.page-about {
  --about-fade-top: rgba(234, 242, 255, .42);
  --about-fade-bottom: rgba(234, 242, 255, .06);
}

/* ---------- 面包屑与页首 ---------- */

.page-about .about-crumb {
  padding-top: clamp(18px, 3vw, 30px);
}

.page-about .about-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  padding-top: clamp(10px, 2.4vw, 22px);
}

.page-about .about-eyebrow {
  margin: 0;
  font-size: 11.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--steel-500);
}

.page-about .about-title {
  margin: 0;
  font-size: clamp(30px, 4.2vw, 52px);
  font-weight: 200;
  line-height: 1.12;
  letter-spacing: -.028em;
  color: var(--cold-white);
  text-wrap: balance;
}

.page-about .about-lede {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.62;
  color: var(--mist-200);
  max-width: 40em;
}

.page-about .about-facts {
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-fact {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--hair);
}

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

.page-about .about-fact dt {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--steel-500);
}

.page-about .about-fact dd {
  margin: 0;
  font-size: 14.5px;
  color: var(--cold-white);
}

@media (min-width: 900px) {
  .page-about .about-head {
    grid-template-columns: minmax(0, 1.18fr) minmax(0, .82fr);
    grid-template-areas:
      "eyebrow eyebrow"
      "title   side";
    column-gap: clamp(32px, 4.5vw, 68px);
    align-items: end;
    row-gap: 12px;
  }

  .page-about .about-eyebrow { grid-area: eyebrow; }
  .page-about .about-title { grid-area: title; }
  .page-about .about-head-side { grid-area: side; }
}

/* ---------- 页首横贯图 ---------- */

.page-about .about-banner {
  margin: clamp(26px, 4vw, 52px) 0 0;
}

.page-about .about-banner img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--radius-m);
  background: var(--ink-800);
}

.page-about .about-banner figcaption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--steel-500);
}

/* ---------- 左栏 + 内容 双栏骨架 ---------- */

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 44px);
  margin-top: clamp(40px, 6vw, 76px);
  padding-bottom: clamp(56px, 9vw, 112px);
}

@media (min-width: 960px) {
  .page-about .about-split {
    grid-template-columns: var(--rail-w) minmax(0, 1fr);
    gap: clamp(40px, 5vw, 84px);
    align-items: start;
  }
}

.page-about .about-rail {
  border-top: 1px solid var(--hair);
  border-bottom: 1px solid var(--hair);
  padding: 16px 0;
}

.page-about .about-rail-title {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--steel-500);
}

.page-about .about-rail-nav {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 6px;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .rail-link {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: baseline;
  gap: 9px;
  padding: 7px 12px;
  border-bottom: 2px solid transparent;
  border-radius: var(--radius-s);
  font-size: 13.5px;
  line-height: 1.4;
  color: var(--mist-200);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--t) var(--ease), background var(--t) var(--ease),
              border-color var(--t) var(--ease);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  color: var(--cold-white);
  background: rgba(27, 47, 92, .5);
}

.page-about .rail-link.is-active,
.page-about .rail-link[aria-current="true"] {
  color: var(--cold-white);
  border-bottom-color: var(--neon);
  background: rgba(27, 47, 92, .62);
}

.page-about .rail-step {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 10.5px;
  letter-spacing: .06em;
  color: var(--steel-500);
}

.page-about .rail-link.is-active .rail-step,
.page-about .rail-link[aria-current="true"] .rail-step {
  color: var(--neon);
}

.page-about .about-rail-meta {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--hair);
  font-size: 12px;
  line-height: 1.6;
  color: var(--steel-500);
}

.page-about .about-rail-meta p {
  margin: 0 0 6px;
}

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

@media (min-width: 960px) {
  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 20px);
    max-height: calc(100vh - var(--header-h) - 40px);
    overflow-y: auto;
    border-top: 0;
    border-bottom: 0;
    padding: 0;
    scrollbar-width: thin;
  }

  .page-about .about-rail-nav {
    display: grid;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
    border-left: 1px solid var(--hair);
  }

