.page-about {
  --about-rail-w: clamp(72px, 8vw, 116px);
  --about-gap: clamp(22px, 3.4vw, 46px);
}

.page-about .about-lead {
  padding-top: calc(var(--header-h) + clamp(26px, 5vw, 58px));
  padding-bottom: clamp(40px, 6vw, 78px);
}

.page-about .about-lead__grid {
  display: grid;
  gap: var(--about-gap);
  margin-top: clamp(24px, 3.4vw, 42px);
}

.page-about .about-lead__title {
  margin: 12px 0 0;
  font-size: var(--step-4);
  line-height: 1.04;
  letter-spacing: -0.03em;
  color: var(--silver);
  max-width: 16ch;
}

.page-about .about-lead .lead {
  margin: 22px 0 0;
  max-width: 54ch;
  font-size: var(--step-1);
  line-height: 1.72;
  color: var(--steel);
}

.page-about .about-fact {
  margin: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-1);
}

.page-about .about-fact__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  padding: 13px 16px;
  background: var(--ink-800);
}

.page-about .about-fact dt {
  font-size: var(--step--1);
  letter-spacing: 0.06em;
  color: var(--steel-dim);
}

.page-about .about-fact dd {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: var(--step-0);
  color: var(--silver);
}

.page-about .about-fact .data {
  color: var(--cyan);
}

/* ---------- 章节分栏 ---------- */

.page-about .about-chapter__inner,
.page-about .about-eco__inner {
  display: grid;
  gap: var(--about-gap);
}

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

.page-about .about-chapter__num,
.page-about .about-eco__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: var(--step-1);
  color: var(--cyan);
  letter-spacing: 0.02em;
}

.page-about .about-chapter__tag,
.page-about .about-eco__tag {
  font-size: var(--step--1);
  letter-spacing: 0.16em;
  color: var(--steel-dim);
}

.page-about .about-chapter__main {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
}

.page-about .about-chapter__title {
  margin: 0 0 18px;
  font-size: var(--step-2);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--silver);
}

.page-about .about-chapter__text p {
  margin: 0 0 14px;
  max-width: 40em;
  line-height: 1.78;
  color: var(--text);
}

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

/* ---------- 图片容器 ---------- */

.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--ink-800);
  overflow: hidden;
  box-shadow: var(--shadow-1);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .about-figure--tight img {
  aspect-ratio: 4 / 3;
}

.page-about .about-figure--wide img {
  aspect-ratio: 16 / 7;
}

.page-about .about-figure figcaption {
  padding: 11px 15px;
  font-size: var(--step--1);
  line-height: 1.6;
  color: var(--steel-dim);
  border-top: 1px solid var(--line-soft);
}

/* ---------- 时间线 ---------- */

.page-about .about-timeline__head {
  max-width: 62ch;
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-timeline__lead {
  margin: 16px 0 0;
  max-width: 56ch;
  color: var(--steel);
}

.page-about .about-timeline .about-figure--wide {
  margin-bottom: clamp(34px, 5vw, 62px);
}

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

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 26px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--line) 26%, var(--line) 100%);
  opacity: 0.78;
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: clamp(24px, 3.2vw, 40px);
}

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

.page-about .timeline__dot {
  position: absolute;
  left: -24px;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 1px solid var(--line);
  transition: border-color 0.3s var(--ease), background-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.page-about .timeline__item:hover .timeline__dot,
.page-about .timeline__item:focus-within .timeline__dot {
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 0 5px var(--cyan-soft);
}

.page-about .timeline__year {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step--1);
  letter-spacing: 0.08em;
  color: var(--violet);
}

.page-about .timeline__title {
  margin: 4px 0 0;
  font-size: var(--step-1);
  letter-spacing: -0.01em;
  color: var(--silver);
}

.page-about .timeline__desc {
  margin: 8px 0 0;
  max-width: 46em;
  line-height: 1.76;
  color: var(--text);
}

/* ---------- 团队 ---------- */

.page-about .about-team__head {
  max-width: 62ch;
}

.page-about .about-team__head .lead {
  margin: 16px 0 0;
  color: var(--steel);
}

