.page-about {
  --ab-rail-w: 216px;
  --ab-col-gap: 48px;
}

/* ---------- 面包屑 ---------- */
.page-about .ab-crumb {
  padding-top: 20px;
}
.page-about .ab-crumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--wl-mono);
  font-size: 12px;
  color: var(--wl-ink-soft);
}
.page-about .ab-crumb__list li + li::before {
  content: "/";
  margin: 0 8px;
  color: var(--wl-rule);
}
.page-about .ab-crumb__list a {
  color: var(--wl-cyan-deep);
  text-decoration: none;
}
.page-about .ab-crumb__list a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 封面 ---------- */
.page-about .ab-cover {
  position: relative;
  margin-top: 16px;
  background: var(--wl-indigo);
  color: #fff;
  overflow: hidden;
  padding: clamp(40px, 7vw, 76px) 0 clamp(40px, 6vw, 68px);
}
.page-about .ab-cover::before {
  content: "";
  position: absolute;
  top: -70px;
  right: -70px;
  width: 300px;
  height: 300px;
  background: var(--wl-cyan);
  opacity: 0.18;
  clip-path: polygon(100% 0, 100% 100%, 0 0);
  pointer-events: none;
}
.page-about .ab-cover::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--wl-cyan) 0 24%, var(--wl-orange) 24% 31%, rgba(255, 255, 255, 0.12) 31% 100%);
}
.page-about .ab-cover__inner {
  position: relative;
  z-index: 1;
}
.page-about .ab-cover__eyebrow {
  font-family: var(--wl-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--wl-cyan);
  margin: 0 0 18px;
}
.page-about .ab-cover__title {
  font-family: var(--wl-serif);
  font-weight: 700;
  font-size: clamp(30px, 5.4vw, 52px);
  line-height: 1.24;
  letter-spacing: -0.01em;
  color: #fff;
  margin: 0 0 20px;
}
.page-about .ab-cover__lede {
  font-size: 16px;
  line-height: 1.95;
  color: rgba(255, 255, 255, 0.86);
  max-width: 38em;
  margin: 0;
}

/* ---------- 分屏骨架 ---------- */
.page-about .ab-rail {
  display: block;
  padding-top: clamp(36px, 5vw, 60px);
  padding-bottom: clamp(56px, 8vw, 96px);
}
.page-about .ab-rail__canvas {
  min-width: 0;
}

.page-about .ab-rail__track {
  list-style: none;
  margin: 0 0 30px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.page-about .ab-rail__item {
  position: relative;
}
.page-about .ab-rail__link {
  display: block;
  padding: 6px 11px;
  background: var(--wl-indigo-soft);
  color: var(--wl-ink-soft);
  font-size: 13px;
  line-height: 1.5;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease;
}
.page-about .ab-rail__link:hover {
  background: var(--wl-cyan-soft);
  color: var(--wl-cyan-deep);
}
.page-about .ab-rail__link.is-active {
  background: var(--wl-cyan-soft);
  color: var(--wl-cyan-deep);
  font-weight: 600;
}

/* ---------- 内容块 ---------- */
.page-about .ab-block {
  padding-block: clamp(32px, 5vw, 52px);
  border-top: 1px solid var(--wl-rule);
}
.page-about .ab-rail__canvas > .ab-block:first-child {
  border-top: 0;
  padding-top: 0;
}
.page-about .ab-block__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 20px;
}
.page-about .ab-block__num {
  flex: none;
  font-family: var(--wl-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--wl-cyan-deep);
}
.page-about .ab-block__title {
  font-family: var(--wl-sans);
  font-weight: 800;
  font-size: clamp(20px, 3.4vw, 28px);
  line-height: 1.35;
  letter-spacing: -0.01em;
  color: var(--wl-ink);
  margin: 0;
}

.page-about .ab-prose {
  max-width: 40em;
}
.page-about .ab-prose p {
  font-size: 16.5px;
  line-height: 1.9;
  color: var(--wl-ink);
  margin: 0 0 16px;
}
.page-about .ab-prose p:last-child {
  margin-bottom: 0;
}

.page-about .ab-note {
  margin: 18px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--wl-ink-soft);
  max-width: 46em;
}

/* ---------- 卡片网格 ---------- */
.page-about .ab-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: 26px;
}
.page-about .ab-card {
  position: relative;
  overflow: hidden;
  background: var(--wl-indigo-soft);
  padding: 22px 22px 24px;
}
.page-about .ab-card--outline {
  background: var(--wl-paper);
  border: 1px solid var(--wl-rule);
}
.page-about .ab-card::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 0;
  height: 0;
  border-top: 22px solid var(--wl-cyan);
  border-left: 22px solid transparent;
  opacity: 0.9;
}
.page-about .ab-card__figure {
  font-family: var(--wl-mono);
  font-size: 34px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--wl-indigo);
  margin: 0 0 12px;
}
.page-about .ab-card__title {
  font-family: var(--wl-sans);
  font-size: 17px;
  font-weight: 700;
  color: var(--wl-ink);
  margin: 0 0 8px;
}
.page-about .ab-card__text {
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--wl-ink-soft);
  margin: 0;
}

