.page-about {
  --about-rail-w: 216px;
  --about-gap: clamp(28px, 4.5vw, 68px);
  --about-unit: .62em;
}

.page-about .about-topbar {
  padding-top: 22px;
}

.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  padding-bottom: 72px;
}

/* ---------- 侧栏索引 ---------- */
.page-about .about-rail__caption {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--cyan-400);
  text-transform: uppercase;
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__list > li {
  flex: 0 0 auto;
}

.page-about .rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 12px;
  border: 1px solid var(--line-700);
  border-radius: var(--radius);
  background: var(--ink-900);
  color: var(--body-text);
  font-size: 13px;
  text-decoration: none;
  white-space: nowrap;
  transition: color 180ms var(--ease), border-color 180ms var(--ease), background-color 180ms var(--ease);
}

.page-about .rail__num {
  font-size: 11px;
  color: var(--mute-400);
  letter-spacing: .06em;
  transition: color 180ms var(--ease);
}

.page-about .rail__link:hover {
  color: var(--paper-050);
  border-color: var(--cyan-650);
}

.page-about .rail__link[aria-current="true"] {
  color: var(--ink-950);
  background: var(--cyan-400);
  border-color: var(--cyan-400);
}

.page-about .rail__link[aria-current="true"] .rail__num {
  color: var(--ink-900);
}

.page-about .rail__link:focus-visible {
  outline: 2px solid var(--amber-500);
  outline-offset: 2px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 6px 0 40px;
  border-bottom: 1px solid var(--line-700);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 96px;
  height: 2px;
  background: var(--cyan-400);
}

.page-about .about-hero__coord {
  margin: 0 0 18px;
  font-size: 11.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--cyan-400);
}

.page-about .about-hero__title {
  margin: 0 0 20px;
  font-size: clamp(30px, 6.4vw, 54px);
  line-height: 1.14;
  letter-spacing: -.02em;
  max-width: 18ch;
  color: var(--paper-050);
}

.page-about .about-hero__lede {
  margin: 0 0 30px;
  max-width: 46em;
  color: var(--body-text);
  font-size: 16.5px;
  line-height: 1.82;
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-700);
  border: 1px solid var(--line-700);
}

.page-about .about-hero__stats > div {
  background: var(--ink-900);
  padding: 14px 16px;
  display: flex;
  flex-direction: column-reverse;
  gap: 4px;
}

.page-about .about-hero__stats dt {
  font-size: 12.5px;
  color: var(--mute-400);
  letter-spacing: .02em;
}

.page-about .about-hero__stats dd {
  margin: 0;
  font-size: 26px;
  line-height: 1.1;
  color: var(--cyan-400);
}

.page-about .about-unit {
  font-size: var(--about-unit);
  margin-left: 2px;
  color: var(--mute-400);
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding-top: 56px;
}

.page-about .about-section + .about-section {
  border-top: 1px solid var(--line-700);
}

.page-about .about-section .section-head {
  margin-bottom: 22px;
}

.page-about .about-section .section-head__num {
  color: var(--cyan-400);
}

.page-about .about-section .section-head__note {
  color: var(--mute-400);
}

.page-about .about-subhead {
  margin: 40px 0 0;
  font-size: 19px;
  letter-spacing: -.01em;
}

/* ---------- 场景清单 ---------- */
.page-about .about-cases {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-700);
  border: 1px solid var(--line-700);
}

.page-about .about-cases__item {
  background: var(--ink-900);
  padding: 20px 18px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
}

.page-about .about-cases__idx {
  margin: 0;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--cyan-650);
}

.page-about .about-cases__title {
  margin: 0;
  font-size: 16.5px;
  line-height: 1.5;
  color: var(--paper-050);
}

.page-about .about-cases__body {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--body-text);
}

/* ---------- 双栏内容 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  align-items: start;
  margin-top: 22px;
}

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

.page-about .about-split__art img,
.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line-700);
  border-radius: var(--radius);
  object-fit: cover;
  background: var(--ink-800);
}

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

.page-about .about-figure--wide {
  margin-top: 40px;
  margin-bottom: 0;
}

.page-about .about-figure .figure__caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mute-400);
}

/* ---------- 折叠面板 ---------- */
.page-about .about-folds {
  margin-top: 26px;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line-700);
}

.page-about .about-folds .fold {
  border-bottom: 1px solid var(--line-700);
  border-left: 2px solid transparent;
  transition: border-color 220ms var(--ease), background-color 220ms var(--ease);
}

.page-about .about-folds .fold[open] {
  border-left-color: var(--cyan-400);
  background: var(--ink-900);
}

.page-about .about-folds .fold__summary {
  cursor: pointer;
  padding: 15px 16px;
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-size: 15.5px;
  color: var(--paper-050);
  list-style: none;
}

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

.page-about .about-folds .fold__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--mono);
  color: var(--cyan-400);
  font-size: 16px;
  line-height: 1;
}

.page-about .about-folds .fold[open] .fold__summary::after {
  content: "−";
}

.page-about .about-folds .fold__idx {
  flex: 0 0 auto;
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--cyan-400);
}

.page-about .about-folds .fold__body {
  padding: 0 16px 18px;
}

.page-about .about-folds .fold__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--body-text);
}

.page-about .about-folds .fold__summary:focus-visible {
  outline: 2px solid var(--amber-500);
  outline-offset: -2px;
}

/* ---------- 团队表格 ---------- */
.page-about .about-tablewrap {
  margin-top: 26px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border: 1px solid var(--line-700);
}

