.page-about {
  --about-gap: clamp(18px, 3vw, 34px);
  --about-block: clamp(40px, 7vw, 78px);
}

.page-about .about-intro {
  padding: clamp(22px, 4vw, 42px) 0 clamp(24px, 4vw, 44px);
  border-bottom: 1px solid var(--hair);
}

.page-about .about-intro__eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .about-intro__title {
  margin: 0 0 20px;
  max-width: 900px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(29px, 6.2vw, 50px);
  line-height: 1.16;
  letter-spacing: .01em;
  color: var(--paper);
  text-shadow: 4px 4px 0 var(--wine-deep);
}

.page-about .about-intro__lede {
  max-width: 66ch;
  margin: 0;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.9;
  color: var(--paper);
  opacity: .86;
}

.page-about .about-chapter {
  position: relative;
  padding: var(--about-block) 0;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-chapter:last-of-type {
  border-bottom: 0;
}

.page-about .about-chapter .section-head {
  margin-bottom: clamp(22px, 3.4vw, 38px);
}

.page-about .about-chapter .section-head__num {
  color: var(--gold);
  font-weight: 600;
}

.page-about .about-chapter .section-head__kicker {
  color: var(--mist);
  font-size: 12px;
  letter-spacing: .14em;
}

.page-about .about-chapter h2 {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(21px, 3.4vw, 32px);
  line-height: 1.32;
  color: var(--paper);
}

.page-about .about-chapter h3 {
  font-size: clamp(16px, 2vw, 20px);
  line-height: 1.4;
  color: var(--paper);
}

.page-about p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.88;
  color: var(--mist);
}

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

/* ---------- 01 品牌起点 ---------- */

.page-about .about-start {
  display: grid;
  gap: var(--about-gap);
}

.page-about .about-start__body p {
  max-width: 62ch;
}

.page-about .about-figure {
  margin: 0;
  border: 2px solid var(--hair-strong);
  background: var(--ink-800);
  box-shadow: var(--shadow-hard);
  overflow: hidden;
  transition: border-color .2s var(--ease), box-shadow .2s var(--ease);
}

.page-about .about-figure:hover {
  border-color: var(--gold);
  box-shadow: var(--shadow-soft);
}

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

/* ---------- 02 三类服务 ---------- */

.page-about .service-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .service-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 22px 20px 24px;
  background: var(--ink-800);
  border: 2px solid var(--hair-strong);
  box-shadow: var(--shadow-hard);
  transition: border-color .18s var(--ease), box-shadow .18s var(--ease), transform .18s var(--ease);
}

.page-about .service-card:hover {
  border-color: var(--gold);
  box-shadow: var(--shadow-soft);
  transform: translateY(-2px);
}

.page-about .service-card__num {
  display: inline-block;
  width: 30px;
  height: 30px;
  line-height: 26px;
  text-align: center;
  font-size: 14px;
  font-weight: 700;
  color: var(--ink-900);
  background: var(--gold);
  border: 2px solid var(--gold-soft);
}

.page-about .service-card__title {
  margin: 0;
}

.page-about .service-card__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--mist);
}

.page-about .service-card__link {
  margin-top: auto;
  padding-top: 8px;
  font-size: 14px;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .18s var(--ease), color .18s var(--ease);
}

.page-about .service-card__link:hover,
.page-about .service-card__link:focus-visible {
  color: var(--gold-soft);
  border-bottom-color: var(--gold-soft);
}

/* ---------- 03 版本时间线 ---------- */

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  top: 12px;
  bottom: 12px;
  left: 13px;
  width: 2px;
  background: linear-gradient(180deg, var(--gold) 0%, var(--wine) 42%, var(--wine-deep) 100%);
}

.page-about .timeline__item {
  position: relative;
  padding-left: 40px;
  margin-bottom: 18px;
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 20px;
  width: 12px;
  height: 12px;
  background: var(--gold);
  border: 2px solid var(--ink-900);
  box-shadow: 0 0 0 2px var(--wine);
  transform: rotate(45deg);
}

