.page-about {
  --about-rail: 104px;
  --about-gap: clamp(1.5rem, 3vw, 2.75rem);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  overflow-wrap: break-word;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about p {
  margin: 0 0 1rem;
  line-height: 1.85;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

.page-about .about-layout {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  column-gap: var(--about-gap);
}

.page-about .about-flow {
  min-width: 0;
}

/* ---------- 坐标刻度栏 ---------- */
.page-about .about-rail {
  min-width: 0;
  padding-block: 0 .4rem;
  border-bottom: 1px solid var(--line);
}

.page-about .about-rail-head {
  margin: 0 0 .5rem;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .18em;
  font-weight: 700;
  color: var(--ochre);
}

.page-about .rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1.1rem;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .rail-list::-webkit-scrollbar {
  display: none;
}

.page-about .rail-item {
  flex: 0 0 auto;
}

.page-about .rail-item > a {
  display: inline-flex;
  align-items: baseline;
  gap: .38rem;
  padding: .32rem 0;
  border-bottom: 2px solid var(--gray);
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .06em;
  color: var(--pine);
  text-decoration: none;
  white-space: nowrap;
}

.page-about .rail-num {
  font-weight: 700;
  color: var(--ochre);
}

.page-about .rail-item > a:hover,
.page-about .rail-item > a:focus-visible {
  color: var(--ochre-deep);
  border-bottom-color: var(--cyan-ink);
}

.page-about .rail-sub {
  display: none;
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  padding-block: clamp(2.4rem, 5vw, 4rem);
  border-top: 1px solid var(--line);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: clamp(1.2rem, 3vw, 2rem);
}

.page-about .crumbs {
  margin-bottom: clamp(1.2rem, 2.5vw, 2rem);
}

.page-about .sec-eyebrow {
  margin: 0 0 .6rem;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .18em;
  font-weight: 700;
  color: var(--ochre);
}

.page-about .sec-title {
  margin: 0 0 1rem;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(1.5rem, 3.2vw, 2.3rem);
  line-height: 1.24;
  letter-spacing: .02em;
  color: var(--ink);
  text-wrap: balance;
}

.page-about .sec-lede {
  margin: 0 0 1.4rem;
  max-width: 62ch;
  font-size: clamp(1rem, 1.2vw, 1.06rem);
  line-height: 1.85;
  color: rgba(27, 26, 23, .82);
}

/* ---------- 首屏 ---------- */
.page-about .hero-grid {
  display: grid;
  gap: clamp(1.6rem, 3vw, 2.6rem);
}

.page-about .hero-mark {
  display: flex;
  align-items: center;
  gap: .6rem;
  margin: 0 0 1.1rem;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .2em;
  color: var(--ochre);
}

.page-about .hero-mark::before {
  content: "";
  width: 2.2rem;
  height: 2px;
  background: var(--ochre);
}

.page-about .hero-h1 {
  margin: 0 0 1.1rem;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(2rem, 5.6vw, 3.7rem);
  line-height: 1.12;
  letter-spacing: .03em;
  color: var(--ink);
}

.page-about .hero-h1 em {
  font-style: normal;
  color: var(--ochre);
  box-shadow: inset 0 -.14em 0 rgba(232, 180, 90, .45);
}

.page-about .hero-lede {
  margin: 0 0 1.6rem;
  max-width: 52ch;
  font-size: clamp(1rem, 1.4vw, 1.12rem);
  line-height: 1.9;
  color: rgba(27, 26, 23, .82);
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
}

.page-about .kpi-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  overflow: hidden;
}

.page-about .kpi {
  background: var(--cold);
  padding: 1rem 1.05rem 1.1rem;
}

.page-about .kpi:first-child {
  background: var(--pine);
}

.page-about .kpi:first-child .kpi-num {
  color: var(--cyan);
}

.page-about .kpi:first-child .kpi-label {
  color: rgba(227, 237, 231, .88);
}

.page-about .kpi-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.3rem, 2.6vw, 1.8rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: .01em;
  color: var(--ochre);
}

