.page-about {
  --about-rail: 200px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(1.25rem, 3.5vw, 2.5rem) clamp(1.25rem, 3.5vw, 2rem);
}

.page-about .hero-frame {
  position: relative;
  margin-top: clamp(1rem, 3vw, 1.75rem);
  padding: clamp(1.25rem, 4.5vw, 3.25rem);
  border: var(--hair) solid var(--rule-2);
  background: var(--glass-strong);
  overflow: hidden;
}

.page-about .hero-frame::before,
.page-about .hero-frame::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border: var(--hair) solid var(--anchor-600);
  pointer-events: none;
}

.page-about .hero-frame::before {
  top: 9px;
  left: 9px;
  border-right: 0;
  border-bottom: 0;
}

.page-about .hero-frame::after {
  right: 9px;
  bottom: 9px;
  border-top: 0;
  border-left: 0;
}

.page-about .hero-title {
  margin: .35rem 0 0;
  font-family: var(--font-display);
  font-size: clamp(2rem, 7.2vw, 4.4rem);
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--ink-900);
  text-wrap: balance;
}

.page-about .hero-lede {
  margin: clamp(1rem, 2.4vw, 1.5rem) 0 0;
  max-width: 40rem;
  font-size: clamp(1rem, 1.35vw, 1.125rem);
  line-height: 1.9;
  color: var(--ink-600);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 1.1rem;
  margin: clamp(1.5rem, 3.5vw, 2.25rem) 0 0;
  padding: clamp(1rem, 2.5vw, 1.4rem) 0 0;
  border-top: var(--hair) solid var(--rule);
  list-style: none;
}

@media (min-width: 720px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1rem 1.5rem;
  }
}

.page-about .hero-stat {
  min-width: 0;
  padding-left: .7rem;
  border-left: 3px solid var(--season-c, var(--rule-2));
}

.page-about .stat-num {
  display: block;
  font-family: var(--font-figure);
  font-size: clamp(1.2rem, 2.3vw, 1.6rem);
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--ink-900);
}

.page-about .stat-label {
  display: block;
  margin-top: .3rem;
  font-size: .8rem;
  line-height: 1.55;
  color: var(--ink-600);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.75rem, 4vw, 2.5rem);
  padding-block: clamp(1.75rem, 4.5vw, 3rem) clamp(2.5rem, 6vw, 5rem);
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2.5rem, 5vw, 5rem);
    align-items: start;
  }
}

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

/* ---------- 四季色变量 ---------- */
.page-about .is-spring { --season-c: var(--spring-400); }
.page-about .is-summer { --season-c: var(--summer-500); }
.page-about .is-autumn { --season-c: var(--autumn-300); }
.page-about .is-winter { --season-c: var(--winter-700); }

/* ---------- 左侧章节索引 ---------- */
.page-about .about-rail {
  min-width: 0;
  padding-top: .7rem;
  border-top: 3px solid var(--ink-900);
}

@media (min-width: 960px) {
  .page-about .about-rail {
    position: sticky;
    top: 5.5rem;
    padding-top: 1rem;
  }
}

.page-about .rail-label {
  margin: 0 0 .6rem;
  font-family: var(--font-figure);
  font-size: .72rem;
  letter-spacing: .2em;
  color: var(--ink-300);
}

.page-about .rail-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .3rem .55rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 960px) {
  .page-about .rail-list {
    grid-template-columns: minmax(0, 1fr);
    gap: .1rem;
  }
}

.page-about .rail-link {
  display: flex;
  gap: .55rem;
  align-items: baseline;
  padding: .45rem .5rem .45rem .7rem;
  border-left: 3px solid var(--season-c, var(--rule-2));
  font-size: .875rem;
  line-height: 1.5;
  color: var(--ink-600);
  text-decoration: none;
  transition: background-color .22s var(--ease), color .22s var(--ease), border-color .22s var(--ease);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  background: var(--paper-100);
  color: var(--ink-900);
  border-left-color: var(--anchor-600);
}

.page-about .rail-num {
  font-family: var(--font-figure);
  font-size: .74rem;
  color: var(--ink-300);
}

/* ---------- 章节 ---------- */
.page-about .chapter {
  padding-bottom: clamp(2rem, 5vw, 3.5rem);
  margin-bottom: clamp(2rem, 5vw, 3.5rem);
  border-bottom: var(--hair) solid var(--rule);
}

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

.page-about .chapter-head {
  display: flex;
  align-items: center;
  gap: .9rem;
  margin-bottom: .55rem;
}

.page-about .chapter-num {
  font-family: var(--font-figure);
  font-size: clamp(1.35rem, 2.8vw, 1.95rem);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--ink-900);
}

