.page-about {
  --about-gap: var(--space-4);
  --about-gap-lg: clamp(48px, 7vw, 80px);
  background: var(--color-paper);
  color: var(--color-body);
  overflow-x: hidden;
}

.page-about .about-section-head {
  margin-bottom: var(--space-4);
}

.page-about .about-section-head h2 {
  margin-top: var(--space-2);
}

/* ---------- 品牌宣言 ---------- */
.page-about .about-manifesto {
  position: relative;
  padding-top: var(--header-h);
  padding-bottom: var(--space-6);
  background:
    radial-gradient(720px 480px at 88% 0%, rgba(27, 58, 123, 0.16), transparent 60%),
    radial-gradient(480px 360px at 0% 30%, rgba(242, 99, 58, 0.08), transparent 55%),
    var(--color-paper);
}

.page-about .about-manifesto__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  align-items: center;
  margin-top: var(--space-4);
}

.page-about .about-manifesto h1 {
  margin: var(--space-2) 0;
  font-size: clamp(2.4rem, 6vw, 3.6rem);
  line-height: 1.12;
  letter-spacing: -0.03em;
}

.page-about .about-manifesto__subtitle {
  margin: var(--space-2) 0 0;
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-accent);
}

.page-about .about-manifesto__copy .lede {
  margin-top: var(--space-3);
}

.page-about .about-manifesto__copy p:not(.lede) {
  margin-top: var(--space-3);
  line-height: 1.8;
}

.page-about .about-manifesto__copy .btn {
  margin-top: var(--space-4);
}

.page-about .about-manifesto__visual {
  position: relative;
  margin: 24px 0 0 24px;
}

.page-about .about-manifesto__visual::before {
  content: "";
  position: absolute;
  top: -24px;
  left: -24px;
  width: 100%;
  height: 100%;
  border-left: 2px solid var(--color-accent);
  border-top: 2px solid var(--color-accent);
  background-image:
    linear-gradient(var(--color-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-line) 1px, transparent 1px);
  background-size: 28px 28px;
  opacity: 0.5;
}

.page-about .about-manifesto__visual img {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--color-line);
  background: var(--color-paper);
}

/* ---------- 发展时间线 ---------- */
.page-about .about-timeline {
  padding: var(--space-6) 0;
  background: #fff;
}

.page-about .about-timeline__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

.page-about .about-timeline__visual {
  margin: 0 0 var(--space-2);
}

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

.page-about .about-timeline__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  object-position: center top;
  background: var(--color-line);
}

.page-about .about-timeline__quote {
  margin: var(--space-3) 0 0;
  padding: var(--space-3);
  background: var(--color-paper);
  border-left: 3px solid var(--color-accent);
  font-size: 0.92rem;
  line-height: 1.75;
  color: var(--color-muted);
}

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

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

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 20px;
  width: 2px;
  background: var(--color-line);
}

.page-about .about-timeline__item {
  position: relative;
  padding-left: 56px;
  padding-bottom: var(--space-5);
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 4px;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--color-accent);
  box-shadow: 0 0 0 4px #fff;
}

.page-about .about-timeline__year {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--color-deep);
  line-height: 1.2;
  margin-bottom: var(--space-2);
}

.page-about .about-timeline__year::after {
  content: "";
  display: block;
  width: 40px;
  height: 3px;
  margin-top: var(--space-1);
  background: var(--color-accent);
}

.page-about .about-timeline__card {
  background: var(--color-paper);
  border: 1px solid var(--color-line);
  border-left: 4px solid var(--color-accent);
  padding: var(--space-3);
}

.page-about .about-timeline__card h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.page-about .about-timeline__card p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.75;
}

/* ---------- 数据事实 ---------- */
.page-about .about-facts {
  position: relative;
  padding: var(--space-6) 0;
  background-color: var(--color-deep);
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 32px 32px;
  color: #fff;
}

.page-about .about-facts .section-tag,
.page-about .about-facts h2 {
  color: #fff;
}

.page-about .about-facts .section-tag::before {
  background: var(--color-accent);
}

.page-about .about-facts__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: var(--space-5) 0 var(--space-3);
}

.page-about .about-fact {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  padding: 20px;
  -webkit-backdrop-filter: blur(4px);
  backdrop-filter: blur(4px);
  transition: border-color 0.3s var(--ease-out), background 0.3s var(--ease-out);
}

.page-about .about-fact:hover {
  border-color: rgba(242, 99, 58, 0.65);
  background: rgba(255, 255, 255, 0.09);
}

.page-about .about-fact--lead {
  background:
    linear-gradient(135deg, rgba(242, 99, 58, 0.22), rgba(242, 99, 58, 0.05)),
    rgba(255, 255, 255, 0.06);
  border-left: 4px solid var(--color-accent);
}

.page-about .about-fact__icon {
  display: block;
  width: 32px;
  height: 32px;
  margin-bottom: 14px;
  color: var(--color-accent);
}

.page-about .about-fact__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  font-weight: 700;
  line-height: 1.1;
  color: #fff;
  letter-spacing: -0.02em;
}

