.page-about {
  --about-aside-w: clamp(200px, 22vw, 250px);
  --about-gap: clamp(2.5rem, 6vw, 5.5rem);
  background: var(--bg-deep);
}

/* ===== Hero ===== */
.about-hero {
  position: relative;
  padding: calc(var(--header-h) + 2.25rem) 0 2.75rem;
  overflow: hidden;
  background:
    linear-gradient(rgba(0, 229, 255, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 229, 255, 0.045) 1px, transparent 1px),
    var(--bg-deep);
  background-size: 34px 34px;
}

.about-hero::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 32%;
  height: 100%;
  background: linear-gradient(135deg, transparent 42%, rgba(198, 255, 0, 0.06) 42%, rgba(198, 255, 0, 0.06) 58%, transparent 58%);
  pointer-events: none;
}

.about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 45%, transparent 78%);
}

.about-hero .container {
  position: relative;
  z-index: 1;
}

.about-hero .breadcrumb {
  margin-bottom: 2.25rem;
}

.about-hero__watermark {
  position: absolute;
  right: 4%;
  top: 1.25rem;
  z-index: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(5rem, 15vw, 11rem);
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px rgba(0, 229, 255, 0.18);
  pointer-events: none;
  user-select: none;
}

.about-hero__grid {
  display: grid;
  gap: 1.5rem;
  align-items: end;
}

.about-hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--secondary);
  margin-bottom: 1rem;
}

.about-hero__eyebrow::before {
  content: "";
  width: 2rem;
  height: 2px;
  background: var(--secondary);
  flex-shrink: 0;
}

.about-hero__title {
  font-family: var(--font-heading);
  font-size: clamp(2.75rem, 8vw, 5.5rem);
  line-height: 0.95;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin: 0 0 1.25rem;
  text-transform: uppercase;
}

.about-hero__title-mark {
  display: inline-block;
  margin-left: 0.15em;
  color: var(--primary);
}

.about-hero__lede {
  max-width: 48ch;
  font-size: clamp(1rem, 2vw, 1.25rem);
  line-height: 1.7;
  color: var(--text-secondary);
  margin: 0;
}

.about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--border-line);
  border: 1px solid var(--border-line);
  margin: 0;
}

.about-hero__fact {
  padding: 1rem 1.1rem 0.9rem;
  background: var(--bg-surface);
  margin: 0;
}

.about-hero__fact dt {
  font-size: 0.72rem;
  color: var(--text-secondary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.3rem;
}

.about-hero__fact dd {
  margin: 0;
}

.about-hero__value {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.35rem, 3vw, 1.75rem);
  line-height: 1.1;
  color: var(--primary);
}

.about-hero__fact:nth-child(even) .about-hero__value {
  color: var(--secondary);
}

/* ===== 主体布局 ===== */
.about-layout {
  display: grid;
  gap: 2rem;
  padding-top: 3.5rem;
  padding-bottom: 4.5rem;
}

.about-layout__main {
  min-width: 0;
}

.about-layout__main > section {
  position: relative;
  scroll-margin-top: calc(var(--header-h) + 1.25rem);
}

.about-layout__main > section + section {
  margin-top: var(--about-gap);
}

.about-layout__main > .file-divider + * {
  margin-top: 2rem;
}

.about-layout__main > * + .file-divider {
  margin-top: clamp(2rem, 4vw, 3rem);
}

.about-section__ref {
  position: absolute;
  right: 0;
  top: -0.5rem;
  z-index: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px rgba(198, 255, 0, 0.22);
  pointer-events: none;
  user-select: none;
}

.about-section__ref + .section-head,
.about-section__ref + .section-head,
.about-section__ref + .section-head {
  position: relative;
  z-index: 1;
}

/* ===== 侧栏索引 ===== */
.about-index {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  padding: 0.85rem 1rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-line);
  border-left: 3px solid var(--primary);
  overflow-x: auto;
  scrollbar-width: none;
}

.about-index::-webkit-scrollbar {
  display: none;
}

.about-index__label {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--secondary);
  border-right: 1px solid var(--border-line);
  padding-right: 0.9rem;
}

