-x: auto;
  padding-bottom: 12px;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

@media (min-width: 1320px) {
  .page-about .about-timeline {
    grid-auto-flow: row;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    overflow-x: visible;
  }
}

.page-about .about-tl {
  position: relative;
  padding: 22px 22px 12px 0;
  border-right: 1px solid var(--grid);
  scroll-snap-align: start;
}

.page-about .about-tl:last-child {
  border-right: 0;
}

@media (min-width: 1320px) {
  .page-about .about-tl {
    padding: 22px 24px 22px 0;
  }

  .page-about .about-tl:nth-child(3n) {
    border-right: 0;
  }
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 7px;
  height: 7px;
  background: var(--gold);
}

.page-about .about-tl::after {
  content: "";
  position: absolute;
  top: 3px;
  left: 14px;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--gold), rgba(201, 162, 74, 0));
}

.page-about .about-tl__year {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.page-about .about-tl__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-tl__text {
  max-width: 42ch;
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: rgba(243, 236, 221, 0.72);
}

/* ---------- 02 团队 ---------- */
.page-about .about-roles {
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

@media (min-width: 768px) {
  .page-about .about-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-role {
  background: var(--ink-raised);
  padding: 24px;
}

.page-about .about-role__tag {
  display: inline-block;
  margin: 0 0 14px;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--gold);
  border: 1px solid rgba(201, 162, 74, 0.5);
}

.page-about .about-role__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-role__text {
  max-width: 44ch;
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: rgba(243, 236, 221, 0.74);
}

/* 编号检索 */
.page-about .about-index {
  margin-top: 32px;
  padding: 22px;
  border: 1px solid var(--grid);
  border-left: 1px solid var(--violet);
  background: rgba(20, 33, 58, 0.55);
}

.page-about .about-index__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-20);
  color: var(--paper);
}

.page-about .about-index__hint {
  margin: 0 0 16px;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--mute);
}

.page-about .about-index__input {
  width: 100%;
  max-width: 420px;
}

.page-about .about-index__list {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
}

.page-about .about-index__item {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--grid);
  font-size: var(--fs-14);
  line-height: 1.7;
  color: rgba(243, 236, 221, 0.76);
}

.page-about .about-index__item[hidden] {
  display: none;
}

.page-about .about-index__item strong {
  color: var(--paper);
  font-weight: 600;
}

.page-about .about-index__code {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--cyan);
}

.page-about .about-index__empty {
  margin: 16px 0 0;
  font-size: var(--fs-14);
  color: var(--rose);
}

.page-about .about-index__empty[hidden] {
  display: none;
}

/* ---------- 03 服务标准 ---------- */
.page-about .about-sla {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--grid);
}

.page-about .about-sla__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 22px 0;
  border-bottom: 1px solid var(--grid);
}

@media (min-width: 768px) {
  .page-about .about-sla__item {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 36px;
    align-items: baseline;
    padding: 26px 0;
  }
}

.page-about .about-sla__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  line-height: 1;
  color: var(--gold);
}

.page-about .about-sla__num span {
  margin-left: 6px;
  font-size: var(--fs-14);
  color: var(--mute);
}

.page-about .about-sla__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-sla__text {
  max-width: 62ch;
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.72;
  color: rgba(243, 236, 221, 0.74);
}

/* ---------- 04 线路 ---------- */
.page-about .about-network {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

@media (min-width: 900px) {
  .page-about .about-network {
    grid-template-columns: minmax(0, 1fr) minmax(0, 400px);
    gap: 44px;
    align-items: start;
  }
}

.page-about .about-regions {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

@media (min-width: 560px) {
  .page-about .about-regions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-regions__item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  background: var(--ink);
}

.page-about .about-regions__name {
  font-size: var(--fs-16);
  color: var(--paper);
}

.page-about .about-stats {
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

@media (min-width: 560px) {
  .page-about .about-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-stats__cell {
  padding: 20px;
  background: var(--ink-raised);
}

.page-about .about-stats__num {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  line-height: 1;
  color: var(--gold);
}

.page-about .about-stats__unit {
  margin-left: 4px;
  font-size: var(--fs-14);
  color: var(--gold-light);
}

.page-about .about-stats__label {
  font-size: var(--fs-14);
  color: var(--mute);
}

.page-about .about-topo {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--grid);
  background: rgba(20, 33, 58, 0.42);
}

.page-about .about-topo__caption {
  margin: 12px 0 0;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--mute);
}

/* ---------- 05 兼容性认证 ---------- */
.page-about .about-filter {
  min-width: 0;
}

.page-about .about-certs {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

@media (min-width: 700px) {
  .page-about .about-certs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1100px) {
  .page-about .about-certs {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-certs__item {
  padding: 22px;
  background: var(--ink-raised);
}

.page-about .about-certs__item[hidden] {
  display: none;
}

.page-about .about-certs__cat {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--violet);
}

.page-about .about-certs__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-16);
  line-height: 1.45;
  color: var(--paper);
}

.page-about .about-certs__text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: rgba(243, 236, 221, 0.74);
}

.page-about .empty-note {
  margin: 20px 0 0;
  font-size: var(--fs-14);
  color: var(--rose);
}

.page-about .empty-note[hidden] {
  display: none;
}

/* ---------- 06 社区与会员 ---------- */
.page-about .about-community {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
}

@media (min-width: 900px) {
  .page-about .about-community {
    grid-template-columns: minmax(0, 1fr) minmax(0, 360px);
    gap: 44px;
    align-items: start;
  }
}

.page-about .about-tiers {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .about-tier {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 18px;
  background: var(--ink);
}

.page-about .about-tier__name {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-16);
  color: var(--gold-light);
}

.page-about .about-tier__text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: rgba(243, 236, 221, 0.72);
}

.page-about .about-community__figure .image-frame {
  border: 1px solid var(--grid);
}

/* ---------- 下一步 ---------- */
.page-about .about-next {
  margin-top: 64px;
  padding: 44px 0 72px;
  border-top: 1px solid var(--gold);
  background:
    radial-gradient(720px 300px at 84% 0%, rgba(53, 224, 214, 0.10), transparent 64%);
}

.page-about .about-next__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 3vw, 36px);
  line-height: 1.2;
  color: var(--paper);
}

.page-about .about-next__grid {
  display: grid;
  gap: 1px;
  margin-top: 28px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

@media (min-width: 700px) {
  .page-about .about-next__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1100px) {
  .page-about .about-next__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-next__card {
  display: block;
  padding: 24px;
  background: var(--ink);
  color: inherit;
  text-decoration: none;
  border-top: 2px solid transparent;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-next__card:hover,
.page-about .about-next__card:focus-visible {
  background: var(--ink-raised);
  border-top-color: var(--gold);
}

.page-about .about-next__num {
  display: block;
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--gold);
}

.page-about .about-next__name {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-next__text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: rgba(243, 236, 221, 0.72);
}

/* ---------- 窄屏收束 ---------- */
@media (max-width: 559px) {
  .page-about .about-hero {
    padding-bottom: 40px;
  }

  .page-about .about-sec {
    padding: 36px 0;
  }

  .page-about .about-index,
  .page-about .about-role,
  .page-about .about-certs__item {
    padding: 18px;
  }

  .page-about .about-index__item {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }

  .page-about .about-next {
    padding-bottom: 56px;
  }
}

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