.page-about {
  --ab-axis: 152px;
  --ab-rule: 175px;
}

/* ---------- 通用排版元素 ---------- */
.page-about .ab-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin: 0;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--orange);
}

.page-about .ab-eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: var(--orange);
  flex: none;
}

.page-about .ab-h2 {
  margin: 0;
  font-size: clamp(26px, 4.4vw, 40px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 800;
  color: var(--ink);
}

.page-about .ab-sec {
  border-top: 1px solid var(--line);
  padding-block: clamp(36px, 6vw, 78px);
}

.page-about .ab-sec--dark {
  background: var(--green);
  border-top-color: rgba(245, 247, 246, 0.14);
  color: var(--mist);
}

.page-about .ab-sec--deep {
  background: var(--blue);
  border-top-color: rgba(245, 247, 246, 0.14);
  color: var(--mist);
}

.page-about .ab-sec--dark .ab-h2,
.page-about .ab-sec--deep .ab-h2,
.page-about .ab-sec--dark h3,
.page-about .ab-sec--deep h3 {
  color: var(--mist);
}

.page-about .ab-sec__head {
  display: grid;
  gap: 10px;
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .ab-sec__note {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
}

.page-about .ab-sec--dark .ab-sec__note,
.page-about .ab-sec--deep .ab-sec__note {
  color: var(--on-dark-dim);
}

/* ---------- 首屏 ---------- */
.page-about .breadcrumb {
  padding-top: clamp(16px, 3vw, 28px);
}

.page-about .ab-hero {
  padding-block: clamp(24px, 4vw, 52px) clamp(32px, 5vw, 60px);
}

.page-about .ab-hero__title {
  margin: 16px 0 0;
  font-size: clamp(32px, 7vw, 64px);
  line-height: 1.06;
  letter-spacing: -0.025em;
  font-weight: 800;
  color: var(--ink);
  max-width: 15em;
}

.page-about .ab-hero__lead {
  margin: 20px 0 0;
  font-size: clamp(15px, 1.7vw, 17px);
  line-height: 1.85;
  color: var(--gray);
  max-width: 46em;
}

.page-about .ab-hero__facts {
  margin: clamp(26px, 4vw, 44px) 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-hero__facts > div {
  background: var(--mist);
  padding: 14px 16px;
}

.page-about .ab-hero__facts dt {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--gray);
}

.page-about .ab-hero__facts dd {
  margin: 8px 0 0;
  display: flex;
  align-items: baseline;
  gap: 6px;
  font-size: 14px;
  color: var(--gray);
}

.page-about .ab-hero__facts dd .mono {
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1;
  color: var(--ink);
}

/* ---------- 起点 ---------- */
.page-about .ab-origin {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
}

.page-about .ab-origin__text .ab-h2 {
  margin-top: 14px;
}

.page-about .ab-prose {
  margin-top: 18px;
  max-width: 42em;
}

.page-about .ab-prose p {
  margin: 0 0 1.2em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
  max-width: 42em;
}

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

.page-about .ab-prose a {
  color: var(--orange);
  text-decoration: none;
  border-bottom: 1px solid rgba(196, 85, 42, 0.35);
  transition: border-color 180ms ease-out, color 180ms ease-out;
}

.page-about .ab-prose a:hover {
  border-bottom-color: var(--orange);
}

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

.page-about .ab-origin__figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

/* ---------- 图片与图注 ---------- */
.page-about .ab-wide-figure {
  margin: 0 0 clamp(24px, 4vw, 44px);
}

.page-about .ab-wide-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .ab-figure__cap {
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  line-height: 1.7;
  color: var(--gray);
}

.page-about .ab-sec--dark .ab-figure__cap,
.page-about .ab-sec--deep .ab-figure__cap {
  color: var(--on-dark-dim);
}

/* ---------- 团队角色 ---------- */
.page-about .ab-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
}

.page-about .ab-role {
  border-top: 1px solid rgba(245, 247, 246, 0.18);
  padding: 20px 0;
}

.page-about .ab-role:first-child {
  border-top: none;
  padding-top: 0;
}

.page-about .ab-role__index {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--orange);
}

.page-about .ab-role__title {
  margin: 8px 0 0;
  font-size: clamp(17px, 2vw, 20px);
  font-weight: 700;
  color: var(--mist);
}

.page-about .ab-role__duty {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--on-dark-dim);
  transition: color 180ms ease-out;
}

.page-about .ab-role:hover .ab-role__duty {
  color: var(--on-dark);
}

/* ---------- 数据流程 ---------- */
.page-about .ab-flow {
  display: grid;
  gap: clamp(26px, 4vw, 48px);
}

.page-about .ab-flow h3 {
  margin: 0 0 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--gray);
}

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

.page-about .ab-sources__list li {
  background: var(--card);
  padding: 16px 18px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: 12px;
  row-gap: 6px;
  align-items: baseline;
}

.page-about .ab-sources__list li span {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--orange);
}

.page-about .ab-sources__list li b {
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ab-sources__list li p {
  grid-column: 1 / -1;
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
}

.page-about .ab-steps__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .ab-steps__list li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: 16px;
  align-items: start;
}

.page-about .ab-steps__num {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--orange);
  line-height: 1.9;
}

.page-about .ab-steps__list b {
  display: block;
  margin-bottom: 4px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ab-steps__list p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
}

.page-about .ab-quote {
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: 20px 22px;
  border-left: 3px solid var(--orange);
  background: var(--card);
  font-size: clamp(15px, 1.8vw, 18px);
  line-height: 1.8;
  color: var(--ink);
}

