.page-about {
  --cream-soft: rgba(241, 231, 214, .86);
  --cream-dim: rgba(241, 231, 214, .7);
  position: relative;
  padding-bottom: 84px;
  background-image: repeating-linear-gradient(0deg, var(--grid-line) 0 1px, transparent 1px 88px);
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  padding-top: 26px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 24px 0 0;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  align-items: end;
}

.page-about .about-hero__kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--mono-grey);
}

.page-about .about-hero__kicker::before {
  content: "";
  flex: 0 0 auto;
  width: 26px;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--amber), var(--red));
}

.page-about h1 {
  margin: 14px 0 0;
  font-family: var(--font-title);
  font-weight: 900;
  font-size: clamp(27px, 5vw, 50px);
  line-height: 1.16;
  letter-spacing: .015em;
  color: var(--cream);
}

.page-about .about-hero__intro {
  margin: 18px 0 0;
  max-width: 46em;
  font-size: clamp(16px, 1.6vw, 19px);
  line-height: 1.65;
  color: var(--cream-soft);
}

.page-about .hero-facts {
  list-style: none;
  margin: 26px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--line-soft);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 20px;
}

.page-about .hero-facts__item {
  min-width: 0;
}

.page-about .hero-facts__value {
  display: block;
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--amber);
  font-variant-numeric: tabular-nums slashed-zero;
  word-break: break-word;
}

.page-about .hero-facts__label {
  display: block;
  margin-top: 4px;
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--mono-grey);
}

.page-about .about-hero__visual {
  min-height: 170px;
}

.page-about .signal {
  display: flex;
  align-items: flex-end;
  gap: 5px;
  height: 176px;
  padding-bottom: 2px;
  border-bottom: 1px solid var(--line);
}

.page-about .signal__bar {
  flex: 1 1 0;
  min-width: 0;
  background: linear-gradient(180deg, var(--cyan), rgba(53, 227, 210, .06));
}

.page-about .signal__bar:nth-child(1) { height: 20%; }
.page-about .signal__bar:nth-child(2) { height: 36%; }
.page-about .signal__bar:nth-child(3) { height: 28%; }
.page-about .signal__bar:nth-child(4) { height: 52%; }
.page-about .signal__bar:nth-child(5) { height: 46%; }
.page-about .signal__bar:nth-child(6) { height: 66%; }
.page-about .signal__bar:nth-child(7) { height: 56%; }
.page-about .signal__bar:nth-child(8) { height: 80%; }
.page-about .signal__bar:nth-child(9) { height: 62%; }
.page-about .signal__bar:nth-child(10) { height: 92%; }
.page-about .signal__bar:nth-child(11) { height: 70%; }
.page-about .signal__bar:nth-child(12) { height: 100%; }
.page-about .signal__bar:nth-child(13) { height: 76%; }
.page-about .signal__bar:nth-child(14) { height: 86%; }

.page-about .signal__bar:nth-child(5),
.page-about .signal__bar:nth-child(10) {
  background: linear-gradient(180deg, var(--amber), rgba(232, 169, 60, .06));
}

/* ---------- 分区骨架 ---------- */
.page-about .about-section {
  margin-top: 56px;
  padding-top: 34px;
  border-top: 1px solid var(--line);
  scroll-margin-top: 96px;
}

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

.page-about .about-rail {
  position: relative;
  padding-left: 16px;
  border-left: 1px solid var(--line-soft);
}

.page-about .about-rail__tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .about-rail__note {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--mono-grey);
}

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

.page-about .about-h2 {
  margin: 0 0 18px;
  font-family: var(--font-title);
  font-weight: 900;
  font-size: clamp(22px, 2.6vw, 31px);
  line-height: 1.26;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .about-body > p {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.72;
  color: var(--cream-dim);
}

.page-about .about-lead {
  font-size: 17px;
  line-height: 1.75;
  color: var(--cream-soft) !important;
}

