.page-about {
  --about-rail-w: 8.5rem;
  --about-ink: #10251F;
  --about-ink-dim: rgba(16, 37, 31, .78);
  --about-ink-teal: #0B6B58;
  --about-hairline: rgba(16, 37, 31, .16);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about__hero {
  position: relative;
  isolation: isolate;
  display: flex;
  align-items: flex-end;
  min-height: clamp(28rem, 62vh, 40rem);
  background: var(--c-bg-deep);
}

.page-about__hero-img {
  position: absolute;
  inset: 0;
  z-index: -2;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 50% 40%;
}

.page-about__hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(180deg, rgba(6, 26, 23, .58) 0%, rgba(6, 26, 23, .88) 58%, var(--c-bg) 100%),
    radial-gradient(120% 80% at 12% 100%, rgba(36, 240, 200, .16) 0%, rgba(36, 240, 200, 0) 62%);
}

.page-about__hero-inner {
  padding-block: clamp(3.5rem, 10vw, 6rem) clamp(2rem, 5vw, 3rem);
}

.page-about .page-about__crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem;
  margin: 0 0 1.25rem;
  padding: 0;
  list-style: none;
  font-size: .82rem;
}

.page-about .page-about__crumbs li + li::before {
  content: "/";
  margin-right: .35rem;
  color: var(--c-line);
}

.page-about .page-about__crumbs a {
  color: var(--c-text-dim);
  text-decoration: none;
}

.page-about .page-about__crumbs a:hover {
  color: var(--c-accent);
}

.page-about .page-about__crumbs [aria-current="page"] {
  color: var(--c-accent);
}

.page-about__eyebrow {
  color: var(--c-accent);
  margin: 0 0 .75rem;
}

.page-about__title {
  margin: 0 0 1rem;
  max-width: 22ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.9rem, 5.4vw, 3.4rem);
  line-height: 1.12;
  letter-spacing: -.01em;
  color: var(--c-text);
}

.page-about__lede {
  margin: 0;
  max-width: 62ch;
  font-size: clamp(1rem, 1.4vw, 1.09rem);
  line-height: 1.8;
  color: var(--c-text-dim);
}

.page-about__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 1.25rem;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about__facts li {
  border-left: 2px solid var(--c-accent);
  padding-left: .75rem;
}

.page-about__fact-num {
  display: block;
  font-size: 1.45rem;
  line-height: 1.2;
  color: var(--c-accent);
}

.page-about__fact-label {
  display: block;
  margin-top: .2rem;
  font-size: .78rem;
  letter-spacing: .04em;
  color: var(--c-text-dim);
}

/* ---------- 主体栅格 ---------- */
.page-about__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  padding-block: clamp(1.5rem, 4vw, 2.5rem) clamp(3rem, 7vw, 5rem);
}

.page-about__rail {
  display: none;
}

.page-about__flow {
  display: grid;
  gap: 0;
  min-width: 0;
}

/* ---------- 章节 ---------- */
.page-about__chapter {
  padding-block: clamp(2rem, 5vw, 3.25rem);
  border-top: 1px solid var(--c-line);
}

.page-about__flow > .page-about__chapter:first-child {
  border-top: 0;
  padding-top: clamp(1rem, 3vw, 1.75rem);
}

.page-about .chapter__num {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  margin: 0 0 .6rem;
  font-family: var(--font-mono);
  font-size: .8rem;
  letter-spacing: .18em;
  color: var(--c-accent);
}

.page-about .chapter__num::before {
  content: "";
  width: 1.6rem;
  height: 1px;
  background: currentColor;
}

.page-about .chapter__title {
  margin: 0 0 .75rem;
  max-width: 26ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.4rem, 3.6vw, 2rem);
  line-height: 1.28;
  color: var(--c-text);
}

.page-about .chapter__lede {
  margin: 0 0 1.25rem;
  max-width: 64ch;
  font-size: 1.03rem;
  line-height: 1.8;
  color: var(--c-text-dim);
}

.page-about__p {
  margin: 0 0 1rem;
  max-width: 66ch;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--c-text-dim);
}

.page-about__note {
  margin: 1.25rem 0 0;
  max-width: 66ch;
  padding-left: .85rem;
  border-left: 2px solid var(--c-action);
  font-size: .92rem;
  line-height: 1.75;
  color: var(--c-text-dim);
}

/* ---------- 双栏卡片 ---------- */
.page-about__duo {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-top: 1.5rem;
}

.page-about__card {
  padding: 1.25rem 1.35rem;
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  background: linear-gradient(160deg, var(--c-surface) 0%, var(--c-surface-2) 100%);
}

.page-about__card-title {
  margin: 0 0 .5rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--c-text);
}

.page-about__card p {
  margin: 0;
  font-size: .94rem;
  line-height: 1.78;
  color: var(--c-text-dim);
}