  .page-about .rail-link {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    align-items: baseline;
    white-space: normal;
    padding: 9px 12px 9px 13px;
    margin-left: -1px;
    border-bottom: 0;
    border-left: 2px solid transparent;
    border-radius: 0 var(--radius-s) var(--radius-s) 0;
  }

  .page-about .rail-link.is-active,
  .page-about .rail-link[aria-current="true"] {
    border-left-color: var(--neon);
    border-bottom-color: transparent;
  }
}

/* ---------- 内容区与章节 ---------- */

.page-about .about-content {
  min-width: 0;
  max-width: min(100%, 940px);
}

.page-about .about-section {
  scroll-margin-top: calc(var(--header-h) + 22px);
  padding-top: clamp(40px, 6vw, 74px);
  border-top: 1px solid var(--hair);
}

.page-about .about-section:first-of-type {
  padding-top: 0;
  border-top: 0;
}

.page-about .about-section + .about-section {
  margin-top: clamp(40px, 6vw, 74px);
}

.page-about .about-sec-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  margin: 0 0 clamp(20px, 3vw, 30px);
}

.page-about .about-sec-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(34px, 5.2vw, 60px);
  font-weight: 300;
  line-height: .88;
  letter-spacing: -.05em;
  background: linear-gradient(170deg, var(--about-fade-top), var(--about-fade-bottom));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  user-select: none;
}

.page-about .about-kicker {
  margin: 0 0 9px;
  font-size: 11.5px;
  font-weight: 700;
  font-style: italic;
  letter-spacing: .14em;
  color: var(--mist-200);
}

.page-about .about-kicker::before {
  content: "";
  display: inline-block;
  width: 14px;
  height: 2px;
  margin-right: 8px;
  vertical-align: middle;
  background: var(--neon);
}

.page-about .about-sec-title {
  margin: 0;
  font-size: clamp(21px, 2.7vw, 31px);
  font-weight: 300;
  line-height: 1.28;
  letter-spacing: -.012em;
  color: var(--cold-white);
  text-wrap: balance;
}

@media (min-width: 760px) {
  .page-about .about-sec-head {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 26px;
    align-items: start;
  }
}

.page-about .about-prose {
  max-width: 42em;
}

.page-about .about-prose p {
  margin: 0 0 15px;
  font-size: 15.5px;
  line-height: 1.62;
  color: var(--mist-200);
}

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

/* ---------- 01 范围对照 ---------- */

.page-about .about-scope {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-top: clamp(24px, 3.4vw, 36px);
}

@media (min-width: 780px) {
  .page-about .about-scope {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }
}

.page-about .about-scope-col {
  padding: 22px 22px 24px;
  border-radius: var(--radius-m);
  border: 1px solid var(--hair);
  background: var(--ink-800);
}

.page-about .about-scope-out {
  background: transparent;
  border-color: rgba(46, 74, 107, .55);
}

.page-about .about-scope-title {
  margin: 0 0 14px;
  font-size: 12px;
  font-weight: 700;
  font-style: italic;
  letter-spacing: .12em;
  color: var(--cold-white);
}

.page-about .about-scope-out .about-scope-title {
  color: var(--steel-500);
}

.page-about .about-scope-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-scope-list li {
  position: relative;
  padding-left: 19px;
  margin-bottom: 11px;
  font-size: 14.5px;
  line-height: 1.56;
  color: var(--mist-200);
}

.page-about .about-scope-list li:last-child {
  margin-bottom: 0;
}

.page-about .about-scope-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .58em;
  width: 7px;
  height: 7px;
  border-radius: 1px;
  background: var(--neon);
}

.page-about .about-scope-out .about-scope-list li::before {
  background: var(--steel-500);
}

/* ---------- 02 口径演进 ---------- */

.page-about .about-timeline {
  list-style: none;
  margin: clamp(24px, 3.4vw, 36px) 0 0;
  padding: 0 0 0 22px;
  border-left: 1px solid var(--hair-strong);
}

.page-about .about-timeline .timeline-item {
  position: relative;
  padding-bottom: 28px;
}

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

.page-about .about-timeline .timeline-mark {
  position: absolute;
  left: -28px;
  top: 5px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 1px solid var(--steel-500);
}