.page-about .kpi-label {
  display: block;
  margin-top: .3rem;
  font-size: .78rem;
  line-height: 1.5;
  letter-spacing: .04em;
  color: var(--pine);
}

/* ---------- 起点 ---------- */
.page-about .origin-grid {
  display: grid;
  gap: clamp(1.4rem, 3vw, 2.4rem);
}

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

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

.page-about .about-img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  background: var(--pine-soft);
}

.page-about .fig-caption {
  margin-top: .7rem;
  padding-left: .7rem;
  border-left: 2px solid var(--gold);
  font-size: .78rem;
  line-height: 1.65;
  color: rgba(27, 26, 23, .62);
}

.page-about .about-figure--team {
  margin-top: 1.6rem;
}

/* ---------- 方法 ---------- */
.page-about .step-list {
  list-style: none;
  margin: 1.6rem 0 0;
  padding: 0;
}

.page-about .step {
  display: grid;
  grid-template-columns: 2.4rem minmax(0, 1fr);
  gap: 0 1rem;
  padding: 1.1rem 0;
  border-top: 1px solid var(--line);
}

.page-about .step:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .step-num {
  padding-top: .2rem;
  font-family: var(--font-mono);
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--ochre);
}

.page-about .step-title {
  margin: 0 0 .4rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(1rem, 1.6vw, 1.16rem);
  line-height: 1.5;
  letter-spacing: .02em;
  color: var(--ink);
}

.page-about .step-body p {
  margin: 0;
  font-size: .95rem;
  color: rgba(27, 26, 23, .78);
}

/* ---------- 历程 ---------- */
.page-about .tl-list {
  list-style: none;
  margin: 1.6rem 0 0;
  padding: 0;
}

.page-about .tl-item {
  position: relative;
  margin-left: .35rem;
  padding: 0 0 1.7rem 1.9rem;
  border-left: 2px solid var(--line);
}

.page-about .tl-item:last-child {
  padding-bottom: .2rem;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -6px;
  top: .5rem;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--paper);
  box-shadow: inset 0 0 0 2px var(--ochre);
}

.page-about .tl-item[data-current="true"]::before {
  background: var(--cyan);
  box-shadow: inset 0 0 0 2px var(--cyan-ink);
}

.page-about .tl-year {
  margin: 0 0 .25rem;
  font-family: var(--font-mono);
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--ochre);
}

.page-about .tl-item[data-current="true"] .tl-year {
  color: var(--cyan-ink);
}

.page-about .tl-title {
  margin: 0 0 .4rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.04rem;
  line-height: 1.55;
  letter-spacing: .02em;
}

.page-about .tl-item p {
  margin: 0;
  max-width: 60ch;
  font-size: .95rem;
  color: rgba(27, 26, 23, .78);
}

/* ---------- 团队 ---------- */
.page-about .team-filter {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .5rem;
  margin: 1.6rem 0 1.5rem;
  padding-bottom: .9rem;
  border-bottom: 1px solid var(--line);
}

.page-about .team-btn {
  appearance: none;
  border: 1px solid var(--line-pine);
  background: transparent;
  color: var(--pine);
  font-family: var(--font-body);
  font-size: .82rem;
  letter-spacing: .04em;
  padding: .42rem .85rem;
  border-radius: 999px;
  cursor: pointer;
  transition: background .18s ease, color .18s ease, border-color .18s ease;
}

.page-about .team-btn:hover {
  border-color: var(--ochre);
  color: var(--ochre);
}

.page-about .team-btn:focus-visible {
  outline: 2px solid var(--cyan-ink);
  outline-offset: 2px;
}

.page-about .team-btn[aria-pressed="true"] {
  background: var(--pine);
  border-color: var(--pine);
  color: var(--cold);
}

