.page-about {
  display: block;
  background: var(--sand-050);
  color: var(--ink-900);
}

.page-about .about-shell {
  width: 100%;
  max-width: 1360px;
  margin: 0 auto;
  padding: clamp(16px, 2.6vw, 36px) clamp(16px, 3vw, 40px) clamp(48px, 7vw, 104px);
}

.page-about .about-crumb {
  margin-bottom: clamp(20px, 3vw, 38px);
}

/* ---------- 布局骨架：左侧窄索引 + 主栏 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 32px);
}

@media (min-width: 1080px) {
  .page-about .about-layout {
    grid-template-columns: 172px minmax(0, 1fr);
    gap: clamp(28px, 3.4vw, 56px);
    align-items: start;
  }
}

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

@media (min-width: 1080px) {
  .page-about .about-index {
    position: sticky;
    top: calc(var(--topbar-h) + 20px);
  }
}

.page-about .about-index__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--jade-700);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-index__list a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
  padding: 8px 12px;
  border: 2px solid var(--mist-200);
  background: rgba(247, 242, 232, 0.72);
  color: var(--ink-900);
  font-size: 13px;
  text-decoration: none;
  transition: border-color 160ms linear, background-color 160ms linear;
}

.page-about .about-index__list a:hover {
  border-color: var(--jade-700);
  background: var(--sand-050);
}

.page-about .about-index__list .bs-data {
  font-size: 11px;
  color: var(--terra-600);
}

@media (min-width: 1080px) {
  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-index__list a {
    border: 0;
    border-left: 3px solid var(--mist-200);
    background: transparent;
    padding: 8px 10px;
    line-height: 1.4;
  }

  .page-about .about-index__list a:hover {
    border-left-color: var(--terra-600);
    background: rgba(184, 69, 43, 0.07);
  }
}

.page-about .about-stack {
  display: flex;
  flex-direction: column;
  gap: var(--gap-stack);
  min-width: 0;
}

/* ---------- 画板通用 ---------- */
.page-about .about-block {
  scroll-margin-top: calc(var(--topbar-h) + 24px);
  padding: clamp(20px, 3vw, 40px);
  min-width: 0;
}

.page-about .about-block:target {
  outline: 3px solid var(--gold-500);
  outline-offset: 6px;
}

.page-about .about-h2 {
  margin: 0 0 1.1rem;
  font-size: clamp(24px, 3.6vw, 40px);
  line-height: 1.22;
  font-weight: 600;
  letter-spacing: -0.01em;
  max-width: 20em;
}

.page-about .about-h2--light {
  color: var(--sand-050);
}

.page-about .about-intro {
  margin: 0 0 clamp(20px, 3vw, 32px);
  font-size: 15px;
  line-height: 1.85;
  max-width: 36em;
  color: rgba(20, 16, 13, 0.78);
}

.page-about .about-caption {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: rgba(20, 16, 13, 0.58);
}

/* ---------- 首屏画板 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-top: clamp(26px, 3.6vw, 52px);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 7px;
  background: linear-gradient(90deg, var(--jade-400), var(--sky-500) 48%, var(--terra-600));
}

.page-about .about-hero__ghost {
  position: absolute;
  right: -0.06em;
  bottom: -0.22em;
  font-family: var(--font-mono);
  font-size: clamp(88px, 20vw, 230px);
  font-weight: 200;
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--terra-600);
  opacity: 0.12;
  pointer-events: none;
  user-select: none;
  z-index: 0;
}

.page-about .about-hero__title {
  position: relative;
  z-index: 1;
  margin: 0 0 1.3rem;
  font-size: clamp(34px, 8.4vw, 96px);
  font-weight: 200;
  line-height: 1.03;
  letter-spacing: -0.02em;
}

.page-about .about-hero__title strong {
  display: block;
  font-weight: 900;
  color: var(--terra-600);
}

.page-about .about-hero__lead {
  position: relative;
  z-index: 1;
  margin: 0;
  max-width: 40em;
  font-size: clamp(15px, 1.5vw, 17.5px);
  line-height: 1.9;
}

.page-about .about-facts {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(22px, 3vw, 34px) 0 0;
  background: var(--ink-900);
  border: 2px solid var(--ink-900);
}

@media (min-width: 760px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-fact {
  background: var(--sand-050);
  padding: 14px 16px;
  margin: 0;
}

