.page-about {
  --hero-bg-start: #0B3D5F;
  --hero-bg-end: #072438;
  --commitment-bg-start: #0B3D5F;
  --commitment-bg-end: #072438;
  --timeline-line-color: #00B4D8;
  --timeline-dot-size: 16px;
  --card-flip-duration: 0.6s;
  display: block;
}

/* ── 面包屑 ── */
.page-about .breadcrumb {
  padding: 1.25rem 1rem 0;
  max-width: var(--max-width, 1200px);
  margin: 0 auto;
  font-size: 0.875rem;
  color: var(--color-text-secondary, #8B9BB4);
}
.page-about .breadcrumb a {
  color: var(--color-accent-blue, #00B4D8);
  text-decoration: none;
  transition: color var(--transition-fast, 0.2s ease);
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--color-accent, #FF6B35);
  text-decoration: underline;
}
.page-about .breadcrumb__separator {
  margin: 0 0.5rem;
  color: var(--color-text-secondary, #8B9BB4);
}

/* ── 首屏 Hero ── */
.page-about .hero {
  background: linear-gradient(135deg, var(--hero-bg-start), var(--hero-bg-end));
  color: #fff;
  padding: 2.5rem 1rem 3rem;
  margin-bottom: 0;
  overflow: hidden;
}
.page-about .hero__inner {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  align-items: center;
  max-width: var(--max-width, 1200px);
  margin: 0 auto;
}
.page-about .hero__content {
  flex: 1 1 50%;
  order: 1;
}
.page-about .hero__kicker {
  display: inline-block;
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-weight: 500;
  font-size: 0.875rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-accent, #FF6B35);
  border-left: 3px solid var(--color-accent, #FF6B35);
  padding-left: 0.75rem;
  margin-bottom: 0.75rem;
}
.page-about .hero h1 {
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-size: 2.441rem;
  font-weight: 700;
  line-height: 1.15;
  margin: 0 0 1rem;
  color: #fff;
}
.page-about .hero__lead {
  font-size: 1.125rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.88);
  margin-bottom: 1.25rem;
  max-width: 520px;
}
.page-about .hero__highlights {
  list-style: none;
  padding: 0;
  margin: 0 0 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.page-about .hero__highlights li {
  position: relative;
  padding-left: 1.5rem;
  font-size: 1rem;
  color: rgba(255, 255, 255, 0.82);
}
.page-about .hero__highlights li::before {
  content: "▸";
  position: absolute;
  left: 0;
  color: var(--color-accent, #FF6B35);
  font-weight: 700;
}
.page-about .hero .btn--primary {
  background: var(--color-accent, #FF6B35);
  color: #fff;
  border: none;
  padding: 0.75rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 4px;
  text-decoration: none;
  display: inline-block;
  transition: background var(--transition-fast, 0.2s ease), transform var(--transition-fast, 0.2s ease);
}
.page-about .hero .btn--primary:hover,
.page-about .hero .btn--primary:focus-visible {
  background: #e85d2a;
  transform: translateY(-2px);
}
.page-about .hero__visual {
  flex: 0 0 auto;
  order: 0;
  max-width: 360px;
  width: 100%;
}
.page-about .hero__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: contain;
  clip-path: polygon(8% 0, 100% 0, 92% 100%, 0 100%);
}

/* ── 章节头部 ── */
.page-about .section-header {
  text-align: center;
  margin-bottom: 2.5rem;
}
.page-about .section-header h2 {
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-size: 1.953rem;
  font-weight: 700;
  color: var(--color-text, #1A1A2E);
  margin: 0 0 0.75rem;
}
.page-about .section-header__desc {
  font-size: 1rem;
  color: var(--color-text-secondary, #8B9BB4);
  max-width: 620px;
  margin: 0 auto;
  line-height: 1.6;
}
.page-about .section-header--light h2 {
  color: #fff;
}
.page-about .section-header--light .section-header__desc {
  color: rgba(255, 255, 255, 0.7);
}