.page-about .timeline__card {
  padding: 18px 18px 20px;
  background: var(--ink-800);
  border: 2px solid var(--hair);
  box-shadow: var(--shadow-soft);
  transition: border-color .2s var(--ease);
}

.page-about .timeline__card:hover {
  border-color: var(--gold);
}

.page-about .timeline__ver {
  margin: 0 0 8px;
  font-size: clamp(20px, 3vw, 26px);
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--gold);
}

.page-about .timeline__title {
  margin: 0 0 8px;
}

.page-about .timeline__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--mist);
}

.page-about .timeline__more {
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px dashed var(--hair-strong);
}

.page-about .timeline__more summary {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  list-style: none;
  font-size: 13px;
  color: var(--cyan);
}

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

.page-about .timeline__more summary::before {
  content: "+";
  font-family: var(--font-mono);
  font-weight: 700;
  width: 12px;
  display: inline-block;
}

.page-about .timeline__more[open] summary::before {
  content: "\2013";
}

.page-about .timeline__more-list {
  margin: 10px 0 0;
  padding-left: 20px;
  font-size: 14px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .timeline__more-list li + li {
  margin-top: 6px;
}

/* ---------- 04 团队与产能 ---------- */

.page-about .crowd-layout {
  display: grid;
  gap: var(--about-gap);
}

.page-about .crowd-stats {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

.page-about .stat {
  padding: 16px 16px 18px;
  background: var(--ink-800);
  border: 2px solid var(--hair-strong);
  border-top: 6px solid var(--gold);
}

.page-about .stat:nth-child(2) {
  border-top-color: var(--cyan);
}

.page-about .stat:nth-child(3) {
  border-top-color: var(--wine);
}

.page-about .stat__num {
  display: block;
  font-size: clamp(30px, 6vw, 42px);
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .stat:nth-child(2) .stat__num {
  color: var(--cyan);
}

.page-about .stat:nth-child(3) .stat__num {
  color: var(--gold-soft);
}

.page-about .stat__label {
  display: block;
  margin: 6px 0 8px;
  font-size: 14px;
  color: var(--paper);
}

.page-about .stat__desc {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .crowd-output {
  display: grid;
  gap: 10px;
  padding: 16px 18px;
  background: rgba(22, 34, 74, .72);
  border-left: 4px solid var(--cyan);
}

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

.page-about .crowd-output__item .mono {
  color: var(--gold-soft);
  font-weight: 600;
  margin-right: 4px;
}

/* ---------- 05 主题簇与标签 ---------- */

.page-about .cluster-layout {
  display: grid;
  gap: var(--about-gap);
}

.page-about .cluster-layout__media {
  max-width: 340px;
  margin-inline: auto;
}

.page-about .cluster-intro {
  max-width: 64ch;
}

.page-about .cluster-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.page-about .cluster {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 14px 12px 16px;
  background: var(--ink-800);
  border: 2px solid var(--hair);
  transition: border-color .18s var(--ease), background .18s var(--ease), transform .18s var(--ease);
}

.page-about .cluster:hover,
.page-about .cluster:focus-within {
  border-color: var(--gold);
  background: var(--ink-900);
  transform: translateY(-2px);
}

.page-about .cluster__idx {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .1em;
  color: var(--wine);
}

.page-about .cluster:hover .cluster__idx {
  color: var(--gold);
}

.page-about .cluster__name {
  margin: 0;
  font-size: 16px;
  color: var(--paper);
}

.page-about .cluster__hint {
  margin: 0;
  font-size: 13px;
  line-height: 1.68;
  color: var(--mist);
  opacity: .72;
  transition: opacity .18s var(--ease), color .18s var(--ease);
}

.page-about .cluster:hover .cluster__hint {
  opacity: 1;
  color: var(--paper);
}

/* ---------- 06 合作生态 ---------- */

.page-about .partner-grid {
  display: grid;
  gap: 16px;
  margin-bottom: 22px;
}