.page-about .team-count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .1em;
  color: rgba(27, 26, 23, .5);
}

.page-about .team-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

.page-about .team-card {
  background: var(--cold);
  border: 1px solid var(--line);
  border-top: 3px solid var(--ochre);
  border-radius: var(--r-m);
  padding: 1.15rem 1.1rem 1.3rem;
  box-shadow: var(--shadow);
}

.page-about .team-card:nth-child(2) {
  border-top-color: var(--pine);
}

.page-about .team-card:nth-child(3) {
  border-top-color: var(--gold);
}

.page-about .team-idx {
  display: block;
  margin-bottom: .5rem;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .14em;
  color: rgba(27, 26, 23, .45);
}

.page-about .team-name {
  margin: 0 0 .6rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.06rem;
  letter-spacing: .03em;
  color: var(--pine);
}

.page-about .team-card p {
  margin: 0;
  font-size: .93rem;
  line-height: 1.78;
  color: rgba(27, 26, 23, .78);
}

/* ---------- 覆盖 ---------- */
.page-about .about-coverage {
  background: var(--pine);
  border-top: 0;
  border-radius: var(--r-l);
  padding-inline: clamp(1.2rem, 3.5vw, 2.6rem);
  margin-block: clamp(1.6rem, 4vw, 2.8rem);
}

.page-about .about-coverage .sec-eyebrow--light {
  color: var(--gold);
}

.page-about .sec-title--light {
  color: var(--cold);
}

.page-about .about-coverage p {
  max-width: 64ch;
  color: rgba(227, 237, 231, .86);
}

.page-about .coverage-figure {
  margin: 1.6rem 0 0;
}

.page-about .coverage-img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--r-m);
  opacity: .94;
}

/* ---------- 检查清单 ---------- */
.page-about .check-list {
  margin-top: 1.4rem;
  border-top: 1px solid var(--line);
}

.page-about .check-item {
  border-bottom: 1px solid var(--line);
}

.page-about .check-trigger {
  width: 100%;
  display: grid;
  grid-template-columns: 2.2rem minmax(0, 1fr) 1rem;
  align-items: center;
  gap: .6rem;
  padding: 1rem 0;
  background: none;
  border: 0;
  text-align: left;
  cursor: pointer;
  color: var(--ink);
  font-family: var(--font-body);
}

.page-about .check-trigger:focus-visible {
  outline: 2px solid var(--cyan-ink);
  outline-offset: 2px;
}

.page-about .check-idx {
  font-family: var(--font-mono);
  font-size: .76rem;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--ochre);
}

.page-about .check-name {
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: .02em;
  transition: color .18s ease;
}

.page-about .check-trigger:hover .check-name {
  color: var(--ochre);
}

.page-about .check-arrow {
  justify-self: end;
  width: 9px;
  height: 9px;
  margin-top: -4px;
  border-right: 2px solid var(--pine);
  border-bottom: 2px solid var(--pine);
  transform: rotate(45deg);
  transition: transform .22s ease, border-color .18s ease;
}

.page-about .check-trigger[aria-expanded="true"] .check-arrow {
  margin-top: 4px;
  transform: rotate(-135deg);
  border-color: var(--ochre);
}

.page-about .check-panel {
  padding: 0 0 1.1rem 2.8rem;
  font-size: .94rem;
  line-height: 1.8;
  color: rgba(27, 26, 23, .78);
}

.page-about .check-panel p {
  margin: 0;
}

/* ---------- 继续 ---------- */
.page-about .next-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
  margin-top: 1.4rem;
}

.page-about .next-card {
  display: block;
  text-decoration: none;
  color: inherit;
  background: var(--cold);
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  padding: 1.15rem 1.1rem 1.25rem;
  transition: border-color .18s ease, transform .18s ease, box-shadow .18s ease;
}

