.page-about {
  --brand-gold-start: #D4AF37;
  --brand-gold-end: #A67C1E;
  --timeline-line-color: #2A2D4A;
  --timeline-dot-size: 18px;
  --card-radius: 10px;
  --milestone-bg: #1A1C2E;
  --commitment-accent: #00CED1;
  display: flex;
  flex-direction: column;
  gap: 0;
  background: var(--bg-primary, #0A0B1A);
  color: var(--text-primary, #fff);
  font-family: var(--font-body, 'Inter', sans-serif);
}

/* 面包屑 */
.page-about .breadcrumb {
  padding: 16px 20px 0;
  font-size: 14px;
  color: var(--text-secondary, #B0B0C0);
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}
.page-about .breadcrumb a {
  color: var(--gold, #D4AF37);
  text-decoration: none;
  transition: color var(--transition-base, 0.3s);
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--cyan, #00CED1);
  outline: none;
  text-decoration: underline;
}
.page-about .breadcrumb .sep {
  user-select: none;
  opacity: 0.5;
}
.page-about .breadcrumb .current {
  color: var(--text-primary, #fff);
  font-weight: 600;
}

/* 容器 */
.page-about .container {
  max-width: var(--content-width, 1200px);
  margin: 0 auto;
  padding: 0 20px;
}

/* 页面区块 */
.page-about .page-section {
  padding: 60px 0;
}

/* ── 品牌定位 ── */
.page-about .brand-position {
  position: relative;
  padding-top: 40px;
  padding-bottom: 60px;
  background: linear-gradient(135deg, #0A0B1A 0%, #14172B 50%, #0A0B1A 100%);
}
.page-about .brand-position::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(90deg, var(--border-color, #2A2D4A) 1px, transparent 1px),
    linear-gradient(0deg, var(--border-color, #2A2D4A) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.15;
  pointer-events: none;
}
.page-about .brand-position__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
  align-items: center;
  position: relative;
  z-index: 1;
}
.page-about .brand-position__emblem {
  display: flex;
  justify-content: center;
}
.page-about .brand-emblem {
  width: 200px;
  height: auto;
  max-width: 100%;
  object-fit: contain;
  border-radius: var(--radius-md, 8px);
  box-shadow: 0 0 30px rgba(212, 175, 55, 0.25);
}
.page-about .brand-position__content {
  text-align: center;
}
.page-about .brand-position__title {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 800;
  font-size: 2.4rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--gold, #D4AF37);
  text-shadow: 0 0 12px rgba(212, 175, 55, 0.4);
  margin: 0 0 8px;
}
.page-about .brand-position__subtitle {
  font-size: 1rem;
  color: var(--cyan, #00CED1);
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  letter-spacing: 0.04em;
  margin: 0 0 20px;
  text-transform: uppercase;
}
.page-about .brand-position__desc {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-secondary, #B0B0C0);
  max-width: 680px;
  margin: 0 auto 28px;
}
.page-about .brand-position__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
}
.page-about .btn-gold {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 32px;
  background: linear-gradient(135deg, var(--brand-gold-start), var(--brand-gold-end));
  color: #0A0B1A;
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 700;
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border: none;
  border-radius: var(--radius-sm, 4px);
  text-decoration: none;
  transition: box-shadow var(--transition-base, 0.3s), transform var(--transition-base, 0.3s);
  cursor: pointer;
}
.page-about .btn-gold:hover,
.page-about .btn-gold:focus-visible {
  box-shadow: 0 0 20px rgba(212, 175, 55, 0.5);
  transform: translateY(-2px);
  outline: none;
}
.page-about .btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 32px;
  background: transparent;
  color: var(--gold, #D4AF37);
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 600;
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border: 2px solid var(--gold, #D4AF37);
  border-radius: var(--radius-sm, 4px);
  text-decoration: none;
  transition: background var(--transition-base, 0.3s), box-shadow var(--transition-base, 0.3s), transform var(--transition-base, 0.3s);
}
.page-about .btn-outline:hover,
.page-about .btn-outline:focus-visible {
  background: rgba(212, 175, 55, 0.08);
  box-shadow: 0 0 16px rgba(212, 175, 55, 0.25);
  transform: translateY(-2px);
  outline: none;
}

/* ── 发展历程 ── */
.page-about .milestones {
  background: var(--bg-surface, #1A1C2E);
  position: relative;
}
.page-about .milestones::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--gold, #D4AF37), transparent);
  opacity: 0.3;
}
.page-about .milestones__title {
  text-align: center;
  margin-bottom: 12px;
}
.page-about .milestones__intro {
  text-align: center;
  color: var(--text-secondary, #B0B0C0);
  font-size: 1rem;
  margin: 0 0 48px;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
}
.page-about .section-title {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 800;
  font-size: 2rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--gold, #D4AF37);
  text-shadow: 0 0 8px rgba(212, 175, 55, 0.3);
  position: relative;
  display: inline-block;
  margin: 0 0 16px;
}
.page-about .section-title::after {
  content: '';
  display: block;
  width: 60%;
  height: 3px;
  margin-top: 6px;
  background: linear-gradient(90deg, var(--gold, #D4AF37), transparent);
  clip-path: polygon(0 0, 100% 0, calc(100% - 12px) 100%, 0 100%);
}