/* ── 时间线区域 ── */
.page-about .timeline-section {
  background: var(--color-bg, #F4F6F9);
  padding: 3rem 1rem 3.5rem;
}
.page-about .timeline {
  position: relative;
  padding-left: 2rem;
  margin: 0 auto 3rem;
  max-width: 800px;
}
.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--timeline-line-color, #00B4D8);
  opacity: 0.5;
}
.page-about .timeline__item {
  position: relative;
  margin-bottom: 2rem;
  padding-left: 1.5rem;
  transition: opacity var(--transition-base, 0.35s ease);
}
.page-about .timeline__marker {
  position: absolute;
  left: -1.65rem;
  top: 6px;
  width: var(--timeline-dot-size, 16px);
  height: var(--timeline-dot-size, 16px);
  border-radius: 50%;
  background: var(--timeline-line-color, #00B4D8);
  border: 3px solid var(--color-bg, #F4F6F9);
  box-shadow: 0 0 0 2px var(--timeline-line-color, #00B4D8);
  z-index: 1;
}
.page-about .timeline__content {
  background: #fff;
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  box-shadow: var(--shadow-card, 0 2px 12px rgba(11, 61, 95, 0.08));
  border: var(--border-thin, 1px solid rgba(139, 155, 180, 0.3));
  transition: box-shadow var(--transition-fast, 0.2s ease);
}
.page-about .timeline__content:hover {
  box-shadow: var(--shadow-hover, 0 6px 24px rgba(11, 61, 95, 0.14));
}
.page-about .timeline__title {
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-primary, #0B3D5F);
  margin: 0 0 0.4rem;
}
.page-about .timeline__content > p {
  font-size: 0.95rem;
  color: var(--color-text, #1A1A2E);
  line-height: 1.6;
  margin: 0 0 0.5rem;
}
.page-about .timeline__details {
  font-size: 0.9rem;
  color: var(--color-text-secondary, #8B9BB4);
  margin-top: 0.25rem;
}
.page-about .timeline__details summary {
  cursor: pointer;
  color: var(--color-accent-blue, #00B4D8);
  font-weight: 500;
  transition: color var(--transition-fast, 0.2s ease);
}
.page-about .timeline__details summary:hover,
.page-about .timeline__details summary:focus-visible {
  color: var(--color-accent, #FF6B35);
}
.page-about .timeline__details[open] summary {
  color: var(--color-accent, #FF6B35);
}
.page-about .timeline__details p {
  margin-top: 0.75rem;
  line-height: 1.6;
  padding: 0.75rem 0 0.25rem;
  border-top: 1px dashed rgba(139, 155, 180, 0.3);
}

/* ── 对比卡片 ── */
.page-about .compare-cards {
  max-width: 960px;
  margin: 0 auto;
}
.page-about .compare-cards__heading {
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text, #1A1A2E);
  text-align: center;
  margin-bottom: 1.5rem;
}
.page-about .compare-cards__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}
.page-about .compare-card {
  perspective: 1200px;
  height: 380px;
}
.page-about .compare-card__inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform var(--card-flip-duration, 0.6s) ease;
  transform-style: preserve-3d;
}
.page-about .compare-card:hover .compare-card__inner,
.page-about .compare-card:focus-within .compare-card__inner {
  transform: rotateY(180deg);
}
.page-about .compare-card__face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  border-radius: 10px;
  overflow: hidden;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  box-shadow: var(--shadow-card, 0 2px 12px rgba(11, 61, 95, 0.08));
  border: var(--border-thin, 1px solid rgba(139, 155, 180, 0.3));
}
.page-about .compare-card__face--old {
  background: linear-gradient(145deg, #e8ecf1, #d5dce5);
  color: var(--color-text, #1A1A2E);
}
.page-about .compare-card__face--new {
  background: linear-gradient(145deg, var(--hero-bg-start, #0B3D5F), #0a314a);
  color: #fff;
  transform: rotateY(180deg);
}
.page-about .compare-card__img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  display: block;
}
.page-about .compare-card__face--old .compare-card__img {
  filter: grayscale(0.5) contrast(0.8);
}
.page-about .compare-card__face--new .compare-card__img {
  filter: saturate(1.1) brightness(1.05);
}
.page-about .compare-card__label {
  padding: 1rem 1.25rem 1.25rem;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}
.page-about .compare-card__label .tag {
  align-self: flex-start;
  font-size: 0.75rem;
  padding: 0.2rem 0.6rem;
  border-radius: 3px;
  font-weight: 600;
}
.page-about .compare-card__label h4 {
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-size: 1.1rem;
  font-weight: 700;
  margin: 0.25rem 0 0.15rem;
}
.page-about .compare-card__label p {
  font-size: 0.85rem;
  line-height: 1.5;
  margin: 0;
  opacity: 0.85;
}

