.page-about {
  --ab-pad: clamp(56px, 9vw, 112px);
  --ab-paper-accent: #0E6B62;
}

.page-about section {
  padding-block: var(--ab-pad);
}

.page-about section[id] {
  scroll-margin-top: 110px;
}

.page-about .ab-kicker {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--gold);
}

.page-about .ab-intro {
  margin: 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-70);
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  margin: 0;
  padding: clamp(18px, 3vw, 32px) 0 0;
  font-size: 14px;
  color: var(--text-55);
}

.page-about .crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .crumbs a {
  color: var(--text-70);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .crumbs li + li::before {
  content: "/ ";
  color: var(--orbit);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding-top: clamp(26px, 4vw, 50px);
  padding-bottom: clamp(40px, 7vw, 88px);
}

.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 5vw, 56px);
}

.page-about .ab-hero__title {
  margin: 0 0 22px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2rem, 6.2vw, 4.1rem);
  line-height: 1.08;
  letter-spacing: -.02em;
  color: var(--dust);
}

.page-about .ab-hero__lede {
  margin: 0 0 16px;
  max-width: 60ch;
  font-size: 17px;
  line-height: 1.8;
  color: var(--text-70);
}

.page-about .ab-hero__note {
  margin: 0 0 28px;
  max-width: 56ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-55);
}

.page-about .ab-hero__cta {
  margin: 0;
  gap: 12px;
}

.page-about .ab-hero__figure {
  position: relative;
  margin: 0;
}

.page-about .ab-hero__figure::before {
  content: "";
  position: absolute;
  top: -34px;
  right: -18px;
  width: 230px;
  height: 230px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(62, 224, 207, .16), transparent 68%);
  pointer-events: none;
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

.page-about .media-frame__note {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-55);
}

/* ---------- 章节索引 ---------- */
.page-about .ab-index {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 22px;
  padding: 16px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-index__label {
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--orbit);
}

.page-about .ab-index__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-index__list a {
  font-size: 14px;
  color: var(--text-70);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .ab-index__list a:hover,
.page-about .ab-index__list a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* ---------- 区块标题 ---------- */
.page-about .section-head {
  max-width: 62ch;
  margin: 0 0 clamp(28px, 4vw, 48px);
}

.page-about .section-head__kicker {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--gold);
}

.page-about .section-head__title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.55rem, 3.6vw, 2.5rem);
  line-height: 1.18;
  letter-spacing: -.015em;
  color: var(--dust);
}

/* ---------- 时间轴 ---------- */
.page-about .ab-timeline {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .tl-row {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px 32px;
  padding: 28px 0 32px 16px;
  border-bottom: 1px solid var(--line);
}

.page-about .tl-row::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 2px;
  height: 100%;
  background: var(--tl-accent, var(--cyan));
  opacity: .35;
  transition: opacity .24s var(--ease), width .24s var(--ease);
}

.page-about .tl-row:hover::before,
.page-about .tl-row:focus-within::before {
  opacity: 1;
  width: 4px;
}

.page-about .tl-row--1 { --tl-accent: var(--orbit); }
.page-about .tl-row--2 { --tl-accent: var(--cyan); }
.page-about .tl-row--3 { --tl-accent: var(--gold); }
.page-about .tl-row--4 { --tl-accent: var(--dust); }

.page-about .tl-year {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .tl-year__num {
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--tl-accent, var(--cyan));
}

.page-about .tl-year__tag {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: .04em;
  color: var(--dust);
}

.page-about .tl-body__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.12rem, 2.4vw, 1.45rem);
  line-height: 1.32;
  color: var(--dust);
}

.page-about .tl-body p {
  margin: 0 0 12px;
  max-width: 68ch;
  font-size: 16px;
  line-height: 1.82;
  color: var(--text-70);
}

.page-about .tl-body__meta {
  margin: 0;
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--text-55);
}

/* ---------- 三条内容线 ---------- */
.page-about .ab-line-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 18px;
}

.page-about .line-band {
  position: relative;
  padding: 26px 22px 24px;
  background: var(--nebula);
  border: 1px solid var(--line);
  border-left: 3px solid var(--band-accent, var(--cyan));
  overflow: hidden;
}

.page-about .line-band::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(100deg, var(--band-tint, rgba(62, 224, 207, .08)), transparent 64%);
  pointer-events: none;
}

.page-about .line-band > * {
  position: relative;
}

.page-about .line-band--rule {
  --band-accent: var(--gold);
  --band-tint: rgba(242, 197, 102, .09);
}

.page-about .line-band--event {
  --band-accent: var(--magenta);
  --band-tint: rgba(255, 63, 142, .09);
}

.page-about .line-band--record {
  --band-accent: var(--cyan);
  --band-tint: rgba(62, 224, 207, .09);
}

.page-about .line-band__code {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--band-accent, var(--cyan));
}

.page-about .line-band__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.05rem, 2.2vw, 1.32rem);
  line-height: 1.34;
  color: var(--dust);
}

.page-about .line-band__text {
  margin: 0 0 16px;
  max-width: 76ch;
  font-size: 16px;
  line-height: 1.82;
  color: var(--text-70);
}

.page-about .line-band__foot {
  margin: 0;
  font-size: 12px;
  letter-spacing: .07em;
  color: var(--text-55);
}

/* ---------- 三次改版 ---------- */
.page-about .ab-versions__figure {
  margin: 0 0 clamp(28px, 4vw, 44px);
}

