.page-about {
  position: relative;
  background: var(--bg-primary);
  color: var(--text-primary);
  overflow-x: hidden;
}

/* ===== 首屏品牌宣言 ===== */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 32px 0 104px;
  background: #0B0D12;
}

.page-about .about-hero__backdrop {
  position: absolute;
  top: -24px;
  left: 0;
  right: 0;
  bottom: -48px;
  z-index: 0;
  overflow: hidden;
}

.page-about .about-hero__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  opacity: 0.36;
  transform: skewY(-3.5deg) scale(1.1);
  transform-origin: top center;
  filter: saturate(1.1) contrast(1.08);
}

.page-about .about-hero__overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(120deg, rgba(13,15,20,0.97) 0%, rgba(13,15,20,0.78) 42%, rgba(0,229,255,0.16) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 4px;
  z-index: 2;
  background: linear-gradient(90deg, var(--accent-green) 0% 34%, var(--accent-blue) 34% 68%, transparent 68%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .breadcrumb {
  margin-bottom: 24px;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 34px;
  margin-top: 28px;
}

.page-about .about-hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  color: var(--accent-green);
  font-family: var(--font-headline);
  font-size: 13px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.page-about .about-hero__eyebrow::before {
  content: "";
  display: inline-block;
  width: 26px;
  height: 2px;
  background: var(--accent-green);
}

.page-about .about-hero h1 {
  margin: 0 0 18px;
  font-family: var(--font-headline);
  font-size: clamp(28px, 6vw, 54px);
  line-height: 1.14;
  letter-spacing: -0.02em;
  max-width: 12em;
}

.page-about .about-hero__lead {
  margin: 0;
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.75;
  max-width: 58ch;
}

.page-about .about-hero__stats {
  position: relative;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  padding: 20px 16px 20px 20px;
  background: rgba(20,24,31,0.82);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--accent-green);
}

.page-about .about-hero__stat {
  display: grid;
  gap: 6px;
  min-width: 0;
}

.page-about .about-hero__stat-num {
  font-family: var(--font-headline);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 5vw, 38px);
  color: var(--accent-green);
  line-height: 1;
}

.page-about .about-hero__stat-label {
  color: var(--text-secondary);
  font-size: 12px;
  line-height: 1.4;
}

/* ===== 品牌使命 ===== */
.page-about .about-mission {
  position: relative;
  background: var(--bg-primary);
}

.page-about .about-mission__grid {
  display: grid;
  gap: 28px;
  padding-top: 56px;
  padding-bottom: 56px;
}

.page-about .about-mission__note {
  display: flex;
  align-items: center;
  gap: 12px;
}

.page-about .about-mission__num {
  font-family: var(--font-headline);
  font-size: 44px;
  line-height: 1;
  color: var(--accent-blue);
  letter-spacing: -0.04em;
}

.page-about .about-mission__content h2,
.page-about .about-data__header h2,
.page-about .about-timeline__header h2,
.page-about .about-tech__content h2 {
  font-family: var(--font-headline);
  font-size: clamp(26px, 4vw, 40px);
  line-height: 1.18;
  margin: 0 0 18px;
}

.page-about .about-mission__content p,
.page-about .about-data__card p,
.page-about .about-timeline__card p,
.page-about .about-tech__content p,
.page-about .about-tech__card p {
  color: var(--text-secondary);
  line-height: 1.75;
  font-size: 15px;
}

.page-about .about-mission__content .btn {
  margin-top: 6px;
}

/* ===== 数据规模与能力 ===== */
.page-about .about-data {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  padding: 64px 0;
}

.page-about .about-data__header {
  margin-bottom: 28px;
}

.page-about .about-data__num,
.page-about .about-timeline__num,
.page-about .about-tech__num {
  font-family: var(--font-headline);
  font-size: 14px;
  color: var(--accent-blue);
  letter-spacing: 0.14em;
  margin: 0 0 10px;
}

.page-about .about-data__header .text-secondary {
  margin-bottom: 0;
}

.page-about .about-data__grid {
  display: grid;
  gap: 16px;
}

.page-about .about-data__card {
  position: relative;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  padding: 24px 22px;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

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

.page-about .about-data__card h3 {
  font-family: var(--font-headline);
  font-size: 18px;
  margin: 0 0 8px;
  color: var(--text-primary);
}

.page-about .about-data__card .data-number {
  display: block;
  font-family: var(--font-headline);
  font-size: 40px;
  color: var(--accent-green);
  line-height: 1;
  margin-bottom: 14px;
  font-variant-numeric: tabular-nums;
}

.page-about .about-data__foot {
  margin-top: 28px;
  padding-top: 18px;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 14px;
}

.page-about .about-data__foot a {
  color: var(--accent-green);
  text-decoration: none;
}