/* ---------- 覆盖规模 ---------- */
.page-about__metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 1.5rem 0;
  padding: 0;
  list-style: none;
  background: var(--c-line);
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about__metric {
  padding: 1.1rem 1rem;
  background: var(--c-bg);
}

.page-about__metric-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 5vw, 2.1rem);
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: .02em;
  color: var(--c-accent);
}

.page-about__metric-label {
  display: block;
  margin-top: .35rem;
  font-size: .78rem;
  line-height: 1.5;
  color: var(--c-text-dim);
}

/* ---------- 米白亮区 ---------- */
.page-about__paper {
  position: relative;
  isolation: isolate;
  margin-block: clamp(1.5rem, 4vw, 2.5rem);
  padding: clamp(1.5rem, 4.5vw, 3rem);
  border-radius: var(--r-lg) 0 0 var(--r-lg);
  color: var(--about-ink);
}

.page-about__paper::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 200vw;
  z-index: -1;
  background: var(--c-paper);
}

.page-about__paper .page-about__chapter--paper {
  border-top: 1px solid var(--about-hairline);
  padding-block: clamp(1.25rem, 3vw, 2rem);
}

.page-about__paper .page-about__chapter--paper:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about__paper .chapter__num {
  color: var(--about-ink-teal);
}

.page-about__paper .chapter__title {
  color: var(--about-ink);
}

.page-about__paper .chapter__lede,
.page-about__paper .page-about__p {
  color: var(--about-ink-dim);
}

.page-about__paper .page-about__note {
  border-left-color: var(--c-action);
  color: var(--about-ink-dim);
}

/* ---------- 团队表格 ---------- */
.page-about__table-wrap {
  margin-top: 1.25rem;
}

.page-about__team {
  width: 100%;
  border-collapse: collapse;
  font-size: .94rem;
}

.page-about__team thead th {
  text-align: left;
  padding: .6rem .75rem;
  font-size: .74rem;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--about-ink-teal);
  border-bottom: 1px solid var(--about-hairline);
}

.page-about__team tbody th {
  text-align: left;
  padding: 1rem .75rem;
  font-weight: 700;
  color: var(--about-ink);
  border-bottom: 1px solid var(--about-hairline);
  white-space: nowrap;
}

.page-about__team tbody td {
  padding: 1rem .75rem;
  vertical-align: top;
  line-height: 1.7;
  color: var(--about-ink-dim);
  border-bottom: 1px solid var(--about-hairline);
}

.page-about__team tbody td:nth-child(2) {
  width: 5.5rem;
  white-space: nowrap;
  color: var(--about-ink-teal);
  font-weight: 600;
}

.page-about__team tbody tr:last-child th,
.page-about__team tbody tr:last-child td {
  border-bottom: 0;
}

/* ---------- 核对流程 ---------- */
.page-about__steps {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
  background: var(--about-hairline);
  border: 1px solid var(--about-hairline);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about__step {
  padding: 1.1rem 1.15rem;
  background: var(--c-paper);
}

.page-about__step-num {
  display: block;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .16em;
  color: var(--about-ink-teal);
}

.page-about__step-title {
  margin: .45rem 0 .35rem;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  color: var(--about-ink);
}

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

.page-about__data-media {
  margin: 1.75rem 0 0;
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about__data-media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 2 / 1;
  object-fit: cover;
}

.page-about__data-media .media__cap {
  margin: 0;
  padding: .65rem .85rem;
  font-size: .82rem;
  line-height: 1.65;
  color: var(--about-ink-dim);
  background: rgba(16, 37, 31, .06);
}

/* ---------- 版本时间线 ---------- */
.page-about__versions {
  display: grid;
  gap: .65rem;
  margin-top: 1.5rem;
}

.page-about__ver {
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  background: var(--c-surface-2);
  overflow: hidden;
}

.page-about__ver > summary {
  display: grid;
  grid-template-columns: auto 1fr 1.25rem;
  align-items: center;
  gap: .6rem .75rem;
  padding: .95rem 1.1rem;
  cursor: pointer;
  list-style: none;
}

.page-about__ver > summary::-webkit-details-marker {
  display: none;
}

.page-about__ver > summary::after {
  content: "+";
  grid-row: 1 / span 2;
  grid-column: 3;
  align-self: center;
  font-family: var(--font-mono);
  font-size: 1.1rem;
  line-height: 1;
  color: var(--c-accent);
  text-align: center;
}

.page-about__ver[open] > summary::after {
  content: "–";
}

.page-about__ver-badge {
  grid-column: 1;
  grid-row: 1;
  padding: .18rem .6rem;
  border-radius: var(--r-pill);
  background: rgba(36, 240, 200, .12);
  border: 1px solid rgba(36, 240, 200, .38);
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .06em;
  color: var(--c-accent);
  white-space: nowrap;
}

.page-about__ver-year {
  grid-column: 1;
  grid-row: 2;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .08em;
  color: var(--c-text-dim);
}

.page-about__ver-title {
  grid-column: 2;
  grid-row: 1 / span 2;
  font-family: var(--font-display);
  font-size: .98rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--c-text);
}