.page-about .ab-ver-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .ver-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 24px 20px 22px;
  background: var(--nebula);
  border: 1px solid var(--line);
  border-top: 3px solid var(--ver-accent, var(--cyan));
}

.page-about .ver-card--classic { --ver-accent: var(--orbit); }
.page-about .ver-card--tag { --ver-accent: var(--gold); }
.page-about .ver-card--matrix { --ver-accent: var(--cyan); }

.page-about .ver-card__code {
  margin: 0;
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--ver-accent, var(--cyan));
}

.page-about .ver-card__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.22rem;
  line-height: 1.3;
  color: var(--dust);
}

.page-about .ver-card__lead {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--text-70);
}

.page-about .ver-card__facts {
  margin: 8px 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  display: grid;
  gap: 12px;
}

.page-about .ver-card__facts div {
  display: grid;
  gap: 4px;
}

.page-about .ver-card__facts dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--ver-accent, var(--cyan));
}

.page-about .ver-card__facts dd {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--text-70);
}

.page-about .ab-ver-note {
  margin: clamp(22px, 3vw, 32px) 0 0;
  max-width: 72ch;
  padding-left: 16px;
  border-left: 2px solid var(--gold);
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-70);
}

/* ---------- 团队 ---------- */
.page-about .ab-team__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 5vw, 56px);
}

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

.page-about .team-item {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 6px 16px;
  padding: 18px 0 18px 14px;
  border-bottom: 1px solid var(--line);
  transition: background-color .2s var(--ease);
}

.page-about .team-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--cyan);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .22s var(--ease);
}

.page-about .team-item:hover {
  background: rgba(62, 224, 207, .05);
}

.page-about .team-item:hover::before {
  transform: scaleY(1);
}

.page-about .team-item__name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.02rem;
  letter-spacing: .02em;
  color: var(--dust);
}

.page-about .team-item__num {
  font-size: 1.05rem;
  letter-spacing: .04em;
  color: var(--cyan);
}

.page-about .team-item__desc {
  grid-column: 1 / -1;
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.76;
  color: var(--text-70);
}

.page-about .ab-team__foot {
  margin: 22px 0 0;
  max-width: 64ch;
  padding-left: 16px;
  border-left: 2px solid var(--line-strong);
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-55);
}

.page-about .ab-team__figure {
  margin: 0;
}

/* ---------- 长期维护 ---------- */
.page-about .ab-upkeep__panel {
  position: relative;
  padding: clamp(24px, 4vw, 42px);
  overflow: hidden;
}

.page-about .ab-upkeep__panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(27, 21, 38, .07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(27, 21, 38, .07) 1px, transparent 1px);
  background-size: 42px 42px;
  pointer-events: none;
}

.page-about .ab-upkeep__list {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .upkeep-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px 24px;
  padding: 18px 0;
  border-bottom: 1px solid rgba(27, 21, 38, .14);
}

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

.page-about .upkeep-item__num {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--ab-paper-accent);
}

.page-about .upkeep-item__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--paper-ink);
}

/* ---------- 覆盖与协作 ---------- */
.page-about .ab-reach__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .reach-stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 22px 18px 24px;
  background: var(--deep);
}

.page-about .reach-stat__num {
  font-size: clamp(1.5rem, 3.4vw, 2.1rem);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--gold);
}

.page-about .reach-stat__label {
  font-size: 14px;
  line-height: 1.62;
  color: var(--text-70);
}

.page-about .ab-reach__notes {
  margin-top: clamp(26px, 4vw, 40px);
  max-width: 72ch;
}

.page-about .ab-reach__notes p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.82;
  color: var(--text-70);
}

.page-about .ab-reach__notes a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(62, 224, 207, .45);
  transition: border-color .18s var(--ease);
}

.page-about .ab-reach__notes a:hover,
.page-about .ab-reach__notes a:focus-visible {
  border-bottom-color: var(--cyan);
}

/* ---------- 收束 ---------- */
.page-about .ab-closing {
  padding-block: clamp(46px, 7vw, 88px) clamp(54px, 8vw, 100px);
  border-top: 1px solid var(--line);
  text-align: center;
}

.page-about .ab-closing__star {
  display: block;
  width: 40px;
  height: 40px;
  margin: 0 auto 18px;
  color: var(--gold);
}

.page-about .ab-closing__text {
  margin: 0 auto 24px;
  max-width: 52ch;
  font-size: 16px;
  line-height: 1.82;
  color: var(--text-70);
}

.page-about .ab-closing__links {
  margin: 0;
  gap: 12px;
  justify-content: center;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .ab-upkeep__list .upkeep-item {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: baseline;
  }

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

@media (min-width: 780px) {
  .page-about .tl-row {
    grid-template-columns: 156px minmax(0, 1fr);
    gap: 0 44px;
    padding-left: 22px;
  }

  .page-about .tl-year {
    position: sticky;
    top: 96px;
    align-self: start;
  }

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

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }
}

@media (min-width: 980px) {
  .page-about .ab-team__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    align-items: start;
  }

  .page-about .ab-team__figure {
    position: sticky;
    top: 110px;
  }
}

@media (min-width: 1080px) {
  .page-about .line-band:nth-child(2) {
    margin-left: clamp(0px, 6vw, 88px);
  }

  .page-about .tl-row:nth-child(even) .tl-body {
    margin-left: clamp(0px, 3vw, 44px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-row::before,
  .page-about .team-item::before,
  .page-about .team-item,
  .page-about .ab-index__list a,
  .page-about .crumbs a,
  .page-about .ab-reach__notes a {
    transition: none;
  }
}