.page-about {
  background: var(--bg-ink);
  color: var(--text-light);
  overflow: hidden;
}

/* ===== 首屏封面 ===== */
.page-about .about-hero {
  position: relative;
  padding: 48px 0 58px;
  border-bottom: 1px solid var(--line-gold);
  background:
    radial-gradient(ellipse at 82% 10%, rgba(226, 192, 126, 0.14), transparent 44%),
    linear-gradient(160deg, var(--bg-ink) 55%, #0d2433 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: -1px;
  width: 62%;
  height: 88px;
  background: linear-gradient(to top, rgba(226, 192, 126, 0.07), transparent);
  clip-path: polygon(14% 100%, 100% 0, 100% 100%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 40px;
  margin-top: 44px;
}

.page-about .about-hero__text {
  max-width: 680px;
}

.page-about .about-hero h1 {
  margin: 14px 0 20px;
  font-family: var(--font-headings);
  font-size: clamp(2rem, 6vw, 3.4rem);
  line-height: 1.15;
  letter-spacing: 0.04em;
  color: var(--text-light);
}

.page-about .about-hero__lead {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text-dim);
  border-left: 2px solid var(--line-gold-strong);
  padding-left: 18px;
}

.page-about .about-hero__facts {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line-gold);
  max-width: 520px;
}

.page-about .about-hero__fact {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 24px;
  padding: 12px 2px;
  border-bottom: 1px solid var(--line-gold);
}

.page-about .about-hero__fact dt {
  font-family: var(--font-body);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--text-dim);
}

.page-about .about-hero__fact dd {
  margin: 0;
  font-family: var(--font-data);
  font-size: 0.95rem;
  color: var(--gold-bright);
}

/* ===== 品牌缘起 ===== */
.page-about .about-origin {
  position: relative;
  padding-top: 76px;
  padding-bottom: 76px;
}

.page-about .about-origin__grid {
  display: grid;
  gap: 44px;
  align-items: start;
}

.page-about .about-origin h2,
.page-about .about-timeline h2,
.page-about .about-security h2,
.page-about .about-scale h2,
.page-about .about-cta h2 {
  margin: 10px 0 22px;
  font-family: var(--font-headings);
  font-size: clamp(1.5rem, 3.6vw, 2.2rem);
  line-height: 1.3;
  letter-spacing: 0.03em;
}

.page-about .about-origin__lead,
.page-about .about-origin__body {
  font-size: 0.98rem;
  line-height: 1.85;
  color: var(--text-dim);
}

.page-about .about-origin__lead {
  margin: 0 0 18px;
  color: var(--text-light);
  font-size: 1.02rem;
}

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

.page-about .about-origin__principles {
  list-style: none;
  margin: 0 0 28px;
  padding: 0;
  border-top: 1px solid var(--line-gold);
}

.page-about .about-origin__principles li {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  padding: 18px 4px;
  border-bottom: 1px solid var(--line-gold);
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--text-light);
}

.page-about .about-origin__num {
  flex: none;
  font-family: var(--font-data);
  font-size: 0.85rem;
  color: var(--gold-bright);
  background: rgba(226, 192, 126, 0.08);
  border: 1px solid var(--line-gold);
  border-radius: 50%;
  width: 34px;
  height: 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-top: 2px;
}

.page-about .about-origin__link {
  display: inline-block;
  margin-top: 4px;
  font-size: 0.95rem;
  color: var(--gold-bright);
  text-decoration: none;
  border-bottom: 1px solid var(--line-gold-strong);
  padding-bottom: 2px;
  transition: color 0.25s var(--ease-out), border-color 0.25s var(--ease-out);
}

.page-about .about-origin__link:hover,
.page-about .about-origin__link:focus-visible {
  color: var(--text-light);
  border-color: var(--gold-bright);
}

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

.page-about .about-origin__image img {
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  aspect-ratio: 1 / 1;
}

.page-about .about-origin__image figcaption {
  margin-top: 12px;
  font-family: var(--font-body);
  font-size: 0.8rem;
  color: var(--text-dim);
  letter-spacing: 0.04em;
}

/* ===== 里程碑时间轴 ===== */
.page-about .about-timeline {
  position: relative;
  padding-top: 76px;
  padding-bottom: 84px;
  background:
    linear-gradient(180deg, rgba(7, 21, 33, 0.4), rgba(17, 40, 54, 0.5)),
    var(--bg-abyss);
  border-top: 1px solid var(--line-gold);
  border-bottom: 1px solid var(--line-gold);
}

.page-about .about-timeline__heading {
  max-width: 640px;
  margin-bottom: 44px;
}

.page-about .about-timeline__heading p:last-child {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--text-dim);
}

.page-about .about-milestones {
  position: relative;
  margin: 0;
  padding-left: 30px;
}

.page-about .about-milestones::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(to bottom, var(--gold-bright), var(--line-gold) 55%, transparent);
  opacity: 0.65;
}

