.page-about {
  --about-rail-top: calc(var(--header-h) + 28px);
  background: var(--paper-bg);
  color: var(--ink);
  overflow-x: hidden;
}

.page-about [id] {
  scroll-margin-top: calc(var(--header-h) + 20px);
}

.page-about .media-frame__cap {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--ink-2);
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(.82) contrast(1.02);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  border-bottom: 1px solid var(--rule);
  padding: calc(var(--header-h) + 40px) 0 48px;
  background-color: var(--paper-bg);
  background-image: repeating-linear-gradient(
    180deg,
    transparent 0 31px,
    rgba(216, 213, 205, .28) 31px 32px
  );
}

.page-about .about-hero .wrap {
  position: relative;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 0;
  margin-top: 26px;
}

.page-about .about-hero__kicker {
  margin: 0;
  padding-left: 12px;
  border-left: 3px solid var(--vermilion);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--ink-2);
}

.page-about .about-hero__title {
  margin: 18px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(32px, 8.2vw, 58px);
  line-height: 1.18;
  letter-spacing: .01em;
  color: var(--ink);
}

.page-about .about-hero__lead {
  margin: 20px 0 0;
  max-width: 44em;
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

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

.page-about .about-status {
  margin-top: 34px;
  padding: 20px 18px 12px;
  box-shadow: var(--shadow-lift);
}

.page-about .about-status__title {
  margin: 0;
  font-size: 11px;
  letter-spacing: .26em;
  color: var(--amber);
}

.page-about .about-status__list {
  margin: 14px 0 0;
}

.page-about .about-status__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 9px 0;
  border-bottom: 1px dashed rgba(251, 250, 247, .22);
  font-size: 13px;
}

.page-about .about-status__row:last-child {
  border-bottom: 0;
}

.page-about .about-status__row dt {
  color: rgba(251, 250, 247, .74);
}

.page-about .about-status__row dd {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--sheet);
  letter-spacing: .04em;
}

/* ---------- 双栏骨架 ---------- */
.page-about .about-layout {
  display: grid;
  gap: 32px;
  padding: 40px 0 72px;
}

.page-about .about-rail {
  align-self: start;
  border: 1px solid var(--rule);
  background: var(--sheet);
  padding: 16px 14px;
  box-shadow: var(--shadow-paper);
}

.page-about .about-rail__label {
  margin: 0;
  font-size: 11px;
  letter-spacing: .24em;
  color: var(--ink-2);
}

.page-about .about-rail__nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px 10px;
  margin-top: 12px;
}

.page-about .about-rail__link {
  display: flex;
  align-items: baseline;
  gap: 7px;
  padding: 7px 8px;
  border-left: 2px solid transparent;
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--ink-2);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease), background-color var(--dur-fast) var(--ease);
}

.page-about .about-rail__link:hover {
  color: var(--ink);
  background: var(--paper-bg);
}

.page-about .about-rail__link[data-active] {
  border-left-color: var(--vermilion);
  background: var(--paper-bg);
  color: var(--ink);
}

.page-about .about-rail__no {
  font-size: 11px;
  color: var(--amber-deep);
}

.page-about .about-rail__scale {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px solid var(--rule);
}

.page-about .about-scale__item {
  display: block;
  margin-top: 10px;
  padding: 2px 0 2px 12px;
  border-left: 2px solid var(--amber);
  font-size: 13px;
  color: var(--ink-2);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease);
}

.page-about .about-scale__item:hover {
  color: var(--ink);
  border-left-color: var(--amber-deep);
}

.page-about .about-scale__item .mono {
  display: block;
  font-size: 10.5px;
  letter-spacing: .16em;
  color: var(--amber-deep);
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  padding: 36px 0;
}

.page-about .about-section + .about-section {
  border-top: 1px solid var(--rule);
}

