.page-about {
  --about-soft: #3B4D58;
  --about-on-dark: #D8E4E9;
  --about-pad: clamp(2.75rem, 6vw, 5rem);
  background: var(--c-sand);
  color: var(--c-ink);
  font-family: var(--font-body);
  line-height: 1.75;
  overflow-x: clip;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.01em;
  margin: 0;
}

.page-about h1 {
  font-size: clamp(2.15rem, 6vw, 4rem);
  line-height: 1.04;
  max-width: 15em;
}

.page-about h2 {
  font-size: clamp(1.5rem, 3.4vw, 2.5rem);
  line-height: 1.14;
  margin-bottom: 0.85rem;
}

.page-about h3 {
  font-size: clamp(1.08rem, 2vw, 1.3rem);
  line-height: 1.3;
}

.page-about p {
  margin: 0 0 0.9rem;
}

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

.page-about .mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.page-about .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.16em;
  color: var(--c-lake);
}

.page-about .eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  background: var(--c-electric);
}

.page-about a:focus-visible,
.page-about [tabindex="0"]:focus-visible {
  outline: 2px solid var(--c-electric);
  outline-offset: 3px;
}

/* 面包屑 */
.page-about .breadcrumb {
  padding-block: clamp(0.9rem, 2vw, 1.5rem) 0;
  font-size: 0.82rem;
}

.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  list-style: none;
  margin: 0;
  padding: 0;
  color: var(--c-mist);
}

.page-about .breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.page-about .breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: var(--c-mist);
}

.page-about .breadcrumb__link {
  color: var(--c-lake);
  text-decoration: none;
}

.page-about .breadcrumb__current {
  color: var(--about-soft);
}

/* 首屏 */
.about-hero {
  display: grid;
  gap: clamp(2rem, 5vw, 3.5rem);
  padding-block: clamp(1.25rem, 3vw, 2rem) clamp(2.5rem, 6vw, 4.5rem);
}

.about-hero__intro {
  margin-top: 1.25rem;
  max-width: 34em;
  font-size: clamp(1rem, 1.5vw, 1.14rem);
  color: var(--about-soft);
}

.about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin: 2.25rem 0 0;
  padding-top: 1.25rem;
  border-top: 1px solid var(--hairline);
}

.hero-stats__item dt {
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  color: var(--c-mist);
}

.hero-stats__item dd {
  margin: 0.3rem 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.45rem, 3vw, 2rem);
  font-weight: 800;
  line-height: 1;
}

.hero-stats__item dd .mono {
  font-size: 0.92em;
}

.about-hero__aside {
  display: grid;
  gap: 1.5rem;
  align-content: start;
}

.about-index {
  display: grid;
  border-top: 1px solid var(--hairline);
}

.about-index__title {
  margin: 0.85rem 0 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--c-mist);
}

.about-index__link {
  display: grid;
  grid-template-columns: 2.1rem minmax(0, 1fr);
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.7rem 0.25rem;
  border-bottom: 1px solid var(--hairline);
  color: var(--c-ink);
  text-decoration: none;
  transition: background 0.16s ease, padding-left 0.16s ease;
}

.about-index__num {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--c-lake);
}

.about-index__label {
  font-family: var(--font-display);
  font-size: 1.04rem;
  font-weight: 700;
}

.about-index__link:hover,
.about-index__link:focus-visible {
  background: rgba(18, 133, 127, 0.09);
  padding-left: 0.65rem;
}

.page-about .media-frame {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--c-rock);
  border: 1px solid var(--hairline);
}

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

.page-about .media-frame__caption {
  padding: 0.6rem 0.85rem;
  margin: 0;
  background: var(--c-paper);
  color: var(--c-mist);
  font-size: 0.76rem;
  line-height: 1.5;
}

.about-hero__figure img {
  aspect-ratio: 3 / 4;
}

/* 通用章节 */
.about-section {
  padding-block: var(--about-pad);
}

/* 内容方法 */
.about-method {
  background: var(--c-paper);
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

.about-method__grid {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
}

.about-method__head p {
  color: var(--about-soft);
  font-size: 0.98rem;
}

.method-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.method-step {
  display: grid;
  grid-template-columns: 2.4rem minmax(0, 1fr);
  gap: 0.35rem 1rem;
  padding-block: 1.35rem;
  border-top: 1px solid var(--hairline);
}

.method-step:last-child {
  border-bottom: 1px solid var(--hairline);
}

.method-step__num {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--c-lake);
  padding-top: 0.35rem;
}

.method-step__body h3 {
  margin-bottom: 0.4rem;
  color: var(--c-highland);
}

.method-step__body p {
  color: var(--about-soft);
  font-size: 0.95rem;
}

/* 记录复核 */
.about-records {
  position: relative;
  background: var(--c-rock);
  color: var(--c-paper);
}