.page-about__ver-body {
  padding: 0 1.1rem 1.1rem;
}

.page-about__ver-body p {
  margin: 0;
  padding-top: .85rem;
  border-top: 1px solid var(--c-line);
  font-size: .92rem;
  line-height: 1.78;
  color: var(--c-text-dim);
}

/* ---------- 合作生态 ---------- */
.page-about__chapter--split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.page-about__split-main {
  min-width: 0;
}

.page-about__partner-media {
  margin: 0;
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about__partner-media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 10 / 7;
  object-fit: cover;
}

.page-about__cta {
  margin-top: 1.25rem;
}

/* ---------- 路线索引 ---------- */
.page-about__routes {
  margin-top: clamp(2rem, 5vw, 3rem);
  padding-top: clamp(1.5rem, 4vw, 2.25rem);
  border-top: 1px solid var(--c-line);
}

.page-about__routes-title {
  margin: 0 0 1.25rem;
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 3vw, 1.6rem);
  font-weight: 800;
  color: var(--c-text);
}

.page-about__routes .route-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--c-line);
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about__routes .route-list li {
  padding: 1.1rem 1.15rem;
  background: var(--c-bg);
}

.page-about__routes .route-list a {
  display: inline-block;
  margin-bottom: .35rem;
  font-family: var(--font-display);
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--c-text);
  text-decoration: none;
  border-bottom: 1px solid rgba(36, 240, 200, .45);
}

.page-about__routes .route-list a:hover {
  color: var(--c-accent);
}

.page-about__routes .route-list p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--c-text-dim);
}

/* ---------- 窄屏卡片式表格 ---------- */
@media (max-width: 47.9rem) {
  .page-about__team thead {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    padding: 0;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
  }

  .page-about__team,
  .page-about__team tbody,
  .page-about__team tr,
  .page-about__team th,
  .page-about__team td {
    display: block;
    width: 100%;
  }

  .page-about__team tbody tr {
    margin-bottom: .75rem;
    padding: .95rem 1rem;
    border: 1px solid var(--about-hairline);
    border-radius: var(--r-md);
    background: rgba(255, 255, 255, .55);
  }

  .page-about__team tbody th {
    padding: 0 0 .5rem;
    border-bottom: 1px solid var(--about-hairline);
    font-size: 1.02rem;
    white-space: normal;
  }

  .page-about__team tbody td {
    padding: .45rem 0 0;
    border-bottom: 0;
  }

  .page-about__team tbody td:nth-child(2) {
    width: auto;
  }

  .page-about__team tbody td::before {
    content: attr(data-label);
    display: inline-block;
    margin-right: .45rem;
    font-size: .72rem;
    letter-spacing: .1em;
    color: var(--about-ink-teal);
  }
}

/* ---------- 桌面布局 ---------- */
@media (min-width: 40rem) {
  .page-about__duo {
    grid-template-columns: 1fr 1fr;
  }

  .page-about__steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about__routes .route-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 60rem) {
  .page-about__layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 0 2.5rem;
    align-items: start;
  }

  .page-about__rail {
    display: block;
    position: sticky;
    top: 7rem;
    padding-top: clamp(1rem, 3vw, 1.75rem);
  }

  .page-about__rail-list {
    position: relative;
    display: grid;
    gap: 1.1rem;
    margin: 0;
    padding: 0 0 0 1rem;
    list-style: none;
    border-left: 1px solid var(--c-line);
  }

  .page-about__rail-link {
    display: grid;
    gap: .15rem;
    text-decoration: none;
    color: var(--c-text-dim);
    transition: color .16s ease;
  }

  .page-about__rail-link::before {
    content: "";
    position: absolute;
    left: -1.3rem;
    width: .6rem;
    height: 1px;
    margin-top: .55rem;
    background: var(--c-line);
    transition: width .16s ease, background-color .16s ease;
  }

  .page-about__rail-list li {
    position: relative;
  }

  .page-about__rail-num {
    font-family: var(--font-mono);
    font-size: .75rem;
    letter-spacing: .12em;
    color: var(--c-line);
    transition: color .16s ease;
  }

  .page-about__rail-label {
    font-size: .85rem;
    letter-spacing: .04em;
  }

  .page-about__rail-link:hover,
  .page-about__rail-link[aria-current="true"] {
    color: var(--c-text);
  }

  .page-about__rail-link:hover .page-about__rail-num,
  .page-about__rail-link[aria-current="true"] .page-about__rail-num {
    color: var(--c-accent);
  }

  .page-about__rail-link[aria-current="true"]::before {
    width: 1.1rem;
    background: var(--c-accent);
  }

  .page-about__metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about__steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about__chapter--split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 22rem);
    gap: 2.5rem;
    align-items: start;
  }

  .page-about__routes .route-list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about__rail-link,
  .page-about__rail-num,
  .page-about__rail-link::before {
    transition: none;
  }
}