.page-about .about-team__grid {
  display: grid;
  gap: 14px;
  margin-top: clamp(28px, 4vw, 46px);
}

.page-about .about-team__media {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--ink-800);
  box-shadow: var(--shadow-1);
  aspect-ratio: 16 / 9;
}

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

.page-about .team-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px 18px;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
  transition: border-color 0.3s var(--ease), transform 0.3s var(--ease);
}

.page-about .team-card:hover {
  border-color: var(--line-soft);
  transform: translateY(-2px);
}

.page-about .team-card__idx {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--step--1);
  letter-spacing: 0.12em;
  color: var(--violet);
}

.page-about .team-card__title {
  margin: 0;
  font-size: var(--step-1);
  letter-spacing: -0.01em;
  color: var(--silver);
}

.page-about .team-card__desc {
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.75;
  color: var(--text);
}

.page-about .team-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: auto 0 0;
  padding-top: 12px;
}

.page-about .about-team__foot {
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--line-soft);
  max-width: 62ch;
}

/* ---------- 三层本地化 ---------- */

.page-about .about-local__head {
  max-width: 62ch;
}

.page-about .about-local__head .lead {
  margin: 16px 0 0;
  color: var(--steel);
}

.page-about .layers {
  margin-top: clamp(28px, 4vw, 46px);
  border-top: 1px solid var(--line);
}

.page-about .layers__row {
  display: grid;
  gap: 10px;
  padding: clamp(20px, 3vw, 28px) 0;
  border-bottom: 1px solid var(--line);
}

.page-about .layers__name {
  margin: 0;
  font-size: var(--step-1);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--cyan);
}

.page-about .layers__body p {
  margin: 0;
  max-width: 46em;
  line-height: 1.78;
  color: var(--text);
}

.page-about .layers__body strong {
  font-weight: 700;
  color: var(--silver);
  font-variant-numeric: tabular-nums;
}

.page-about .about-local__link,
.page-about .about-eco__link {
  margin: clamp(22px, 3vw, 32px) 0 0;
  font-size: var(--step--1);
  line-height: 1.8;
  color: var(--steel-dim);
}

.page-about .about-local__link a,
.page-about .about-eco__link a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--cyan-soft);
  transition: border-color 0.25s var(--ease);
}

.page-about .about-local__link a:hover,
.page-about .about-eco__link a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 稳定性 ---------- */

.page-about .about-reliability__grid {
  display: grid;
  gap: clamp(28px, 4vw, 54px);
}

.page-about .about-reliability__text .section-head__title {
  margin: 12px 0 18px;
}

.page-about .about-reliability__text p {
  margin: 0 0 14px;
  max-width: 40em;
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-reliability__text .data {
  color: var(--cyan);
  font-weight: 700;
}

.page-about .meters {
  display: grid;
  gap: 18px;
  align-content: start;
}

.page-about .meter {
  padding: 18px 18px 20px;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
}

.page-about .meter__head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 14px;
}

.page-about .meter__label {
  font-size: var(--step--1);
  line-height: 1.5;
  color: var(--steel);
}

.page-about .meter__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: var(--step-2);
  line-height: 1;
  color: var(--cyan);
  white-space: nowrap;
}

.page-about .meter__unit {
  margin-left: 4px;
  font-size: var(--step--1);
  font-weight: 500;
  color: var(--steel-dim);
}

.page-about .meter__track {
  position: relative;
  height: 6px;
  border-radius: 3px;
  background: rgba(28, 53, 95, 0.7);
  overflow: hidden;
}

.page-about .meter__fill {
  display: block;
  height: 100%;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--ice), var(--cyan));
}

.page-about .meter__fill--latency {
  width: 88%;
}

.page-about .meter__fill--uptime {
  width: 99.96%;
}

.page-about .about-nodes {
  list-style: none;
  display: grid;
  gap: 12px;
  margin: clamp(26px, 3.6vw, 40px) 0 0;
  padding: 22px 0 0;
  border-top: 1px solid var(--line);
}

.page-about .about-nodes__item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: var(--step--1);
  line-height: 1.6;
  color: var(--text);
}

