.page-about {
  --about-gap: 22px;
  --about-radius: 2px;
  background: var(--deep);
  color: var(--paper);
  font-family: var(--f-body);
  font-size: 16px;
  line-height: 1.75;
  padding: 18px 0 56px;
  overflow-x: hidden;
}

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

.page-about a:hover,
.page-about a:focus-visible {
  color: var(--mint);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-wrap {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.page-about .about-crumb {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--sand);
  margin: 0 0 20px;
}

.page-about .about-crumb a {
  color: var(--sand);
}

.page-about .breadcrumb__sep {
  margin: 0 8px;
  color: var(--line);
}

/* 布局：目录 + 正文 */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
}

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

/* 目录 */
.page-about .about-toc {
  border: 1px solid var(--line);
  border-top: 2px solid var(--mint);
  background: var(--panel);
  padding: 16px 16px 18px;
  border-radius: var(--about-radius);
}

.page-about .about-toc__title {
  margin: 0 0 12px;
  color: var(--mint);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px 14px;
}

.page-about .about-toc__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 0;
  font-size: 14px;
  color: var(--sand);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  color: var(--mint);
  text-decoration: none;
}

.page-about .about-toc__num {
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--amber);
  letter-spacing: 0.08em;
}

.page-about .about-toc__foot {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
}

.page-about .about-toc__k {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--sand);
}

.page-about .about-toc__v {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  color: var(--amber);
}

.page-about .about-toc__foot .btn {
  margin-left: auto;
}

/* 首屏 */
.page-about .about-hero {
  padding: 4px 0 28px;
  border-bottom: 1px solid var(--line);
}

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

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

.page-about .about-hero__kicker {
  margin: 0 0 12px;
  color: var(--mint);
}

.page-about .about-hero h1 {
  margin: 0 0 16px;
  font-family: var(--f-display);
  font-weight: 800;
  font-size: clamp(28px, 7vw, 52px);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--paper);
  max-width: 15em;
}

.page-about .about-hero__text {
  margin: 0 0 22px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--sand);
  max-width: 38em;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* 首屏数据面板 */
.page-about .about-facts {
  border: 1px solid var(--line);
  background: linear-gradient(180deg, var(--panel) 0%, var(--panel-lift) 100%);
  padding: 16px 16px 8px;
  border-radius: var(--about-radius);
}

.page-about .about-facts__head {
  margin: 0 0 10px;
  color: var(--amber);
}

.page-about .about-fact {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-fact__n {
  font-size: 26px;
  font-weight: 700;
  color: var(--mint);
  line-height: 1.1;
}

.page-about .about-fact__unit {
  font-size: 14px;
  margin-left: 2px;
  color: var(--aqua);
}

.page-about .about-fact__l {
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--sand);
  text-align: right;
}

/* 章节骨架 */
.page-about .about-sec {
  padding: 34px 0 6px;
  border-top: 1px solid var(--line);
  margin-top: 30px;
  scroll-margin-top: calc(var(--top-h) + 16px);
}

.page-about .about-sec:first-of-type {
  border-top: 0;
  margin-top: 26px;
  padding-top: 0;
}

.page-about .about-sec__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 16px;
}

.page-about .about-sec__num {
  font-size: 12px;
  color: var(--amber);
  letter-spacing: 0.1em;
  flex: 0 0 auto;
  padding: 2px 6px;
  border: 1px solid var(--line);
}

.page-about .about-sec h2 {
  margin: 0;
  font-family: var(--f-display);
  font-size: clamp(20px, 4.4vw, 30px);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.015em;
  color: var(--paper);
}

.page-about .about-sec h3 {
  margin: 0 0 8px;
  font-family: var(--f-display);
  font-size: 17px;
  font-weight: 800;
  color: var(--paper);
}

.page-about .about-sec p {
  margin: 0 0 16px;
  color: var(--sand);
  max-width: 40em;
}

.page-about .about-sec__lead {
  font-size: 16px;
  color: var(--sand);
}

.page-about .about-sec__note {
  font-size: 13px;
  color: var(--sand);
  opacity: 0.85;
  border-left: 2px solid var(--line);
  padding-left: 12px;
}

/* 场景列表 */
.page-about .about-scenes {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line);
}

.page-about .about-scenes__item {
  background: var(--panel);
  padding: 14px 16px;
  display: grid;
  gap: 4px;
}

.page-about .about-scenes__t {
  font-family: var(--f-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--mint);
}

.page-about .about-scenes__d {
  font-size: 14px;
  line-height: 1.7;
  color: var(--sand);
}

/* 图片 */
.page-about .about-figure {
  margin: 0 0 22px;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 8px;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.86) contrast(1.04);
}

.page-about .about-figure figcaption {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--sand);
  padding: 8px 4px 2px;
}

/* 时间线 */
.page-about .about-timeline {
  position: relative;
  margin-top: 8px;
  padding-left: 22px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 10px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(180deg, var(--amber) 0%, var(--line) 38%, var(--line) 100%);
}

