.page-about {
  --ab-rail: 28px;
  --ab-gap: 10px;
  position: relative;
  display: block;
  color: var(--hf-ink);
  background: var(--hf-night);
  overflow-x: clip;
  padding-bottom: clamp(56px, 8vw, 110px);
}

@media (min-width: 760px) {
  .page-about {
    --ab-rail: 72px;
    --ab-gap: 28px;
  }
}

.page-about::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(43, 240, 200, .045) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(43, 240, 200, .045) 1px, transparent 1px);
  background-size: 96px 96px;
}

.page-about::after {
  content: "";
  position: absolute;
  z-index: 0;
  pointer-events: none;
  top: 0;
  left: 62%;
  width: min(560px, 68vw);
  height: min(560px, 68vw);
  border: 1px solid rgba(43, 240, 200, .08);
  border-radius: 50%;
  transform: translate(-50%, -58%);
}

/* ---------- 分节骨架：左编号栏 + 右叙述栏 ---------- */

.page-about .ab-section {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: var(--ab-rail) minmax(0, 1fr);
  gap: 0 var(--ab-gap);
  padding-top: clamp(44px, 6vw, 92px);
}

.page-about .ab-cover {
  padding-top: clamp(22px, 4vw, 48px);
}

.page-about .ab-rail {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-right: 8px;
  border-right: 1px solid var(--hf-line);
  padding-top: 6px;
}

.page-about .ab-rail__num {
  font-size: .68rem;
  line-height: 1.2;
  letter-spacing: .14em;
  color: var(--hf-amber);
}

.page-about .ab-rail__tag {
  display: none;
  font-size: .66rem;
  line-height: 1.4;
  letter-spacing: .18em;
  color: var(--hf-dim);
}

@media (min-width: 760px) {
  .page-about .ab-rail__num {
    font-size: .8125rem;
  }

  .page-about .ab-rail__tag {
    display: block;
  }
}

.page-about .ab-body {
  min-width: 0;
}

.page-about .ab-body h2 {
  margin: 0 0 14px;
  font-family: var(--hf-font-display);
  font-size: clamp(1.55rem, 4vw, 2.4rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--hf-ink);
}

.page-about .ab-intro {
  max-width: 38em;
  margin: 0 0 clamp(20px, 3vw, 34px);
  font-size: 1rem;
  line-height: 1.78;
  color: var(--hf-dim);
}

.page-about .ab-sub-title {
  margin: clamp(28px, 4vw, 44px) 0 14px;
  font-family: var(--hf-font-display);
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: .02em;
  color: var(--hf-ink);
}

.page-about .ab-tail {
  max-width: 38em;
  margin: clamp(20px, 3vw, 32px) 0 0;
  font-size: .9rem;
  line-height: 1.78;
  color: var(--hf-dim);
}

.page-about .ab-link {
  color: var(--hf-cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--hf-line-2);
  transition: color 160ms var(--hf-ease), border-color 160ms var(--hf-ease);
}

.page-about .ab-link:hover {
  color: var(--hf-mist);
  border-bottom-color: var(--hf-mist);
}

.page-about > .hf-index-bar {
  margin-top: clamp(16px, 2.6vw, 30px);
}

/* ---------- 封面 ---------- */

.page-about .ab-kicker {
  margin: 0 0 12px;
  font-size: .66rem;
  letter-spacing: .22em;
  color: var(--hf-violet);
}

@media (min-width: 760px) {
  .page-about .ab-kicker {
    font-size: .7rem;
  }
}

.page-about .ab-cover h1 {
  margin: 0 0 clamp(18px, 2.6vw, 30px);
  font-family: var(--hf-font-display);
  font-size: clamp(2.3rem, 7.5vw, 4.8rem);
  font-weight: 900;
  line-height: .98;
  letter-spacing: -0.02em;
  color: var(--hf-ink);
}

.page-about .ab-cover__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 4vw, 46px);
  align-items: end;
}

@media (min-width: 900px) {
  .page-about .ab-cover__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
  }
}