.page-about .about-fact--lead .about-fact__num {
  font-size: clamp(2.4rem, 6vw, 3.6rem);
  color: var(--color-accent);
}

.page-about .about-fact__label {
  display: block;
  margin: 8px 0 0;
  color: rgba(244, 246, 250, 0.78);
  font-size: 0.9rem;
  line-height: 1.5;
}

.page-about .about-fact__desc {
  margin: 12px 0 0;
  color: rgba(244, 246, 250, 0.7);
  font-size: 0.88rem;
  line-height: 1.7;
  max-width: 48ch;
}

.page-about .about-facts__visual {
  margin: var(--space-4) auto 0;
  max-width: 960px;
}

.page-about .about-facts__visual img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 8 / 5;
  object-fit: cover;
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.page-about .about-facts__visual figcaption {
  margin-top: 10px;
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: rgba(244, 246, 250, 0.6);
  text-align: right;
}

/* ---------- 资质与认证 ---------- */
.page-about .about-cert {
  padding: var(--space-6) 0;
  background: var(--color-paper);
}

.page-about .about-cert__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: var(--space-4);
}

.page-about .about-cert__card {
  background: #fff;
  border: 1px solid var(--color-line);
  padding: var(--space-4);
  transition: transform 0.3s var(--ease-out), border-color 0.3s var(--ease-out);
}

.page-about .about-cert__card:hover {
  transform: translateY(-3px);
  border-color: var(--color-accent);
}

.page-about .about-cert__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 76px;
  height: 76px;
  margin-bottom: 20px;
  background: var(--color-paper);
  border: 1px solid var(--color-line);
  color: var(--color-deep);
  transition: color 0.3s var(--ease-out), background 0.3s var(--ease-out), border-color 0.3s var(--ease-out);
}

.page-about .about-cert__icon svg {
  width: 34px;
  height: 34px;
}

.page-about .about-cert__card:hover .about-cert__icon {
  color: var(--color-accent);
  border-color: var(--color-accent);
  background: #fff;
}

.page-about .about-cert__card h3 {
  margin: 0 0 10px;
  font-size: 1.15rem;
}

.page-about .about-cert__card p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.75;
}

.page-about .about-cert__note {
  margin-top: var(--space-4);
  padding: var(--space-3);
  border-left: 3px solid var(--color-accent);
  background: #fff;
  font-size: 0.92rem;
  line-height: 1.7;
  max-width: 70ch;
}

/* ---------- 合作生态 ---------- */
.page-about .about-eco {
  padding: var(--space-6) 0;
  background: #fff;
  border-top: 1px solid var(--color-line);
}

.page-about .about-eco__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

.page-about .about-eco__content > p {
  line-height: 1.75;
}

.page-about .about-eco__principles {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: var(--space-4) 0;
}

.page-about .about-eco__principle {
  background: var(--color-paper);
  border-left: 3px solid var(--color-accent);
  padding: var(--space-3);
}

.page-about .about-eco__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.12em;
}

.page-about .about-eco__principle h3 {
  margin: 6px 0;
  font-size: 1.05rem;
}

.page-about .about-eco__principle p {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--color-muted);
}

.page-about .about-eco__trust {
  margin: var(--space-4) 0;
  padding: var(--space-3) var(--space-4);
  border-left: 4px solid var(--color-accent);
  background: var(--color-paper);
  font-family: var(--font-mono);
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--color-deep);
}

.page-about .about-eco__trust p {
  margin: 0;
}

.page-about .about-eco__cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}

.page-about .about-eco__link {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--color-deep);
  text-decoration: none;
  border-bottom: 1px solid var(--color-accent);
  padding-bottom: 2px;
  transition: color 0.25s ease, border-color 0.25s ease;
}

.page-about .about-eco__link:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* ---------- 响应式策略 ---------- */
@media (min-width: 720px) {
  .page-about .about-manifesto__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    gap: var(--space-5);
  }

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

  .page-about .about-fact--lead {
    grid-column: 1 / -1;
  }

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

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

  .page-about .about-timeline__item {
    display: grid;
    grid-template-columns: 180px 1fr;
    gap: 0;
    padding-left: 0;
  }

  .page-about .about-timeline__item::before {
    left: 0;
  }

  .page-about .about-timeline__list::before {
    left: 12px;
  }

  .page-about .about-timeline__year {
    padding-right: 24px;
    text-align: right;
  }

  .page-about .about-timeline__year::after {
    margin-left: auto;
  }
}

@media (min-width: 920px) {
  .page-about .about-timeline__layout {
    grid-template-columns: minmax(0, 3fr) minmax(0, 9fr);
    gap: var(--about-gap-lg);
  }

  .page-about .about-timeline__visual {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    align-self: start;
    margin-bottom: 0;
  }

  .page-about .about-timeline__media img {
    aspect-ratio: auto;
  }

  .page-about .about-eco__layout {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    gap: clamp(32px, 5vw, 72px);
  }

  .page-about .about-eco__layout .about-section-head {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    align-self: start;
    margin-bottom: 0;
  }
}