.page-about {
  --about-grid-line: rgba(10, 37, 64, 0.06);
  --about-grid-size: 24px;
  --about-orange-deep: #E55E00;
  --about-card-border: rgba(10, 37, 64, 0.08);
  --about-offset: 0;
}

/* 面包屑 */
.page-about__breadcrumb {
  padding: 16px var(--blue-gutter) 0;
  font-family: var(--blue-mono);
  font-size: 12px;
  color: var(--blue-gray);
  letter-spacing: 0.04em;
}

.page-about__breadcrumb a {
  color: var(--blue-deep);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--blue-transition), border-color var(--blue-transition);
}

.page-about__breadcrumb a:hover {
  color: var(--blue-orange);
  border-bottom-color: var(--blue-orange);
}

.page-about__breadcrumb-sep {
  margin: 0 8px;
  color: var(--blue-gray);
}

.page-about__breadcrumb-current {
  color: var(--blue-orange);
  font-weight: 500;
}

/* 首屏 */
.page-about__hero {
  position: relative;
  padding: 48px 0 56px;
  background-image:
    linear-gradient(var(--about-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--about-grid-line) 1px, transparent 1px);
  background-size: var(--about-grid-size) var(--about-grid-size);
  overflow: hidden;
}

.page-about__hero::before {
  content: '';
  position: absolute;
  top: -80px;
  right: -80px;
  width: 320px;
  height: 320px;
  background: var(--blue-gradient);
  opacity: 0.08;
  filter: blur(60px);
  border-radius: 50%;
  pointer-events: none;
}

.page-about__hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  position: relative;
  z-index: 1;
}

.page-about__hero-copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.page-about__hero-tag {
  color: var(--blue-orange);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.page-about__hero-title {
  font-family: var(--blue-font-display);
  font-size: clamp(30px, 5vw, 56px);
  line-height: 1.08;
  color: var(--blue-deep);
  margin: 16px 0 20px;
  text-transform: uppercase;
  letter-spacing: 0.01em;
  transform: skewX(-4deg);
}

.page-about__hero-sep {
  color: var(--blue-orange);
  margin: 0 4px;
}

.page-about__hero-lead {
  font-family: var(--blue-font-body);
  font-size: 16px;
  line-height: 1.7;
  color: var(--blue-ink);
  max-width: 520px;
  margin-bottom: 28px;
}

.page-about__hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 36px;
}

.page-about__hero-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  width: 100%;
  max-width: 520px;
}

.page-about__hero-stat {
  background: var(--blue-white);
  border: 1px solid var(--about-card-border);
  border-radius: var(--blue-radius-sm);
  padding: 14px 12px;
  text-align: center;
  box-shadow: 0 2px 8px rgba(10, 37, 64, 0.04);
}

.page-about__stat-num {
  display: block;
  font-family: var(--blue-mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--blue-orange);
  line-height: 1.2;
}

.page-about__stat-label {
  display: block;
  font-family: var(--blue-font-body);
  font-size: 12px;
  color: var(--blue-gray);
  margin-top: 4px;
}

.page-about__hero-visual {
  position: relative;
  border-radius: var(--blue-radius);
  overflow: hidden;
  box-shadow: var(--blue-shadow);
  max-width: 600px;
  width: 100%;
  aspect-ratio: 3 / 4;
  margin: 0 auto;
}

.page-about__hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.page-about__hero-coord {
  position: absolute;
  bottom: 12px;
  left: 12px;
  font-family: var(--blue-mono);
  font-size: 11px;
  color: var(--blue-white);
  background: rgba(10, 37, 64, 0.72);
  padding: 4px 10px;
  border-radius: 4px;
  letter-spacing: 0.08em;
}

.page-about__hero-arch {
  position: absolute;
  top: 12px;
  right: 20px;
  font-family: var(--blue-font-display);
  font-size: 120px;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px rgba(10, 37, 64, 0.12);
  pointer-events: none;
  z-index: 0;
  display: none;
}

/* 主体布局 */
.page-about__body {
  padding-top: 16px;
  padding-bottom: 64px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

/* 目录索引 */
.page-about__toc {
  display: flex;
  flex-direction: row;
  overflow-x: auto;
  gap: 8px;
  padding: 12px 16px;
  background: var(--blue-white);
  border: 1px solid var(--about-card-border);
  border-radius: var(--blue-radius-sm);
  -webkit-overflow-scrolling: touch;
  scroll-snap-type: x proximity;
}