.page-about .ab-lede {
  max-width: 30em;
  margin: 0 0 18px;
  font-size: clamp(1rem, 1.6vw, 1.125rem);
  line-height: 1.8;
  color: var(--hf-ink);
}

.page-about .ab-cover__note {
  max-width: 32em;
  margin: 0 0 24px;
  font-size: .9rem;
  line-height: 1.75;
  color: var(--hf-dim);
}

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

.page-about .ab-cover__media {
  position: relative;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--hf-line);
  background: var(--hf-stand);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 8% 92%);
}

.page-about .ab-cover__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  opacity: .82;
  filter: saturate(.85) contrast(1.06);
}

.page-about .ab-cover__media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(140deg, rgba(43, 240, 200, .14), rgba(4, 18, 14, .72) 72%);
}

.page-about .ab-cover__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(26px, 4vw, 46px);
  background: var(--hf-line-soft);
  border: 1px solid var(--hf-line-soft);
}

@media (min-width: 720px) {
  .page-about .ab-cover__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .ab-stat {
  background: var(--hf-night);
  padding: clamp(14px, 1.8vw, 20px) clamp(14px, 2vw, 22px);
}

.page-about .ab-stat__num {
  display: block;
  font-size: clamp(1.3rem, 3.2vw, 1.95rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--hf-cyan);
}

.page-about .ab-stat__label {
  display: block;
  margin-top: 8px;
  font-size: .78rem;
  line-height: 1.55;
  color: var(--hf-dim);
}

/* ---------- 通栏图片带 ---------- */

.page-about .ab-band {
  position: relative;
  margin: 0 0 clamp(24px, 3.4vw, 40px);
  overflow: hidden;
  border: 1px solid var(--hf-line);
  background: var(--hf-turf);
}

.page-about .ab-band img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  opacity: .66;
  filter: saturate(.8) contrast(1.08);
}

.page-about .ab-band::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(112deg, rgba(4, 18, 14, .78), rgba(4, 18, 14, 0) 62%);
}

/* ---------- 版本演进线 ---------- */

.page-about .ab-timeline {
  border-top: 1px solid var(--hf-line-2);
}

.page-about .ab-timeline .hf-acc__head {
  margin: 0;
  font-weight: inherit;
}

.page-about .ab-timeline .hf-acc__item {
  background: transparent;
  border-bottom: 1px solid var(--hf-line-soft);
  transition: background-color 180ms var(--hf-ease);
}

.page-about .ab-timeline .hf-acc__item:hover {
  background: var(--hf-tint);
}

.page-about .ab-timeline .hf-acc__trigger {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
  width: 100%;
  padding: 16px 2px;
  background: none;
  border: 0;
  font: inherit;
  color: inherit;
  text-align: left;
  cursor: pointer;
}

.page-about .ab-timeline .hf-acc__trigger:focus-visible {
  outline: 2px solid var(--hf-mist);
  outline-offset: 2px;
}

.page-about .ab-timeline .hf-acc__idx {
  flex: 0 0 auto;
  font-size: .8125rem;
  letter-spacing: .12em;
  color: var(--hf-amber);
}

.page-about .ab-timeline .ab-node__stage {
  flex: 0 0 auto;
}

.page-about .ab-timeline .ab-node__title {
  flex: 1 1 auto;
  min-width: 0;
  font-size: 1rem;
  font-weight: 650;
  line-height: 1.45;
  color: var(--hf-ink);
}

@media (max-width: 620px) {
  .page-about .ab-timeline .ab-node__title {
    flex: 1 1 100%;
  }
}

.page-about .ab-timeline .hf-acc__mark {
  flex: 0 0 auto;
  width: 10px;
  height: 10px;
  border: 1px solid var(--hf-cyan);
  transition: transform 200ms var(--hf-ease), background-color 200ms var(--hf-ease);
}

.page-about .ab-timeline .hf-acc__trigger[aria-expanded="true"] .hf-acc__mark {
  background: var(--hf-cyan);
  transform: rotate(45deg);
}

.page-about .ab-timeline .hf-acc__panel {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 240ms var(--hf-ease);
}

