.page-about {
  --about-rail: 262px;
  background: var(--paper-50);
  color: var(--text-900);
  overflow-x: hidden;
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding-top: var(--s-20);
}

/* ---------- 首屏框景 ---------- */
.page-about .about-hero {
  position: relative;
  margin-top: var(--s-16);
  padding: var(--s-40) 0 var(--s-56);
  background:
    radial-gradient(140% 120% at 8% 0%, #14395C 0%, rgba(16, 42, 68, 0) 62%),
    linear-gradient(160deg, var(--ink-800) 0%, var(--ink-950) 68%);
  color: var(--text-invert);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(47, 227, 196, .06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(47, 227, 196, .06) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

.page-about .about-frame {
  position: relative;
  z-index: 1;
  padding: var(--s-20);
  border: 1px solid var(--glass-line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255, 255, 255, .10), rgba(255, 255, 255, .02));
}

.page-about .about-frame__ruler {
  display: flex;
  justify-content: space-between;
  margin: calc(var(--s-20) * -1) calc(var(--s-20) * -1) var(--s-20);
  padding: 6px var(--s-16) 6px;
  border-bottom: 1px dashed rgba(155, 243, 228, .35);
  font-size: 12px;
  letter-spacing: .1em;
  color: rgba(155, 243, 228, .7);
}

.page-about .about-frame__eyebrow {
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--cyan-400);
}

.page-about .about-frame__title {
  margin-top: var(--s-12);
  font-size: 28px;
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -.01em;
  color: #fff;
}

.page-about .about-frame__lead {
  margin-top: var(--s-16);
  font-size: 16px;
  line-height: 1.8;
  color: rgba(232, 240, 247, .88);
  max-width: 62ch;
}

.page-about .about-facts {
  list-style: none;
  margin-top: var(--s-28);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: rgba(155, 243, 228, .22);
  border: 1px solid rgba(155, 243, 228, .22);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.page-about .about-facts li {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--s-16);
  background: rgba(8, 19, 31, .66);
}

.page-about .about-facts__num {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--cyan-400);
}

.page-about .about-facts__label {
  font-size: 13px;
  line-height: 1.55;
  color: rgba(232, 240, 247, .72);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--s-28);
  padding: var(--s-40) 0 var(--s-56);
}

/* ---------- 左侧章节时间轴 ---------- */
.page-about .about-timeline__cap {
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--text-500);
  margin-bottom: var(--s-12);
}

.page-about .about-timeline__list {
  list-style: none;
  display: flex;
  gap: var(--s-12);
  overflow-x: auto;
  padding-bottom: var(--s-12);
  -webkit-overflow-scrolling: touch;
}

.page-about .about-timeline__list > li {
  flex: none;
}

.page-about .about-timeline__link {
  position: relative;
  display: flex;
  align-items: flex-start;
  gap: var(--s-12);
  padding: var(--s-12) var(--s-16);
  border: 1px solid var(--paper-200);
  border-radius: var(--radius-sm);
  background: #fff;
  color: var(--text-900);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color .22s var(--ease), background .22s var(--ease);
}

.page-about .about-timeline__num {
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--text-500);
  flex: none;
  transition: color .22s var(--ease);
}

.page-about .about-timeline__body {
  display: flex;
  flex-direction: column;
  gap: 2px;
  transition: transform .22s var(--ease);
}

.page-about .about-timeline__label {
  font-size: 14px;
  font-weight: 600;
  line-height: 1.5;
}

.page-about .about-timeline__hint {
  display: none;
  font-size: 12px;
  line-height: 1.6;
  color: var(--text-500);
}

.page-about .about-timeline__link:hover {
  border-color: var(--cyan-200);
}

.page-about .about-timeline__link.is-active {
  border-color: var(--cyan-600);
  background: #EAFBF7;
}

.page-about .about-timeline__link.is-active .about-timeline__num {
  color: var(--cyan-600);
}

/* ---------- 章节 ---------- */
.page-about .about-sections {
  min-width: 0;
}

.page-about .about-section {
  padding: var(--s-28) 0;
  border-top: 1px solid var(--paper-200);
  scroll-margin-top: 110px;
}

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

.page-about .about-sec-head {
  display: flex;
  align-items: baseline;
  gap: var(--s-12);
  margin-bottom: var(--s-16);
}

.page-about .about-sec-head__num {
  flex: none;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--orange-500);
}

.page-about .about-sec-head__title {
  font-size: 20px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--text-900);
}

