.page-about {
  background: var(--ice);
  color: var(--ink);
  font-family: var(--font-body);
  overflow-x: clip;
}

/* ---------- 首屏框景 ---------- */
.page-about .about-hero {
  position: relative;
  background: var(--lake);
  color: var(--white);
  padding: calc(var(--header-h) + 68px) 0 52px;
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(90deg, rgba(191, 208, 216, .13) 0 1px, transparent 1px 92px),
    linear-gradient(180deg, rgba(6, 47, 71, .6), rgba(11, 74, 111, 0) 62%);
  pointer-events: none;
}

.page-about .about-hero .container {
  position: relative;
  z-index: 1;
}

.page-about .about-frame {
  position: relative;
  border: 1px solid rgba(191, 208, 216, .34);
  padding: 30px 20px 32px;
}

.page-about .about-frame::before,
.page-about .about-frame::after {
  content: "";
  position: absolute;
  width: 56px;
  height: 56px;
  pointer-events: none;
}

.page-about .about-frame::before {
  top: -1px;
  left: -1px;
  border-top: 2px solid var(--metal);
  border-left: 2px solid var(--metal);
}

.page-about .about-frame::after {
  right: -1px;
  bottom: -1px;
  border-right: 2px solid var(--metal);
  border-bottom: 2px solid var(--metal);
}

.page-about .about-crumbs {
  margin-bottom: 24px;
}

.page-about .about-crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 13px;
}

.page-about .about-crumbs li {
  color: rgba(191, 208, 216, .78);
}

.page-about .about-crumbs li + li::before {
  content: "·";
  margin-right: 10px;
  color: rgba(191, 208, 216, .5);
}

.page-about .about-crumbs a {
  color: rgba(244, 246, 244, .92);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

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

.page-about .about-crumbs [aria-current="page"] {
  color: var(--metal);
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5.4vw, 60px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--white);
  max-width: 17em;
}

.page-about .about-lead {
  margin: 22px 0 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(244, 246, 244, .86);
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 24px;
  margin: 34px 0 0;
  padding: 24px 0 0;
  list-style: none;
  border-top: 1px solid rgba(191, 208, 216, .3);
}

.page-about .hs-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 4.6vw, 36px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--metal);
}

.page-about .hs-unit {
  display: block;
  margin-top: 9px;
  font-family: var(--font-serif);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: rgba(191, 208, 216, .92);
}

/* ---------- 轨道与正文骨架 ---------- */
.page-about .about-shell-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  padding-top: 34px;
  padding-bottom: 56px;
}

.page-about .about-rail {
  padding-bottom: 18px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--mist);
}

.page-about .rail-plate {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 15px 16px 16px;
  margin-bottom: 18px;
  background: var(--lake);
  color: var(--white);
}

.page-about .rail-plate-label {
  font-family: var(--font-serif);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--metal);
}

.page-about .rail-plate-span {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.page-about .rail-plate-note {
  font-size: 12px;
  color: rgba(191, 208, 216, .86);
}

.page-about .about-toc ol {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .toc-link {
  display: block;
  white-space: nowrap;
  padding: 8px 13px;
  font-size: 13.5px;
  line-height: 1.3;
  color: var(--lake);
  text-decoration: none;
  background: var(--white);
  border: 1px solid var(--mist);
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), background var(--t-fast) var(--ease);
}

.page-about .toc-link:hover {
  border-color: var(--barley);
  color: var(--lake-deep);
}

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

/* ---------- 章节通用 ---------- */
.page-about .about-sec,
.page-about .about-meter {
  scroll-margin-top: calc(var(--header-h) + 22px);
}

.page-about .about-sec {
  padding: 40px 0 44px;
  border-top: 1px solid var(--mist);
}

.page-about .sec-head {
  margin-bottom: 20px;
}

.page-about .sec-index {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--barley);
}

.page-about .about-sec h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 3.5vw, 34px);
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: var(--lake-deep);
}

.page-about .sec-intro {
  margin: 0 0 6px;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(10, 26, 36, .8);
}

.page-about .sec-cols {
  display: grid;
  gap: 28px;
  margin-top: 22px;
}

.page-about .sec-text p {
  margin: 0 0 1.1em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink);
}

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

/* 图片 */
.page-about .sec-figure {
  margin: 0;
}

.page-about .sec-figure img,
.page-about .archive-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  filter: saturate(.94) contrast(1.04);
}

.page-about .media-caption {
  margin-top: 10px;
  font-family: var(--font-serif);
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: .02em;
  color: rgba(10, 26, 36, .62);
}

/* ---------- 数字铭牌窄段 ---------- */
.page-about .about-meter {
  margin: 8px 0 0;
  padding: 24px 20px;
  background: var(--lake-deep);
}

.page-about .meter-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 22px;
}

.page-about .meter-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 600;
  line-height: 1;
  color: var(--metal);
  letter-spacing: -0.02em;
}

.page-about .meter-txt {
  display: block;
  margin-top: 9px;
  font-size: 12.5px;
  line-height: 1.65;
  color: rgba(191, 208, 216, .9);
}

/* ---------- 团队分工 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 24px;
  background: var(--mist);
  border: 1px solid var(--mist);
}

.page-about .team-card {
  background: var(--white);
  padding: 22px 20px 24px;
}

.page-about .team-num {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--barley);
}

.page-about .team-card h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--lake-deep);
}

.page-about .team-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: rgba(10, 26, 36, .84);
}

