.page-about {
  --about-num-size: clamp(56px, 9vw, 124px);
  --about-line: 1px solid var(--line);
  --about-line-dark: 1px solid rgba(19, 26, 23, 0.16);
  background: var(--ink);
  color: var(--cream);
  overflow-x: hidden;
}

.page-about a {
  color: inherit;
}

.page-about a:focus-visible,
.page-about [tabindex]:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .mono {
  font-family: var(--font-mono);
  letter-spacing: 0;
  color: var(--cyan);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  padding-top: calc(var(--header-h) + clamp(32px, 6vw, 72px));
  padding-bottom: clamp(40px, 6vw, 76px);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(120% 90% at 82% 8%, rgba(76, 242, 200, 0.13), transparent 58%),
    radial-gradient(85% 65% at 2% 98%, rgba(242, 178, 60, 0.11), transparent 62%),
    linear-gradient(180deg, #0A1F1A 0%, #0A1F1A 58%, #0b241e 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image: repeating-linear-gradient(115deg, rgba(46, 74, 66, 0.55) 0 1px, transparent 1px 104px);
  opacity: 0.45;
  pointer-events: none;
}

.page-about .about-hero__title {
  margin: clamp(18px, 3vw, 30px) 0 0;
  font-family: var(--font-display);
  font-size: clamp(38px, 8.4vw, 100px);
  font-weight: 800;
  line-height: 0.98;
  letter-spacing: -0.035em;
  max-width: 15ch;
}

.page-about .about-hero__title em {
  font-style: normal;
  color: var(--cyan);
}

.page-about .about-hero__lede {
  margin: clamp(20px, 3vw, 30px) 0 0;
  max-width: 60ch;
  font-size: clamp(15px, 1.35vw, 17px);
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(24px, 3.4vw, 36px);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(36px, 5.6vw, 64px) 0 0;
  padding: 0;
  background: var(--line);
  border-top: var(--about-line);
  border-bottom: var(--about-line);
}

.page-about .hero-stats__item {
  background: var(--ink);
  padding: clamp(16px, 2.2vw, 24px) clamp(14px, 1.8vw, 22px);
}

.page-about .hero-stats__label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .hero-stats__value {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(22px, 3.2vw, 34px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--cream);
}

.page-about .hero-stats__value span {
  margin-left: 4px;
  font-size: 0.46em;
  font-weight: 500;
  letter-spacing: 0;
  color: var(--muted);
}

/* ---------- 章节索引 ---------- */
.page-about .about-toc {
  background: var(--ink-deep);
  border-top: var(--about-line);
  border-bottom: var(--about-line);
}

.page-about .about-toc__list {
  display: flex;
  gap: clamp(6px, 1vw, 14px);
  margin: 0;
  padding: clamp(10px, 1.6vw, 15px) 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

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

.page-about .about-toc__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 13px;
  white-space: nowrap;
  color: var(--muted);
  text-decoration: none;
  transition: color 180ms var(--ease), border-color 180ms var(--ease), background 180ms var(--ease);
}

.page-about .about-toc__link span {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--amber);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  color: var(--cyan);
  border-color: var(--line);
  background: var(--surface);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  padding: clamp(48px, 7vw, 96px) 0;
  border-top: var(--about-line);
}

.page-about .about-chapter--surface {
  background: var(--ink-deep);
}

.page-about .about-chapter--sand {
  background: var(--sand);
  color: var(--ink-on-sand);
  border-top-color: rgba(19, 26, 23, 0.14);
}

.page-about .about-chapter--join {
  background: var(--surface);
}

.page-about .chapter-head {
  display: grid;
  gap: clamp(10px, 1.8vw, 18px);
  margin-bottom: clamp(28px, 4.4vw, 56px);
}

.page-about .chapter-head__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--about-num-size);
  font-weight: 700;
  line-height: 0.78;
  letter-spacing: -0.05em;
  color: transparent;
  -webkit-text-stroke: 1px var(--line);
  user-select: none;
}

.page-about .about-chapter--sand .chapter-head__num {
  -webkit-text-stroke-color: rgba(19, 26, 23, 0.34);
}

.page-about .chapter-head__title {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-size: clamp(26px, 3.6vw, 44px);
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: -0.02em;
  max-width: 20ch;
}

/* ---------- 01 内容构成 ---------- */
.page-about .topic-list {
  display: grid;
  gap: clamp(24px, 3.4vw, 40px);
}