.page-about .chapter-rule {
  flex: 1;
  height: 3px;
  background: var(--season-c, var(--rule-2));
  opacity: .85;
}

.page-about .chapter-title {
  margin: 0 0 clamp(.9rem, 2vw, 1.2rem);
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 3.4vw, 2.1rem);
  line-height: 1.32;
  letter-spacing: -.01em;
  color: var(--ink-900);
}

.page-about .chapter-body {
  display: grid;
  gap: 1rem;
  max-width: 36rem;
}

.page-about .chapter-body > * {
  min-width: 0;
}

.page-about .chapter-body--tail {
  margin-top: clamp(1.1rem, 2.6vw, 1.5rem);
}

.page-about .chapter-body p {
  margin: 0;
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--ink-600);
}

.page-about .text-link {
  color: var(--ink-900);
  text-decoration: none;
  border-bottom: 1px solid var(--anchor-600);
  padding-bottom: 1px;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .text-link:hover,
.page-about .text-link:focus-visible {
  color: var(--anchor-600);
  border-bottom-color: var(--ink-900);
}

/* ---------- 引文 ---------- */
.page-about .quote {
  margin: .4rem 0;
  max-width: 28rem;
  padding: 1.05rem 1.25rem;
  border-left: 4px solid var(--ink-900);
  background: var(--paper-100);
  font-family: var(--font-display);
  font-size: clamp(1.05rem, 2.3vw, 1.28rem);
  line-height: 1.75;
  color: var(--ink-900);
  transition: transform .28s var(--ease), border-left-color .28s var(--ease);
}

.page-about .quote:hover {
  transform: translateY(-4px);
  border-left-color: var(--anchor-600);
}

/* ---------- 图片 ---------- */
.page-about .chapter-figure {
  margin: clamp(1.25rem, 3vw, 2rem) 0 0;
  min-width: 0;
}

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

/* ---------- 四季栏目卡 ---------- */
.page-about .season-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: .7rem;
  margin: clamp(1.25rem, 3vw, 1.75rem) 0 0;
}

@media (min-width: 560px) {
  .page-about .season-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1180px) {
  .page-about .season-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .season-card {
  min-width: 0;
  padding: 1rem 1rem 1.15rem;
  border: var(--hair) solid var(--rule);
  border-top: 4px solid var(--season-c, var(--rule-2));
  background: var(--paper-000);
}

.page-about .season-card.is-spring { background: rgba(127, 164, 106, .09); }
.page-about .season-card.is-summer { background: rgba(63, 127, 150, .08); }
.page-about .season-card.is-autumn { background: rgba(221, 164, 94, .12); }
.page-about .season-card.is-winter { background: rgba(31, 43, 69, .07); }

.page-about .season-card__season {
  display: block;
  font-family: var(--font-figure);
  font-size: .72rem;
  letter-spacing: .18em;
  color: var(--ink-600);
}

.page-about .season-card__title {
  margin: .35rem 0 .45rem;
  font-family: var(--font-display);
  font-size: 1.12rem;
  line-height: 1.38;
  color: var(--ink-900);
}

.page-about .season-card p {
  margin: 0;
  font-size: .875rem;
  line-height: 1.75;
  color: var(--ink-600);
}

/* ---------- 印刷式步骤图 ---------- */
.page-about .proof-flow {
  margin: clamp(1.25rem, 3vw, 1.75rem) 0;
  max-width: 36rem;
}

.page-about .proof-flow__scroll {
  overflow-x: auto;
  padding-bottom: .4rem;
}

.page-about .proof-flow__svg {
  display: block;
  width: 100%;
  min-width: 470px;
  height: auto;
}

.page-about .proof-flow__box {
  fill: var(--paper-000);
  stroke: var(--ink-900);
  stroke-width: 1;
}

.page-about .proof-flow__step {
  font-family: var(--font-display);
  font-size: 18px;
  fill: var(--ink-900);
  text-anchor: middle;
}

.page-about .proof-flow__note {
  font-family: var(--font-ui);
  font-size: 12px;
  fill: var(--ink-600);
  text-anchor: middle;
}

.page-about .proof-flow__line {
  stroke: var(--ink-900);
  stroke-width: 1;
}

.page-about .proof-flow__arrowhead {
  fill: var(--ink-900);
}

.page-about .proof-flow__caption {
  margin-top: .8rem;
  font-size: .85rem;
  line-height: 1.7;
  color: var(--ink-300);
}