.page-about .about-table {
  width: 100%;
  min-width: 660px;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .about-table th,
.page-about .about-table td {
  text-align: left;
  vertical-align: top;
  padding: 16px 18px;
  border-bottom: 1px solid var(--line-700);
  line-height: 1.7;
  color: var(--body-text);
}

.page-about .about-table thead th {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--cyan-400);
  border-bottom: 1px solid var(--cyan-650);
  white-space: nowrap;
  background: var(--ink-900);
}

.page-about .about-table tbody th {
  color: var(--paper-050);
  font-weight: 600;
  white-space: nowrap;
}

.page-about .about-table tbody tr:nth-child(even) {
  background: var(--ink-900);
}

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

.page-about .about-table td.mono {
  color: var(--cyan-400);
  font-size: 16px;
}

/* ---------- 步骤 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-700);
}

.page-about .about-steps > li {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 5px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line-700);
}

.page-about .about-steps__num {
  margin: 0;
  font-size: 11.5px;
  letter-spacing: .14em;
  color: var(--cyan-400);
}

.page-about .about-steps__title {
  margin: 0;
  font-size: 17px;
  line-height: 1.5;
  color: var(--paper-050);
}

.page-about .about-steps > li > p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--body-text);
  max-width: 46em;
}

.page-about .about-quote {
  margin-top: 30px;
  padding: 22px 24px;
  background: var(--ink-900);
  border-left: 2px solid var(--amber-500);
}

.page-about .about-quote p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--paper-050);
  max-width: 46em;
}

/* ---------- 状态标签 ---------- */
.page-about .about-tags {
  margin-top: 28px;
  display: grid;
  gap: 1px;
  background: var(--line-700);
  border: 1px solid var(--line-700);
}

.page-about .about-tags__item {
  background: var(--ink-900);
  padding: 18px 18px 20px;
}

.page-about .about-tags__item p {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--body-text);
}

/* ---------- 阶段时间轴 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
}

.page-about .about-timeline > li {
  position: relative;
  padding: 0 0 14px 26px;
  border-left: 1px solid var(--line-700);
}

.page-about .about-timeline > li::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 20px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--amber-500);
  box-shadow: 0 0 0 3px rgba(245, 165, 36, .16);
}

.page-about .about-timeline > li:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .about-timeline .fold {
  border-bottom: 1px solid var(--line-700);
}

.page-about .about-timeline .fold__summary {
  cursor: pointer;
  padding: 12px 0 14px;
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-size: 15.5px;
  color: var(--paper-050);
  list-style: none;
}

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

.page-about .about-timeline .fold__summary::after {
  content: "展开";
  margin-left: auto;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--cyan-400);
}

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

.page-about .about-timeline .fold__summary:focus-visible {
  outline: 2px solid var(--amber-500);
  outline-offset: 2px;
}

.page-about .about-timeline .fold__idx {
  flex: 0 0 auto;
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--cyan-400);
}

.page-about .about-timeline .fold__body {
  padding: 0 0 16px;
}

.page-about .about-timeline .fold__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--body-text);
  max-width: 44em;
}

/* ---------- 合作区 ---------- */
.page-about .about-partner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-top: 8px;
}

.page-about .about-partner__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-700);
  border: 1px solid var(--line-700);
}

.page-about .about-partner__list > li {
  background: var(--ink-900);
  padding: 16px 18px;
}

.page-about .about-partner__key {
  display: block;
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--amber-300);
  margin-bottom: 8px;
}

.page-about .about-partner__list p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--body-text);
}

.page-about .about-cta {
  margin-top: 32px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-section--end {
  padding-bottom: 8px;
}

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

  .page-about .about-cases__item {
    grid-template-columns: 62px minmax(0, 1fr);
    column-gap: 18px;
    padding: 22px 22px;
  }

  .page-about .about-cases__idx {
    grid-column: 1;
    grid-row: 1;
    padding-top: 4px;
  }

  .page-about .about-cases__title,
  .page-about .about-cases__body {
    grid-column: 2;
  }

  .page-about .about-cases__title {
    grid-row: 1;
  }

  .page-about .about-cases__body {
    grid-row: 2;
  }

  .page-about .about-steps > li {
    grid-template-columns: 108px minmax(0, 1fr);
    column-gap: 20px;
    align-items: baseline;
  }

  .page-about .about-steps__num {
    grid-column: 1;
    grid-row: 1;
    padding-top: 4px;
  }

  .page-about .about-steps__title,
  .page-about .about-steps > li > p {
    grid-column: 2;
  }

  .page-about .about-steps__title {
    grid-row: 1;
  }

  .page-about .about-steps > li > p {
    grid-row: 2;
    margin-top: 6px;
  }

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

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
    padding-bottom: 96px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 26px);
    align-self: start;
    max-height: calc(100vh - var(--header-h) - 52px);
    overflow-y: auto;
    scrollbar-width: thin;
    padding-right: 6px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding: 0 0 0 10px;
    border-left: 1px solid var(--line-700);
  }

  .page-about .about-rail__list > li {
    flex: 1 1 auto;
  }

  .page-about .rail__link {
    width: 100%;
    display: flex;
    justify-content: flex-start;
    padding: 9px 12px;
    border-color: transparent;
    background: transparent;
    white-space: normal;
    line-height: 1.5;
  }

  .page-about .rail__link[aria-current="true"] {
    background: var(--cyan-400);
    border-color: var(--cyan-400);
  }

  .page-about .about-hero {
    padding-top: 14px;
    padding-bottom: 52px;
  }

  .page-about .about-hero__stats {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    gap: 44px;
  }

  .page-about .about-partner {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-timeline > li {
    padding-left: 34px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail__link,
  .page-about .about-folds .fold {
    transition: none;
  }
}