/* 时间轴 */
.page-about .timeline {
  position: relative;
  padding: 8px 0 8px 32px;
  max-width: 760px;
  margin: 0 auto;
}
.page-about .timeline::before {
  content: '';
  position: absolute;
  left: 14px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--gold, #D4AF37), var(--purple, #7B2D8E), var(--cyan, #00CED1));
  opacity: 0.5;
  border-radius: 2px;
}
.page-about .timeline__node {
  position: relative;
  padding: 0 0 40px 16px;
  list-style: none;
}
.page-about .timeline__node:last-child {
  padding-bottom: 0;
}
.page-about .timeline__dot {
  position: absolute;
  left: -26px;
  top: 6px;
  width: var(--timeline-dot-size);
  height: var(--timeline-dot-size);
  border-radius: 50%;
  background: var(--bg-surface, #1A1C2E);
  border: 3px solid var(--gold, #D4AF37);
  box-shadow: 0 0 8px rgba(212, 175, 55, 0.3);
  z-index: 2;
}
.page-about .timeline__dot--current {
  background: var(--gold, #D4AF37);
  box-shadow: 0 0 16px rgba(212, 175, 55, 0.7);
  border-color: var(--gold, #D4AF37);
}
.page-about .timeline__card {
  background: var(--milestone-bg);
  border: 1px solid var(--border-color, #2A2D4A);
  border-radius: var(--card-radius);
  padding: 4px 0;
  transition: border-color var(--transition-base, 0.3s), box-shadow var(--transition-base, 0.3s);
}
.page-about .timeline__card:hover {
  border-color: var(--gold, #D4AF37);
  box-shadow: 0 0 12px rgba(212, 175, 55, 0.08);
}
.page-about .timeline__card--highlight {
  border-color: var(--gold, #D4AF37);
  box-shadow: 0 0 16px rgba(212, 175, 55, 0.12);
}
.page-about .timeline__summary {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 20px;
  cursor: pointer;
  list-style: none;
  font-weight: 600;
  transition: background var(--transition-base, 0.3s);
  border-radius: var(--card-radius);
}
.page-about .timeline__summary::-webkit-details-marker {
  display: none;
}
.page-about .timeline__summary:hover {
  background: rgba(212, 175, 55, 0.04);
}
.page-about .timeline__version {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--border-color, #2A2D4A);
  color: var(--text-primary, #fff);
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 800;
  font-size: 0.85rem;
  padding: 4px 12px;
  border-radius: var(--radius-sm, 4px);
  letter-spacing: 0.04em;
  min-width: 48px;
  text-align: center;
  transition: background var(--transition-base, 0.3s), color var(--transition-base, 0.3s);
}
.page-about .timeline__version--gold {
  background: var(--gold, #D4AF37);
  color: #0A0B1A;
}
.page-about .timeline__label {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 700;
  font-size: 1.05rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-primary, #fff);
}
.page-about .timeline__detail {
  padding: 0 20px 18px;
  color: var(--text-secondary, #B0B0C0);
  font-size: 0.95rem;
  line-height: 1.65;
  border-top: 1px solid var(--border-color, #2A2D4A);
  margin: 0 12px 0 12px;
  padding-top: 14px;
}
.page-about .timeline__detail p {
  margin: 0;
}
.page-about .timeline__node[data-milestone] details[open] .timeline__summary {
  background: rgba(212, 175, 55, 0.04);
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
}
.page-about .milestones__visual {
  margin-top: 48px;
  display: flex;
  justify-content: center;
}
.page-about .milestones__img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md, 8px);
  box-shadow: 0 0 20px rgba(212, 175, 55, 0.1);
  border: 1px solid var(--border-color, #2A2D4A);
}

