.page-about {
  --section-accent: var(--clr-orange);
  background: var(--clr-bg);
  color: var(--clr-text);
  font-family: var(--font-body);
  overflow-x: hidden;
  padding-bottom: var(--space-7);
}

/* 面包屑 */
.page-about .breadcrumb {
  max-width: var(--max-width);
  margin-inline: auto;
  padding: var(--space-4) 20px 0;
}
.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
}
.page-about .breadcrumb__link {
  color: var(--clr-text-secondary);
  font-size: 13px;
  text-decoration: none;
  transition: color 0.2s;
}
.page-about .breadcrumb__link:hover {
  color: var(--clr-orange);
}
.page-about .breadcrumb__sep {
  color: var(--clr-text-secondary);
  font-size: 13px;
}
.page-about .breadcrumb__current {
  color: var(--clr-orange);
  font-size: 13px;
  font-weight: 700;
}

/* Hero 首屏 */
.page-about__hero {
  max-width: var(--max-width);
  margin-inline: auto;
  padding: var(--space-5) 20px;
  background: repeating-linear-gradient(-45deg, rgba(255, 107, 53, 0.06) 0, rgba(255, 107, 53, 0.06) 4px, transparent 4px, transparent 16px);
  border-bottom: 4px solid var(--clr-bg-card);
}
.page-about__hero-title {
  font-family: var(--font-headline);
  font-size: clamp(1.875rem, 4.5vw, 3.4rem);
  line-height: 1.12;
  letter-spacing: -0.2px;
  margin: var(--space-3) 0;
}
.page-about__hero-lead {
  max-width: 72ch;
  color: var(--clr-text-secondary);
  font-size: 17px;
  line-height: 1.8;
  margin-bottom: var(--space-4);
}
.page-about__hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}
.page-about__hero-visual {
  margin-top: var(--space-5);
  overflow: hidden;
}
.page-about__hero-img {
  display: block;
  width: 100%;
  height: auto;
  border: 4px solid var(--clr-orange);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card-hover);
  transform: rotate(-1deg);
}

/* 档案夹布局与胶囊目录 */
.page-about__layout {
  max-width: var(--max-width);
  margin-inline: auto;
  padding: var(--space-6) 20px 0;
}
.page-about__toc {
  margin-bottom: var(--space-5);
}
.page-about__toc-list {
  display: flex;
  gap: 8px;
  list-style: none;
  margin: 0 calc(-1 * 20px);
  padding: 4px 20px 12px;
  overflow-x: auto;
  scrollbar-width: none;
}
.page-about__toc-list::-webkit-scrollbar {
  display: none;
}
.page-about__toc-link {
  display: block;
  white-space: nowrap;
  padding: 10px 18px;
  border: 2px solid transparent;
  border-radius: 999px;
  background: var(--clr-bg-card);
  color: var(--clr-text-secondary);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}
.page-about__toc-link:hover,
.page-about__toc-link:focus-visible {
  background: var(--clr-orange);
  color: var(--clr-bg);
}

/* 内容区 */
.page-about__content {
  min-width: 0;
}

/* 档案夹章节卡片 */
.page-about__section {
  --section-accent: var(--clr-orange);
  position: relative;
  background: linear-gradient(135deg, var(--clr-bg-card-2) 0%, var(--clr-bg-card) 100%);
  border: 4px solid #2c3540;
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  padding: var(--space-5) var(--space-4);
  margin-bottom: var(--space-5);
  scroll-margin-top: 120px;
}
.page-about__section--history {
  --section-accent: var(--clr-green);
}
.page-about__section--data {
  --section-accent: var(--clr-purple);
}
.page-about__section--team {
  --section-accent: var(--clr-green);
}
.page-about__section--partners {
  --section-accent: var(--clr-orange);
}
.page-about__section::before {
  content: "";
  position: absolute;
  left: 28px;
  top: -4px;
  width: 76px;
  height: 14px;
  background: var(--section-accent);
  border-radius: 0 0 10px 10px;
}
.page-about__section:target {
  border-color: var(--section-accent);
  box-shadow: 0 0 0 4px rgba(0, 255, 158, 0.06), var(--shadow-card);
}
.page-about__section-head {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}
.page-about__section-num {
  font-family: var(--font-headline);
  font-size: 2.5rem;
  line-height: 1;
  color: var(--section-accent);
  opacity: 0.3;
  margin-right: 2px;
}
.page-about__section-heading-wrap {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.page-about__section-title {
  font-family: var(--font-headline);
  font-size: 1.75rem;
  line-height: 1.15;
  margin: 0;
}
.page-about__section-body {
  line-height: 1.8;
}
.page-about__section-body > p:not(.page-about__data-note):not(.page-about__section-note):not(.page-about__partner-note) {
  margin: 0 0 var(--space-4);
  color: var(--clr-text-secondary);
}
.page-about__section-note {
  color: var(--clr-text-secondary);
  font-size: 14px;
  margin-bottom: var(--space-3) !important;
}