.page-about .about-body > p.about-footnote,
.page-about .about-footnote {
  margin: 22px 0 0;
  padding: 14px 16px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mono-grey);
  border: 1px solid var(--line-soft);
  background: linear-gradient(135deg, var(--cyan-a10), transparent 60%);
  clip-path: var(--cut-sm);
}

/* ---------- 定位护栏 ---------- */
.page-about .guard-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .guard-list__item {
  position: relative;
  padding: 20px 4px 20px 56px;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .guard-list__num {
  position: absolute;
  left: 0;
  top: 20px;
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--cyan);
  border: 1px solid var(--cyan-a24);
  clip-path: var(--cut-sm);
}

.page-about .guard-list__title {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--cream);
}

.page-about .guard-list__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mono-grey);
}

/* ---------- 字段清单 ---------- */
.page-about .field-list {
  list-style: none;
  margin: 24px 0 26px;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .field-list__item {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 6px 14px;
  padding: 15px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .field-list__key {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--amber);
  padding-top: 2px;
}

.page-about .field-list__name {
  font-size: 15px;
  font-weight: 700;
  color: var(--cream);
}

.page-about .field-list__desc {
  grid-column: 2;
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--mono-grey);
}

/* ---------- 阶段索引（左栏） ---------- */
.page-about .rail-index__list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .rail-index__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 7px 8px;
  font-size: 13px;
  line-height: 1.4;
  color: var(--mono-grey);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color 140ms var(--ease), border-color 140ms var(--ease), background 140ms var(--ease);
}

.page-about .rail-index__link .num {
  color: var(--amber);
  font-size: 12px;
  letter-spacing: .06em;
}

.page-about .rail-index__link:hover,
.page-about .rail-index__link:focus-visible {
  color: var(--cyan);
  border-left-color: var(--cyan);
  background: var(--cyan-a10);
}

/* ---------- 阶段列表 ---------- */
.page-about .stage-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .stage-list__item {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 0 18px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line-soft);
  scroll-margin-top: 104px;
}

.page-about .stage-list__item:target {
  box-shadow: inset 2px 0 0 var(--cyan);
}

.page-about .stage-list__mark {
  font-family: var(--font-mono);
  font-size: 19px;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: .03em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums slashed-zero;
}

.page-about .stage-list__main {
  min-width: 0;
}

.page-about .stage-list__title {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--cream);
}

.page-about .stage-list__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mono-grey);
}

/* ---------- 纠错流程 ---------- */
.page-about .flow {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

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

.page-about .flow__summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 16px 4px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .flow__summary::after {
  content: "+";
  margin-left: 12px;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--cyan);
}

.page-about .flow__item details[open] .flow__summary::after {
  content: "–";
}

.page-about .flow__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--amber);
  white-space: nowrap;
}

.page-about .flow__title {
  font-size: 16px;
  font-weight: 700;
  color: var(--cream);
}

.page-about .flow__hint {
  margin-left: auto;
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--mono-grey);
  text-align: right;
}

.page-about .flow__body {
  padding: 0 4px 20px 4px;
}

.page-about .flow__body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mono-grey);
}

.page-about .flow__summary:focus-visible {
  outline: 1px solid var(--cyan);
  outline-offset: 2px;
}

/* ---------- 运营主体 ---------- */
.page-about .org-list {
  margin: 0;
  border-top: 1px solid var(--line);
}

.page-about .org-list__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .org-list__key {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--mono-grey);
}

.page-about .org-list__val {
  margin: 0;
  font-size: 15px;
  line-height: 1.65;
  color: var(--cream);
  word-break: break-word;
}

.page-about .org-list__val--copy {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

.page-about .copy-btn {
  flex: 0 0 auto;
  padding: 5px 11px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--cyan);
  background: transparent;
  border: 1px solid var(--cyan-a24);
  cursor: pointer;
  clip-path: var(--cut-sm);
  transition: color 140ms var(--ease), border-color 140ms var(--ease);
}