.page-about .about-timeline .timeline-item[data-state="current"] .timeline-mark {
  background: var(--neon);
  border-color: var(--neon);
  box-shadow: 0 0 0 4px rgba(75, 255, 158, .14);
}

.page-about .about-timeline .timeline-stamp {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--steel-500);
}

.page-about .about-timeline .timeline-item[data-state="current"] .timeline-stamp {
  color: var(--neon);
}

.page-about .about-tl-title {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 600;
  font-style: italic;
  letter-spacing: -.008em;
  color: var(--cold-white);
}

.page-about .about-tl-text {
  margin: 0;
  max-width: 40em;
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--mist-200);
}

.page-about .about-figure {
  margin: clamp(24px, 3.4vw, 38px) 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--radius-m);
  background: var(--ink-800);
}

.page-about .about-figure-diagram img {
  aspect-ratio: 12 / 7;
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--steel-500);
}

/* ---------- 03 四类维度 ---------- */

.page-about .about-dims {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-top: clamp(24px, 3.4vw, 36px);
}

.page-about .about-dim {
  position: relative;
  padding: 22px 22px 24px;
  border-radius: var(--radius-m);
  border: 1px solid var(--hair);
  background: linear-gradient(180deg, rgba(20, 34, 56, .72), rgba(11, 20, 40, .92));
  transition: border-color var(--t) var(--ease), background var(--t) var(--ease),
              transform var(--t) var(--ease);
}

.page-about .about-dim::after {
  content: "#";
  position: absolute;
  top: 18px;
  right: 20px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--steel-500);
  opacity: 0;
  transition: opacity var(--t) var(--ease), color var(--t) var(--ease);
}

.page-about .about-dim:hover,
.page-about .about-dim:focus-visible {
  border-color: rgba(75, 255, 158, .38);
  background: linear-gradient(180deg, rgba(27, 47, 92, .62), rgba(11, 20, 40, .94));
  transform: translateY(-2px);
  outline: none;
}

.page-about .about-dim:focus-visible {
  box-shadow: 0 0 0 2px rgba(75, 255, 158, .55);
}

.page-about .about-dim:hover::after,
.page-about .about-dim:focus-visible::after {
  opacity: 1;
  color: var(--neon);
}

.page-about .about-dim-label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--steel-500);
}

.page-about .about-dim-title {
  margin: 0 0 9px;
  font-size: 22px;
  font-weight: 300;
  letter-spacing: -.014em;
  color: var(--cold-white);
}

.page-about .about-dim-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.58;
  color: var(--mist-200);
}

.page-about .about-dim-note {
  margin: 0;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-size: 12.5px;
  line-height: 1.55;
  color: var(--steel-500);
  transition: max-height 200ms var(--ease), opacity 200ms var(--ease),
              margin-top 200ms var(--ease);
}

.page-about .about-dim:hover .about-dim-note,
.page-about .about-dim:focus-visible .about-dim-note,
.page-about .about-dim:focus-within .about-dim-note {
  max-height: 6em;
  opacity: 1;
  margin-top: 12px;
}

@media (hover: none) {
  .page-about .about-dim-note {
    max-height: none;
    opacity: 1;
    margin-top: 12px;
  }
}

.page-about .about-dim-figure {
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--hair);
}

.page-about .about-dim-num {
  font-size: 19px;
  line-height: 1.1;
  color: var(--cold-white);
  font-variant-numeric: tabular-nums;
}

.page-about .about-dim-unit {
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--steel-500);
}

@media (min-width: 960px) {
  .page-about .about-dims {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: 18px 20px;
  }

  .page-about .about-dim:nth-child(1) { grid-column: 1 / span 7; }
  .page-about .about-dim:nth-child(2) { grid-column: 8 / span 5; }
  .page-about .about-dim:nth-child(3) { grid-column: 1 / span 5; }
  .page-about .about-dim:nth-child(4) { grid-column: 6 / span 7; }
}

.page-about .about-crossref {
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding-left: 16px;
  border-left: 2px solid var(--neon);
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--mist-200);
}