.page-about .about-body > .about-section:first-child {
  padding-top: 0;
}

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

.page-about .about-lede {
  margin: 0 0 18px;
  padding-left: 16px;
  border-left: 3px solid var(--vermilion);
  font-family: var(--font-display);
  font-size: 18px;
  line-height: 1.7;
  color: var(--ink);
}

.page-about .about-text {
  margin: 0 0 16px;
  font-size: 15.5px;
  line-height: 1.95;
  color: var(--ink);
}

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

.page-about .note-line {
  margin: 18px 0 0;
  padding: 2px 0 2px 14px;
  border-left: 2px solid var(--amber);
  font-size: 13px;
  line-height: 1.8;
  color: var(--ink-2);
}

.page-about .about-list {
  margin: 0;
  padding-left: 0;
  list-style: none;
}

.page-about .about-list li {
  position: relative;
  margin-bottom: 12px;
  padding-left: 20px;
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .78em;
  width: 10px;
  height: 2px;
  background: var(--vermilion);
}

.page-about .about-list strong {
  font-weight: 700;
}

.page-about .about-list li:last-child {
  margin-bottom: 0;
}

/* 折叠 */
.page-about .about-fold {
  margin-top: 22px;
  border: 1px solid var(--rule);
  background: var(--sheet);
  box-shadow: var(--shadow-paper);
}

.page-about .about-fold > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 14px 16px;
  font-size: 14.5px;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-fold > summary::after {
  content: "展开";
  flex: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--amber-deep);
}

.page-about .about-fold[open] > summary::after {
  content: "收起";
}

.page-about .about-fold[open] > summary {
  border-bottom: 1px solid var(--rule);
}

.page-about .about-fold__body {
  padding: 18px 16px 20px;
  font-size: 15px;
  line-height: 2;
  color: var(--ink);
}

.page-about .about-fold__body p {
  margin: 0 0 14px;
}

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

.page-about .about-fold__body .note-line {
  margin-top: 16px;
}

/* ---------- 板块结构 ---------- */
.page-about .about-structure__fig {
  margin: 0 0 26px;
}

.page-about .about-map-wrap {
  border: 1px solid var(--rule);
  background: var(--sheet);
  padding: 14px 12px 10px;
  box-shadow: var(--shadow-paper);
}

.page-about .about-map-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-map {
  display: block;
  width: 100%;
  min-width: 560px;
  height: auto;
}

.page-about .about-map__note {
  margin: 10px 0 0;
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--ink-2);
}

.page-about .about-blocks {
  display: grid;
  gap: 16px;
  margin-top: 26px;
}

.page-about .about-block {
  padding: 18px 18px 20px;
}

.page-about .about-block__name {
  margin: 10px 0 8px;
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--ink);
}

.page-about .about-block__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .about-block__list {
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink-2);
}

.page-about .about-block__list li {
  position: relative;
  padding-left: 16px;
}

.page-about .about-block__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 8px;
  height: 2px;
  background: var(--cyan-pale);
}

.page-about .about-block__link {
  display: inline-block;
  margin-top: 16px;
  padding-bottom: 2px;
  border-bottom: 1px solid var(--cyan-pale);
  font-size: 13.5px;
  color: var(--mineral);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease);
}

.page-about .about-block__link:hover {
  color: var(--vermilion);
  border-bottom-color: var(--vermilion);
}

/* ---------- 归档规则 ---------- */
.page-about .about-rules {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.page-about .about-rule {
  display: grid;
  gap: 8px;
  padding: 20px 0;
  border-bottom: 1px solid var(--rule);
}

.page-about .about-rule__no {
  font-size: 13px;
  letter-spacing: .18em;
  color: var(--amber-deep);
}

.page-about .about-rule__title {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-rule__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--ink);
}

/* ---------- 流程 ---------- */
.page-about .about-process {
  display: grid;
  gap: 26px;
}

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

.page-about .about-flow {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.page-about .about-flow__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  padding: 14px 16px;
  border: 1px solid var(--rule);
  border-left: 3px solid var(--cyan-deep);
  background: var(--sheet);
}