.page-about .topic {
  border-top: var(--about-line);
  padding-top: clamp(16px, 2vw, 22px);
}

.page-about .about-chapter--sand .topic {
  border-top-color: rgba(19, 26, 23, 0.18);
}

.page-about .topic__tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .about-chapter--sand .topic__tag {
  color: #1a5f4f;
}

.page-about .topic__title {
  margin: 10px 0 0;
  font-size: clamp(17px, 1.6vw, 19px);
  font-weight: 700;
  line-height: 1.45;
  letter-spacing: -0.01em;
}

.page-about .topic__text {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-chapter--sand .topic__text {
  color: rgba(19, 26, 23, 0.78);
}

.page-about .about-chapter--sand .topic__text .mono {
  color: #1a5f4f;
}

/* ---------- 02 团队 ---------- */
.page-about .team-layout {
  display: grid;
  gap: clamp(24px, 3.4vw, 40px);
}

.page-about .team-list {
  display: grid;
  gap: 1px;
  background: rgba(19, 26, 23, 0.18);
  border: var(--about-line-dark);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .team-card {
  background: var(--cream);
  padding: clamp(18px, 2.4vw, 26px);
}

.page-about .team-card__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(30px, 4vw, 42px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--ink-on-sand);
}

.page-about .team-card__num span {
  margin-left: 3px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0;
  color: rgba(19, 26, 23, 0.5);
}

.page-about .team-card__role {
  margin: 10px 0 0;
  font-size: clamp(17px, 1.6vw, 19px);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .team-card__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(19, 26, 23, 0.78);
}

.page-about .team-card__link {
  margin: 12px 0 0;
}

.page-about .team-card__link a {
  font-size: 13px;
  font-weight: 700;
  color: #0e5b4a;
  text-decoration: none;
  border-bottom: 1px solid rgba(14, 91, 74, 0.35);
  transition: border-color 180ms var(--ease);
}

.page-about .team-card__link a:hover {
  border-bottom-color: #0e5b4a;
}

/* ---------- 图片容器 ---------- */
.page-about .about-figure {
  margin: 0;
  border: var(--about-line);
  border-radius: var(--radius);
  background: var(--ink-deep);
  overflow: hidden;
}

.page-about .about-chapter--sand .about-figure {
  border-color: rgba(19, 26, 23, 0.2);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-figure figcaption {
  padding: 11px 14px;
  border-top: var(--about-line);
  font-size: 12px;
  line-height: 1.65;
  color: var(--muted);
  background: var(--ink-deep);
}

.page-about .about-figure--flow {
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .about-figure--history {
  margin-bottom: clamp(24px, 3vw, 32px);
}

/* ---------- 03 流程 ---------- */
.page-about .flow {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .flow__step {
  position: relative;
  padding: 0 0 clamp(26px, 3.4vw, 34px) 28px;
}

.page-about .flow__step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 5px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  border: 1px solid var(--cyan);
  background: var(--ink);
  z-index: 1;
  transition: background 180ms var(--ease), box-shadow 180ms var(--ease);
}

.page-about .flow__step::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 15px;
  bottom: 0;
  width: 1px;
  background: var(--line);
}

.page-about .flow__step:last-child {
  padding-bottom: 0;
}

.page-about .flow__step:last-child::after {
  display: none;
}

.page-about .flow__step:hover::before,
.page-about .flow__step:focus-within::before {
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(76, 242, 200, 0.16);
}

.page-about .flow__title {
  margin: 0;
  font-size: clamp(16px, 1.5vw, 18px);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .flow__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .flow__meta {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: rgba(159, 181, 172, 0.68);
  transition: color 180ms var(--ease);
}

.page-about .flow__step:hover .flow__meta,
.page-about .flow__step:focus-within .flow__meta {
  color: var(--amber);
}

/* ---------- 04 发展历程 ---------- */
.page-about .history-layout {
  display: grid;
  gap: clamp(24px, 3.4vw, 40px);
}

.page-about .roadmap {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: var(--about-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .roadmap__item {
  display: grid;
  gap: 8px;
  padding: clamp(18px, 2.4vw, 26px) clamp(16px, 2vw, 24px);
  background: var(--ink-deep);
  transition: background 180ms var(--ease);
}