/* ── 服务承诺 ── */
.page-about .commitments {
  background: linear-gradient(180deg, #0A0B1A 0%, #101224 100%);
  position: relative;
}
.page-about .commitments::before {
  content: '';
  position: absolute;
  top: 0;
  left: 10%;
  right: 10%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--purple, #7B2D8E), transparent);
  opacity: 0.3;
}
.page-about .commitments__title {
  text-align: center;
  display: block;
  margin: 0 auto 16px;
}
.page-about .commitments__title::after {
  margin-left: auto;
  margin-right: auto;
}
.page-about .commitments__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin: 40px auto 32px;
  max-width: 960px;
}
.page-about .commitment-card {
  background: var(--bg-surface, #1A1C2E);
  border: 1px solid var(--border-color, #2A2D4A);
  border-radius: var(--card-radius);
  padding: 32px 24px;
  text-align: center;
  transition: border-color var(--transition-base, 0.3s), box-shadow var(--transition-base, 0.3s), transform var(--transition-base, 0.3s);
}
.page-about .commitment-card:hover {
  border-color: var(--commitment-accent, #00CED1);
  box-shadow: 0 0 20px rgba(0, 206, 209, 0.1);
  transform: translateY(-4px);
}
.page-about .commitment-card__icon-wrap {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: 20px;
  color: var(--gold, #D4AF37);
}
.page-about .commitment-card__icon {
  width: 48px;
  height: 48px;
  filter: drop-shadow(0 0 6px rgba(212, 175, 55, 0.3));
}
.page-about .commitment-card:nth-child(2) .commitment-card__icon-wrap {
  color: var(--cyan, #00CED1);
}
.page-about .commitment-card:nth-child(2) .commitment-card__icon {
  filter: drop-shadow(0 0 6px rgba(0, 206, 209, 0.3));
}
.page-about .commitment-card:nth-child(3) .commitment-card__icon-wrap {
  color: var(--purple, #7B2D8E);
}
.page-about .commitment-card:nth-child(3) .commitment-card__icon {
  filter: drop-shadow(0 0 6px rgba(123, 45, 142, 0.3));
}
.page-about .commitment-card__title {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 700;
  font-size: 1.2rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-primary, #fff);
  margin: 0 0 12px;
}
.page-about .commitment-card__desc {
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--text-secondary, #B0B0C0);
  margin: 0;
}
.page-about .commitments__banner {
  display: flex;
  justify-content: center;
  margin: 16px 0 20px;
}
.page-about .commitments__img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md, 8px);
  border: 1px solid var(--border-color, #2A2D4A);
  box-shadow: 0 0 12px rgba(123, 45, 142, 0.08);
}
.page-about .commitments__footnote {
  text-align: center;
  font-size: 0.95rem;
  color: var(--text-secondary, #B0B0C0);
  margin: 8px 0 0;
}
.page-about .commitments__footnote a {
  color: var(--gold, #D4AF37);
  text-decoration: underline;
  transition: color var(--transition-base, 0.3s);
}
.page-about .commitments__footnote a:hover,
.page-about .commitments__footnote a:focus-visible {
  color: var(--cyan, #00CED1);
  outline: none;
}

/* ── 响应式：桌面端 ── */
@media (min-width: 768px) {
  .page-about .page-section {
    padding: 80px 0;
  }
  .page-about .brand-position {
    padding-top: 60px;
    padding-bottom: 80px;
  }
  .page-about .brand-position__grid {
    grid-template-columns: 1fr 1.2fr;
    gap: 48px;
  }
  .page-about .brand-position__emblem {
    justify-content: flex-end;
  }
  .page-about .brand-emblem {
    width: 320px;
  }
  .page-about .brand-position__content {
    text-align: left;
  }
  .page-about .brand-position__desc {
    margin: 0 0 28px;
  }
  .page-about .brand-position__actions {
    justify-content: flex-start;
  }
  .page-about .brand-position__title {
    font-size: 3.2rem;
  }
  .page-about .brand-position__subtitle {
    font-size: 1.1rem;
  }
  .page-about .brand-position__desc {
    font-size: 1.05rem;
  }
  .page-about .section-title {
    font-size: 2.4rem;
  }
  .page-about .milestones__intro {
    font-size: 1.05rem;
  }
  .page-about .timeline {
    padding-left: 48px;
  }
  .page-about .timeline::before {
    left: 22px;
  }
  .page-about .timeline__dot {
    left: -38px;
    width: 22px;
    height: 22px;
  }
  .page-about .timeline__node {
    padding-left: 24px;
    padding-bottom: 48px;
  }
  .page-about .timeline__summary {
    padding: 18px 24px;
  }
  .page-about .timeline__detail {
    padding: 16px 24px 20px;
  }
  .page-about .timeline__version {
    font-size: 0.9rem;
    padding: 6px 16px;
    min-width: 56px;
  }
  .page-about .timeline__label {
    font-size: 1.15rem;
  }
  .page-about .commitments__grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
  }
  .page-about .commitment-card {
    padding: 40px 28px;
  }
  .page-about .commitment-card__title {
    font-size: 1.3rem;
  }
  .page-about .commitments__banner {
    margin: 24px 0 20px;
  }
  .page-about .breadcrumb {
    padding: 20px 20px 0;
    font-size: 15px;
  }
}

@media (min-width: 1024px) {
  .page-about .brand-position__title {
    font-size: 3.8rem;
  }
  .page-about .brand-emblem {
    width: 380px;
  }
  .page-about .brand-position__grid {
    gap: 64px;
  }
  .page-about .timeline {
    max-width: 820px;
  }
  .page-about .commitments__grid {
    gap: 40px;
  }
}

/* ── 工具类 ── */
.page-about .text-gold {
  color: var(--gold, #D4AF37);
}
.page-about .text-cyan {
  color: var(--cyan, #00CED1);
}
.page-about .text-muted {
  color: var(--text-secondary, #B0B0C0);
}
.page-about .uppercase {
  text-transform: uppercase;
}
.page-about .mono {
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
}