.page-about .about-flow__no {
  font-size: 14px;
  letter-spacing: .1em;
  color: var(--cyan-deep);
  line-height: 1.6;
}

.page-about .about-flow__name {
  margin: 0 0 4px;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-flow__desc {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--ink-2);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 16px;
  margin-top: 24px;
}

.page-about .about-team__card {
  padding: 18px 18px 20px;
}

.page-about .about-team__num {
  margin: 0;
  font-size: clamp(36px, 10vw, 46px);
  line-height: 1;
  letter-spacing: .02em;
  color: var(--cyan-deep);
}

.page-about .about-team__name {
  margin: 12px 0 8px;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-team__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--ink-2);
}

/* ---------- 发展阶段 ---------- */
.page-about .about-stages {
  position: relative;
  margin: 28px 0 0;
  padding: 0 0 0 32px;
  list-style: none;
}

.page-about .about-stages::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 8px;
  bottom: 22px;
  width: 2px;
  background: linear-gradient(180deg, var(--amber), rgba(201, 138, 46, .18));
}

.page-about .about-stage {
  position: relative;
  padding-bottom: 30px;
}

.page-about .about-stage:last-child {
  padding-bottom: 8px;
}

.page-about .about-stage::before {
  content: "";
  position: absolute;
  left: -24px;
  top: 5px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--sheet);
  border: 2px solid var(--amber);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-stage:hover::before {
  transform: scale(1.15);
  border-color: var(--amber-deep);
}

.page-about .about-stage__no {
  margin: 0;
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--amber-deep);
  transition: color var(--dur-fast) var(--ease);
}

.page-about .about-stage:hover .about-stage__no {
  color: var(--vermilion);
}

.page-about .about-stage__title {
  margin: 6px 0 8px;
  font-family: var(--font-head);
  font-size: 18.5px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-stage__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-stage__add {
  display: block;
  margin-top: 10px;
  padding-left: 12px;
  border-left: 2px solid var(--cyan-pale);
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--ink-2);
}

.page-about .about-stages__cap {
  margin: 30px 0 0;
}

/* ---------- 收束 ---------- */
.page-about .about-section--last {
  padding-bottom: 0;
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-blocks {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .about-block:nth-child(even) {
    margin-top: 22px;
  }

  .page-about .about-rule {
    grid-template-columns: 58px minmax(0, 1fr);
    gap: 0 20px;
    align-items: baseline;
  }

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

  .page-about .about-status__row {
    font-size: 14px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: calc(var(--header-h) + 56px) 0 62px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(280px, .85fr);
    column-gap: 52px;
    align-items: start;
    margin-top: 30px;
  }

  .page-about .about-hero__kicker,
  .page-about .about-hero__title,
  .page-about .about-hero__lead,
  .page-about .about-hero__actions {
    grid-column: 1;
  }

  .page-about .about-status {
    grid-column: 2;
    grid-row: 1 / span 4;
    margin-top: 46px;
    padding: 24px 22px 14px;
  }

  .page-about .about-process {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 40px;
    align-items: start;
  }
}

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: 258px minmax(0, 1fr);
    gap: 56px;
    padding: 56px 0 88px;
  }

  .page-about .about-rail {
    position: sticky;
    top: var(--about-rail-top);
    padding: 20px 16px;
  }

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

  .page-about .about-section {
    padding: 44px 0;
  }

  .page-about .about-lede {
    font-size: 19px;
    max-width: 34em;
  }

  .page-about .about-text {
    max-width: 52em;
  }
}

@media (min-width: 1100px) {
  .page-about .about-hero__rot {
    display: block;
    position: absolute;
    top: 8px;
    right: 0;
    margin: 0;
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: .34em;
    color: var(--ink-2);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stage::before,
  .page-about .about-rail__link,
  .page-about .about-scale__item,
  .page-about .about-block__link,
  .page-about .about-stage__no {
    transition: none;
  }

  .page-about .about-stage:hover::before {
    transform: none;
  }
}