.page-about .roadmap__item:hover {
  background: var(--surface);
}

.page-about .roadmap__year {
  font-family: var(--font-mono);
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--amber);
}

.page-about .roadmap__title {
  margin: 0;
  font-size: clamp(15px, 1.4vw, 17px);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .roadmap__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 05 把关与合作 ---------- */
.page-about .partner-grid {
  display: grid;
  gap: clamp(28px, 3.6vw, 48px);
}

.page-about .subhead {
  margin: 0 0 clamp(14px, 2vw, 20px);
  font-size: clamp(18px, 2vw, 22px);
  font-weight: 800;
  letter-spacing: -0.01em;
}

.page-about .check-list,
.page-about .coop-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0;
}

.page-about .check-list__item {
  position: relative;
  padding: clamp(14px, 2vw, 18px) 0 clamp(14px, 2vw, 18px) 26px;
  border-top: var(--about-line-dark);
  font-size: 14px;
  line-height: 1.8;
  color: rgba(19, 26, 23, 0.82);
}

.page-about .check-list__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: calc(clamp(14px, 2vw, 18px) + 11px);
  width: 11px;
  height: 2px;
  background: var(--ink);
}

.page-about .coop-list__item {
  padding: clamp(14px, 2vw, 18px) 0;
  border-top: var(--about-line-dark);
}

.page-about .coop-list__role {
  margin: 0;
  font-size: 15px;
  font-weight: 700;
}

.page-about .coop-list__text {
  margin: 6px 0 0;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(19, 26, 23, 0.78);
}

.page-about .coop-note {
  margin: clamp(16px, 2vw, 22px) 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: rgba(19, 26, 23, 0.58);
}

/* ---------- 如何开始 ---------- */
.page-about .paths {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: var(--about-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .paths__item {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: clamp(20px, 2.6vw, 28px);
  background: var(--ink);
  transition: background 180ms var(--ease);
}

.page-about .paths__item:hover {
  background: var(--ink-deep);
}

.page-about .paths__label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .paths__text {
  flex: 1;
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .paths__link {
  align-self: flex-start;
  font-size: 14px;
  font-weight: 700;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 180ms var(--ease);
}

.page-about .paths__link:hover,
.page-about .paths__link:focus-visible {
  border-bottom-color: var(--cyan);
}

.page-about .paths__more {
  margin: clamp(24px, 3vw, 34px) 0 0;
  font-size: 13px;
  line-height: 1.9;
  color: var(--muted);
}

.page-about .paths__more a {
  color: var(--cream);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .paths__more a:hover {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* ---------- 入场 ---------- */
.page-about [data-reveal].has-reveal {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 460ms var(--ease), transform 460ms var(--ease);
}

.page-about [data-reveal].has-reveal.in {
  opacity: 1;
  transform: none;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .paths {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

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

  .page-about .roadmap__item {
    grid-template-columns: 110px minmax(0, 1fr);
    gap: clamp(16px, 3vw, 36px);
    align-items: baseline;
  }
}

@media (min-width: 860px) {
  .page-about .chapter-head {
    grid-template-columns: minmax(96px, 0.32fr) minmax(0, 1fr);
    align-items: end;
    gap: clamp(20px, 4vw, 60px);
  }

  .page-about .topic-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: clamp(20px, 3vw, 40px);
  }

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

@media (min-width: 900px) {
  .page-about .flow {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: clamp(10px, 1.4vw, 22px);
    border-top: var(--about-line);
  }

  .page-about .flow__step {
    padding: clamp(26px, 3vw, 36px) clamp(6px, 1vw, 14px) 0 0;
  }

  .page-about .flow__step::before {
    left: 0;
    top: -6px;
  }

  .page-about .flow__step::after {
    display: none;
  }

  .page-about .team-layout {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: clamp(24px, 3vw, 48px);
    align-items: start;
  }

  .page-about .about-figure--history {
    margin-bottom: 0;
  }
}

@media (min-width: 960px) {
  .page-about .history-layout {
    grid-template-columns: minmax(0, 0.76fr) minmax(0, 1fr);
    gap: clamp(24px, 3.4vw, 52px);
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal].has-reveal {
    transform: none;
    transition: opacity 200ms linear;
  }

  .page-about .flow__step::before,
  .page-about .flow__meta,
  .page-about .roadmap__item,
  .page-about .paths__item,
  .page-about .about-toc__link {
    transition: none;
  }
}