.page-about {
  --about-rail: 212px;
  --about-gap: clamp(28px, 4vw, 64px);
  --about-line: rgba(29, 46, 77, .85);
  --about-soft: rgba(159, 180, 208, .18);
  padding-top: var(--header-h);
}

/* ---------- 面包屑上方留白 ---------- */
.page-about .breadcrumbs {
  padding-top: 18px;
  padding-bottom: 4px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(24px, 5vw, 56px) 0 clamp(40px, 7vw, 84px);
}

.page-about .about-hero__inner {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
  align-items: start;
}

.page-about .about-hero__text .eyebrow {
  margin-bottom: 14px;
}

.page-about .about-hero__text .display-1 {
  margin: 0 0 20px;
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.05;
  max-width: 15ch;
}

.page-about .about-hero__text .lede {
  max-width: 54ch;
  color: var(--mist-100);
  margin: 0;
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 14px 30px;
}

.page-about .about-hero__facts li {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding-right: 26px;
  border-right: 1px solid var(--about-line);
}

.page-about .about-hero__facts li:last-child {
  border-right: 0;
  padding-right: 0;
}

.page-about .about-hero__facts .data-num {
  font-size: clamp(1.5rem, 3.4vw, 2rem);
  font-weight: 800;
  color: var(--cyan);
  line-height: 1;
}

.page-about .about-hero__facts em {
  font-style: normal;
  font-size: .88rem;
  color: var(--ice-300);
  letter-spacing: .02em;
}

.page-about .about-hero__media {
  margin: 0;
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--about-line);
  background:
    linear-gradient(160deg, rgba(41, 240, 224, .07), transparent 55%),
    var(--ink-900);
}

.page-about .about-hero__media .media-frame__img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  filter: saturate(.92) contrast(1.04);
}

.page-about .about-caption {
  display: block;
  font-size: .78rem;
  line-height: 1.6;
  color: var(--ice-300);
  padding: 9px 2px 0;
  letter-spacing: .02em;
}

.page-about .about-hero__media .about-caption {
  padding: 9px 14px 13px;
  background: var(--ink-900);
}

/* ---------- 主体框架：侧栏索引 + 内容 ---------- */
.page-about .about-shell {
  display: block;
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about .about-rail {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
  padding: 0 0 14px;
  margin: 0 0 10px;
  border-bottom: 1px solid var(--about-line);
  position: sticky;
  top: var(--header-h);
  z-index: 4;
  background: linear-gradient(180deg, var(--ink-950) 72%, rgba(6, 11, 24, .72));
}

.page-about .about-rail::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__title {
  display: none;
}

.page-about .about-rail .index-rail__link {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 13px;
  font-size: .82rem;
  color: var(--ice-300);
  text-decoration: none;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-pill);
  white-space: nowrap;
  transition: color .22s var(--ease), border-color .22s var(--ease), background-color .22s var(--ease);
}

.page-about .about-rail .index-rail__link .data-num {
  font-size: .72rem;
  color: var(--ink-500);
}

.page-about .about-rail .index-rail__link:hover,
.page-about .about-rail .index-rail__link:focus-visible {
  color: var(--mist-100);
  border-color: var(--ink-500);
}

.page-about .about-rail .index-rail__link[aria-current="true"] {
  color: var(--cyan);
  border-color: rgba(41, 240, 224, .6);
  background: rgba(41, 240, 224, .08);
}

.page-about .about-rail .index-rail__link[aria-current="true"] .data-num {
  color: var(--cyan);
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  position: relative;
  padding: clamp(40px, 7vw, 68px) 0;
  border-top: 1px solid var(--about-line);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: clamp(26px, 4vw, 40px);
}

.page-about .about-sec--loose {
  padding: clamp(56px, 9vw, 96px) 0;
}

.page-about .about-sec--closing {
  padding-bottom: clamp(28px, 4vw, 44px);
}

.page-about .about-sec__num {
  display: inline-block;
  font-size: .8rem;
  letter-spacing: .18em;
  color: var(--cyan);
  margin: 0 0 10px;
  padding-left: 22px;
  position: relative;
}

.page-about .about-sec__num::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 14px;
  height: 1px;
  background: var(--cyan);
  opacity: .8;
}

.page-about .about-sec__title {
  margin: 0 0 18px;
  font-size: clamp(1.45rem, 3.4vw, 2.1rem);
  line-height: 1.32;
  max-width: 26ch;
  color: var(--white);
}

.page-about .about-sec__lede {
  margin: 0 0 26px;
  max-width: 60ch;
  color: var(--ice-300);
  font-size: 1rem;
  line-height: 1.85;
}