.page-about .about-nodes__dot {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 3px var(--cyan-soft);
}

/* ---------- 合作与认可 ---------- */

.page-about .about-eco__lead {
  margin: 16px 0 0;
  max-width: 52ch;
  color: var(--steel);
}

.page-about .about-eco__list {
  list-style: none;
  margin: clamp(24px, 3.4vw, 38px) 0 0;
  padding: 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-eco__list li {
  display: grid;
  gap: 6px;
  padding: 16px 0 16px 16px;
  border-bottom: 1px solid var(--line-soft);
  border-left: 2px solid transparent;
  transition: border-left-color 0.3s var(--ease), background-color 0.3s var(--ease);
}

.page-about .about-eco__list li:hover {
  border-left-color: var(--violet);
  background: var(--violet-soft);
}

.page-about .about-eco__key {
  font-size: var(--step-0);
  font-weight: 700;
  color: var(--silver);
  letter-spacing: -0.005em;
}

.page-about .about-eco__val {
  font-size: var(--step--1);
  line-height: 1.76;
  color: var(--text);
}

/* ---------- 联络信息 ---------- */

.page-about .about-contact {
  border-top: 1px solid var(--line);
}

.page-about .about-contact__head {
  max-width: 60ch;
}

.page-about .about-contact__head .lead {
  margin: 16px 0 0;
  color: var(--steel);
}

.page-about .about-contact__grid {
  display: grid;
  gap: 14px;
  margin-top: clamp(26px, 4vw, 44px);
}

.page-about .about-contact__item {
  padding: 20px 18px;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
}

.page-about .about-contact__label {
  margin: 0 0 10px;
  font-size: var(--step--1);
  letter-spacing: 0.16em;
  color: var(--steel-dim);
}

.page-about .about-contact__value {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-0);
  line-height: 1.55;
  color: var(--silver);
  word-break: break-word;
}

.page-about .about-contact__note {
  margin: 12px 0 0;
  font-size: var(--step--1);
  line-height: 1.72;
  color: var(--steel-dim);
}

.page-about .about-contact__foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-top: clamp(26px, 4vw, 44px);
  padding-top: 22px;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-contact__foot p {
  margin: 0;
  flex: 1 1 260px;
  font-size: var(--step--1);
  line-height: 1.72;
  color: var(--steel-dim);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-nodes {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-team__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-team__media {
    grid-column: span 2;
    aspect-ratio: 21 / 9;
  }
}

@media (min-width: 760px) {
  .page-about .layers__row {
    grid-template-columns: minmax(0, 170px) minmax(0, 1fr);
    gap: 34px;
    align-items: start;
  }

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

  .page-about .timeline__item {
    display: grid;
    grid-template-columns: 118px minmax(0, 1fr);
    column-gap: 26px;
  }

  .page-about .timeline__year {
    grid-area: 1 / 1;
    padding-top: 5px;
  }

  .page-about .timeline__title {
    grid-area: 1 / 2;
    margin-top: 0;
  }

  .page-about .timeline__desc {
    grid-area: 2 / 2;
  }
}

@media (min-width: 900px) {
  .page-about .about-lead__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    align-items: end;
    gap: clamp(30px, 4vw, 60px);
  }

  .page-about .about-chapter__inner,
  .page-about .about-eco__inner {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(26px, 4vw, 58px);
  }

  .page-about .about-chapter__rail,
  .page-about .about-eco__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    position: sticky;
    top: calc(var(--header-h-scrolled) + 26px);
    align-self: start;
    padding-top: 4px;
  }

  .page-about .about-chapter__main {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 0.86fr) repeat(2, minmax(0, 1fr));
    grid-template-rows: auto auto;
    gap: 16px;
  }

  .page-about .about-team__media {
    grid-column: 1 / 2;
    grid-row: 1 / 3;
    aspect-ratio: auto;
    min-height: 300px;
  }

  .page-about .about-reliability__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.96fr);
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .team-card,
  .page-about .timeline__dot,
  .page-about .about-eco__list li {
    transition: none;
  }

  .page-about .team-card:hover {
    transform: none;
  }
}