.about-records::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 5px;
  background: linear-gradient(90deg, var(--c-electric), var(--c-lake) 55%, rgba(108, 132, 148, 0.2));
}

.about-records .eyebrow {
  color: var(--c-electric);
}

.about-records__grid {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
  padding-top: 0.5rem;
}

.about-records__body > p:not(.eyebrow) {
  color: var(--about-on-dark);
  font-size: 0.97rem;
}

.about-records__figure img {
  aspect-ratio: 3 / 2;
}

.about-records__figure .media-frame__caption {
  background: var(--c-highland);
  color: rgba(252, 251, 247, 0.7);
  border-top: 1px solid rgba(108, 132, 148, 0.3);
}

.records-dims {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.7rem;
}

.records-dims li {
  display: grid;
  grid-template-columns: 1.9rem minmax(0, 1fr);
  gap: 0.2rem 0.7rem;
  padding: 0.85rem 0.9rem;
  background: rgba(252, 251, 247, 0.06);
  border-left: 3px solid var(--c-lake);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.records-dims__k {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--c-electric);
  padding-top: 0.2rem;
}

.records-dims__v {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
}

.records-dims__d {
  grid-column: 1 / -1;
  font-size: 0.83rem;
  line-height: 1.6;
  color: var(--about-on-dark);
}

.check-fields {
  margin-top: 1.6rem;
  padding-top: 1.3rem;
  border-top: 1px solid rgba(108, 132, 148, 0.45);
}

.check-fields__label {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  color: var(--c-electric);
  margin-bottom: 0.75rem;
}

.check-fields__list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  margin: 0 0 0.9rem;
  padding: 0;
}

.check-chip {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  padding: 0.32rem 0.7rem;
  border-radius: 999px;
  background: rgba(47, 211, 192, 0.14);
  border: 1px solid rgba(47, 211, 192, 0.45);
  color: var(--c-paper);
}

.check-fields__note {
  font-size: 0.85rem;
  color: var(--about-on-dark);
  line-height: 1.7;
}

.check-fields__note .tag {
  vertical-align: 1px;
}

/* 团队 */
.about-team__head {
  max-width: 44em;
}

.about-team__head > p:not(.eyebrow) {
  color: var(--about-soft);
}

.team-split {
  display: grid;
  gap: 1.15rem;
  margin-top: clamp(1.5rem, 3vw, 2.25rem);
}

.team-panel {
  padding: clamp(1.2rem, 2.6vw, 2rem);
  border-radius: var(--radius-lg);
  background: var(--c-paper);
  border: 1px solid var(--hairline);
  transition: border-color 0.16s ease, box-shadow 0.16s ease;
}

.team-panel--narrow {
  background: rgba(18, 133, 127, 0.08);
  border-color: rgba(18, 133, 127, 0.3);
}

.team-panel:focus-visible,
.team-panel:focus-within {
  border-color: var(--c-lake);
  box-shadow: 0 0 0 3px rgba(47, 211, 192, 0.28);
  outline: none;
}

.team-panel__kicker {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 600;
  color: var(--c-lake);
  margin: 0 0 0.2rem;
  line-height: 1.1;
}

.team-panel h3 {
  margin-bottom: 0.9rem;
  color: var(--c-highland);
}

.staff-list {
  list-style: none;
  margin: 0 0 1rem;
  padding: 0;
  display: grid;
  gap: 0.8rem;
}

.staff-row {
  display: grid;
  grid-template-columns: 5.2rem minmax(0, 1fr) 2rem;
  align-items: center;
  gap: 0.7rem;
}

.staff-row__name {
  font-size: 0.9rem;
  color: var(--about-soft);
}

.staff-row__bar {
  position: relative;
  height: 8px;
  border-radius: 999px;
  background: var(--c-sand);
  overflow: hidden;
}

.staff-row__bar::after {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--w, 50%);
  border-radius: inherit;
  background: linear-gradient(90deg, var(--c-lake), var(--c-electric));
}

.staff-row__num {
  font-family: var(--font-mono);
  font-size: 0.92rem;
  font-weight: 600;
  text-align: right;
  color: var(--c-lake);
}

.team-panel__note {
  font-size: 0.88rem;
  color: var(--about-soft);
  line-height: 1.7;
}

.observer-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  list-style: none;
  margin: 0 0 1rem;
  padding: 0;
}

.observer-tags li {
  padding: 0.28rem 0.7rem;
  border-radius: 999px;
  background: var(--c-paper);
  border: 1px solid rgba(18, 133, 127, 0.35);
  font-size: 0.82rem;
  color: var(--c-highland);
}

/* 时间轴 */
.about-history {
  background: var(--c-paper);
  border-top: 1px solid var(--hairline);
}