.about-index__nav {
  display: flex;
  gap: 0.25rem;
  white-space: nowrap;
}

.about-index__link {
  display: inline-flex;
  align-items: baseline;
  gap: 0.35rem;
  padding: 0.4rem 0.6rem;
  font-size: 0.85rem;
  color: var(--text-primary);
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease;
}

.about-index__link:hover {
  background: var(--bg-elevated);
  color: var(--secondary);
}

.about-index__num {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--primary);
}

.about-index__cta {
  display: none;
  flex-shrink: 0;
  margin-left: auto;
  white-space: nowrap;
  font-size: 0.8rem;
}

/* ===== 品牌故事 ===== */
.about-story__media {
  margin: 1.5rem 0 1.5rem;
}

.about-story__prose {
  display: grid;
  gap: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.75;
  font-size: 1rem;
  margin-top: 0.25rem;
}

.about-story__prose p {
  margin: 0;
}

.about-story__quote {
  margin: 2rem 0 0;
  padding: 1.25rem 1.5rem 1.25rem 2rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-line);
  border-left: 3px solid var(--primary);
}

.about-story__quote p {
  margin: 0;
  font-family: var(--font-heading);
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text-primary);
}

/* ===== 图片外框 ===== */
.about-frame {
  border: 1px solid var(--border-line);
  padding: 0.5rem;
  background: var(--bg-surface);
  transition: border-color 0.25s ease;
}

.about-frame:hover {
  border-color: var(--secondary);
}

.about-frame img {
  display: block;
  width: 100%;
  height: auto;
}

/* ===== 时间轴 ===== */
.about-timeline {
  position: relative;
  padding-left: 2rem;
  margin-top: 2rem;
}

.about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 4px;
  bottom: 4px;
  width: 2px;
  background: linear-gradient(to bottom, var(--primary), var(--secondary) 72%, transparent);
}

.about-timeline__item {
  position: relative;
  padding-bottom: clamp(1.5rem, 4vw, 2.25rem);
}

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

.about-timeline__node {
  position: absolute;
  left: -2rem;
  top: 0.4rem;
  width: 0.75rem;
  height: 0.75rem;
  background: var(--primary);
  transition: background 0.2s ease, box-shadow 0.2s ease;
}

.about-timeline__item:hover .about-timeline__node {
  background: var(--secondary);
  box-shadow: 0 0 0 4px rgba(0, 229, 255, 0.15);
}

.about-timeline__body {
  padding: 1.1rem 1.25rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-line);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.about-timeline__item:hover .about-timeline__body {
  border-color: var(--secondary);
  transform: translateX(4px);
}

.about-timeline__period {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--secondary);
  margin-bottom: 0.5rem;
}

.about-timeline__body h3 {
  font-family: var(--font-heading);
  font-size: 1.12rem;
  margin: 0 0 0.5rem;
  color: var(--text-primary);
}

.about-timeline__body p {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

/* ===== 团队与数据能力 ===== */
.about-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--border-line);
  border: 1px solid var(--border-line);
  margin: 1.5rem 0;
}

.about-stats__item {
  padding: 1.5rem 1rem 1.3rem;
  text-align: center;
  background: var(--bg-surface);
}

.about-stats__value {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(2.25rem, 6vw, 3.5rem);
  line-height: 1;
  color: var(--primary);
}

.about-stats__item:nth-child(even) .about-stats__value {
  color: var(--secondary);
}

.about-stats__label {
  display: block;
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
  letter-spacing: 0.04em;
}

.about-team__media {
  margin: 0 0 1.5rem;
}

.about-team__caption {
  margin: 0.6rem 0 0;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-secondary);
  letter-spacing: 0.04em;
}

.about-cap {
  margin-top: 2rem;
  padding: 1.4rem 1.5rem 1.4rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border-line);
  border-top: 3px solid var(--primary);
}

.about-cap h3 {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  margin: 0 0 0.9rem;
  color: var(--text-primary);
}