.page-about .ab-timeline .hf-acc__panel[data-open] {
  grid-template-rows: 1fr;
}

.page-about .ab-timeline .hf-acc__inner {
  min-height: 0;
  overflow: hidden;
}

.page-about .ab-timeline .hf-acc__body {
  padding: 0 2px 20px 0;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--hf-dim);
}

.page-about .ab-timeline .hf-acc__body ul {
  margin: 0;
  padding-left: 18px;
  list-style: none;
}

.page-about .ab-timeline .hf-acc__body li {
  position: relative;
  margin-bottom: 8px;
}

.page-about .ab-timeline .hf-acc__body li::before {
  content: "";
  position: absolute;
  left: -18px;
  top: .66em;
  width: 6px;
  height: 6px;
  background: var(--hf-cyan);
  opacity: .72;
}

/* ---------- 三组分工 ---------- */

.page-about .ab-teams {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--hf-line-soft);
  border: 1px solid var(--hf-line-soft);
}

@media (min-width: 800px) {
  .page-about .ab-teams {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .ab-role {
  background: var(--hf-stand);
  padding: clamp(18px, 2.2vw, 26px);
}

.page-about .ab-role__idx {
  display: block;
  margin-bottom: 10px;
  font-size: .66rem;
  letter-spacing: .18em;
  color: var(--hf-violet);
}

.page-about .ab-role__name {
  margin: 0 0 10px;
  font-family: var(--hf-font-display);
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: .01em;
  color: var(--hf-ink);
}

.page-about .ab-role__desc {
  margin: 0 0 14px;
  font-size: .9rem;
  line-height: 1.72;
  color: var(--hf-dim);
}

.page-about .ab-role__list {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-role__list li {
  position: relative;
  padding-left: 14px;
  font-size: .85rem;
  line-height: 1.62;
  color: var(--hf-ink);
}

.page-about .ab-role__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 5px;
  height: 5px;
  border: 1px solid var(--hf-cyan);
}

.page-about .ab-handoffs {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--hf-line-soft);
  border-left: 2px solid var(--hf-cyan);
}

.page-about .ab-handoff {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 12px;
  padding: 16px 18px;
  background: var(--hf-night);
}

.page-about .ab-handoff__idx {
  padding-top: 3px;
  font-size: .75rem;
  letter-spacing: .12em;
  color: var(--hf-amber);
}

.page-about .ab-handoff p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.72;
  color: var(--hf-dim);
}

.page-about .ab-handoff strong {
  display: block;
  margin-bottom: 4px;
  font-weight: 650;
  color: var(--hf-ink);
}

/* ---------- 校对流程与筛选 ---------- */

.page-about .ab-filter {
  position: relative;
  margin-top: clamp(14px, 2vw, 22px);
}

.page-about .ab-filter__input {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  border: 0;
  white-space: nowrap;
}

.page-about .ab-filter__label {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 16px;
  padding: 7px 14px 7px 10px;
  border: 1px solid var(--hf-line-2);
  font-family: var(--hf-font-mono);
  font-size: .74rem;
  letter-spacing: .1em;
  color: var(--hf-dim);
  cursor: pointer;
  user-select: none;
  transition: color 160ms var(--hf-ease), border-color 160ms var(--hf-ease);
}

.page-about .ab-filter__label:hover {
  color: var(--hf-ink);
  border-color: var(--hf-cyan);
}

.page-about .ab-filter__box {
  width: 11px;
  height: 11px;
  border: 1px solid var(--hf-dim);
  transition: background-color 160ms var(--hf-ease), border-color 160ms var(--hf-ease);
}

.page-about .ab-filter__input:checked ~ .ab-filter__label {
  color: var(--hf-cyan);
  border-color: var(--hf-cyan);
}

.page-about .ab-filter__input:checked ~ .ab-filter__label .ab-filter__box {
  background: var(--hf-cyan);
  border-color: var(--hf-cyan);
}

.page-about .ab-filter__input:focus-visible ~ .ab-filter__label {
  outline: 2px solid var(--hf-mist);
  outline-offset: 3px;
}