.about-history__head {
  max-width: 46em;
}

.about-history__head > p:not(.eyebrow) {
  color: var(--about-soft);
}

.about-history__figure {
  margin-top: clamp(1.4rem, 3vw, 2rem);
}

.about-history__figure img {
  aspect-ratio: 16 / 7;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 3rem), 0 100%);
}

.timeline {
  position: relative;
  margin-top: clamp(1.6rem, 3.5vw, 2.6rem);
}

.timeline__axis {
  display: none;
}

.timeline__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: clamp(1.4rem, 3vw, 2rem);
}

.tl-node {
  position: relative;
  padding-top: 1.4rem;
  border-top: 2px solid var(--hairline);
}

.tl-node__dot {
  position: absolute;
  top: -6px;
  left: 0;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--c-paper);
  border: 2px solid var(--c-lake);
  transition: background 0.16s ease, border-color 0.16s ease;
  z-index: 1;
}

.tl-node__year {
  margin: 0 0 0.2rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  color: var(--c-lake);
}

.tl-node__title {
  margin-bottom: 0.4rem;
  color: var(--c-highland);
  font-size: clamp(1.05rem, 1.9vw, 1.24rem);
  transition: color 0.16s ease;
}

.tl-node__text {
  font-size: 0.92rem;
  color: var(--about-soft);
}

.tl-node__more {
  margin: 0.55rem 0 0;
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--c-lake);
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.2s ease, opacity 0.2s ease;
}

.tl-node:hover .tl-node__more,
.tl-node:focus-visible .tl-node__more,
.tl-node:focus-within .tl-node__more {
  max-height: 6rem;
  opacity: 1;
}

.tl-node:hover .tl-node__dot,
.tl-node:focus-visible .tl-node__dot {
  background: var(--c-lake);
  border-color: var(--c-lake);
}

.tl-node:hover .tl-node__title,
.tl-node:focus-visible .tl-node__title {
  color: var(--c-lake);
}

.tl-node:focus-visible {
  outline: 2px solid var(--c-electric);
  outline-offset: 4px;
}

/* 协作与范围 */
.about-scope {
  background: var(--c-highland);
  color: var(--c-paper);
}

.about-scope .eyebrow {
  color: var(--c-electric);
}

.about-scope__head {
  max-width: 46em;
}

.about-scope__head > p:not(.eyebrow) {
  color: var(--about-on-dark);
  font-size: 0.97rem;
}

.scope-stats {
  display: grid;
  gap: 1rem;
  list-style: none;
  margin: clamp(1.75rem, 4vw, 2.75rem) 0 0;
  padding: 0;
}

.scope-stats__item {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding-top: 0.85rem;
  border-top: 1px solid rgba(108, 132, 148, 0.45);
}

.scope-stats__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(2rem, 4.6vw, 3rem);
  font-weight: 600;
  line-height: 1;
  color: var(--c-electric);
}

.scope-stats__label {
  font-size: 0.88rem;
  color: var(--about-on-dark);
}

.about-scope__cta {
  display: grid;
  gap: 1.25rem;
  margin-top: clamp(1.75rem, 4vw, 2.75rem);
  padding: clamp(1.2rem, 2.6vw, 1.9rem);
  border-radius: var(--radius-lg);
  background: rgba(243, 237, 226, 0.07);
  border: 1px solid rgba(47, 211, 192, 0.32);
}

.about-scope__cta-text h3 {
  margin-bottom: 0.5rem;
  font-size: clamp(1.1rem, 2vw, 1.35rem);
}

.about-scope__cta-text p {
  font-size: 0.9rem;
  color: var(--about-on-dark);
}

.about-scope__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}

/* 断点 */
@media (min-width: 640px) {
  .scope-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .scope-stats__item {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .records-dims {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

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

  .about-method__grid {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    gap: clamp(2rem, 5vw, 4rem);
  }

  .about-method__head {
    position: sticky;
    top: 2rem;
    align-self: start;
  }

  .about-records__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
  }

  .team-split {
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
    gap: 1.5rem;
  }

  .timeline__axis {
    display: block;
    width: 100%;
    height: 24px;
    margin-bottom: -12px;
  }

  .timeline__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1.5rem;
  }

  .tl-node {
    border-top: 0;
    padding-top: 1.35rem;
  }

  .about-scope__cta {
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
    align-items: center;
    gap: 2rem;
  }

  .about-scope__actions {
    justify-content: flex-end;
  }
}

@media (min-width: 1100px) {
  .about-hero__aside {
    padding-top: 0.35rem;
  }
}

@media (hover: none) {
  .tl-node__more {
    max-height: none;
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .tl-node__more {
    max-height: none;
    opacity: 1;
  }
}

@keyframes aboutRise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.page-about [data-reveal].is-revealed {
  animation: aboutRise 0.32s ease both;
  animation-delay: calc(var(--reveal-delay, 0) * 60ms);
}

.page-about {
  --reveal-delay: inherit;
  --w: 1rem;
}