.page-about {
  --about-rail: 96px;
  --about-gap: 44px;
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  padding-top: clamp(16px, 3vw, 30px);
  padding-bottom: clamp(36px, 6vw, 76px);
}

.page-about .about-hero__frame {
  margin-top: clamp(16px, 3vw, 28px);
  padding: clamp(26px, 4vw, 54px);
  background:
    radial-gradient(120% 90% at 88% 4%, var(--yd-ice-2) 0%, transparent 58%),
    radial-gradient(90% 80% at 4% 96%, var(--yd-pine-3) 0%, transparent 62%),
    var(--yd-white);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(28px, 4vw, 52px);
  grid-template-columns: 1fr;
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--yd-font-title);
  font-size: clamp(28px, 6.2vw, 44px);
  font-weight: 900;
  line-height: var(--yd-lh-title);
  letter-spacing: -.02em;
  color: var(--yd-pine);
}

.page-about .about-hero__intro {
  margin: 18px 0 0;
  max-width: 46ch;
  font-size: var(--yd-fs-base);
  line-height: var(--yd-lh-body);
  color: var(--yd-ink);
}

.page-about .about-hero__intro--soft {
  margin-top: 12px;
  color: var(--yd-muted);
  font-size: 16px;
}

.page-about .about-hero__actions {
  margin-top: clamp(22px, 3vw, 32px);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 22px;
}

.page-about .about-hero__textlink {
  font-size: 15px;
  font-weight: 700;
  color: var(--yd-pine-2);
  text-decoration: underline;
  text-underline-offset: 5px;
  text-decoration-thickness: 2px;
  text-decoration-color: var(--yd-pine-3);
  transition: color var(--yd-t), text-decoration-color var(--yd-t);
}

.page-about .about-hero__textlink:hover {
  color: var(--yd-orange);
  text-decoration-color: var(--yd-orange-2);
}

.page-about .about-hero__facts {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .about-hero__fact {
  padding: 16px 18px;
  border-radius: var(--yd-radius-card);
  background: var(--yd-snow);
  border: 1px solid var(--yd-line-soft);
}

.page-about .about-hero__fact dt {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--yd-ice);
}

.page-about .about-hero__fact dd {
  margin: 8px 0 0;
  font-family: var(--yd-font-title);
  font-size: clamp(18px, 3.4vw, 22px);
  font-weight: 900;
  line-height: 1.25;
  color: var(--yd-pine);
}

/* ============ 章节头 ============ */
.page-about .about-head {
  max-width: 62ch;
  margin-bottom: clamp(30px, 4.5vw, 56px);
}

.page-about .about-head h2 {
  margin: 12px 0 0;
  font-family: var(--yd-font-title);
  font-size: clamp(23px, 4.6vw, 33px);
  font-weight: 900;
  line-height: var(--yd-lh-title);
  letter-spacing: -.015em;
  color: var(--yd-pine);
}

.page-about .about-head__sub {
  margin: 14px 0 0;
  font-size: 16px;
  line-height: var(--yd-lh-body);
  color: var(--yd-muted);
}

/* ============ 时间轴 ============ */
.page-about .about-path {
  background: linear-gradient(180deg, var(--yd-snow) 0%, var(--yd-white) 100%);
}

.page-about .about-tl {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .about-tl__item {
  position: relative;
  margin-bottom: clamp(34px, 5vw, 68px);
}

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

.page-about .about-tl__year {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 12px;
}

.page-about .about-tl__num {
  font-family: var(--yd-font-title);
  font-size: 30px;
  font-weight: 900;
  letter-spacing: -.03em;
  color: var(--yd-pine);
  line-height: 1;
}

.page-about .about-tl__tag {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--yd-ice);
}

.page-about .about-tl__body {
  min-width: 0;
}

.page-about .about-tl__body h3 {
  margin: 0 0 12px;
  font-family: var(--yd-font-title);
  font-size: clamp(18px, 3.3vw, 22px);
  font-weight: 800;
  line-height: 1.4;
  color: var(--yd-pine);
}

.page-about .about-tl__body p {
  margin: 0;
  font-size: var(--yd-fs-base);
  line-height: var(--yd-lh-body);
  color: var(--yd-ink);
}

.page-about .about-tl__figure {
  margin: clamp(18px, 2.6vw, 26px) 0 0;
}

/* ============ 覆盖 ============ */
.page-about .about-reach__grid {
  display: grid;
  gap: clamp(30px, 4.5vw, 56px);
  grid-template-columns: 1fr;
  align-items: start;
}

.page-about .about-reach__text p {
  margin: 0 0 16px;
  font-size: var(--yd-fs-base);
  line-height: var(--yd-lh-body);
  color: var(--yd-ink);
}