.page-about .about-milestone {
  position: relative;
  padding-bottom: 18px;
}

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

.page-about .about-milestone__stud {
  position: absolute;
  left: -28px;
  top: 18px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--bg-ink);
  border: 2px solid var(--gold-bright);
  box-shadow: 0 0 0 3px rgba(226, 192, 126, 0.14);
  transition: box-shadow 0.3s var(--ease-out), transform 0.3s var(--ease-out);
}

.page-about .about-milestone:hover .about-milestone__stud {
  box-shadow: 0 0 0 6px rgba(226, 192, 126, 0.24);
  transform: scale(1.06);
}

.page-about .about-milestone__card {
  display: block;
  background: rgba(17, 40, 54, 0.82);
  border: 1px solid var(--line-gold);
  border-left: 2px solid var(--gold-bright);
  border-radius: var(--radius);
  padding: 18px 20px;
  transition: background 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out);
}

.page-about .about-milestone__card[open] {
  background: rgba(17, 40, 54, 0.96);
  box-shadow: 0 10px 30px rgba(7, 21, 33, 0.5), 0 0 0 1px var(--line-gold-strong);
}

.page-about .about-milestone__card:hover {
  background: rgba(20, 50, 66, 0.9);
}

.page-about .about-milestone__summary {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 14px;
  cursor: pointer;
  font-family: var(--font-body);
}

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

.page-about .about-milestone__year {
  font-size: 0.92rem;
  color: var(--gold-bright);
  letter-spacing: 0.08em;
}

.page-about .about-milestone__name {
  font-family: var(--font-headings);
  font-size: 1.05rem;
  color: var(--text-light);
  letter-spacing: 0.02em;
}

.page-about .about-milestone__summary::after {
  content: "";
  margin-left: auto;
  width: 18px;
  height: 18px;
  border-right: 1px solid var(--gold-bright);
  border-bottom: 1px solid var(--gold-bright);
  transform: rotate(45deg);
  transition: transform 0.3s var(--ease-out);
  opacity: 0.7;
}

.page-about .about-milestone__card[open] .about-milestone__summary::after {
  transform: rotate(225deg);
  margin-top: 6px;
}

.page-about .about-milestone__body {
  padding-top: 12px;
  border-top: 1px solid var(--line-gold);
  margin-top: 14px;
}

.page-about .about-milestone__body p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--text-dim);
}

/* ===== 安全与合规 ===== */
.page-about .about-security {
  position: relative;
  padding-top: 76px;
  padding-bottom: 80px;
}

.page-about .about-security__gable {
  position: absolute;
  right: -20px;
  bottom: -10px;
  width: 220px;
  height: auto;
  opacity: 0.8;
  pointer-events: none;
}

.page-about .about-security__grid {
  display: grid;
  gap: 40px;
  align-items: start;
}

.page-about .about-security__image {
  margin: 0;
  max-width: 300px;
}

.page-about .about-security__image img {
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  aspect-ratio: 1 / 1;
}

.page-about .about-security__lead {
  margin: 0 0 28px;
  font-size: 0.98rem;
  line-height: 1.85;
  color: var(--text-dim);
}

.page-about .about-security__lead a {
  color: var(--gold-bright);
  text-decoration: none;
  border-bottom: 1px solid var(--line-gold-strong);
  transition: color 0.25s var(--ease-out);
}

.page-about .about-security__lead a:hover,
.page-about .about-security__lead a:focus-visible {
  color: var(--text-light);
}

.page-about .about-security__badges {
  list-style: none;
  margin: 0 0 26px;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.page-about .about-security__badge {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 16px 16px 14px;
  background: rgba(17, 40, 54, 0.76);
  border: 1px solid var(--line-gold);
  border-radius: var(--radius);
  transition: background 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out), transform 0.2s var(--ease-lounge);
}

.page-about .about-security__badge:hover,
.page-about .about-security__badge:focus-within {
  background: rgba(17, 40, 54, 0.98);
  box-shadow: 0 0 0 1px var(--line-gold-strong), 0 8px 24px rgba(7, 21, 33, 0.45);
  transform: translateY(-2px);
}

.page-about .about-security__disc {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-data);
  font-size: 0.85rem;
  color: var(--bg-abyss);
  background: linear-gradient(135deg, var(--gold-bright), var(--gold-shadow));
  margin-bottom: 12px;
  box-shadow: 0 2px 10px rgba(226, 192, 126, 0.25);
  transition: box-shadow 0.3s var(--ease-out);
}

.page-about .about-security__badge:hover .about-security__disc {
  box-shadow: 0 4px 16px rgba(226, 192, 126, 0.4);
}

.page-about .about-security__name {
  font-family: var(--font-headings);
  font-size: 0.95rem;
  color: var(--text-light);
  letter-spacing: 0.02em;
}

.page-about .about-security__sub {
  margin-top: 4px;
  font-family: var(--font-data);
  font-size: 0.72rem;
  color: var(--text-dim);
  letter-spacing: 0.04em;
}

.page-about .about-security .note {
  margin: 0;
  max-width: 520px;
}

/* ===== 服务规模 ===== */
.page-about .about-scale {
  position: relative;
  padding-top: 76px;
  padding-bottom: 84px;
  isolation: isolate;
  background: var(--bg-abyss);
  border-top: 1px solid var(--line-gold);
}