.page-about .about-fact__label {
  font-size: 12px;
  line-height: 1.5;
  color: var(--jade-700);
  margin: 0 0 4px;
}

.page-about .about-fact__num {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 2.4vw, 28px);
  letter-spacing: 0.01em;
}

/* ---------- 00 来历 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 2.4vw, 32px);
}

@media (min-width: 900px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: start;
  }
}

.page-about .about-split__main p {
  margin: 0 0 1rem;
  font-size: 15.5px;
  line-height: 1.85;
}

.page-about .about-note {
  border: 2px solid var(--ink-900);
  border-left: 8px solid var(--gold-500);
  background: rgba(201, 154, 52, 0.1);
  box-shadow: var(--hard-sm);
  padding: 16px 16px 18px;
}

.page-about .about-note p {
  margin: 0.7rem 0 0;
  font-size: 14px;
  line-height: 1.8;
}

/* ---------- 01 数据生产（深色画板） ---------- */
.page-about .about-block--pipeline {
  background: var(--terra-900);
  color: var(--sand-050);
  border-color: var(--ink-900);
  box-shadow: var(--hard-lg);
}

.page-about .about-block--pipeline .bs-no {
  color: var(--gold-500);
}

.page-about .about-block--pipeline .bs-kicker {
  color: rgba(247, 242, 232, 0.68);
}

.page-about .about-figure {
  margin: 0 0 clamp(20px, 3vw, 32px);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 2px solid rgba(247, 242, 232, 0.32);
}

.page-about .about-block--versions .about-figure img,
.page-about .about-block--column .about-figure img {
  border-color: var(--ink-900);
}

.page-about .about-figure figcaption {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.02em;
  color: rgba(247, 242, 232, 0.6);
}

.page-about .about-block--versions .about-figure figcaption {
  color: rgba(20, 16, 13, 0.58);
}

.page-about .about-steps {
  list-style: none;
  margin: 0 0 clamp(22px, 3vw, 34px);
  padding: 0;
  border-top: 1px solid rgba(247, 242, 232, 0.28);
}

.page-about .about-steps > li {
  border-bottom: 1px solid rgba(247, 242, 232, 0.28);
}

.page-about .about-step > summary {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 14px;
  padding: 16px 2px;
  cursor: pointer;
  list-style: none;
}

.page-about .about-step > summary::-webkit-details-marker {
  display: none;
}

.page-about .about-step__no {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--gold-500);
}

.page-about .about-step__text {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}

.page-about .about-step__name {
  font-size: 17px;
  font-weight: 600;
  color: var(--sand-050);
}

.page-about .about-step__meta {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: rgba(247, 242, 232, 0.6);
}

.page-about .about-step__mark {
  font-family: var(--font-mono);
  font-size: 20px;
  line-height: 1;
  color: var(--jade-400);
  transition: transform 180ms linear;
}

.page-about .about-step[open] .about-step__mark {
  transform: rotate(45deg);
}

.page-about .about-step__body {
  padding: 0 0 20px clamp(0px, 4vw, 34px);
  max-width: 36em;
}

.page-about .about-step__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(247, 242, 232, 0.84);
}

/* ---------- 02 团队 ---------- */
.page-about .about-team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

@media (min-width: 720px) {
  .page-about .about-team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1240px) {
  .page-about .about-team-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    padding-bottom: 46px;
  }

  .page-about .about-team-card:nth-child(2) {
    margin-top: 14px;
  }

  .page-about .about-team-card:nth-child(3) {
    margin-top: 28px;
  }

  .page-about .about-team-card:nth-child(4) {
    margin-top: 42px;
  }
}

.page-about .about-team-card {
  --accent: var(--jade-700);
  border: 2px solid var(--ink-900);
  border-top: 8px solid var(--accent);
  background: var(--sand-050);
  box-shadow: var(--hard-sm);
  padding: 18px 18px 22px;
  transition: box-shadow 200ms linear, transform 200ms linear;
}

.page-about .about-team-card:nth-child(1) {
  --accent: var(--jade-700);
}

.page-about .about-team-card:nth-child(2) {
  --accent: var(--sky-500);
}

.page-about .about-team-card:nth-child(3) {
  --accent: var(--terra-600);
}

.page-about .about-team-card:nth-child(4) {
  --accent: var(--gold-500);
}

.page-about .about-team-card:hover {
  box-shadow: 2px 2px 0 rgba(20, 16, 13, 0.16);
  transform: translate(2px, 2px);
}

