.page-about {
  --about-gap: clamp(20px, 3vw, 40px);
  --about-rail: 200px;
  --about-card-shadow: 6px 6px 0 rgba(0, 0, 0, .28);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-top: clamp(20px, 3.4vw, 44px);
  padding-bottom: clamp(36px, 5vw, 72px);
  background:
    radial-gradient(880px 420px at 92% -14%, rgba(217, 154, 43, .18), transparent 68%),
    radial-gradient(620px 380px at 4% 108%, rgba(46, 139, 139, .16), transparent 70%),
    linear-gradient(180deg, var(--ink-2) 0%, var(--ink) 100%);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero__inner {
  display: grid;
  gap: clamp(28px, 4vw, 56px);
  grid-template-columns: minmax(0, 1fr);
  align-items: start;
}

.page-about .about-hero__text h1 {
  margin: 12px 0 0;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(30px, 5.6vw, 54px);
  line-height: 1.1;
  letter-spacing: -.01em;
  color: var(--paper);
  max-width: 16ch;
}

.page-about .about-hero__lead {
  margin: 20px 0 0;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: var(--gray);
  max-width: 60ch;
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
  border-top: 1px solid var(--line);
  padding-top: 24px;
}

.page-about .about-hero__facts li {
  position: relative;
  padding-left: 20px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--gray);
}

.page-about .about-hero__facts li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 8px;
  height: 8px;
  background: var(--amber);
}

.page-about .about-hero__fact-key {
  display: inline-block;
  margin-right: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--amber);
  border: 1px solid rgba(217, 154, 43, .45);
  border-radius: var(--radius);
  padding: 1px 6px;
  vertical-align: 1px;
}

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

.page-about .about-hero__figure {
  margin: 0;
  position: relative;
}

.page-about .about-hero__figure .media-frame {
  box-shadow: var(--about-card-shadow);
}

/* ---------- 章节通用 ---------- */
.page-about .about-auth,
.page-about .about-team {
  background: var(--ink);
}

.page-about .about-auth__head,
.page-about .about-team .section-head,
.page-about .about-timeline .section-head {
  max-width: 68ch;
}

.page-about .about-auth__head .section-sub,
.page-about .about-team .section-sub,
.page-about .about-timeline .section-sub,
.page-about .about-eco__intro p {
  margin-top: 16px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--gray);
}

/* ---------- 授权区域 ---------- */
.page-about .about-auth__layout {
  margin-top: clamp(28px, 3.6vw, 48px);
  display: grid;
  gap: clamp(20px, 3vw, 36px);
  grid-template-columns: minmax(0, 1fr);
}

.page-about .about-auth__rail {
  border-left: 2px solid var(--amber);
  padding: 4px 0 4px 16px;
}

.page-about .about-auth__rail-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .about-auth__rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.page-about .about-auth__rail-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--gray);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .about-auth__rail-link:hover,
.page-about .about-auth__rail-link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--amber);
}

.page-about .about-auth__rail-dot {
  width: 9px;
  height: 9px;
  flex: none;
  border-radius: 50%;
  background: var(--gray);
}

.page-about .about-auth__rail-dot.is-bj { background: var(--bj); }
.page-about .about-auth__rail-dot.is-sz { background: var(--sz); }
.page-about .about-auth__rail-dot.is-sh { background: var(--sh); }
.page-about .about-auth__rail-dot.is-hz { background: var(--hz); }

.page-about .about-auth__cards {
  gap: clamp(16px, 2.2vw, 24px);
}

.page-about .auth-card {
  display: flex;
  flex-direction: column;
}

.page-about .auth-card .panel__title {
  margin-top: 10px;
}

.page-about .auth-card .panel__meta {
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--gray);
}

.page-about .auth-card .panel__list li {
  font-size: 14px;
  line-height: 1.75;
}

.page-about .auth-card__more {
  margin-top: auto;
  border-top: 1px dashed var(--line-2);
  padding-top: 12px;
}

.page-about .auth-card__more summary {
  cursor: pointer;
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--amber);
  padding: 2px 0;
  border-radius: var(--radius);
}

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

.page-about .auth-card__more summary::after {
  content: "＋";
  font-size: 13px;
  line-height: 1;
}

.page-about .auth-card__more[open] summary::after {
  content: "－";
}

.page-about .auth-card__more summary:hover {
  color: var(--signal);
}

.page-about .auth-card__more summary:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

.page-about .auth-card__more p {
  margin: 12px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--gray);
}

.page-about .auth-card:focus-within {
  border-color: var(--amber);
}

.page-about .about-auth__figure {
  margin: clamp(28px, 3.6vw, 48px) 0 0;
}

.page-about .about-auth__figure .media-frame {
  border: 1px solid var(--line-2);
}

/* ---------- 发展历程 ---------- */
.page-about .about-timeline {
  position: relative;
  overflow: hidden;
}

.page-about .about-timeline__list {
  list-style: none;
  margin: clamp(28px, 3.6vw, 48px) 0 0;
  padding: 0 0 0 30px;
  position: relative;
  display: grid;
  gap: clamp(16px, 2.2vw, 24px);
}

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(180deg, var(--amber), var(--signal) 55%, var(--hz));
  opacity: .55;
}

.page-about .about-timeline__item {
  position: relative;
}

.page-about .about-timeline__marker {
  position: absolute;
  left: -30px;
  top: 22px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--amber);
  box-sizing: border-box;
}