.page-about .partner {
  padding: 20px 20px 22px;
  background: var(--ink-800);
  border: 2px solid var(--hair-strong);
  border-left: 6px solid var(--wine);
  box-shadow: var(--shadow-soft);
}

.page-about .partner__num {
  display: block;
  font-size: clamp(32px, 6vw, 46px);
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .partner__label {
  margin: 8px 0 10px;
  font-size: 16px;
  color: var(--paper);
}

.page-about .partner__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .partner-note,
.page-about .region-note {
  max-width: 68ch;
  padding-left: 16px;
  border-left: 3px solid var(--gold);
  font-size: 14px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 07 服务范围 ---------- */

.page-about .region-intro {
  max-width: 64ch;
  margin-bottom: 20px;
}

.page-about .region-dots {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.page-about .region-dot {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 10px;
  border: 1px solid var(--hair);
  font-size: 14px;
  color: var(--mist);
  transition: border-color .16s var(--ease), background .16s var(--ease), color .16s var(--ease);
}

.page-about .region-dot:hover,
.page-about .region-dot:focus-within {
  border-color: var(--cyan);
  background: rgba(63, 216, 200, .1);
  color: var(--paper);
}

.page-about .region-dot__mark {
  flex: 0 0 auto;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--gold);
  transition: background .16s var(--ease), box-shadow .16s var(--ease);
}

.page-about .region-dot:hover .region-dot__mark,
.page-about .region-dot:focus-within .region-dot__mark {
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(63, 216, 200, .22);
}

.page-about .region-dot__name {
  line-height: 1.4;
}

/* ---------- 结尾行动区 ---------- */

.page-about .about-cta {
  margin: clamp(30px, 5vw, 52px) 0 0;
  padding: clamp(22px, 4vw, 34px);
  background: linear-gradient(135deg, var(--wine-deep) 0%, var(--wine) 58%, var(--ink-800) 100%);
  border: 2px solid var(--gold);
  box-shadow: var(--shadow-hard);
}

.page-about .about-cta__text {
  max-width: 46ch;
  margin: 0 0 20px;
  font-size: clamp(16px, 2.4vw, 20px);
  line-height: 1.7;
  color: var(--paper);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 桌面端 ---------- */

@media (min-width: 640px) {
  .page-about .region-dots {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 780px) {
  .page-about .service-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .service-list > .service-card:nth-child(2) {
    margin-top: 26px;
  }

  .page-about .service-list > .service-card:nth-child(3) {
    margin-top: 52px;
  }

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

  .page-about .cluster-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 880px) {
  .page-about .timeline::before {
    left: 50%;
    transform: translateX(-1px);
  }

  .page-about .timeline__item {
    width: 50%;
    padding-left: 0;
    padding-right: 48px;
    margin-bottom: 26px;
  }

  .page-about .timeline__item::before {
    left: auto;
    right: -7px;
    top: 22px;
  }

  .page-about .timeline__item:nth-child(even) {
    margin-left: 50%;
    padding-right: 0;
    padding-left: 48px;
  }

  .page-about .timeline__item:nth-child(even)::before {
    left: -7px;
    right: auto;
  }
}

@media (min-width: 900px) {
  .page-about .about-start {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.02fr);
    align-items: start;
  }

  .page-about .crowd-layout {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    align-items: start;
  }

  .page-about .cluster-layout {
    grid-template-columns: 300px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .cluster-layout__media {
    max-width: none;
    margin-inline: 0;
    position: sticky;
    top: calc(var(--topbar-h) + 20px);
  }
}

@media (min-width: 980px) {
  .page-about .region-dots {
    grid-template-columns: repeat(8, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .service-card,
  .page-about .cluster,
  .page-about .about-figure,
  .page-about .region-dot {
    transition: none;
  }

  .page-about .service-card:hover,
  .page-about .cluster:hover {
    transform: none;
  }
}