/* 我们是谁 */
.page-about__fact-list {
  display: grid;
  gap: 10px;
  list-style: none;
  margin: var(--space-4) 0 0;
  padding: 0;
}
.page-about__fact-list li {
  border-left: 4px solid var(--clr-orange);
  background: rgba(255, 107, 53, 0.08);
  padding: 12px 14px;
  font-size: 14px;
  font-weight: 700;
}

/* 发展历程时间线 */
.page-about__timeline {
  position: relative;
}
.page-about__timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 10px;
  width: 4px;
  background: linear-gradient(180deg, var(--clr-orange) 0%, var(--clr-green) 45%, var(--clr-purple) 100%);
  border-radius: 2px;
}
.page-about__milestone {
  position: relative;
  padding-left: 38px;
  padding-bottom: var(--space-3);
}
.page-about__milestone:last-child {
  padding-bottom: 0;
}
.page-about__milestone::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 26px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--clr-bg);
  border: 4px solid var(--clr-orange);
  box-shadow: 0 0 0 4px rgba(255, 107, 53, 0.12);
}
.page-about__milestone .accordion__heading {
  margin: 0;
}
.page-about__milestone-btn {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  width: 100%;
  padding: var(--space-3) 0;
  text-align: left;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--clr-text);
}
.page-about__milestone-btn .accordion__trigger-icon {
  margin-left: auto;
  color: var(--clr-green);
  flex-shrink: 0;
}
.page-about__milestone-btn:hover .page-about__milestone-label {
  color: var(--clr-green);
}
.page-about__milestone-year {
  font-family: var(--font-headline);
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  line-height: 0.9;
  color: var(--clr-orange);
  flex-shrink: 0;
}
.page-about__milestone-label {
  font-size: 1.05rem;
  font-weight: 800;
  line-height: 1.3;
  transition: color 0.2s;
}
.page-about__milestone-detail {
  border-left: 3px solid #3b4754;
  margin: 2px 0 8px;
  padding-left: var(--space-3);
}
.page-about__milestone-detail p {
  margin: 0;
  color: var(--clr-text-secondary);
  font-size: 14px;
  line-height: 1.7;
}

/* 数据规模与更新 */
.page-about__data-layout {
  display: grid;
  gap: var(--space-4);
}
.page-about__stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-3);
}
.page-about__stat-card {
  padding: var(--space-4) var(--space-3);
}
.page-about__stat-line {
  display: block;
  width: 36px;
  height: 4px;
  background: var(--clr-green);
  border-radius: 2px;
  margin-bottom: var(--space-3);
}
.page-about__stat-value {
  font-family: var(--font-headline);
  font-size: 2.2rem;
  line-height: 0.95;
  color: var(--clr-orange);
  margin: 0 0 8px;
}
.page-about__stat-unit {
  font-size: 1.1rem;
  color: var(--clr-text-secondary);
  margin-left: 3px;
}
.page-about__stat-label {
  font-weight: 800;
  margin: 0 0 4px;
}
.page-about__stat-desc {
  margin: 0;
  color: var(--clr-text-secondary);
  font-size: 13px;
  line-height: 1.5;
}
.page-about__data-visual {
  margin: 0;
}
.page-about__data-visual img {
  display: block;
  width: 100%;
  height: auto;
  border: 4px solid var(--clr-bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
}
.page-about__data-visual figcaption,
.page-about__team-visual figcaption {
  border-left: 4px solid var(--clr-green);
  color: var(--clr-text-secondary);
  font-size: 13px;
  margin-top: 10px;
  padding-left: 12px;
}
.page-about__data-note {
  background: rgba(255, 107, 53, 0.07);
  border: 2px dashed rgba(255, 107, 53, 0.35);
  border-radius: var(--radius);
  color: var(--clr-text);
  line-height: 1.8;
  margin: var(--space-4) 0 0;
  padding: var(--space-4);
}
.page-about__inline-link {
  color: var(--clr-green);
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.2s;
}
.page-about__inline-link:hover {
  color: var(--clr-orange);
}