.page-about .about-data__foot a:hover {
  text-decoration: underline;
}

/* ===== 发展历程时间线 ===== */
.page-about .about-timeline {
  position: relative;
  background: var(--bg-primary);
  padding: 64px 0 24px;
}

.page-about .about-timeline__header {
  margin-bottom: 44px;
}

.page-about .about-timeline__header .text-secondary {
  margin-bottom: 0;
}

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

.page-about .about-timeline__list::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 0;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--accent-green) 0%, var(--border-color) 100%);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 48px 46px;
}

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

.page-about .about-timeline__marker {
  position: absolute;
  top: 5px;
  left: 9px;
  width: 11px;
  height: 11px;
}

.page-about .about-timeline__node {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  background: var(--accent-green);
  box-shadow: 0 0 0 4px rgba(0,255,135,0.12), 0 0 20px rgba(0,255,135,0.35);
}

.page-about .about-timeline__card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 24px 20px;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

.page-about .about-timeline__card:hover {
  border-color: var(--accent-green);
  transform: translateY(-2px);
}

.page-about .about-timeline__period {
  display: inline-block;
  font-family: var(--font-headline);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-blue);
  background: rgba(0,229,255,0.08);
  border: 1px solid rgba(0,229,255,0.22);
  padding: 4px 10px;
  margin-bottom: 14px;
}

.page-about .about-timeline__card h3 {
  font-family: var(--font-headline);
  font-size: 20px;
  margin: 0 0 10px;
  color: var(--text-primary);
}

.page-about .about-timeline__card img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  margin-top: 18px;
  border: 1px solid var(--border-color);
  background: var(--bg-tertiary);
}

/* ===== 技术迭代方向 ===== */
.page-about .about-tech {
  background: var(--bg-primary);
  padding: 64px 0 0;
}

.page-about .about-tech__grid {
  display: grid;
  gap: 32px;
  padding-bottom: 48px;
}

.page-about .about-tech__content h2 {
  margin-bottom: 16px;
}

.page-about .about-tech__list {
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.page-about .about-tech__list li {
  position: relative;
  padding-left: 22px;
  color: var(--text-primary);
  font-size: 15px;
  line-height: 1.6;
}

.page-about .about-tech__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 8px;
  height: 8px;
  background: var(--accent-green);
  transform: rotate(45deg);
}

.page-about .about-tech__side {
  display: grid;
  gap: 18px;
  align-content: start;
}

.page-about .about-tech__card {
  position: relative;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 24px 22px;
  overflow: hidden;
}

.page-about .about-tech__card::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 90px;
  height: 90px;
  background: radial-gradient(circle, rgba(0,229,255,0.18) 0%, transparent 70%);
  pointer-events: none;
}

.page-about .about-tech__card-label {
  font-size: 13px;
  color: var(--accent-blue);
  letter-spacing: 0.08em;
  margin: 0 0 8px;
}

.page-about .about-tech__card-value {
  font-family: var(--font-headline);
  font-size: 30px;
  color: var(--text-primary);
  line-height: 1.2;
  margin: 0 0 10px;
}

.page-about .about-tech__help {
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.7;
}

.page-about .about-tech__help a {
  color: var(--accent-green);
  text-decoration: none;
  font-weight: 600;
}

.page-about .about-tech__help a:hover {
  text-decoration: underline;
}

/* ===== 桌面端 ===== */
@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 56px 0 140px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: 1.2fr 0.8fr;
    align-items: end;
    gap: 48px;
    margin-top: 36px;
  }

  .page-about .about-hero__stats {
    padding: 26px 22px 26px 28px;
  }

  .page-about .about-mission__grid {
    grid-template-columns: 160px 1fr;
    gap: 48px;
    padding-top: 64px;
    padding-bottom: 72px;
  }

  .page-about .about-mission__note {
    flex-direction: column;
    align-items: flex-start;
  }

  .page-about .about-mission__num {
    font-size: 64px;
  }

  .page-about .about-data__header {
    display: grid;
    grid-template-columns: 160px 1fr;
    gap: 48px;
    align-items: end;
    margin-bottom: 36px;
  }

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

  .page-about .about-timeline__list::before {
    left: 50%;
    transform: translateX(-0.5px);
  }

  .page-about .about-timeline__item {
    width: 50%;
    padding: 0 52px 56px 0;
  }

  .page-about .about-timeline__item:nth-child(even) {
    margin-left: 50%;
    padding: 0 0 56px 52px;
  }

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

  .page-about .about-timeline__marker {
    top: 8px;
  }

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

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

  .page-about .about-timeline__card {
    padding: 28px 24px;
  }

  .page-about .about-tech__grid {
    grid-template-columns: 1fr 340px;
    gap: 56px;
    align-items: start;
    padding-bottom: 72px;
  }
}