/* ---------- 团队 ---------- */
.page-about .crew-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: clamp(1.1rem, 2.6vw, 1.5rem) 0 0;
  padding: 0;
  list-style: none;
  max-width: 40rem;
}

@media (min-width: 640px) {
  .page-about .crew-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 1.75rem;
  }
}

.page-about .crew-item {
  display: grid;
  grid-template-columns: 4.6rem minmax(0, 1fr);
  gap: .2rem .85rem;
  padding: 1rem 0;
  border-top: var(--hair) solid var(--rule);
  min-width: 0;
}

.page-about .crew-num {
  grid-row: 1 / span 2;
  font-family: var(--font-figure);
  font-size: clamp(1.5rem, 3.2vw, 2.05rem);
  line-height: 1.1;
  color: var(--ink-900);
}

.page-about .crew-role {
  font-size: .95rem;
  line-height: 1.5;
  color: var(--ink-900);
}

.page-about .crew-item p {
  margin: 0;
  font-size: .875rem;
  line-height: 1.7;
  color: var(--ink-600);
}

/* ---------- 阶段时间轴 ---------- */
.page-about .milestones {
  display: grid;
  gap: 0;
  margin: clamp(1.1rem, 2.6vw, 1.5rem) 0 0;
  padding: 0;
  list-style: none;
  max-width: 34rem;
}

.page-about .milestone {
  position: relative;
  padding: 0 0 1.4rem 1.6rem;
  border-left: 2px solid var(--rule);
}

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

.page-about .milestone::before {
  content: "";
  position: absolute;
  top: .42rem;
  left: -7px;
  width: 12px;
  height: 12px;
  background: var(--season-c, var(--ink-900));
}

.page-about .milestone__stage {
  display: block;
  margin-bottom: .2rem;
  font-family: var(--font-figure);
  font-size: .73rem;
  letter-spacing: .18em;
  color: var(--ink-300);
}

.page-about .milestone h3 {
  margin: 0 0 .25rem;
  font-family: var(--font-display);
  font-size: 1.08rem;
  line-height: 1.42;
  color: var(--ink-900);
}

.page-about .milestone p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.78;
  color: var(--ink-600);
}

/* ---------- 协作 ---------- */
.page-about .partner-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: .7rem;
  margin: clamp(1.2rem, 3vw, 1.75rem) 0 0;
}

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

.page-about .partner-cell {
  min-width: 0;
  padding: 1.1rem 1.05rem 1.2rem;
  border: var(--hair) solid var(--rule);
  border-left: 4px solid var(--season-c, var(--rule-2));
  background: var(--paper-000);
}

.page-about .partner-num {
  display: block;
  font-family: var(--font-figure);
  font-size: clamp(1.2rem, 2.6vw, 1.55rem);
  line-height: 1.2;
  color: var(--ink-900);
}

.page-about .partner-cell p {
  margin: .5rem 0 0;
  font-size: .875rem;
  line-height: 1.75;
  color: var(--ink-600);
}

/* ---------- 结尾指路 ---------- */
.page-about .about-next {
  padding-block: clamp(2rem, 5vw, 3.5rem);
  background: var(--paper-100);
  border-top: var(--hair) solid var(--rule-2);
}

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

.page-about .about-next__title {
  margin: 0 0 clamp(1rem, 2.6vw, 1.5rem);
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 2.9vw, 1.85rem);
  line-height: 1.35;
  color: var(--ink-900);
}

.page-about .about-next__list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: .6rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 760px) {
  .page-about .about-next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: .8rem 1.25rem;
  }
}

.page-about .about-next__link {
  display: grid;
  grid-template-columns: 2.2rem minmax(0, 1fr);
  gap: .15rem .8rem;
  align-items: baseline;
  min-width: 0;
  padding: .95rem 1rem;
  background: var(--paper-000);
  border: var(--hair) solid var(--rule);
  text-decoration: none;
  color: var(--ink-900);
  transition: transform .22s var(--ease), border-color .22s var(--ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  transform: translateY(-3px);
  border-color: var(--anchor-600);
}

.page-about .about-next__num {
  grid-row: 1 / span 2;
  font-family: var(--font-figure);
  font-size: .85rem;
  color: var(--anchor-600);
}

.page-about .about-next__label {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.45;
}

.page-about .about-next__desc {
  font-size: .85rem;
  line-height: 1.65;
  color: var(--ink-600);
}

/* ---------- 降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .quote,
  .page-about .rail-link,
  .page-about .text-link,
  .page-about .about-next__link {
    transition: none;
  }

  .page-about .quote:hover,
  .page-about .about-next__link:hover,
  .page-about .about-next__link:focus-visible {
    transform: none;
  }
}