.page-about .about-scale__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -2;
  opacity: 0.26;
}

.page-about .about-scale::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: linear-gradient(180deg, rgba(7, 21, 33, 0.78) 0%, rgba(17, 40, 54, 0.9) 100%);
}

.page-about .about-scale__desc {
  max-width: 620px;
  margin: 0 0 36px;
  font-size: 0.98rem;
  line-height: 1.85;
  color: var(--text-dim);
}

.page-about .about-scale__stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .about-scale__card {
  padding: 26px 18px 24px;
  background: rgba(17, 40, 54, 0.88);
  border: 1px solid var(--line-gold);
  border-top: 2px solid var(--gold-bright);
  border-radius: var(--radius);
  box-shadow: 0 12px 30px rgba(7, 21, 33, 0.4);
  transition: transform 0.25s var(--ease-out), box-shadow 0.25s var(--ease-out);
}

.page-about .about-scale__card:hover,
.page-about .about-scale__card:focus-within {
  transform: translateY(-4px);
  box-shadow: 0 18px 36px rgba(7, 21, 33, 0.5), 0 0 0 1px var(--line-gold-strong);
}

.page-about .about-scale__num {
  display: block;
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  color: var(--gold-bright);
  letter-spacing: 0.02em;
  line-height: 1.25;
}

.page-about .about-scale__label {
  display: block;
  margin-top: 8px;
  font-size: 0.9rem;
  color: var(--text-light);
}

.page-about .about-scale__extras {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 24px;
  padding: 20px;
  background: rgba(7, 21, 33, 0.66);
  border: 1px solid var(--line-gold);
  border-radius: var(--radius);
}

.page-about .about-scale__extra {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  align-items: baseline;
  padding: 8px 2px;
  border-bottom: 1px solid var(--line-gold);
}

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

.page-about .about-scale__extra .data-text {
  font-size: 1rem;
  color: var(--gold-bright);
}

.page-about .about-scale__extra span:last-child {
  font-size: 0.88rem;
  color: var(--text-dim);
}

.page-about .about-scale__note {
  margin: 28px 0 0;
  font-size: 0.9rem;
  color: var(--text-dim);
}

.page-about .about-scale__note a {
  color: var(--gold-bright);
  text-decoration: none;
  border-bottom: 1px solid var(--line-gold-strong);
}

.page-about .about-scale__note a:hover,
.page-about .about-scale__note a:focus-visible {
  color: var(--text-light);
}

/* ===== CTA 收尾 ===== */
.page-about .about-cta {
  padding-top: 72px;
  padding-bottom: 72px;
}

.page-about .about-cta__card {
  padding: 36px 28px 42px;
  text-align: center;
  background:
    radial-gradient(ellipse at 50% 0%, rgba(226, 192, 126, 0.12), transparent 60%),
    rgba(17, 40, 54, 0.64);
  border: 1px solid var(--line-gold);
  border-radius: var(--radius);
}

.page-about .about-cta p {
  margin: 0 auto 28px;
  max-width: 560px;
  font-size: 0.96rem;
  line-height: 1.8;
  color: var(--text-dim);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
}

.page-about .about-cta__actions .btn {
  min-width: 160px;
  justify-content: center;
}

/* ===== 响应式增强 ===== */
@media (min-width: 640px) {
  .page-about .about-hero__grid {
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: end;
  }

  .page-about .about-hero__facts {
    border-top: 0;
    margin-top: 70px;
  }

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

  .page-about .about-scale__stats {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .about-scale__extras {
    grid-template-columns: 1fr 1fr;
    gap: 4px 32px;
  }

  .page-about .about-cta__actions .btn {
    min-width: 180px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 64px 0 78px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 4fr);
    gap: 64px;
    margin-top: 56px;
  }

  .page-about .about-origin__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: 72px;
  }

  .page-about .about-origin__image {
    margin-top: 12px;
  }

  .page-about .about-security__grid {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    gap: 64px;
    align-items: center;
  }

  .page-about .about-security__image {
    max-width: 320px;
    justify-self: center;
  }

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

  .page-about .about-scale__stats {
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
  }

  .page-about .about-scale__extras {
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
  }

  .page-about .about-scale__extra {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    border-bottom: 0;
    border-left: 1px solid var(--line-gold);
    padding-left: 16px;
  }

  .page-about .about-scale__extra .data-text {
    font-size: 1.15rem;
  }

  .page-about .about-milestones {
    padding-left: 0;
  }

  .page-about .about-milestones::before {
    left: 46px;
  }

  .page-about .about-milestone__stud {
    left: 32px;
    top: 20px;
  }

  .page-about .about-milestone__card {
    margin-left: 76px;
    padding: 20px 24px;
  }

  .page-about .about-security__gable {
    width: 300px;
    right: 40px;
    bottom: 0;
  }

  .page-about .about-cta__card {
    padding: 48px 56px 54px;
  }
}