.page-about .next-card:hover,
.page-about .next-card:focus-visible {
  border-color: var(--ochre);
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}

.page-about .next-card-label {
  display: block;
  margin-bottom: .5rem;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .14em;
  color: var(--ochre);
}

.page-about .next-card-title {
  display: block;
  margin-bottom: .4rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.06rem;
  letter-spacing: .02em;
  color: var(--ink);
}

.page-about .next-card-text {
  display: block;
  font-size: .9rem;
  line-height: 1.7;
  color: rgba(27, 26, 23, .72);
}

.page-about .contact-strip {
  margin-top: 1.6rem;
  padding: 1.1rem 1.15rem;
  border: 1px dashed var(--line-pine);
  border-radius: var(--r-m);
  display: grid;
  gap: .55rem;
  font-size: .92rem;
  color: rgba(27, 26, 23, .82);
}

.page-about .contact-strip .ci {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .6rem;
}

.page-about .ci-label {
  min-width: 3.6rem;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .12em;
  color: var(--ochre);
}

/* ---------- 中屏 ---------- */
@media (min-width: 700px) {
  .page-about .team-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    padding-bottom: 1.4rem;
  }

  .page-about .team-card:nth-child(2) {
    transform: translateY(1.1rem);
  }

  .page-about .team-card:nth-child(3) {
    transform: translateY(.45rem);
  }

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

@media (min-width: 840px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .origin-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    align-items: start;
  }
}

/* ---------- 桌面：坐标刻度纵向贯穿 ---------- */
@media (min-width: 980px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
  }

  .page-about .about-rail {
    position: sticky;
    top: 6rem;
    align-self: start;
    padding-block: 0;
    border-bottom: 0;
  }

  .page-about .about-rail-head {
    padding-bottom: .6rem;
    border-bottom: 2px solid var(--ochre);
  }

  .page-about .rail-list {
    display: flex;
    flex-direction: column;
    gap: 0;
    overflow: visible;
    position: relative;
  }

  .page-about .rail-list::before {
    content: "";
    position: absolute;
    left: 0;
    top: .6rem;
    bottom: 1.4rem;
    width: 2px;
    background: linear-gradient(180deg, var(--ochre), var(--pine) 62%, var(--gray));
  }

  .page-about .rail-item {
    flex: 0 0 auto;
  }

  .page-about .rail-item > a {
    display: block;
    position: relative;
    padding: .38rem 0 .38rem 1.15rem;
    border-bottom: 0;
  }

  .page-about .rail-item > a::before {
    content: "";
    position: absolute;
    left: -3.5px;
    top: 50%;
    width: 9px;
    height: 9px;
    margin-top: -4.5px;
    border-radius: 50%;
    background: var(--paper);
    box-shadow: inset 0 0 0 2px var(--gray);
    transition: background .2s ease, box-shadow .2s ease;
  }

  .page-about .rail-item > a:hover::before,
  .page-about .rail-item > a:focus-visible::before {
    background: var(--gold);
    box-shadow: inset 0 0 0 2px var(--gold);
  }

  .page-about .rail-sub {
    display: block;
    list-style: none;
    margin: 0;
    padding: 0 0 .35rem 1.15rem;
  }

  .page-about .rail-sub a {
    display: block;
    padding: .16rem 0 .16rem .6rem;
    border-left: 1px solid var(--line-pine);
    font-family: var(--font-mono);
    font-size: .68rem;
    letter-spacing: .08em;
    color: var(--pine);
    opacity: .72;
    text-decoration: none;
  }

  .page-about .rail-sub a:hover,
  .page-about .rail-sub a:focus-visible {
    opacity: 1;
    color: var(--ochre);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .next-card,
  .page-about .team-btn,
  .page-about .check-arrow,
  .page-about .rail-item > a::before {
    transition: none;
  }

  .page-about .next-card:hover,
  .page-about .next-card:focus-visible {
    transform: none;
  }
}