/* ---------- 数字墙 ---------- */
.page-about .ab-figures {
  position: relative;
  background: var(--wl-indigo);
  color: #fff;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  padding: clamp(30px, 4.5vw, 46px) clamp(22px, 4vw, 40px);
  margin-block: clamp(36px, 5vw, 56px);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}
.page-about .ab-figures__num {
  font-family: var(--wl-mono);
  font-size: clamp(42px, 6.5vw, 68px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
  color: #fff;
}
.page-about .ab-figures__unit {
  font-family: var(--wl-sans);
  font-size: 15px;
  color: var(--wl-cyan);
  margin-left: 8px;
}
.page-about .ab-figures__note {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.74);
  max-width: 22em;
}

/* ---------- 流程步骤 ---------- */
.page-about .ab-steps {
  list-style: none;
  counter-reset: abstep;
  display: grid;
  gap: 12px;
  margin: 26px 0 0;
  padding: 0;
}
.page-about .ab-steps__item {
  position: relative;
  background: var(--wl-paper);
  border: 1px solid var(--wl-rule);
  border-left: 3px solid var(--wl-cyan);
  padding: 20px 20px 20px 60px;
}
.page-about .ab-steps__item::before {
  counter-increment: abstep;
  content: counter(abstep, decimal-leading-zero);
  position: absolute;
  left: 18px;
  top: 22px;
  font-family: var(--wl-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--wl-cyan-deep);
}
.page-about .ab-steps__title {
  font-family: var(--wl-sans);
  font-size: 16.5px;
  font-weight: 700;
  color: var(--wl-ink);
  margin: 0 0 6px;
}
.page-about .ab-steps__text {
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--wl-ink-soft);
  margin: 0;
  max-width: 46em;
}

/* ---------- 阶段折叠 ---------- */
.page-about .ab-phases {
  margin-top: clamp(24px, 4vw, 34px);
  border-top: 1px solid var(--wl-rule);
}
.page-about .ab-phase {
  border-bottom: 1px solid var(--wl-rule);
}
.page-about .ab-phase__head {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--wl-sans);
  font-size: 16px;
  font-weight: 600;
  color: var(--wl-ink);
}
.page-about .ab-phase__head::-webkit-details-marker {
  display: none;
}
.page-about .ab-phase__head::after {
  content: "";
  flex: none;
  width: 9px;
  height: 9px;
  margin-left: auto;
  border-right: 2px solid var(--wl-cyan-deep);
  border-bottom: 2px solid var(--wl-cyan-deep);
  transform: rotate(45deg);
  transition: transform 0.26s ease;
}
.page-about .ab-phase[open] .ab-phase__head::after {
  transform: rotate(-135deg);
}
.page-about .ab-phase__tag {
  flex: none;
  font-family: var(--wl-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--wl-cyan-deep);
  background: var(--wl-cyan-soft);
  padding: 4px 9px;
}
.page-about .ab-phase__body {
  padding: 0 0 18px;
}
.page-about .ab-phase__body p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--wl-ink-soft);
  max-width: 46em;
}

/* ---------- 图片 ---------- */
.page-about .ab-figure {
  margin: clamp(24px, 4vw, 34px) 0 0;
}
.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--wl-rule);
  object-fit: cover;
}
.page-about .ab-figure--wide img {
  aspect-ratio: 16 / 9;
}
.page-about .ab-figure--photo img {
  aspect-ratio: 3 / 2;
}
.page-about .ab-figure__caption {
  margin-top: 10px;
  font-family: var(--wl-mono);
  font-size: 12px;
  line-height: 1.6;
  color: var(--wl-ink-soft);
}

/* ---------- 标签墙 ---------- */
.page-about .ab-tagwall {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: clamp(24px, 4vw, 34px) 0 0;
  padding: 0;
}
.page-about .ab-tagwall__item {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  background: var(--wl-cyan-soft);
  border: 1px solid transparent;
  color: var(--wl-cyan-deep);
  font-size: 13.5px;
  font-weight: 600;
  cursor: default;
  transition: border-color 0.2s ease, background-color 0.2s ease;
}
.page-about .ab-tagwall__item:hover {
  border-color: var(--wl-cyan);
  background: #fff;
}
.page-about .ab-tagwall__dot {
  flex: none;
  width: 6px;
  height: 6px;
  background: var(--wl-orange);
}
.page-about .ab-tagwall__tip {
  position: absolute;
  left: 50%;
  bottom: calc(100% + 8px);
  z-index: 4;
  width: max-content;
  max-width: 220px;
  padding: 7px 10px;
  background: var(--wl-indigo);
  color: #fff;
  font-size: 12px;
  font-weight: 400;
  line-height: 1.6;
  text-align: left;
  transform: translate(-50%, 4px);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s;
}
.page-about .ab-tagwall__item:hover .ab-tagwall__tip,
.page-about .ab-tagwall__item:focus-within .ab-tagwall__tip {
  opacity: 1;
  visibility: visible;
  transform: translate(-50%, 0);
}