.page-about .ab-filter__input:checked ~ .ab-flow .ab-flow__item:not(.is-check) {
  display: none;
}

.page-about .ab-flow {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--hf-line-2);
}

.page-about .ab-flow__item {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr);
  gap: 4px 12px;
  padding: 15px 0;
  border-bottom: 1px solid var(--hf-line-soft);
}

@media (min-width: 680px) {
  .page-about .ab-flow__item {
    grid-template-columns: 34px 22ch minmax(0, 1fr);
    align-items: baseline;
    gap: 4px 22px;
  }
}

.page-about .ab-flow__idx {
  font-size: .75rem;
  letter-spacing: .1em;
  color: var(--hf-amber);
}

.page-about .ab-flow__name {
  margin: 0;
  font-size: .95rem;
  font-weight: 650;
  line-height: 1.5;
  color: var(--hf-ink);
}

.page-about .ab-flow__desc {
  margin: 0;
  font-size: .875rem;
  line-height: 1.72;
  color: var(--hf-dim);
}

.page-about .ab-flow__item.is-check .ab-flow__idx {
  color: var(--hf-cyan);
}

/* ---------- 河北接入 ---------- */

.page-about .ab-measure {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 40px);
  margin-top: clamp(6px, 1.4vw, 14px);
}

@media (min-width: 860px) {
  .page-about .ab-measure {
    grid-template-columns: minmax(0, .78fr) minmax(0, 1.22fr);
    align-items: start;
  }
}

.page-about .ab-measure__value {
  padding: clamp(20px, 3vw, 30px);
  border: 1px solid var(--hf-line-2);
  background:
    linear-gradient(135deg, rgba(43, 240, 200, .1), rgba(43, 240, 200, 0) 64%),
    var(--hf-stand);
  clip-path: polygon(0 0, 100% 0, 100% 86%, 86% 100%, 0 100%);
}

.page-about .ab-measure__num {
  display: block;
  font-size: clamp(2.8rem, 9vw, 5rem);
  line-height: .9;
  letter-spacing: -0.03em;
  color: var(--hf-cyan);
}

.page-about .ab-measure__cap {
  display: block;
  margin-top: 14px;
  font-size: .85rem;
  line-height: 1.68;
  color: var(--hf-dim);
}

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

.page-about .ab-measure__list > li {
  padding: 16px 18px;
  background: var(--hf-night);
}

.page-about .ab-measure__list h3 {
  margin: 0 0 6px;
  font-size: .95rem;
  font-weight: 700;
  color: var(--hf-ink);
}

.page-about .ab-measure__list p {
  margin: 0;
  font-size: .875rem;
  line-height: 1.72;
  color: var(--hf-dim);
}

/* ---------- 协作角色 ---------- */

.page-about .ab-collab {
  display: grid;
  gap: 1px;
  margin-bottom: clamp(6px, 1.4vw, 14px);
  background: var(--hf-line-soft);
  border: 1px solid var(--hf-line-soft);
}

.page-about .ab-collab__item {
  display: grid;
  gap: 8px;
  padding: clamp(16px, 2vw, 22px);
  background: var(--hf-night);
  border-left: 2px solid transparent;
  transition: border-color 180ms var(--hf-ease);
}

.page-about .ab-collab__item:hover {
  border-left-color: var(--hf-violet);
}

@media (min-width: 720px) {
  .page-about .ab-collab__item {
    grid-template-columns: 132px minmax(0, 1fr);
    align-items: baseline;
    gap: 6px 24px;
  }
}

.page-about .ab-collab__name {
  margin: 0;
  font-family: var(--hf-font-display);
  font-size: 1rem;
  font-weight: 800;
  letter-spacing: .02em;
  color: var(--hf-mist);
}

.page-about .ab-collab__desc {
  margin: 0;
  font-size: .9rem;
  line-height: 1.72;
  color: var(--hf-dim);
}

/* ---------- 可访问性与动效降级 ---------- */

.page-about .hf-acc__head {
  font-weight: inherit;
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}