.page-about {
  --about-block: clamp(44px, 6vw, 68px);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(30px, 5vw, 52px) 0 clamp(48px, 7vw, 86px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line) 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: .5;
  pointer-events: none;
  -webkit-mask-image: linear-gradient(155deg, transparent 34%, #000 78%);
  mask-image: linear-gradient(155deg, transparent 34%, #000 78%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: min(42%, 440px);
  height: 100%;
  background: rgba(111, 191, 158, .1);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
  margin-top: 24px;
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(30px, 4.4vw, 50px);
  line-height: 1.24;
  letter-spacing: -.012em;
  max-width: 17em;
}

.page-about .about-hero .lede {
  margin: 18px 0 0;
  font-size: 16.5px;
  line-height: 1.82;
  color: var(--muted);
  max-width: 40em;
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-stat {
  background: var(--paper);
  padding: 14px 14px 16px;
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--mono);
  font-size: 24px;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--ink);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 6px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--muted);
}

.page-about .about-hero__media {
  margin: 0;
}

.page-about .about-hero__media .media__frame {
  border: 1px solid var(--line);
  background: var(--deep);
  overflow: hidden;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  filter: saturate(.82) contrast(1.02);
}

.page-about .about-hero__media .media__caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

@media (min-width: 620px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 940px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.04fr) minmax(0, .96fr);
    gap: 58px;
    margin-top: 34px;
    align-items: end;
  }
}

/* ---------- 页面骨架：左侧年份轨 + 右侧主线 ---------- */
.page-about .about-frame {
  box-sizing: border-box;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 20px var(--about-block);
}

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

.page-about .about-stream {
  min-width: 0;
  border-left: 1px solid var(--line);
  padding-left: 20px;
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  position: relative;
  padding: 0 0 var(--about-block);
}

.page-about .about-section + .about-section {
  padding-top: var(--about-block);
}

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

.page-about .about-section__head {
  position: relative;
  margin-bottom: 24px;
}

.page-about .about-section__head::before {
  content: "";
  position: absolute;
  top: 8px;
  left: -24px;
  width: 9px;
  height: 9px;
  background: var(--summer);
}

.page-about .about-section__index {
  display: block;
  margin-bottom: 8px;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--autumn-ink);
}

.page-about .about-section .section-title {
  margin: 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(21px, 2.5vw, 30px);
  line-height: 1.38;
  letter-spacing: -.01em;
  max-width: 22em;
}

/* ---------- 01 品牌起点 ---------- */
.page-about .origin-grid {
  display: grid;
  gap: 28px;
}

.page-about .origin-grid__text p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.82;
  color: var(--muted);
}

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

.page-about .origin-notes {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .origin-note {
  background: var(--paper);
  padding: 18px 18px 20px;
}

.page-about .origin-note__tag {
  display: block;
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--summer);
}

.page-about .origin-note h3 {
  margin: 0 0 8px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 17px;
  line-height: 1.4;
}

.page-about .origin-note p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--muted);
}

@media (min-width: 860px) {
  .page-about .origin-grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    gap: 40px;
    align-items: start;
  }
}

/* ---------- 02 大事时间轴 ---------- */
.page-about .milestone-figure {
  margin: 0 0 30px;
  border: 1px solid var(--line);
  background: var(--paper-2);
}

.page-about .milestone-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 12 / 7;
  object-fit: cover;
  filter: saturate(.86);
}

.page-about .milestone-figure figcaption {
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .milestone-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .milestone {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 120px;
}

.page-about .milestone:first-child {
  padding-top: 0;
}

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

.page-about .milestone__year {
  font-family: var(--mono);
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--winter-ink);
  padding-top: 2px;
}

.page-about .milestone__card {
  border: 1px solid var(--line);
  border-left: 5px solid var(--line);
  background: var(--paper-2);
  padding: 18px 20px 20px;
}

.page-about .milestone__card--spring { border-left-color: var(--spring); }
.page-about .milestone__card--summer { border-left-color: var(--summer); }
.page-about .milestone__card--autumn { border-left-color: var(--autumn); }
.page-about .milestone__card--winter { border-left-color: var(--winter); }

.page-about .milestone__tag {
  display: block;
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--muted);
}

.page-about .milestone__title {
  margin: 10px 0 8px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(17px, 1.8vw, 21px);
  line-height: 1.45;
}

.page-about .milestone__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--muted);
}

@media (min-width: 720px) {
  .page-about .milestone {
    grid-template-columns: 116px minmax(0, 1fr);
    gap: 32px;
    align-items: start;
  }
}

/* ---------- 03 观测网络与团队 ---------- */
.page-about .network-figure {
  margin: 0 0 28px;
  border: 1px solid var(--line);
  background: var(--deep);
  overflow: hidden;
}

.page-about .network-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 2 / 1;
  object-fit: cover;
  filter: saturate(.7);
}

.page-about .network-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .network-stat {
  background: var(--paper);
  padding: 20px 18px 22px;
}

.page-about .network-stat__num {
  display: block;
  font-family: var(--mono);
  font-size: clamp(24px, 2.8vw, 32px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--summer);
}

.page-about .network-stat:nth-child(2) .network-stat__num { color: var(--spring-ink); }
.page-about .network-stat:nth-child(3) .network-stat__num { color: var(--autumn-ink); }

.page-about .network-stat__label {
  display: block;
  margin-top: 10px;
  font-size: 14.5px;
  color: var(--ink);
}