/* ---------- 校对与规范（沙白分区） ---------- */
.page-about .about-sec--sand {
  padding: 44px 20px 48px;
  background: var(--sand);
  border-top: 0;
}

.page-about .gate-track {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  background: rgba(11, 74, 111, .16);
  border-top: 2px solid var(--barley);
}

.page-about .gate {
  position: relative;
  background: var(--ice);
  padding: 22px 20px 24px;
}

.page-about .gate-num {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--sunset);
}

.page-about .gate h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 17px;
  color: var(--lake-deep);
}

.page-about .gate p {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: rgba(10, 26, 36, .84);
}

.page-about .standards-body {
  margin-top: 28px;
}

/* ---------- 档案建设（深湖蓝分区） ---------- */
.page-about .about-sec--deep {
  padding: 44px 20px 48px;
  background: var(--lake-deep);
  color: var(--ice);
  border-top: 0;
  margin: 12px 0;
}

.page-about .about-sec--deep h2 {
  color: var(--white);
}

.page-about .about-sec--deep .sec-index {
  color: var(--metal);
}

.page-about .archive-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-top: 26px;
}

.page-about .archive-card {
  padding-top: 16px;
  border-top: 2px solid var(--metal);
}

.page-about .archive-card h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 18px;
  color: var(--white);
}

.page-about .archive-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.84;
  color: rgba(244, 246, 244, .82);
}

.page-about .archive-figure {
  margin: 32px 0 0;
  border: 1px solid rgba(191, 208, 216, .3);
}

.page-about .about-sec--deep .media-caption {
  margin: 10px 12px 12px;
  color: rgba(244, 246, 244, .68);
}

/* ---------- 协作与荣誉 ---------- */
.page-about .net-figure {
  margin: 0;
}

.page-about .net-map {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  overflow: visible;
}

.page-about .net-map .net-lines line {
  stroke: var(--mist);
  stroke-width: 1;
}

.page-about .net-map .net-nodes circle {
  fill: var(--metal);
}

.page-about .net-map .net-core {
  fill: var(--sunset);
}

.page-about .net-note {
  margin: 12px 0 0;
  font-family: var(--font-serif);
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: .02em;
  color: rgba(10, 26, 36, .6);
}

/* ---------- 开始合作 ---------- */
.page-about .about-sec--cta {
  padding-bottom: 24px;
}

.page-about .connect-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 24px;
  background: var(--mist);
  border: 1px solid var(--mist);
}

.page-about .connect-card {
  display: flex;
  flex-direction: column;
  padding: 24px 22px 26px;
  background: var(--white);
}

.page-about .connect-card h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 17px;
  color: var(--lake-deep);
}

.page-about .connect-card p {
  flex: 1 1 auto;
  margin: 0 0 16px;
  font-size: 14px;
  line-height: 1.82;
  color: rgba(10, 26, 36, .84);
}

.page-about .connect-card .btn {
  align-self: flex-start;
}

.page-about .connect-note {
  margin: 22px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: rgba(10, 26, 36, .78);
}

.page-about .connect-note a {
  color: var(--lake);
  text-decoration: none;
  border-bottom: 1px solid var(--barley);
}

.page-about .connect-note a:hover {
  color: var(--lake-deep);
}

.page-about .about-backtop {
  margin: 26px 0 0;
}

.page-about .about-backtop a {
  display: inline-block;
  padding-bottom: 3px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--lake);
  text-decoration: none;
  border-bottom: 1px solid var(--barley);
  transition: color var(--t-fast) var(--ease);
}

.page-about .about-backtop a:hover {
  color: var(--sunset);
}

/* ---------- 响应式 ---------- */
@media (min-width: 600px) {
  .page-about .about-frame {
    padding: 38px 32px 38px;
  }

  .page-about .about-hero {
    padding-bottom: 64px;
  }

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

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

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

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

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

  .page-about .about-sec--sand,
  .page-about .about-sec--deep {
    padding-left: 32px;
    padding-right: 32px;
  }
}

@media (min-width: 860px) {
  .page-about .sec-cols {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    align-items: start;
  }

  .page-about .sec-cols--reverse {
    grid-template-columns: minmax(0, .85fr) minmax(0, 1.15fr);
  }

  .page-about .sec-cols--network {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, .8fr);
    align-items: center;
  }

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

@media (min-width: 1024px) {
  .page-about .about-shell-grid {
    grid-template-columns: 232px minmax(0, 1fr);
    gap: 0 56px;
    padding-top: 56px;
    padding-bottom: 72px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
    padding-bottom: 0;
    margin-bottom: 0;
    border-bottom: 0;
  }

  .page-about .rail-plate {
    display: flex;
  }

  .page-about .about-toc ol {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-toc li + li {
    margin-top: 2px;
  }

  .page-about .toc-link {
    background: transparent;
    border: 0;
    border-left: 2px solid var(--mist);
    padding: 7px 0 7px 16px;
    font-size: 14px;
  }

  .page-about .toc-link:hover,
  .page-about .toc-link[aria-current],
  .page-about .toc-link.is-active {
    border-left-color: var(--barley);
    color: var(--lake-deep);
    font-weight: 600;
  }

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

  .page-about .about-sec {
    padding: 52px 0 56px;
  }

  .page-about .about-sec--sand,
  .page-about .about-sec--deep {
    padding: 52px 40px 56px;
  }

  .page-about .about-meter {
    padding: 28px 40px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }

  .page-about .toc-link,
  .page-about .about-crumbs a,
  .page-about .about-backtop a {
    transition: none;
  }
}