.page-about .about-timeline__item:nth-child(2) .about-timeline__marker { border-color: var(--sz); }
.page-about .about-timeline__item:nth-child(3) .about-timeline__marker { border-color: var(--sh); }
.page-about .about-timeline__item:nth-child(4) .about-timeline__marker { border-color: var(--hz); }

.page-about .about-timeline__card {
  background: var(--ink-3);
  border: 1px solid var(--line);
  border-left: 3px solid var(--amber);
  border-radius: var(--radius);
  padding: clamp(16px, 2.2vw, 22px);
  transition: transform .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-timeline__card:hover {
  transform: translateX(2px);
  border-color: var(--line-2);
}

.page-about .about-timeline__card h3 {
  margin: 8px 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(18px, 2.2vw, 22px);
  color: var(--paper);
}

.page-about .about-timeline__card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray);
  max-width: 68ch;
}

.page-about .about-timeline__item:nth-child(2) .about-timeline__card { border-left-color: var(--sz); }
.page-about .about-timeline__item:nth-child(3) .about-timeline__card { border-left-color: var(--sh); }
.page-about .about-timeline__item:nth-child(4) .about-timeline__card { border-left-color: var(--hz); }

.page-about .about-timeline__figure {
  margin: clamp(28px, 3.6vw, 44px) 0 0;
}

/* ---------- 团队 ---------- */
.page-about .about-team__grid {
  margin-top: clamp(28px, 3.6vw, 48px);
}

.page-about .about-team__card {
  position: relative;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-top: 3px solid var(--amber);
  border-radius: var(--radius);
  padding: clamp(20px, 2.6vw, 28px);
  transition: border-color .2s var(--ease), transform .2s var(--ease);
}

.page-about .about-team__card:hover {
  border-top-color: var(--signal);
  transform: translateY(-2px);
}

.page-about .about-team__num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--amber);
  border-bottom: 2px solid rgba(217, 154, 43, .4);
  padding-bottom: 6px;
}

.page-about .about-team__card h3 {
  margin: 16px 0 10px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 19px;
  color: var(--paper);
}

.page-about .about-team__card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: var(--gray);
}

/* ---------- 合作生态 ---------- */
.page-about .about-eco__inner {
  display: grid;
  gap: clamp(24px, 3.4vw, 48px);
  grid-template-columns: minmax(0, 1fr);
  align-items: start;
}

.page-about .about-eco__intro .section-title {
  color: var(--ink);
}

.page-about .about-eco__intro .eyebrow {
  color: var(--ink-2);
  opacity: .85;
}

.page-about .about-eco__intro p {
  color: var(--ink-3);
}

.page-about .about-eco__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
  grid-template-columns: minmax(0, 1fr);
}

.page-about .about-eco__item {
  background: rgba(11, 27, 51, .07);
  border: 1px solid rgba(11, 27, 51, .18);
  border-radius: var(--radius);
  padding: 18px;
}

.page-about .about-eco__item .tag {
  color: var(--ink);
  border-color: rgba(11, 27, 51, .4);
  background: rgba(11, 27, 51, .06);
}

.page-about .about-eco__item h3 {
  margin: 12px 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 16px;
  color: var(--ink);
}

.page-about .about-eco__item p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--ink-3);
}

/* ---------- 下一步 ---------- */
.page-about .about-next {
  background: linear-gradient(180deg, var(--ink) 0%, var(--ink-2) 100%);
  border-top: 1px solid var(--line);
}

.page-about .about-next__inner {
  display: grid;
  gap: clamp(24px, 3.4vw, 48px);
  grid-template-columns: minmax(0, 1fr);
  align-items: start;
}

.page-about .about-next__copy p {
  margin: 16px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--gray);
  max-width: 62ch;
}

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

.page-about .about-next__side {
  background: var(--ink-3);
  border: 1px solid var(--line);
  border-left: 3px solid var(--signal);
  border-radius: var(--radius);
  padding: clamp(18px, 2.4vw, 24px);
}

.page-about .about-next__side-title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--signal);
}

.page-about .about-next__side ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-next__side li {
  position: relative;
  padding-left: 16px;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--gray);
}

.page-about .about-next__side li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 6px;
  height: 6px;
  background: var(--amber);
}

/* ---------- 桌面 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.16fr) minmax(0, .84fr);
    align-items: center;
  }

  .page-about .about-hero__facts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px 24px;
  }

  .page-about .about-auth__layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-auth__rail {
    position: sticky;
    top: calc(var(--rail-h) + var(--bar-h) + 20px);
  }

  .page-about .about-auth__rail-list {
    flex-direction: column;
    gap: 12px;
  }

  .page-about .about-eco__inner {
    grid-template-columns: minmax(0, .86fr) minmax(0, 1.14fr);
  }

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

  .page-about .about-next__inner {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, .8fr);
  }
}

@media (min-width: 1080px) {
  .page-about .about-timeline__list {
    padding-left: 36px;
  }

  .page-about .about-timeline__marker {
    left: -36px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-timeline__card,
  .page-about .about-team__card,
  .page-about .about-auth__rail-link {
    transition: none;
  }

  .page-about .about-timeline__card:hover,
  .page-about .about-team__card:hover {
    transform: none;
  }
}