.page-about__toc-label {
  flex-shrink: 0;
  color: var(--blue-gray);
  font-size: 12px;
  letter-spacing: 0.1em;
  margin-bottom: 0;
  padding-right: 4px;
}

.page-about__toc-link {
  flex-shrink: 0;
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-family: var(--blue-font-body);
  font-size: 14px;
  color: var(--blue-deep);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid rgba(10, 37, 64, 0.06);
  white-space: nowrap;
  transition: background var(--blue-transition), color var(--blue-transition), border-color var(--blue-transition);
}

.page-about__toc-link:hover,
.page-about__toc-link:focus-visible {
  background: rgba(255, 107, 0, 0.08);
  color: var(--blue-orange);
  border-color: rgba(255, 107, 0, 0.25);
  outline: none;
}

.page-about__toc-num {
  font-family: var(--blue-mono);
  font-size: 12px;
  color: var(--blue-deep);
  font-weight: 700;
}

.page-about__toc-link:hover .page-about__toc-num {
  color: var(--blue-orange);
}

/* 内容区 */
.page-about__content {
  display: flex;
  flex-direction: column;
  gap: 56px;
}

/* 章节通用 */
.page-about__section {
  position: relative;
  padding-top: 12px;
  padding-left: 14px;
}

.page-about__section::before {
  content: '';
  position: absolute;
  top: 12px;
  left: 0;
  width: 3px;
  height: 28px;
  background: var(--blue-orange);
  border-radius: 2px;
}

.page-about__section-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
}

.page-about__section-num {
  font-family: var(--blue-font-display);
  font-size: 48px;
  line-height: 1;
  color: var(--blue-orange);
  min-width: 56px;
  opacity: 0.9;
  transform: skewX(-6deg);
}

.page-about__section-title {
  font-family: var(--blue-font-display);
  font-size: 28px;
  line-height: 1.2;
  color: var(--blue-deep);
  margin: 4px 0 0;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  transform: skewX(-3deg);
}

.page-about__section-lead {
  font-family: var(--blue-font-body);
  font-size: 15px;
  line-height: 1.7;
  color: var(--blue-gray);
  margin: 0 0 24px;
  max-width: 640px;
}

/* 品牌宣言 */
.page-about__declaration-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.page-about__declaration-quote {
  margin: 0;
  padding: 24px;
  background: var(--blue-deep);
  border-radius: var(--blue-radius);
  border-left: 6px solid var(--blue-orange);
  position: relative;
  overflow: hidden;
}

.page-about__declaration-quote::after {
  content: '';
  position: absolute;
  right: -20px;
  bottom: -20px;
  width: 100px;
  height: 100px;
  background: var(--blue-neon);
  opacity: 0.16;
  border-radius: 50%;
}

.page-about__declaration-quote p {
  font-family: var(--blue-font-display);
  font-size: 24px;
  line-height: 1.4;
  color: var(--blue-white);
  margin: 0;
  position: relative;
  z-index: 1;
}

.page-about__declaration-copy {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.page-about__declaration-copy p {
  font-family: var(--blue-font-body);
  font-size: 15px;
  line-height: 1.7;
  color: var(--blue-ink);
  margin: 0;
}

.page-about__declaration-foot {
  font-family: var(--blue-mono);
  font-size: 13px;
  color: var(--blue-gray);
}

.page-about__declaration-foot a,
.page-about__team-contact a {
  color: var(--blue-orange);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 107, 0, 0.3);
  transition: border-color var(--blue-transition);
}

.page-about__declaration-foot a:hover,
.page-about__team-contact a:hover {
  border-bottom-color: var(--blue-orange);
}

/* 数据理念流程图 */
.page-about__flow {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 32px;
}

.page-about__flow-node {
  background: var(--blue-white);
  border: 1px solid var(--about-card-border);
  border-radius: var(--blue-radius-sm);
  padding: 16px 20px;
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 8px 12px;
  align-items: start;
  transition: box-shadow var(--blue-transition), transform var(--blue-transition);
}

.page-about__flow-node:hover {
  box-shadow: var(--blue-shadow);
  transform: translateY(-2px);
}