/* ---------- 版本时间线 ---------- */
.page-about .filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: clamp(24px, 4vw, 40px);
}

.page-about .filter-bar__btn {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 8px 14px;
  background: transparent;
  border: 1px solid var(--line);
  color: var(--gray);
  cursor: pointer;
  transition: color 180ms ease-out, border-color 180ms ease-out, background 180ms ease-out;
}

.page-about .filter-bar__btn:hover {
  border-color: var(--orange);
  color: var(--ink);
}

.page-about .filter-bar__btn.is-active,
.page-about .filter-bar__btn[aria-pressed="true"] {
  background: var(--green);
  border-color: var(--green);
  color: var(--mist);
}

.page-about .filter-bar__count {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gray);
  margin-left: auto;
}

.page-about .ab-timeline {
  position: relative;
  padding-left: 22px;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: var(--line);
}

.page-about .ab-node {
  position: relative;
  display: grid;
  gap: 8px;
  padding-bottom: clamp(30px, 4vw, 46px);
}

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: -21px;
  top: 9px;
  width: 9px;
  height: 9px;
  background: var(--orange);
}

.page-about .ab-node__marker {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .ab-node__ver {
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .ab-node__stage {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--gray);
}

.page-about .ab-node__body h3 {
  margin: 0 0 8px;
  font-size: clamp(18px, 2.2vw, 22px);
  line-height: 1.35;
  font-weight: 700;
  color: var(--ink);
}

.page-about .ab-node__body > p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--gray);
  max-width: 42em;
}

.page-about .ab-node--figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

/* 折叠详情 */
.page-about .fold__trigger {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  background: transparent;
  border: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--orange);
  cursor: pointer;
  transition: border-color 180ms ease-out, background 180ms ease-out;
}

.page-about .fold__trigger::after {
  content: "＋";
  font-size: 12px;
  line-height: 1;
}

.page-about .fold__trigger[aria-expanded="true"]::after {
  content: "－";
}

.page-about .fold__trigger:hover {
  border-color: var(--orange);
  background: var(--card);
}

.page-about .ab-node__list {
  list-style: none;
  margin: 12px 0 0;
  padding: 14px 16px;
  background: var(--card);
  display: grid;
  gap: 9px;
}

.page-about .ab-node__list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .ab-node__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 6px;
  height: 1px;
  background: var(--orange);
}

/* ---------- 运营 ---------- */
.page-about .ab-ops {
  display: grid;
  gap: clamp(22px, 3vw, 32px);
}

.page-about .ab-ops__col h3 {
  margin: 0 0 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(245, 247, 246, 0.18);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--orange);
}

.page-about .ab-ops__col p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--on-dark);
}

.page-about .ab-sec--deep a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid rgba(245, 247, 246, 0.4);
  transition: border-color 180ms ease-out, color 180ms ease-out;
}

.page-about .ab-sec--deep a:hover {
  border-bottom-color: var(--orange);
}

/* ---------- 断点 ---------- */
@media (min-width: 760px) {
  .page-about .ab-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-ops {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    column-gap: clamp(24px, 3vw, 44px);
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    display: grid;
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    column-gap: clamp(32px, 5vw, 72px);
    align-items: end;
  }

  .page-about .ab-hero .ab-eyebrow {
    grid-column: 1 / -1;
  }

  .page-about .ab-hero__title {
    grid-column: 1;
  }

  .page-about .ab-hero__lead {
    grid-column: 2;
    margin-top: 0;
  }

  .page-about .ab-hero__facts {
    grid-column: 1 / -1;
  }

  .page-about .ab-sec__head {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    column-gap: clamp(32px, 5vw, 72px);
    align-items: end;
  }

  .page-about .ab-sec__head .ab-eyebrow {
    grid-column: 1 / -1;
  }

  .page-about .ab-origin {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    column-gap: clamp(32px, 5vw, 72px);
    align-items: start;
  }

  .page-about .ab-origin__figure {
    margin-top: 48px;
  }

  .page-about .ab-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(32px, 4vw, 64px);
  }

  .page-about .ab-role {
    border-top: 1px solid rgba(245, 247, 246, 0.18);
    padding: 22px 0;
  }

  .page-about .ab-role:nth-child(2) {
    border-top: none;
    padding-top: 0;
  }

  .page-about .ab-role:first-child {
    border-top: none;
    padding-top: 0;
  }

  .page-about .ab-flow {
    grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
    column-gap: clamp(32px, 4vw, 64px);
  }

  .page-about .ab-timeline {
    padding-left: 0;
  }

  .page-about .ab-timeline::before {
    left: var(--ab-rule);
    top: 12px;
    bottom: 24px;
  }

  .page-about .ab-node {
    grid-template-columns: var(--ab-axis) minmax(0, 1fr);
    column-gap: clamp(32px, 4vw, 56px);
  }

  .page-about .ab-node::before {
    left: calc(var(--ab-rule) - 4px);
    top: 10px;
  }

  .page-about .ab-node__marker {
    flex-direction: column;
    align-items: flex-start;
    gap: 5px;
  }

  .page-about .ab-node__ver {
    font-size: 17px;
  }

  .page-about .ab-node--figure {
    grid-template-columns: var(--ab-rule) minmax(0, 1fr);
    column-gap: clamp(32px, 4vw, 56px);
  }

  .page-about .ab-node--figure img,
  .page-about .ab-node--figure .ab-figure__cap {
    grid-column: 2;
  }
}

@media (min-width: 1100px) {
  .page-about .ab-hero__lead {
    padding-bottom: 6px;
  }
}