.page-about .network-stat__desc {
  display: block;
  margin-top: 5px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .team-split {
  display: grid;
  gap: 1px;
  margin-top: 22px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .team-split__col {
  background: var(--paper);
  padding: 22px 20px 24px;
}

.page-about .team-split__col h3 {
  margin: 0 0 10px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 18px;
  line-height: 1.4;
}

.page-about .team-split__col p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--muted);
}

@media (min-width: 760px) {
  .page-about .network-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .team-split {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* ---------- 04 合作生态与认可 ---------- */
.page-about .partner-lede {
  margin: 0 0 26px;
  font-size: 16px;
  line-height: 1.82;
  color: var(--muted);
  max-width: 46em;
}

.page-about .partner-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .partner-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--paper);
  padding: 22px 20px 24px;
  transition: background .2s var(--ease);
}

.page-about .partner-card:hover {
  background: var(--paper-2);
}

.page-about .partner-card h3 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 18px;
  line-height: 1.4;
}

.page-about .partner-card p {
  flex: 1;
  margin: 0;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--muted);
}

.page-about .partner-card__note {
  display: block;
  margin-top: auto;
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  font-size: 12px;
  letter-spacing: .02em;
  color: var(--summer-ink);
  opacity: .62;
  transition: opacity .2s var(--ease), transform .2s var(--ease);
}

.page-about .partner-card:hover .partner-card__note {
  opacity: 1;
  transform: translateY(-2px);
}

.page-about .honor-row {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .honor {
  background: var(--deep);
  padding: 20px 18px 22px;
}

.page-about .honor__year {
  display: block;
  margin-bottom: 8px;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--autumn);
}

.page-about .honor p {
  margin: 0;
  font-size: 15px;
  line-height: 1.74;
  color: rgba(246, 243, 236, .88);
}

@media (min-width: 760px) {
  .page-about .partner-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .honor-row {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 05 今天的四季中心 ---------- */
.page-about .today-panel {
  border: 1px solid var(--line);
  border-top: 3px solid var(--summer);
  background: var(--paper-2);
  padding: 24px 20px 28px;
}

.page-about .today-facts {
  margin: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .today-fact {
  background: var(--paper);
  padding: 16px 18px 18px;
}

.page-about .today-fact dt {
  margin-bottom: 6px;
  font-size: 13px;
  color: var(--muted);
}

.page-about .today-fact dd {
  margin: 0;
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink);
}

.page-about .today-fact dd.mono {
  font-family: var(--mono);
  font-size: 22px;
  letter-spacing: -.01em;
}

.page-about .today-lede {
  margin: 24px 0 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--muted);
  max-width: 44em;
}

.page-about .today-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 18px;
}

.page-about .today-note {
  margin: 20px 0 0;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--muted);
}

.page-about .today-note a {
  color: var(--summer);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

/* ---------- 桌面骨架 ---------- */
@media (min-width: 1024px) {
  .page-about .about-frame {
    display: grid;
    grid-template-columns: 118px minmax(0, 1fr);
    column-gap: 42px;
    padding: 0 32px var(--about-block);
  }

  .page-about .about-rail {
    display: block;
    position: sticky;
    top: 132px;
    align-self: start;
    padding-top: 4px;
  }

  .page-about .about-rail__label {
    margin: 0 0 12px;
    font-size: 12px;
    letter-spacing: .08em;
    color: var(--muted);
  }

  .page-about .about-rail__list {
    list-style: none;
    margin: 0;
    padding: 0;
  }

  .page-about .about-rail__list a {
    position: relative;
    display: block;
    padding: 7px 0 7px 16px;
    border-left: 1px solid var(--line);
    font-family: var(--mono);
    font-size: 13px;
    color: var(--muted);
    text-decoration: none;
    transition: color .18s var(--ease);
  }

  .page-about .about-rail__list a::before {
    content: "";
    position: absolute;
    top: 50%;
    left: -1px;
    width: 8px;
    height: 1px;
    background: var(--line);
    transform: translateY(-50%);
    transition: width .18s var(--ease), background .18s var(--ease);
  }

  .page-about .about-rail__list a:hover,
  .page-about .about-rail__list a:focus-visible {
    color: var(--ink);
  }

  .page-about .about-rail__list a:hover::before,
  .page-about .about-rail__list a:focus-visible::before {
    width: 15px;
    background: var(--signal);
  }

  .page-about .about-stream {
    padding-left: 40px;
  }

  .page-about .about-section__head::before {
    left: -44px;
  }
}

/* ---------- 滚动显现 ---------- */
@media (prefers-reduced-motion: no-preference) {
  .page-about [data-reveal] {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity .24s var(--ease), transform .24s var(--ease);
  }

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

  .page-about [data-reveal-group] > * {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity .24s var(--ease), transform .24s var(--ease);
  }

  .page-about [data-reveal-group].is-visible > * {
    opacity: 1;
    transform: none;
  }

  .page-about [data-reveal-group].is-visible > *:nth-child(1) { transition-delay: 0ms; }
  .page-about [data-reveal-group].is-visible > *:nth-child(2) { transition-delay: 60ms; }
  .page-about [data-reveal-group].is-visible > *:nth-child(3) { transition-delay: 120ms; }
  .page-about [data-reveal-group].is-visible > *:nth-child(4) { transition-delay: 180ms; }
  .page-about [data-reveal-group].is-visible > *:nth-child(5) { transition-delay: 240ms; }
  .page-about [data-reveal-group].is-visible > *:nth-child(6) { transition-delay: 300ms; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }
}