.page-about .copy-btn:hover {
  border-color: var(--cyan);
}

.page-about .copy-btn:focus-visible {
  outline: none;
  box-shadow: inset 0 0 0 2px var(--cyan);
}

/* ---------- 边界清单 ---------- */
.page-about .boundary-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .boundary-list__item {
  position: relative;
  padding: 16px 18px 16px 22px;
  border: 1px solid var(--line-soft);
  background: linear-gradient(135deg, var(--red-a18), transparent 62%);
  clip-path: var(--cut-sm);
}

.page-about .boundary-list__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--red);
}

.page-about .boundary-list__title {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .boundary-list__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mono-grey);
}

/* ---------- 图注与图框 ---------- */
.page-about .about-figure {
  margin: 28px 0;
}

.page-about .about-figure .media-frame__media {
  aspect-ratio: 12 / 7;
  overflow: hidden;
  background: var(--umber);
}

.page-about .about-figure--banner .media-frame__media {
  aspect-ratio: 14 / 5;
}

.page-about .about-figure--land .media-frame__media {
  aspect-ratio: 3 / 2;
}

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

/* ---------- 交叉链接 ---------- */
.page-about .about-section--cross {
  border-top: 1px solid var(--line);
}

.page-about .cross-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border-top: 1px solid var(--line-soft);
}

.page-about .cross-links__item {
  border-bottom: 1px solid var(--line-soft);
  min-width: 0;
}

.page-about .cross-links__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 15px 4px;
  font-size: 15px;
  line-height: 1.5;
  color: var(--cream-soft);
  text-decoration: none;
  transition: color 140ms var(--ease), background 140ms var(--ease);
}

.page-about .cross-links__link::before {
  content: "→";
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--cyan);
}

.page-about .cross-links__link:hover,
.page-about .cross-links__link:focus-visible {
  color: var(--cyan);
  background: var(--cyan-a10);
}

/* ---------- 固定返回入口 ---------- */
.page-about .about-return {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 40;
  padding: 10px 15px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--ink-green);
  background: var(--cyan);
  text-decoration: none;
  clip-path: var(--cut-sm);
}

.page-about .about-return:focus-visible {
  outline: none;
  box-shadow: inset 0 0 0 2px var(--ink-green);
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .field-list__item {
    grid-template-columns: 64px 148px minmax(0, 1fr);
    align-items: baseline;
    gap: 6px 16px;
  }

  .page-about .field-list__desc {
    grid-column: auto;
  }

  .page-about .org-list__row {
    grid-template-columns: 118px minmax(0, 1fr);
    gap: 6px 20px;
    align-items: baseline;
  }

  .page-about .cross-links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 28px;
  }
}

@media (min-width: 920px) {
  .page-about .about-hero {
    padding-top: 32px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 56px;
    align-items: end;
  }

  .page-about .about-hero__visual {
    min-height: 220px;
  }

  .page-about .signal {
    height: 224px;
    gap: 7px;
  }

  .page-about .h1,
  .page-about h1 {
    margin-top: 16px;
  }

  .page-about .about-section {
    margin-top: 72px;
    padding-top: 44px;
  }

  .page-about .about-row {
    grid-template-columns: minmax(0, 3fr) minmax(0, 8fr);
    gap: 56px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
    align-self: start;
    padding-left: 20px;
  }

  .page-about .guard-list__item {
    padding-left: 62px;
  }

  .page-about .stage-list__item {
    grid-template-columns: 76px minmax(0, 1fr);
    gap: 0 24px;
  }
}

@media (min-width: 1080px) {
  .page-about .cross-links {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .page-about .about-return {
    right: 12px;
    bottom: 12px;
    padding: 9px 12px;
    font-size: 12px;
  }

  .page-about .flow__hint {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-index__link,
  .page-about .cross-links__link,
  .page-about .copy-btn {
    transition: none;
  }
}