.page-about .about-team-card__count {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--accent);
}

.page-about .about-team-card__title {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
}

.page-about .about-team-card p:last-child {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(20, 16, 13, 0.8);
}

/* ---------- 03 版本演进：横向时间条 ---------- */
.page-about .about-block--versions .about-figure {
  margin-bottom: clamp(18px, 2.6vw, 28px);
}

.page-about .about-rail {
  display: flex;
  gap: 18px;
  overflow-x: auto;
  padding: 4px 4px 20px;
  scroll-snap-type: x proximity;
  scrollbar-width: thin;
  scrollbar-color: var(--mist-200) transparent;
}

.page-about .about-rail:focus-visible {
  outline: 3px solid var(--sky-500);
  outline-offset: 4px;
}

.page-about .about-rail__item {
  position: relative;
  flex: 0 0 min(300px, 76vw);
  scroll-snap-align: start;
  border: 2px solid var(--ink-900);
  background: var(--sand-050);
  box-shadow: var(--hard-sm);
  padding: 22px 18px 20px;
  transition: box-shadow 200ms linear, transform 200ms linear;
}

.page-about .about-rail__item::before {
  content: "";
  position: absolute;
  top: -2px;
  left: -2px;
  width: 14px;
  height: 14px;
  background: var(--gold-500);
}

.page-about .about-rail__item:hover {
  box-shadow: 2px 2px 0 rgba(20, 16, 13, 0.16);
  transform: translate(2px, 2px);
}

.page-about .about-rail__ver {
  display: block;
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1;
  color: var(--terra-600);
  margin-bottom: 10px;
}

.page-about .about-rail__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
}

.page-about .about-rail__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(20, 16, 13, 0.8);
}

/* ---------- 04 节奏与质检 ---------- */
.page-about .about-quality {
  margin: 0;
  border-top: 2px solid var(--ink-900);
}

.page-about .about-quality__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 2px solid var(--ink-900);
}

@media (min-width: 760px) {
  .page-about .about-quality__row {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 28px;
    align-items: baseline;
  }
}

.page-about .about-quality__key {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.05em;
  color: var(--jade-700);
  font-variant-numeric: tabular-nums;
}

.page-about .about-quality__val {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  max-width: 36em;
}

/* ---------- 05 栏目与选题 ---------- */
.page-about .about-topics {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

@media (min-width: 760px) {
  .page-about .about-topics {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(20px, 3vw, 40px);
  }
}

.page-about .about-topics li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--mist-200);
}

.page-about .about-topics__no {
  grid-row: 1 / span 2;
  align-self: start;
  padding-top: 4px;
  font-size: 12px;
  color: var(--terra-600);
}

.page-about .about-topics h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
}

.page-about .about-topics p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(20, 16, 13, 0.8);
  max-width: 32em;
}

/* ---------- 06 延伸入口 ---------- */
.page-about .about-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

@media (min-width: 760px) {
  .page-about .about-links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-links a {
  display: flex;
  flex-direction: column;
  gap: 4px;
  height: 100%;
  padding: 16px 18px;
  border: 2px solid var(--ink-900);
  background: var(--sand-050);
  box-shadow: var(--hard-sm);
  color: var(--ink-900);
  text-decoration: none;
  font-size: 17px;
  font-weight: 600;
  transition: box-shadow 200ms linear, transform 200ms linear, background-color 200ms linear;
}

.page-about .about-links a span {
  font-size: 13.5px;
  font-weight: 400;
  line-height: 1.7;
  color: rgba(20, 16, 13, 0.72);
}

.page-about .about-links a:hover {
  background: rgba(47, 127, 191, 0.08);
  box-shadow: 2px 2px 0 rgba(20, 16, 13, 0.16);
  transform: translate(2px, 2px);
}

/* ---------- 降级与窄屏保护 ---------- */
@media (max-width: 480px) {
  .page-about .about-facts {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .about-step > summary {
    gap: 10px;
  }

  .page-about .about-rail__item {
    flex-basis: 82vw;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-team-card,
  .page-about .about-rail__item,
  .page-about .about-links a,
  .page-about .about-step__mark {
    transition: none;
  }

  .page-about .about-team-card:hover,
  .page-about .about-rail__item:hover,
  .page-about .about-links a:hover {
    transform: none;
  }
}