.page-about .about-reach__cities {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-reach__cities .yd-tag {
  font-size: 14px;
}

.page-about .about-reach__map {
  padding: clamp(16px, 2.6vw, 28px);
  border-radius: var(--yd-radius-lg);
  background:
    radial-gradient(80% 70% at 20% 15%, var(--yd-ice-2) 0%, transparent 62%),
    var(--yd-snow);
  border: 1px solid var(--yd-line-soft);
}

.page-about .about-map__svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-map__land {
  fill: var(--yd-pine-3);
  fill-opacity: .72;
  stroke: var(--yd-pine-2);
  stroke-width: 1.6;
  stroke-dasharray: 7 6;
}

.page-about .about-map__pin circle {
  fill: var(--yd-pine-2);
  stroke: var(--yd-white);
  stroke-width: 3;
  transform-box: fill-box;
  transform-origin: center;
  transition: fill var(--yd-t), transform var(--yd-t);
}

.page-about .about-map__pin--hub circle {
  fill: var(--yd-ice);
}

.page-about .about-map__pin:hover circle,
.page-about .about-map__pin:focus-within circle {
  fill: var(--yd-orange);
  transform: scale(1.25);
}

.page-about .about-map__label {
  font-family: var(--yd-font-title);
  font-size: 15px;
  font-weight: 800;
  fill: var(--yd-pine);
  text-anchor: middle;
  opacity: 0;
  paint-order: stroke;
  stroke: var(--yd-snow);
  stroke-width: 5;
  stroke-linejoin: round;
  transition: opacity var(--yd-t);
  pointer-events: none;
}

.page-about .about-map__pin:hover .about-map__label,
.page-about .about-map__pin:focus-within .about-map__label {
  opacity: 1;
}

.page-about .about-map__hint {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--yd-muted);
}

.page-about .about-reach__figure {
  margin: clamp(34px, 5vw, 60px) 0 0;
  max-width: 720px;
}

/* ============ 培训与质检 ============ */
.page-about .about-quality {
  background: linear-gradient(180deg, var(--yd-white) 0%, var(--yd-snow) 100%);
}

.page-about .about-quality__grid {
  display: grid;
  gap: clamp(30px, 4.5vw, 56px);
  grid-template-columns: 1fr;
  align-items: start;
}

.page-about .about-quality__intro h2 {
  margin: 12px 0 0;
  font-family: var(--yd-font-title);
  font-size: clamp(23px, 4.6vw, 32px);
  font-weight: 900;
  line-height: var(--yd-lh-title);
  letter-spacing: -.015em;
  color: var(--yd-pine);
}

.page-about .about-quality__intro p {
  margin: 16px 0 0;
  font-size: var(--yd-fs-base);
  line-height: var(--yd-lh-body);
  color: var(--yd-ink);
}

.page-about .about-quality__figure {
  margin: clamp(24px, 3.4vw, 34px) 0 0;
}

.page-about .about-quality__facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 14px;
}

.page-about .about-stat {
  padding: 20px 20px 22px;
  border-radius: var(--yd-radius-card);
  background: var(--yd-white);
  border: 1px solid var(--yd-line-soft);
  box-shadow: var(--yd-shadow-1);
}

.page-about .about-stat__figure {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 5px;
}

.page-about .about-stat__num {
  font-family: var(--yd-font-title);
  font-size: clamp(34px, 6vw, 48px);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -.035em;
  color: var(--yd-pine);
}

.page-about .about-stat__unit {
  font-family: var(--yd-font-title);
  font-size: 15px;
  font-weight: 700;
  color: var(--yd-ice);
}

.page-about .about-stat__note {
  margin: 12px 0 0;
  font-size: 14.5px;
  line-height: var(--yd-lh-card);
  color: var(--yd-muted);
}

/* ============ 协作 ============ */
.page-about .about-partners__grid {
  align-items: start;
}

.page-about .about-partner {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about .about-partner .yd-tag {
  align-self: flex-start;
  font-size: 13px;
}

.page-about .about-partner h3 {
  margin: 0;
  font-family: var(--yd-font-title);
  font-size: 19px;
  font-weight: 800;
  line-height: 1.45;
  color: var(--yd-pine);
}

.page-about .about-partner p {
  margin: 0;
  font-size: 16px;
  line-height: var(--yd-lh-body);
  color: var(--yd-ink);
}

/* ============ 长期投入 ============ */
.page-about .about-long {
  background: linear-gradient(180deg, var(--yd-snow) 0%, var(--yd-white) 100%);
}

.page-about .about-long__grid {
  display: grid;
  gap: clamp(22px, 3.4vw, 36px);
  grid-template-columns: 1fr;
  align-items: start;
}