/* ---------- 长期指标 ---------- */
.page-about .ab-record {
  margin-top: 22px;
  border-top: 1px solid var(--wl-rule);
}
.page-about .ab-record__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  align-items: baseline;
  padding: 20px 0;
  border-bottom: 1px solid var(--wl-rule);
}
.page-about .ab-record__num {
  font-family: var(--wl-mono);
  font-size: clamp(30px, 5vw, 44px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--wl-indigo);
}
.page-about .ab-record__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--wl-ink-soft);
  max-width: 44em;
}

/* ---------- 延伸阅读 ---------- */
.page-about .ab-next {
  margin-top: clamp(40px, 6vw, 64px);
  padding: clamp(24px, 3.5vw, 34px);
  background: var(--wl-indigo-soft);
  border-left: 4px solid var(--wl-cyan);
}
.page-about .ab-next__title {
  font-family: var(--wl-sans);
  font-size: 18px;
  font-weight: 700;
  color: var(--wl-ink);
  margin: 0 0 16px;
}
.page-about .ab-next__list {
  list-style: none;
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
}
.page-about .ab-next__list a {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  font-size: 15px;
  line-height: 1.7;
  color: var(--wl-ink);
  text-decoration: none;
  transition: color 0.2s ease;
}
.page-about .ab-next__list a::before {
  content: "\2192";
  flex: none;
  font-family: var(--wl-mono);
  color: var(--wl-cyan-deep);
}
.page-about .ab-next__list a:hover {
  color: var(--wl-cyan-deep);
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 760px) {
  .page-about .ab-grid--3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .ab-figures {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0;
  }
  .page-about .ab-figures__item {
    padding-inline: clamp(16px, 2.4vw, 28px);
  }
  .page-about .ab-figures__item:first-child {
    padding-left: 0;
  }
  .page-about .ab-figures__item:last-child {
    padding-right: 0;
  }
  .page-about .ab-figures__item + .ab-figures__item {
    border-left: 1px solid rgba(255, 255, 255, 0.2);
  }
  .page-about .ab-record__row {
    grid-template-columns: minmax(0, 170px) minmax(0, 1fr);
    gap: 26px;
  }
  .page-about .ab-next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px 28px;
  }
}

/* ---------- 桌面：非对称双栏 ---------- */
@media (min-width: 960px) {
  .page-about .ab-rail {
    display: grid;
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    column-gap: var(--ab-col-gap);
    align-items: start;
  }
  .page-about .ab-rail__track {
    position: sticky;
    top: 104px;
    display: block;
    margin: 0;
    padding: 0;
  }
  .page-about .ab-rail__item {
    padding: 14px 0 14px 24px;
  }
  .page-about .ab-rail__item::before {
    content: "";
    position: absolute;
    left: 0;
    top: 16px;
    width: 9px;
    height: 9px;
    box-sizing: content-box;
    border: 2px solid var(--wl-rule);
    border-radius: 50%;
    background: var(--wl-paper);
    transition: border-color 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;
  }
  .page-about .ab-rail__item::after {
    content: "";
    position: absolute;
    left: 6px;
    top: 34px;
    bottom: -16px;
    width: 1px;
    background: var(--wl-rule);
  }
  .page-about .ab-rail__item:last-child::after {
    display: none;
  }
  .page-about .ab-rail__link {
    display: inline;
    padding: 0;
    background: none;
    border-radius: 0;
    font-size: 13.5px;
    line-height: 1.55;
  }
  .page-about .ab-rail__link:hover {
    background: none;
    color: var(--wl-cyan-deep);
  }
  .page-about .ab-rail__link.is-active {
    background: none;
    color: var(--wl-ink);
    font-weight: 700;
  }
  .page-about .ab-rail__item.is-active::before,
  .page-about .ab-rail__item:has(.ab-rail__link.is-active)::before {
    border-color: var(--wl-cyan);
    background: var(--wl-cyan);
    box-shadow: 0 0 0 4px var(--wl-cyan-soft);
  }
  .page-about .ab-rail__canvas > .ab-block:first-child {
    padding-top: 0;
  }
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .ab-rail__link,
  .page-about .ab-rail__item::before,
  .page-about .ab-phase__head::after,
  .page-about .ab-tagwall__item,
  .page-about .ab-tagwall__tip,
  .page-about .ab-next__list a {
    transition: none;
  }
}
</main>