/* ── 承诺区域 ── */
.page-about .commitment-section {
  background: linear-gradient(135deg, var(--commitment-bg-start), var(--commitment-bg-end));
  color: #fff;
  padding: 3.5rem 1rem 4rem;
  position: relative;
  background-attachment: fixed;
}
.page-about .commitment-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  max-width: 800px;
  margin: 0 auto 3rem;
}
.page-about .commitment-item {
  background: rgba(255, 255, 255, 0.07);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  border-radius: 8px;
  padding: 1.25rem 1.5rem 1.25rem 2rem;
  position: relative;
  border-left: 4px solid transparent;
  transition: border-color var(--transition-fast, 0.2s ease), background var(--transition-fast, 0.2s ease);
}
.page-about .commitment-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: var(--color-accent, #FF6B35);
  border-radius: 2px;
  transform: scaleY(0);
  transform-origin: top;
  transition: transform var(--transition-base, 0.35s ease);
}
.page-about .commitment-item:hover::before,
.page-about .commitment-item:focus-within::before {
  transform: scaleY(1);
}
.page-about .commitment-item:hover,
.page-about .commitment-item:focus-within {
  background: rgba(255, 255, 255, 0.12);
  border-left-color: var(--color-accent, #FF6B35);
}
.page-about .commitment-item__title {
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-size: 1.125rem;
  font-weight: 700;
  margin: 0 0 0.35rem;
  color: #fff;
}
.page-about .commitment-item__desc {
  font-size: 0.9rem;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.78);
  margin: 0;
}

/* ── 承诺 CTA ── */
.page-about .commitment-cta {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  align-items: center;
  max-width: 960px;
  margin: 0 auto;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}
.page-about .commitment-cta__visual {
  flex: 0 0 auto;
  max-width: 280px;
  width: 100%;
}
.page-about .commitment-cta__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: contain;
  border-radius: 12px;
}
.page-about .commitment-cta__content {
  flex: 1 1 55%;
  text-align: center;
}
.page-about .commitment-cta__content h3 {
  font-family: var(--font-heading, "Source Han Sans SC", sans-serif);
  font-size: 1.563rem;
  font-weight: 700;
  margin: 0 0 0.75rem;
  color: #fff;
}
.page-about .commitment-cta__content p {
  font-size: 1rem;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.78);
  margin-bottom: 1.5rem;
}
.page-about .commitment-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}
.page-about .commitment-cta .btn--primary {
  background: var(--color-accent, #FF6B35);
  color: #fff;
  border: none;
  padding: 0.65rem 1.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 4px;
  text-decoration: none;
  transition: background var(--transition-fast, 0.2s ease), transform var(--transition-fast, 0.2s ease);
}
.page-about .commitment-cta .btn--primary:hover,
.page-about .commitment-cta .btn--primary:focus-visible {
  background: #e85d2a;
  transform: translateY(-2px);
}
.page-about .commitment-cta .btn--secondary {
  background: transparent;
  color: #fff;
  border: 2px solid var(--color-accent-blue, #00B4D8);
  padding: 0.65rem 1.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 4px;
  text-decoration: none;
  transition: background var(--transition-fast, 0.2s ease), border-color var(--transition-fast, 0.2s ease), transform var(--transition-fast, 0.2s ease);
}
.page-about .commitment-cta .btn--secondary:hover,
.page-about .commitment-cta .btn--secondary:focus-visible {
  background: rgba(0, 180, 216, 0.15);
  border-color: var(--color-accent, #FF6B35);
  transform: translateY(-2px);
}