.page-about .about-sec .prose p {
  color: var(--mist-100);
}

.page-about .about-sec .prose a {
  color: var(--cyan);
  text-underline-offset: 3px;
}

/* ---------- 双栏叙事 ---------- */
.page-about .about-split {
  display: grid;
  gap: clamp(22px, 3vw, 38px);
  align-items: start;
}

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

.page-about .about-split--media .about-split__media {
  margin: 0;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--about-line);
  background: var(--ink-900);
}

.page-about .about-split--media .media-frame__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-split--media .about-caption {
  padding: 9px 14px 13px;
  background: var(--ink-900);
}

/* ---------- 侧记 ---------- */
.page-about .about-note {
  position: relative;
  padding: 20px 22px 22px;
  border-radius: var(--radius);
  background:
    linear-gradient(150deg, rgba(41, 240, 224, .1), transparent 62%),
    var(--ink-800);
  border: 1px solid rgba(41, 240, 224, .22);
}

.page-about .about-note::after {
  content: "";
  position: absolute;
  left: 22px;
  bottom: 0;
  width: 46px;
  height: 2px;
  background: var(--cyan);
}

.page-about .about-note__k {
  margin: 0 0 10px;
  font-size: .74rem;
  letter-spacing: .16em;
  color: var(--cyan);
  text-transform: uppercase;
}

.page-about .about-note__v {
  margin: 0;
  color: var(--mist-100);
  line-height: 1.8;
  font-size: .96rem;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 6px 0 0;
  position: relative;
  display: grid;
  gap: 20px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 14px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), rgba(41, 240, 224, .06));
}

.page-about .about-timeline__item {
  position: relative;
  padding-left: 38px;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 20px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  border: 2px solid var(--cyan);
  background: var(--ink-950);
  box-shadow: 0 0 0 5px rgba(41, 240, 224, .07);
  transition: box-shadow .28s var(--ease), background-color .28s var(--ease);
}

.page-about .about-timeline__card {
  padding: 20px 22px 22px;
  border-radius: var(--radius);
  background: var(--ink-900);
  border: 1px solid var(--about-line);
  transition: border-color .28s var(--ease), transform .28s var(--ease), background-color .28s var(--ease);
}

.page-about .about-timeline__card:hover,
.page-about .about-timeline__card:focus-within {
  border-color: rgba(41, 240, 224, .5);
  background: var(--ink-800);
  transform: translateX(4px);
}

.page-about .about-timeline__item:hover::before,
.page-about .about-timeline__item:focus-within::before {
  background: var(--cyan);
  box-shadow: 0 0 0 7px rgba(41, 240, 224, .12);
}

.page-about .about-timeline__ver {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .14em;
  color: var(--orange);
}

.page-about .about-timeline__card .heading-3 {
  margin: 0 0 10px;
  color: var(--white);
}

.page-about .about-timeline__card p:last-child {
  margin: 0;
  color: var(--ice-300);
  line-height: 1.8;
  font-size: .95rem;
}

/* ---------- 更新节奏 ---------- */
.page-about .about-cadence {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-cadence li {
  background: var(--ink-900);
  padding: 18px 20px;
}

.page-about .about-cadence__k {
  margin: 0 0 6px;
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--cyan);
  letter-spacing: .04em;
}

.page-about .about-cadence__v {
  margin: 0;
  color: var(--ice-300);
  font-size: .92rem;
  line-height: 1.75;
}

/* ---------- 四类字段 ---------- */
.page-about .about-fields {
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr;
}

.page-about .about-field {
  position: relative;
  padding: 24px 22px 24px;
  border-radius: var(--radius);
  background:
    linear-gradient(200deg, rgba(29, 46, 77, .55), transparent 70%),
    var(--ink-900);
  border: 1px solid var(--about-line);
  overflow: hidden;
  transition: border-color .28s var(--ease), transform .28s var(--ease);
}

.page-about .about-field::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(74, 100, 145, .16) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(74, 100, 145, .16) 1px, transparent 1px);
  background-size: 34px 34px;
  opacity: .5;
  pointer-events: none;
}

.page-about .about-field:hover {
  border-color: rgba(41, 240, 224, .42);
  transform: translateY(-3px);
}

.page-about .about-field__idx {
  position: relative;
  margin: 0 0 12px;
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--ink-500);
  letter-spacing: .04em;
}

.page-about .about-field .heading-3 {
  position: relative;
  margin: 0 0 10px;
  color: var(--white);
}

.page-about .about-field p:last-child {
  position: relative;
  margin: 0;
  color: var(--ice-300);
  font-size: .93rem;
  line-height: 1.78;
}

.page-about .about-fields__foot {
  margin: 22px 0 0;
  padding-left: 18px;
  border-left: 2px solid var(--orange);
  color: var(--ice-300);
  font-size: .93rem;
  line-height: 1.8;
  max-width: 62ch;
}