.page-about__flow-num {
  grid-row: 1 / span 2;
  font-family: var(--blue-font-display);
  font-size: 26px;
  color: var(--blue-orange);
  line-height: 1;
}

.page-about__flow-node strong {
  font-family: var(--blue-font-body);
  font-size: 16px;
  color: var(--blue-deep);
}

.page-about__flow-node p {
  grid-column: 2;
  font-size: 13px;
  line-height: 1.5;
  color: var(--blue-gray);
  margin: 0;
}

.page-about__flow-arrow {
  text-align: center;
  color: var(--blue-neon);
  font-family: var(--blue-mono);
  font-size: 18px;
  font-weight: 700;
  line-height: 1;
}

/* 数据理念指标 */
.page-about__philosophy-metrics {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 20px;
}

.page-about__metric {
  background: linear-gradient(135deg, rgba(255, 107, 0, 0.06) 0%, rgba(10, 37, 64, 0.04) 100%);
  border: 1px solid rgba(255, 107, 0, 0.15);
  border-radius: var(--blue-radius-sm);
  padding: 16px;
}

.page-about__metric-num {
  display: block;
  font-family: var(--blue-mono);
  font-size: 24px;
  font-weight: 700;
  color: var(--blue-deep);
  line-height: 1.2;
}

.page-about__metric-label {
  display: block;
  font-size: 13px;
  color: var(--blue-gray);
  margin-top: 4px;
}

.page-about__philosophy-note {
  font-size: 14px;
  line-height: 1.6;
  color: var(--blue-gray);
  background: rgba(0, 229, 160, 0.08);
  border-left: 4px solid var(--blue-neon);
  padding: 12px 16px;
  border-radius: 0 var(--blue-radius-sm) var(--blue-radius-sm) 0;
}

/* 发展里程碑时间线 */
.page-about__timeline {
  position: relative;
  padding-left: 0;
  margin-bottom: 24px;
}

.page-about__timeline::before {
  content: '';
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--blue-orange) 0%, var(--blue-deep) 60%, var(--blue-neon) 100%);
  border-radius: 2px;
  opacity: 0.7;
}

.page-about__milestone {
  position: relative;
  margin-bottom: 24px;
  padding-left: 40px;
}

.page-about__milestone:last-child {
  margin-bottom: 0;
}

.page-about__milestone-marker {
  position: absolute;
  left: -5px;
  top: 16px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--blue-white);
  border: 3px solid var(--blue-orange);
  box-shadow: 0 0 0 4px rgba(255, 107, 0, 0.12);
}

.page-about__milestone-card {
  background: var(--blue-white);
  border: 1px solid var(--about-card-border);
  border-radius: var(--blue-radius-sm);
  padding: 20px 20px 24px;
  box-shadow: 0 2px 12px rgba(10, 37, 64, 0.04);
  transition: transform var(--blue-transition), box-shadow var(--blue-transition);
}

.page-about__milestone-card:hover {
  transform: translateX(4px);
  box-shadow: var(--blue-shadow);
}

.page-about__milestone-version {
  display: inline-block;
  font-family: var(--blue-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--blue-white);
  background: var(--blue-deep);
  padding: 3px 10px;
  border-radius: 4px;
  margin-bottom: 10px;
  letter-spacing: 0.06em;
}

.page-about__milestone-year {
  display: inline-block;
  font-family: var(--blue-mono);
  font-size: 13px;
  color: var(--blue-gray);
  margin-left: 8px;
}

.page-about__milestone-card h3 {
  font-family: var(--blue-font-body);
  font-size: 17px;
  font-weight: 700;
  color: var(--blue-deep);
  margin: 0 0 8px;
}

.page-about__milestone-card p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--blue-gray);
  margin: 0;
}

.page-about__milestone-img {
  width: 100%;
  height: auto;
  max-width: 400px;
  border-radius: var(--blue-radius);
  margin: 24px 0 12px;
  display: block;
}

.page-about__milestone-note {
  font-family: var(--blue-mono);
  font-size: 12px;
  color: var(--blue-gray);
  margin: 0 0 8px;
}

/* 团队构成 */
.page-about__team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.page-about__team-copy {
  display: flex;
  flex-direction: column;
}

.page-about__team-roles {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about__team-roles li {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--blue-ink);
  padding: 12px 16px;
  background: var(--blue-white);
  border: 1px solid var(--about-card-border);
  border-radius: var(--blue-radius-sm);
}