/* ── 桌面端（≥768px） ── */
@media (min-width: 768px) {
  .page-about .breadcrumb {
    padding-left: 2rem;
    padding-right: 2rem;
  }
  .page-about .hero {
    padding: 3rem 2rem 4rem;
  }
  .page-about .hero__inner {
    flex-direction: row;
    gap: 3rem;
  }
  .page-about .hero__content {
    order: 0;
  }
  .page-about .hero__visual {
    order: 1;
    max-width: 440px;
  }
  .page-about .hero h1 {
    font-size: 3.052rem;
  }
  .page-about .timeline-section {
    padding: 4rem 2rem 4.5rem;
  }
  .page-about .timeline {
    padding-left: 0;
  }
  .page-about .timeline::before {
    left: 50%;
    transform: translateX(-50%);
  }
  .page-about .timeline__item {
    padding-left: 0;
    width: 50%;
    margin-left: auto;
    margin-bottom: 2.5rem;
  }
  .page-about .timeline__item:nth-child(odd) {
    margin-left: 0;
    margin-right: auto;
    padding-right: 2.5rem;
  }
  .page-about .timeline__item:nth-child(even) {
    margin-left: auto;
    margin-right: 0;
    padding-left: 2.5rem;
  }
  .page-about .timeline__marker {
    left: auto;
    right: -9px;
    top: 12px;
  }
  .page-about .timeline__item:nth-child(odd) .timeline__marker {
    right: -9px;
    left: auto;
  }
  .page-about .timeline__item:nth-child(even) .timeline__marker {
    left: -9px;
    right: auto;
  }
  .page-about .compare-cards__grid {
    grid-template-columns: 1fr 1fr;
  }
  .page-about .commitment-section {
    padding: 4.5rem 2rem 5rem;
  }
  .page-about .commitment-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
  }
  .page-about .commitment-cta {
    flex-direction: row;
    text-align: left;
  }
  .page-about .commitment-cta__content {
    text-align: left;
  }
  .page-about .commitment-cta__actions {
    justify-content: flex-start;
  }
}

/* ── 大桌面端（≥1024px） ── */
@media (min-width: 1024px) {
  .page-about .hero {
    padding: 4rem 2rem 5rem;
  }
  .page-about .hero__visual {
    max-width: 520px;
  }
  .page-about .timeline-section {
    padding: 5rem 2rem 5.5rem;
  }
  .page-about .commitment-section {
    padding: 5.5rem 2rem 6rem;
  }
  .page-about .compare-card {
    height: 420px;
  }
  .page-about .compare-card__img {
    height: 210px;
  }
}

/* ── 可访问性：减少 motion ── */
@media (prefers-reduced-motion: reduce) {
  .page-about .compare-card__inner {
    transition: none;
  }
  .page-about .compare-card:hover .compare-card__inner,
  .page-about .compare-card:focus-within .compare-card__inner {
    transform: none;
  }
  .page-about .compare-card__face--new {
    transform: none;
  }
  .page-about .commitment-item::before {
    transition: none;
  }
  .page-about .commitment-item:hover::before {
    transform: scaleY(1);
  }
  .page-about .commitment-cta .btn--primary,
  .page-about .commitment-cta .btn--secondary,
  .page-about .hero .btn--primary {
    transition: none;
  }
  .page-about .commitment-item:hover {
    background: rgba(255, 255, 255, 0.12);
  }
}