/* ---------- 覆盖与协作 ---------- */
.page-about .about-stats {
  list-style: none;
  margin: 0 0 32px;
  padding: 0;
  display: grid;
  gap: 1px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  background: var(--about-line);
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-stats li {
  background: var(--ink-800);
  padding: 20px 18px;
}

.page-about .about-stats__n {
  margin: 0 0 8px;
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 800;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -.01em;
}

.page-about .about-stats__l {
  margin: 0;
  font-size: .84rem;
  line-height: 1.65;
  color: var(--ice-300);
}

.page-about .about-collab {
  padding: 24px 24px 26px;
  border-radius: var(--radius);
  border: 1px solid var(--about-line);
  background: var(--ink-900);
}

.page-about .about-collab .heading-3 {
  margin: 0 0 14px;
  color: var(--white);
}

.page-about .about-collab p {
  margin: 0 0 14px;
  color: var(--mist-100);
  line-height: 1.85;
  font-size: .96rem;
}

.page-about .about-collab p:last-child {
  margin-bottom: 0;
  color: var(--ice-300);
}

/* ---------- 贵州线索 ---------- */
.page-about .about-sec--ridge {
  position: relative;
  overflow: hidden;
}

.page-about .about-ridge {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -10px;
  width: 100%;
  height: clamp(180px, 30vw, 320px);
  pointer-events: none;
  opacity: .55;
}

.page-about .about-ridge path {
  fill: none;
  stroke: var(--green);
  stroke-width: 1.2;
  vector-effect: non-scaling-stroke;
  opacity: .55;
}

.page-about .about-ridge path:nth-child(2) {
  opacity: .38;
}

.page-about .about-ridge path:nth-child(3) {
  opacity: .24;
}

.page-about .about-sec--ridge .about-sec__inner {
  position: relative;
  z-index: 1;
}

/* ---------- 联系 ---------- */
.page-about .about-contact {
  display: grid;
  gap: 1px;
  margin-top: 6px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-contact__item {
  background: var(--ink-900);
  padding: 18px 20px;
}

.page-about .about-contact__k {
  margin: 0 0 7px;
  font-size: .74rem;
  letter-spacing: .14em;
  color: var(--ink-500);
  text-transform: uppercase;
}

.page-about .about-contact__v {
  margin: 0;
  color: var(--mist-100);
  font-size: .96rem;
  line-height: 1.7;
  word-break: break-word;
}

.page-about .about-contact__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-closing {
  margin: 30px 0 0;
  padding-top: 22px;
  border-top: 1px solid var(--about-line);
  font-family: var(--font-serif);
  font-size: clamp(1rem, 2.4vw, 1.22rem);
  line-height: 1.7;
  color: var(--cyan);
  max-width: 34ch;
}

/* ---------- 平板 ---------- */
@media (min-width: 700px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    align-items: stretch;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  }

  .page-about .about-split--media {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  }

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

  .page-about .about-cadence {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-contact {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-contact__item--wide {
    grid-column: 1 / -1;
  }
}

/* ---------- 桌面：固定侧栏索引 ---------- */
@media (min-width: 960px) {
  .page-about .about-shell {
    display: grid;
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }

  .page-about .about-rail {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    position: sticky;
    top: calc(var(--header-h) + 34px);
    padding: 0;
    margin: 0;
    border-bottom: 0;
    background: none;
    z-index: 3;
  }

  .page-about .about-rail__title {
    display: block;
    margin: 0 0 14px;
    font-size: .72rem;
    letter-spacing: .2em;
    color: var(--ink-500);
    text-transform: uppercase;
  }

  .page-about .about-rail .index-rail__link {
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
    padding: 9px 0 9px 14px;
    white-space: normal;
    line-height: 1.5;
    font-size: .875rem;
  }

  .page-about .about-rail .index-rail__link:hover,
  .page-about .about-rail .index-rail__link:focus-visible {
    border-left-color: var(--ink-500);
    background: none;
  }

  .page-about .about-rail .index-rail__link[aria-current="true"] {
    border-left-color: var(--cyan);
    background: none;
  }

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

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.7fr) minmax(0, 1fr);
  }

  .page-about .about-split--media {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  }

  .page-about .about-fields {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 1180px) {
  .page-about .about-note {
    padding: 26px 28px 28px;
  }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-timeline__card,
  .page-about .about-field,
  .page-about .about-timeline__item::before,
  .page-about .about-rail .index-rail__link {
    transition: none;
  }

  .page-about .about-timeline__card:hover,
  .page-about .about-timeline__card:focus-within,
  .page-about .about-field:hover {
    transform: none;
  }
}