.page-about .about-node {
  position: relative;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 21px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--deep);
  border: 2px solid var(--amber);
  transition: background 0.16s var(--ease), border-color 0.16s var(--ease);
}

.page-about .about-node[open]::before {
  background: var(--mint);
  border-color: var(--mint);
}

.page-about .about-node__sum {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 15px 24px 15px 0;
  cursor: pointer;
  list-style: none;
  position: relative;
  transition: color 0.16s var(--ease);
}

.page-about .about-node__sum::-webkit-details-marker {
  display: none;
}

.page-about .about-node__sum::after {
  content: "+";
  position: absolute;
  right: 2px;
  top: 14px;
  font-family: var(--f-mono);
  font-size: 15px;
  line-height: 1;
  color: var(--mint);
}

.page-about .about-node[open] > .about-node__sum::after {
  content: "–";
  color: var(--amber);
}

.page-about .about-node__year {
  flex: 0 0 auto;
  font-size: 15px;
  font-weight: 700;
  color: var(--amber);
  letter-spacing: 0.02em;
}

.page-about .about-node__title {
  font-size: 15px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-node__body {
  padding: 0 24px 16px 0;
}

.page-about .about-node__body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
}

/* 内容与安全共用的双列 */
.page-about .about-content__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

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

.page-about .about-flow {
  list-style: none;
  margin: 18px 0 0;
  padding: 14px 16px;
  border-left: 2px solid var(--mint);
  background: var(--panel);
  display: grid;
  gap: 8px;
}

.page-about .about-flow__step {
  font-size: 14px;
  color: var(--sand);
  display: flex;
  gap: 10px;
  align-items: baseline;
}

.page-about .about-flow__n {
  color: var(--amber);
  font-size: 12px;
  letter-spacing: 0.08em;
}

/* 覆盖与响应 */
.page-about .about-metrics {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  margin: 6px 0 22px;
}

.page-about .about-metric {
  background: var(--panel);
  padding: 16px;
  display: grid;
  gap: 4px;
}

.page-about .about-metric__n {
  font-size: 28px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--mint);
}

.page-about .about-metric__u {
  font-size: 13px;
  margin-left: 3px;
  color: var(--aqua);
  font-weight: 600;
}

.page-about .about-metric__l {
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--sand);
}

.page-about .about-team {
  list-style: none;
  margin: 0 0 16px;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-team__row {
  background: var(--panel-lift);
  padding: 13px 14px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 4px 12px;
  cursor: default;
  transition: background 0.16s var(--ease);
}

.page-about .about-team__row:hover,
.page-about .about-team__row:focus-within,
.page-about .about-team__row:focus {
  background: var(--panel);
  outline: none;
}

.page-about .about-team__role {
  font-size: 14px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-team__num {
  font-size: 20px;
  font-weight: 700;
  color: var(--amber);
  text-align: right;
}

.page-about .about-team__duty {
  grid-column: 1 / -1;
  font-size: 13px;
  line-height: 1.65;
  color: var(--sand);
  opacity: 0.72;
  transition: opacity 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .about-team__row:hover .about-team__duty,
.page-about .about-team__row:focus .about-team__duty,
.page-about .about-team__row:focus-within .about-team__duty {
  opacity: 1;
  color: var(--aqua);
}

/* 下一步 */
.page-about .about-next {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin-bottom: 26px;
}

.page-about .about-next__card {
  border: 1px solid var(--line);
  border-top: 2px solid var(--line);
  background: var(--panel);
  padding: 16px;
  transition: border-color 0.16s var(--ease), transform 0.16s var(--ease);
}

.page-about .about-next__card:hover {
  border-top-color: var(--mint);
  transform: translateY(-2px);
}

.page-about .about-next__tag {
  margin: 0 0 10px;
}

.page-about .about-next__card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
}

/* 结尾引导 */
.page-about .about-cta {
  border: 1px solid var(--line);
  border-left: 3px solid var(--amber);
  background: linear-gradient(90deg, var(--panel) 0%, var(--panel-lift) 100%);
  padding: 18px 16px;
  display: grid;
  gap: 14px;
}

.page-about .about-cta__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--sand);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-cta__actions .btn {
  flex: 0 0 auto;
}

/* 平板 */
@media (min-width: 640px) {
  .page-about .about-scenes {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

/* 桌面 */
@media (min-width: 960px) {
  .page-about {
    padding-top: 24px;
  }

  .page-about .about-layout {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: calc(var(--top-h) + 22px);
  }

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

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: 36px;
    align-items: end;
  }

  .page-about .about-content__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 4fr);
    gap: 26px;
    align-items: start;
  }

  .page-about .about-content__grid--flip {
    grid-template-columns: minmax(0, 4fr) minmax(0, 6fr);
  }

  .page-about .about-figure--wide {
    margin-top: 22px;
  }

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

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    padding: 20px 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-next__card,
  .page-about .about-node::before,
  .page-about .about-team__row,
  .page-about .about-team__duty {
    transition: none;
    transform: none;
  }
}