.page-about__role-tag {
  flex-shrink: 0;
  font-family: var(--blue-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--blue-white);
  background: var(--blue-orange);
  padding: 3px 8px;
  border-radius: 4px;
  margin-top: 2px;
}

.page-about__team-roles li:nth-child(even) .page-about__role-tag {
  background: var(--blue-deep);
}

.page-about__team-contact {
  font-size: 14px;
  line-height: 1.6;
  color: var(--blue-gray);
  margin: 0;
}

.page-about__team-img {
  width: 100%;
  height: auto;
  border-radius: var(--blue-radius);
  box-shadow: var(--blue-shadow);
  display: block;
  object-fit: cover;
}

/* 键盘焦点 */
.page-about__toc-link:focus-visible,
.page-about__breadcrumb a:focus-visible,
.page-about__declaration-foot a:focus-visible,
.page-about__team-contact a:focus-visible {
  outline: 2px solid var(--blue-orange);
  outline-offset: 2px;
}

/* ===== 平板及桌面 ===== */
@media (min-width: 768px) {
  .page-about__hero-stats {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about__philosophy-metrics {
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
  }

  .page-about__declaration-grid {
    grid-template-columns: 0.8fr 1.2fr;
    gap: 32px;
  }
}

@media (min-width: 960px) {
  .page-about__hero {
    padding: 64px 0 72px;
  }

  .page-about__hero-arch {
    display: block;
    font-size: 160px;
    top: 40px;
    right: 40px;
  }

  .page-about__hero-grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: 48px;
    align-items: center;
  }

  .page-about__hero-title {
    font-size: clamp(40px, 4.4vw, 58px);
  }

  .page-about__hero-visual {
    max-height: 640px;
    margin: 0;
  }

  .page-about__body {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 48px;
    align-items: start;
    padding-top: 24px;
  }

  .page-about__toc {
    flex-direction: column;
    overflow: visible;
    gap: 4px;
    padding: 16px;
    position: sticky;
    top: calc(var(--blue-nav-h) + 24px);
  }

  .page-about__toc-label {
    margin-bottom: 8px;
    padding-right: 0;
  }

  .page-about__toc-link {
    justify-content: flex-start;
    white-space: normal;
    border: none;
    border-bottom: 1px solid rgba(10, 37, 64, 0.06);
    padding: 8px 4px;
    border-radius: 4px;
    font-size: 15px;
  }

  .page-about__toc-link:last-child {
    border-bottom: none;
  }

  .page-about__toc-link:hover,
  .page-about__toc-link:focus-visible {
    padding-left: 12px;
  }

  .page-about__content {
    gap: 72px;
  }

  .page-about__section {
    padding-left: 20px;
  }

  .page-about__section::before {
    width: 4px;
    height: 36px;
  }

  .page-about__section-num {
    font-size: 56px;
    min-width: 68px;
  }

  .page-about__section-title {
    font-size: 32px;
  }

  .page-about__section-lead {
    font-size: 16px;
  }

  .page-about__flow {
    display: grid;
    grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr;
    align-items: stretch;
    gap: 8px;
    margin-bottom: 32px;
  }

  .page-about__flow-arrow {
    display: flex;
    align-items: center;
    font-size: 20px;
    padding: 0 4px;
  }

  .page-about__flow-node {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .page-about__flow-num {
    grid-row: auto;
  }

  .page-about__flow-node p {
    grid-column: 1;
  }

  .page-about__timeline {
    padding-left: 0;
  }

  .page-about__timeline::before {
    left: 12px;
    transform: rotate(5deg);
    transform-origin: top left;
  }

  .page-about__milestone {
    padding-left: 40px;
  }

  .page-about__milestone:nth-child(1) {
    margin-left: 0;
  }

  .page-about__milestone:nth-child(2) {
    margin-left: 32px;
  }

  .page-about__milestone:nth-child(3) {
    margin-left: 64px;
  }

  .page-about__milestone:nth-child(4) {
    margin-left: 96px;
  }

  .page-about__milestone:nth-child(5) {
    margin-left: 128px;
  }

  .page-about__milestone-marker {
    left: -5px;
  }

  .page-about__milestone-card:hover {
    transform: translateY(-4px);
  }

  .page-about__team-grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
  }

  .page-about__team-img {
    max-height: 500px;
  }
}