.page-about .about-crossref a,
.page-about .about-team-desc a,
.page-about .about-next-text a {
  color: var(--cold-white);
  text-decoration: none;
  border-bottom: 1px solid rgba(75, 255, 158, .45);
  transition: color var(--t) var(--ease), border-color var(--t) var(--ease);
}

.page-about .about-crossref a:hover,
.page-about .about-team-desc a:hover,
.page-about .about-next-text a:hover,
.page-about .about-crossref a:focus-visible,
.page-about .about-team-desc a:focus-visible,
.page-about .about-next-text a:focus-visible {
  color: var(--neon);
  border-bottom-color: var(--neon);
}

/* ---------- 04 团队与节奏 ---------- */

.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.6vw, 40px);
  align-items: start;
}

.page-about .about-team-cards {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(20px, 3vw, 30px);
}

@media (min-width: 700px) {
  .page-about .about-team-cards {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-team-card {
  padding: 18px 18px 20px;
  border-radius: var(--radius-m);
  border: 1px solid var(--hair);
  background: rgba(11, 20, 40, .78);
  transition: border-color var(--t) var(--ease), background var(--t) var(--ease);
}

.page-about .about-team-card:hover {
  border-color: var(--hair-strong);
  background: rgba(27, 47, 92, .45);
}

.page-about .about-team-count {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--steel-500);
}

.page-about .about-team-count .num {
  font-size: 20px;
  color: var(--neon);
  font-variant-numeric: tabular-nums;
}

.page-about .about-team-name {
  margin: 0 0 8px;
  font-size: 15px;
  font-weight: 700;
  font-style: italic;
  letter-spacing: .01em;
  color: var(--cold-white);
}

.page-about .about-team-desc {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.58;
  color: var(--mist-200);
}

.page-about .about-team-figure {
  margin-top: 0;
}

.page-about .about-team-figure img {
  aspect-ratio: 14 / 9;
}

@media (min-width: 1000px) {
  .page-about .about-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 340px);
    gap: clamp(30px, 4vw, 52px);
  }
}

.page-about .about-subhead {
  margin: clamp(34px, 5vw, 54px) 0 16px;
  font-size: 12px;
  font-weight: 700;
  font-style: italic;
  letter-spacing: .14em;
  color: var(--cold-white);
}

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

.page-about .about-cadence-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-cadence-key {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--steel-500);
}

.page-about .about-cadence-val {
  font-size: 14.5px;
  line-height: 1.55;
  color: var(--mist-200);
}

@media (min-width: 700px) {
  .page-about .about-cadence-row {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

/* ---------- 05 覆盖与纠错 ---------- */

.page-about .about-steps {
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin: clamp(24px, 3.4vw, 36px) 0 0;
  padding: 0;
}

.page-about .about-step {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 16px;
  padding: 18px 20px 20px;
  border-radius: var(--radius-m);
  border: 1px solid var(--hair);
  background: rgba(11, 20, 40, .72);
  transition: border-color var(--t) var(--ease);
}

.page-about .about-step:hover {
  border-color: rgba(75, 255, 158, .3);
}

.page-about .about-step-num {
  font-size: 15px;
  line-height: 1.35;
  color: var(--neon);
  font-variant-numeric: tabular-nums;
}

.page-about .about-step-title {
  margin: 0 0 7px;
  font-size: 15.5px;
  font-weight: 600;
  font-style: italic;
  color: var(--cold-white);
}

.page-about .about-step-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.58;
  color: var(--mist-200);
}

@media (min-width: 780px) {
  .page-about .about-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .about-step {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
  }
}

.page-about .about-next {
  margin-top: clamp(26px, 3.6vw, 38px);
  padding: 20px 22px;
  border-radius: var(--radius-m);
  background: linear-gradient(120deg, rgba(27, 47, 92, .78), rgba(11, 20, 40, .5));
  border-left: 2px solid var(--amber);
}

.page-about .about-next-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--mist-200);
}

@media (max-width: 480px) {
  .page-about .about-scope-col,
  .page-about .about-dim,
  .page-about .about-team-card,
  .page-about .about-step,
  .page-about .about-next {
    padding-left: 16px;
    padding-right: 16px;
  }

  .page-about .about-title {
    font-size: clamp(26px, 8vw, 34px);
  }
}