.page-about .about-section > p {
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-900);
  max-width: 68ch;
}

.page-about .about-section > p + p {
  margin-top: var(--s-16);
}

.page-about .about-section > p.about-section__lead {
  font-size: 17px;
  font-weight: 500;
  line-height: 1.8;
}

.page-about .about-section a:not(.btn) {
  color: var(--cyan-600);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 两张并置卡 ---------- */
.page-about .about-grid2 {
  display: grid;
  gap: var(--s-16);
  margin-top: var(--s-20);
}

.page-about .about-card {
  padding: var(--s-20);
  border: 1px solid var(--paper-200);
  border-radius: var(--radius-sm);
  background: #fff;
}

.page-about .about-card--accent {
  background: #F0FBF8;
  border-color: rgba(12, 140, 121, .28);
}

.page-about .about-card__title {
  font-size: 16px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--text-900);
}

.page-about .about-list {
  list-style: none;
  margin-top: var(--s-12);
}

.page-about .about-list li {
  position: relative;
  padding-left: var(--s-20);
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-500);
}

.page-about .about-list li + li {
  margin-top: 8px;
}

.page-about .about-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 8px;
  height: 1px;
  background: var(--cyan-600);
}

/* ---------- 图版 ---------- */
.page-about .about-figure {
  margin: var(--s-20) 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--paper-200);
  border-radius: var(--radius-sm);
  object-fit: cover;
}

.page-about .about-figure figcaption {
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--text-500);
}

/* ---------- 可展开的分类组 ---------- */
.page-about .about-fold {
  margin-top: var(--s-12);
  border: 1px solid var(--paper-200);
  border-radius: var(--radius-sm);
  background: #fff;
  overflow: hidden;
}

.page-about .about-fold__summary {
  display: flex;
  align-items: center;
  gap: var(--s-12);
  padding: var(--s-16);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.6;
  color: var(--text-900);
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-fold__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--cyan-600);
}

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

.page-about .about-fold[open] .about-fold__summary {
  border-bottom: 1px solid var(--paper-200);
}

.page-about .about-fold__idx {
  flex: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--orange-100);
  color: var(--orange-700);
  font-size: 12px;
}

.page-about .about-fold__body {
  padding: var(--s-16);
}

.page-about .about-fold__body p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-500);
}

/* ---------- 服务范围 ---------- */
.page-about .about-scope {
  display: grid;
  gap: var(--s-20);
  margin-top: var(--s-20);
}

.page-about .about-metrics {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--hair-ink);
  border: 1px solid var(--hair-ink);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.page-about .about-metrics li {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: var(--s-20) var(--s-16);
  background: var(--ink-950);
}

.page-about .about-metrics__num {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--cyan-400);
}

.page-about .about-metrics__label {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(232, 240, 247, .75);
}

.page-about .about-figure--scope {
  margin: 0;
}

.page-about .about-figure--scope img {
  height: 100%;
  min-height: 180px;
}

/* ---------- 更新节奏 ---------- */
.page-about .about-rhythm {
  list-style: none;
  margin-top: var(--s-20);
  border-top: 1px solid var(--paper-200);
}

.page-about .about-rhythm li {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: var(--s-16) 0;
  border-bottom: 1px solid var(--paper-200);
}

.page-about .about-rhythm__key {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--orange-700);
}

.page-about .about-rhythm p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-500);
}

/* ---------- 协作链路 ---------- */
.page-about .about-flow {
  list-style: none;
  margin-top: var(--s-20);
  display: grid;
  gap: var(--s-16);
}

.page-about .about-flow li {
  padding: var(--s-16);
  border: 1px solid var(--paper-200);
  border-left: 3px solid var(--cyan-400);
  border-radius: var(--radius-sm);
  background: #fff;
}

.page-about .about-flow__idx {
  display: block;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--text-500);
}

.page-about .about-flow__title {
  margin-top: 6px;
  font-size: 16px;
  font-weight: 700;
  color: var(--text-900);
}

.page-about .about-flow li p {
  margin-top: 6px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-500);
}

/* ---------- 发展节点 ---------- */
.page-about .about-steps {
  list-style: none;
  position: relative;
  margin-top: var(--s-20);
  padding-left: var(--s-20);
}

.page-about .about-steps::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--paper-200);
}

.page-about .about-steps li {
  position: relative;
  padding-bottom: var(--s-28);
}