/* 团队与资质 */
.page-about__team-layout {
  display: grid;
  gap: var(--space-4);
}
.page-about__team-copy > p {
  color: var(--clr-text-secondary);
  line-height: 1.8;
  margin: 0 0 var(--space-3);
}
.page-about__team-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.page-about__team-list li {
  position: relative;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  padding: 10px 0 10px 28px;
  color: var(--clr-text);
  font-size: 14px;
}
.page-about__team-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 14px;
  height: 4px;
  background: var(--clr-green);
  border-radius: 2px;
}
.page-about__team-visual {
  margin: 0;
}
.page-about__team-visual img {
  display: block;
  width: 100%;
  height: auto;
  border: 4px solid var(--clr-bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
}
.page-about__cert-grid {
  display: grid;
  gap: var(--space-3);
  margin-top: var(--space-5);
}
.page-about__cert-card {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
}
.page-about__cert-shield,
.page-about__cert-badge {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
}
.page-about__cert-card h3 {
  font-family: var(--font-headline);
  font-size: 1.1rem;
  margin: 0 0 4px;
}
.page-about__cert-card p {
  margin: 0;
  color: var(--clr-text-secondary);
  font-size: 13px;
}

/* 合作生态 */
.page-about__partner-grid {
  display: grid;
  gap: var(--space-3);
  margin-top: var(--space-4);
}
.page-about__partner-card {
  padding: var(--space-4);
  text-align: center;
}
.page-about__partner-num {
  display: block;
  font-family: var(--font-headline);
  font-size: 2.2rem;
  line-height: 1;
  color: var(--clr-orange);
  margin-bottom: 8px;
}
.page-about__partner-card h3 {
  font-size: 1rem;
  margin: 0 0 6px;
}
.page-about__partner-card p {
  margin: 0;
  color: var(--clr-text-secondary);
  font-size: 13px;
}
.page-about__partner-note {
  border-left: 4px solid var(--clr-green);
  color: var(--clr-text-secondary);
  margin: var(--space-4) 0 0;
  padding-left: var(--space-3);
}

/* 平板增强 */
@media (min-width: 700px) {
  .page-about__fact-list {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-about__cert-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-about__partner-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* 桌面布局 */
@media (min-width: 900px) {
  .page-about__hero {
    padding-top: var(--space-6);
    padding-bottom: var(--space-6);
  }
  .page-about__hero-visual {
    margin-top: var(--space-6);
  }
  .page-about__layout {
    display: grid;
    grid-template-columns: 240px minmax(0, 1fr);
    gap: 44px;
    align-items: start;
    padding-top: var(--space-6);
  }
  .page-about__toc {
    position: sticky;
    top: 120px;
    margin-bottom: 0;
  }
  .page-about__toc-list {
    flex-direction: column;
    gap: 8px;
    margin: 0;
    padding: 12px;
    overflow: visible;
    background: var(--clr-bg-card);
    border: 4px solid #2e3540;
    border-radius: 999px;
  }
  .page-about__toc-link {
    background: transparent;
    text-align: center;
  }
  .page-about__toc-link:hover,
  .page-about__toc-link:focus-visible {
    background: var(--clr-orange);
    color: var(--clr-bg);
  }
  .page-about__data-layout {
    grid-template-columns: 1.1fr 0.9fr;
    align-items: center;
  }
  .page-about__data-visual {
    margin: 0;
  }
  .page-about__team-layout {
    grid-template-columns: 1fr 0.9fr;
    align-items: start;
  }
  .page-about__stat-grid {
    grid-template-columns: repeat(4, 1fr);
  }
  .page-about__section {
    padding: var(--space-6);
  }
}