.page-about .about-long__item h3 {
  margin: 0 0 14px;
  font-family: var(--yd-font-title);
  font-size: clamp(19px, 3.4vw, 23px);
  font-weight: 900;
  line-height: 1.4;
  color: var(--yd-pine);
}

.page-about .about-long__item p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: var(--yd-lh-body);
  color: var(--yd-ink);
}

.page-about .about-long__link {
  display: inline-block;
  margin-top: 4px;
  font-size: 15px;
  font-weight: 800;
  color: var(--yd-orange);
  text-decoration: underline;
  text-underline-offset: 5px;
  text-decoration-thickness: 2px;
  text-decoration-color: var(--yd-orange-2);
  transition: color var(--yd-t), text-decoration-color var(--yd-t);
}

.page-about .about-long__link:hover {
  color: var(--yd-orange-deep);
  text-decoration-color: var(--yd-orange);
}

.page-about .about-long__item--repeat {
  background: var(--yd-white);
  border: 1px solid var(--yd-line);
}

/* ============ 收尾入口 ============ */
.page-about .about-cta__panel {
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
  grid-template-columns: 1fr;
  align-items: center;
}

.page-about .about-cta__text h2 {
  margin: 0;
  font-family: var(--yd-font-title);
  font-size: clamp(22px, 4.4vw, 30px);
  font-weight: 900;
  line-height: var(--yd-lh-title);
  color: var(--yd-snow);
}

.page-about .about-cta__text p {
  margin: 14px 0 0;
  max-width: 46ch;
  font-size: 16px;
  line-height: var(--yd-lh-body);
  color: var(--yd-on-dark);
}

.page-about .about-cta__action {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: flex-start;
}

.page-about .about-cta__note {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--yd-on-dark-soft);
}

/* ============ 返回顶部 ============ */
.page-about .about-top {
  position: fixed;
  right: clamp(14px, 3vw, 28px);
  bottom: clamp(14px, 3vw, 28px);
  z-index: 40;
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--yd-pine);
  color: var(--yd-snow);
  font-size: 19px;
  line-height: 1;
  text-decoration: none;
  box-shadow: var(--yd-shadow-2);
  transition: background var(--yd-t), transform var(--yd-t);
}

.page-about .about-top:hover {
  background: var(--yd-orange);
  transform: translateY(-2px);
}

/* ============ 响应式 ============ */
@media (min-width: 700px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-hero__facts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-reach__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  }

  .page-about .about-quality__grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  }

  .page-about .about-long__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-long__item--care {
    margin-top: 0;
  }

  .page-about .about-long__item--repeat {
    margin-top: 48px;
  }

  .page-about .about-cta__panel {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
  }

  .page-about .about-cta__action {
    align-items: flex-end;
    text-align: right;
  }
}

@media (min-width: 860px) {
  .page-about .about-tl {
    padding-left: 140px;
  }

  .page-about .about-tl::before {
    content: "";
    position: absolute;
    left: var(--about-rail);
    top: 16px;
    bottom: 16px;
    width: 1px;
    background: linear-gradient(180deg, var(--yd-line), var(--yd-line-soft) 78%, transparent);
  }

  .page-about .about-tl__item::before {
    content: "";
    position: absolute;
    left: calc(var(--about-rail) - 6px);
    top: 14px;
    width: 13px;
    height: 13px;
    border-radius: 50%;
    background: var(--yd-white);
    border: 3px solid var(--yd-pine-2);
    z-index: 1;
  }

  .page-about .about-tl__item:nth-child(2)::before {
    border-color: var(--yd-ice);
  }

  .page-about .about-tl__item:nth-child(4)::before {
    border-color: var(--yd-orange);
  }

  .page-about .about-tl__year {
    position: absolute;
    left: 0;
    top: 8px;
    width: var(--about-rail);
    display: block;
    text-align: right;
    margin-bottom: 0;
  }

  .page-about .about-tl__num {
    display: block;
    font-size: 34px;
  }

  .page-about .about-tl__tag {
    display: block;
    margin-top: 8px;
  }

  .page-about .about-tl__item:nth-child(1) .about-tl__body {
    width: 100%;
  }

  .page-about .about-tl__item:nth-child(2) .about-tl__body {
    width: 90%;
    margin-left: 10%;
  }

  .page-about .about-tl__item:nth-child(3) .about-tl__body {
    width: 86%;
  }

  .page-about .about-tl__item:nth-child(4) .about-tl__body {
    width: 93%;
    margin-left: 6%;
  }
}

@media (max-width: 699px) {
  .page-about .about-reach__figure {
    max-width: 100%;
  }

  .page-about .about-cta__action .yd-btn {
    width: 100%;
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-map__pin circle,
  .page-about .about-map__label,
  .page-about .about-top,
  .page-about .about-hero__textlink,
  .page-about .about-long__link {
    transition-duration: 1ms;
  }
}