.page-about .about-steps li:last-child {
  padding-bottom: 0;
}

.page-about .about-steps li::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 6px;
  width: 9px;
  height: 9px;
  border: 2px solid var(--cyan-400);
  border-radius: 50%;
  background: var(--paper-50);
  box-sizing: content-box;
}

.page-about .about-steps__mark {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--orange-100);
  color: var(--orange-700);
  font-size: 13px;
  letter-spacing: .06em;
}

.page-about .about-steps h3 {
  margin-top: 10px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--text-900);
}

.page-about .about-steps li p {
  margin-top: 6px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-500);
  max-width: 62ch;
}

/* ---------- 结尾动作 ---------- */
.page-about .about-cta {
  position: relative;
  margin-top: var(--s-40);
  padding: var(--s-28) var(--s-20);
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--ink-800) 0%, var(--ink-950) 72%);
  color: var(--text-invert);
  overflow: hidden;
}

.page-about .about-cta::before {
  content: "";
  position: absolute;
  right: -60px;
  top: -60px;
  width: 220px;
  height: 220px;
  background: radial-gradient(circle, rgba(47, 227, 196, .3), rgba(47, 227, 196, 0) 68%);
  pointer-events: none;
}

.page-about .about-cta__title {
  position: relative;
  font-size: 20px;
  font-weight: 700;
  line-height: 1.4;
  color: #fff;
}

.page-about .about-cta__text {
  position: relative;
  margin-top: var(--s-12);
  font-size: 15px;
  line-height: 1.8;
  color: rgba(232, 240, 247, .82);
  max-width: 62ch;
}

.page-about .about-cta__actions {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-12);
  margin-top: var(--s-20);
}

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

  .page-about .about-frame {
    padding: var(--s-28);
  }

  .page-about .about-frame__ruler {
    margin: calc(var(--s-28) * -1) calc(var(--s-28) * -1) var(--s-28);
    padding-left: var(--s-20);
    padding-right: var(--s-20);
  }

  .page-about .about-frame__title {
    font-size: 40px;
  }

  .page-about .about-sec-head__title {
    font-size: 22px;
  }

  .page-about .about-sec-head__num {
    font-size: 22px;
  }

  .page-about .about-grid2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-rhythm li {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: var(--s-20);
    align-items: baseline;
  }

  .page-about .about-cta {
    padding: var(--s-40);
  }
}

@media (min-width: 900px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--s-40);
    align-items: start;
  }

  .page-about .about-timeline {
    position: sticky;
    top: 104px;
  }

  .page-about .about-timeline__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
    border-left: 1px solid var(--paper-200);
  }

  .page-about .about-timeline__list > li {
    flex: none;
  }

  .page-about .about-timeline__link {
    padding: 12px 0 12px 18px;
    border: 0;
    border-radius: 0;
    background: none;
    white-space: normal;
  }

  .page-about .about-timeline__link::before {
    content: "";
    position: absolute;
    left: -1px;
    top: 50%;
    width: 3px;
    height: 8px;
    background: var(--paper-200);
    transform: translateY(-50%);
    transition: height .22s var(--ease), background .22s var(--ease);
  }

  .page-about .about-timeline__link:hover {
    background: none;
  }

  .page-about .about-timeline__link.is-active {
    background: none;
  }

  .page-about .about-timeline__link.is-active::before {
    height: 22px;
    background: var(--cyan-400);
  }

  .page-about .about-timeline__link.is-active .about-timeline__num {
    color: var(--cyan-600);
  }

  .page-about .about-timeline__link.is-active .about-timeline__body {
    transform: translateX(4px);
  }

  .page-about .about-timeline__hint {
    display: block;
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height .25s var(--ease), opacity .2s var(--ease);
  }

  .page-about .about-timeline__link:hover .about-timeline__hint,
  .page-about .about-timeline__link:focus-visible .about-timeline__hint,
  .page-about .about-timeline__link.is-active .about-timeline__hint {
    max-height: 3.4em;
    opacity: 1;
  }

  .page-about .about-scope {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: stretch;
  }

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

  .page-about .about-flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--s-16);
  }

  .page-about .about-steps {
    padding-left: var(--s-28);
  }

  .page-about .about-steps li::before {
    left: -34px;
  }
}

@media (min-width: 1100px) {
  .page-about .about-frame__title {
    font-size: 56px;
    max-width: 22ch;
  }

  .page-about .about-sec-head__title {
    font-size: 24px;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-timeline__link,
  .page-about .about-timeline__body,
  .page-about .about-timeline__hint,
  .page-about .about-timeline__link::before {
    transition: none;
  }
}