.page-about {
  --about-sidebar-width: 200px;
  --about-gap: 2.5rem;
  --about-section-spacing: 3.5rem;
  --about-card-min-height: 180px;
  --about-accent-color: #FF6B35;
  --about-secondary-color: #0A2540;
  --about-bg-alt: #F0F4F8;
  color: #1A1A1A;
  font-family: var(--font-body);
  line-height: 1.6;
}

.page-about .breadcrumb {
  margin-bottom: 1.5rem;
  padding-top: 1rem;
}

/* 布局 — 类似杂志专题页：左侧竖排标题，右侧内容区 */
.about-layout {
  display: flex;
  flex-direction: column;
  gap: var(--about-gap);
}

.about-sidebar {
  position: sticky;
  top: calc(var(--header-top-height) + var(--header-bottom-height) + 1rem);
  align-self: flex-start;
  width: 100%;
  padding: 1.25rem 0;
  border-bottom: 2px solid var(--about-accent-color);
}

.about-sidebar__title {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--about-secondary-color);
  margin: 0 0 0.25rem;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.about-sidebar__subtitle {
  font-size: 0.9rem;
  color: #7A8B99;
  margin: 0 0 1.25rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.about-sidebar__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
}

.about-sidebar__link {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  color: #5A6B7A;
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
  white-space: nowrap;
}

.about-sidebar__link:hover,
.about-sidebar__link:focus-visible {
  color: var(--about-accent-color);
  border-bottom-color: var(--about-accent-color);
}

.about-content {
  flex: 1;
  min-width: 0;
}

/* section 通用样式 */
.about-section {
  margin-bottom: var(--about-section-spacing);
  padding-bottom: var(--about-section-spacing);
  border-bottom: 1px solid #E0E6EC;
}

.about-section:last-of-type {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.about-section__heading,
.about-section__section-heading {
  font-family: var(--font-heading);
  font-size: 1.65rem;
  font-weight: 700;
  color: var(--about-secondary-color);
  margin: 0 0 1rem;
  line-height: 1.3;
  letter-spacing: -0.02em;
  position: relative;
  display: inline-block;
}

.about-section__heading::after {
  content: '';
  display: block;
  width: 48px;
  height: 4px;
  background: var(--about-accent-color);
  margin-top: 0.5rem;
  border-radius: 2px;
}

.about-section__desc {
  font-size: 1rem;
  color: #2A3A4A;
  margin: 0 0 1.25rem;
  max-width: 680px;
}

/* 使命部分图文混排 */
.about-section:first-of-type {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.about-figure {
  margin: 0;
  border-radius: 12px;
  overflow: hidden;
  background: #EAF0F5;
  box-shadow: 0 2px 8px rgba(10,37,64,0.08);
}

.about-figure__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.about-figure--mission {
  max-width: 300px;
  align-self: flex-start;
  flex-shrink: 0;
}

/* 核心功能网格 */
.about-features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.about-feature-card {
  background: #FFFFFF;
  border-radius: 16px;
  padding: 1.75rem 1.5rem 1.5rem;
  box-shadow: 0 2px 10px rgba(10,37,64,0.06);
  border: 1px solid #E8EDF2;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  display: flex;
  flex-direction: column;
  min-height: var(--about-card-min-height);
}

.about-feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(255,107,53,0.12);
}

.about-feature-card__icon {
  font-size: 2rem;
  display: block;
  margin-bottom: 0.75rem;
  line-height: 1;
}

.about-feature-card__title {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--about-secondary-color);
  margin: 0 0 0.5rem;
}

.about-feature-card__text {
  font-size: 0.95rem;
  color: #3A4A5A;
  margin: 0 0 1rem;
  flex: 1;
}

.about-feature-card__link {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--about-accent-color);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  transition: gap 0.2s ease;
}

.about-feature-card__link:hover,
.about-feature-card__link:focus-visible {
  gap: 0.5rem;
  text-decoration: underline;
}

/* 数据来源部分 */
.about-section--data .about-section__text {
  max-width: 100%;
}

.about-data-visual {
  margin-top: 1.5rem;
  border-radius: 12px;
  overflow: hidden;
  background: var(--about-bg-alt);
  max-width: 600px;
}

.about-data-visual__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.about-data-visual__note {
  font-size: 0.85rem;
  color: #6A7A8A;
  padding: 0.75rem 1rem;
  background: rgba(10,37,64,0.04);
  text-align: center;
  border-top: 1px solid #DCE2E8;
}

/* 联系我们卡片 */
.about-contact-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin: 1.5rem 0 2rem;
}

.about-contact-card {
  background: #FFFFFF;
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
  border: 1px solid #E8EDF2;
  border-left: 4px solid var(--about-accent-color);
  box-shadow: 0 1px 4px rgba(10,37,64,0.04);
  transition: box-shadow 0.2s ease;
}

.about-contact-card:hover {
  box-shadow: 0 4px 16px rgba(10,37,64,0.08);
}

.about-contact-card__label {
  display: block;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #7A8B99;
  margin-bottom: 0.25rem;
}

.about-contact-card__value {
  display: block;
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--about-secondary-color);
  margin-bottom: 0.25rem;
  word-break: break-word;
}

a.about-contact-card__value {
  text-decoration: none;
  transition: color 0.2s ease;
}

a.about-contact-card__value:hover {
  color: var(--about-accent-color);
  text-decoration: underline;
}

.about-contact-card__note {
  font-size: 0.85rem;
  color: #6A7A8A;
  margin: 0;
}

.about-figure--team {
  margin-top: 1.5rem;
  max-width: 800px;
}

/* ============================
   Media Query — 桌面端
   ============================ */
@media (min-width: 768px) {
  .about-layout {
    flex-direction: row;
    gap: 3rem;
  }

  .about-sidebar {
    width: var(--about-sidebar-width);
    min-width: var(--about-sidebar-width);
    padding: 1.5rem 0 0;
    border-bottom: none;
    border-right: 2px solid var(--about-accent-color);
    margin-right: 0;
  }

  .about-sidebar__nav {
    flex-direction: column;
    gap: 0.75rem;
  }

  .about-sidebar__link {
    white-space: normal;
    font-size: 1rem;
  }

  .about-section:first-of-type {
    flex-direction: row;
    align-items: flex-start;
    gap: 2rem;
  }

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

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

  .about-section__heading {
    font-size: 1.85rem;
  }

  .about-section__section-heading {
    font-size: 1.85rem;
  }
}

/* ============================
   Media Query — 超大桌面
   ============================ */
@media (min-width: 1024px) {
  .about-sidebar {
    width: 240px;
    min-width: 240px;
  }

  .about-section__heading {
    font-size: 2rem;
  }

  .about-section__section-heading {
    font-size: 2rem;
  }
}