.about-cap ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.75rem;
}

.about-cap li {
  position: relative;
  padding-left: 1.4rem;
  color: var(--text-secondary);
  font-size: 0.94rem;
  line-height: 1.6;
}

.about-cap li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55rem;
  width: 0.6rem;
  height: 2px;
  background: var(--secondary);
}

/* ===== 资质与合作 ===== */
.about-cred__grid {
  display: grid;
  gap: 1px;
  background: var(--border-line);
  border: 1px solid var(--border-line);
  margin: 1.5rem 0 1.75rem;
}

.about-cred__card {
  background: var(--bg-surface);
  padding: 1.5rem;
}

.about-cred__num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(2rem, 5vw, 3rem);
  line-height: 1;
  color: var(--primary);
  margin-bottom: 0.75rem;
}

.about-cred__card:nth-child(even) .about-cred__num {
  color: var(--secondary);
}

.about-cred__card h3 {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  margin: 0 0 0.5rem;
  color: var(--text-primary);
}

.about-cred__card p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

.about-cred__media {
  display: grid;
  gap: 1.5rem;
  margin: 0 0 1.5rem;
  align-items: center;
}

.about-cred__note h3 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  margin: 0 0 0.75rem;
  color: var(--text-primary);
}

.about-cred__note p {
  margin: 0 0 1rem;
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

.about-cred__note p:last-of-type {
  margin-bottom: 1.25rem;
}

.about-cred__disclaimer {
  margin: 0;
  padding: 1rem 1.25rem;
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--text-secondary);
  background: rgba(255, 90, 54, 0.05);
  border: 1px solid rgba(255, 90, 54, 0.35);
}

/* ===== 底部跳转卡 ===== */
.about-card {
  margin-top: clamp(3rem, 6vw, 5rem);
  padding: clamp(1.5rem, 4vw, 2.5rem);
  background: linear-gradient(135deg, var(--bg-elevated), var(--bg-surface));
  border: 1px solid var(--border-line);
  border-left: 3px solid var(--primary);
}

.about-card__eyebrow {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--secondary);
}

.about-card h3 {
  font-family: var(--font-heading);
  font-size: clamp(1.5rem, 3vw, 2rem);
  margin: 0.5rem 0 0.5rem;
  color: var(--text-primary);
}

.about-card__desc {
  margin: 0 0 1.5rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.about-card__links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* ===== 桌面端适配 ===== */
@media (min-width: 860px) {
  .about-hero {
    padding-top: calc(var(--header-h) + 3.25rem);
    padding-bottom: 3.25rem;
  }

  .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(280px, 0.9fr);
    gap: 2.5rem;
  }

  .about-hero__facts {
    grid-template-columns: repeat(2, 1fr);
  }

  .about-index__cta {
    display: inline-flex;
  }
}

@media (min-width: 1024px) {
  .about-layout {
    grid-template-columns: var(--about-aside-w) minmax(0, 1fr);
    gap: clamp(2.5rem, 6vw, 5.5rem);
    align-items: start;
    padding-top: 4.5rem;
    padding-bottom: 5.5rem;
  }

  .about-layout__aside {
    position: sticky;
    top: calc(var(--header-h) + 1.5rem);
  }

  .about-index {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 1.5rem 1.25rem;
    overflow: visible;
    scrollbar-width: auto;
  }

  .about-index::-webkit-scrollbar {
    display: block;
  }

  .about-index__label {
    border-right: none;
    border-bottom: 1px solid var(--border-line);
    padding-right: 0;
    padding-bottom: 0.75rem;
    margin-bottom: 0.75rem;
  }

  .about-index__nav {
    flex-direction: column;
    gap: 0.25rem;
    white-space: normal;
  }

  .about-index__link {
    padding: 0.65rem 0.75rem;
    border-left: 2px solid transparent;
    white-space: normal;
  }

  .about-index__link:hover {
    background: var(--bg-elevated);
    border-left-color: var(--secondary);
  }

  .about-index__cta {
    margin-left: 0;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-line);
  }

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

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

  .about-cred__media {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: 2rem;
  }
}