.page-about {
  --about-cut: 18px;
  --about-line: rgba(195, 217, 143, .2);
  --about-line-strong: rgba(195, 217, 143, .38);
  --about-rail-w: 15rem;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  padding-bottom: clamp(3rem, 9vw, 7rem);
  overflow-x: clip;
}

.page-about .about-crumbs {
  margin-top: clamp(1rem, 3vw, 1.7rem);
  margin-bottom: 0;
}

/* ---------- 开场 ---------- */

.page-about .about-hero {
  position: relative;
  isolation: isolate;
  padding-block: clamp(1.6rem, 4.4vw, 3rem) clamp(2.2rem, 5.4vw, 3.8rem);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -4rem;
  right: -18%;
  width: min(52rem, 108vw);
  height: min(30rem, 72vw);
  background: linear-gradient(118deg,
      rgba(127, 168, 59, .3) 0%,
      rgba(30, 110, 140, .34) 52%,
      rgba(30, 110, 140, 0) 84%);
  clip-path: polygon(22% 0, 100% 0, 82% 100%, 0 100%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(1.8rem, 4.4vw, 2.6rem);
}

.page-about .about-kicker {
  margin: 0 0 .9rem;
  font-family: var(--font-numeric);
  font-size: .78rem;
  letter-spacing: .22em;
  color: var(--barley-soft);
}

.page-about h1 {
  margin: 0 0 1.1rem;
  font-family: var(--font-display);
  font-weight: 900;
  letter-spacing: -.02em;
  line-height: 1.05;
  font-size: clamp(2.15rem, 6.4vw, 3.9rem);
  color: var(--paper);
}

.page-about .about-hero__lead {
  margin: 0 0 1.5rem;
  max-width: 34em;
  font-size: clamp(1rem, 1.5vw, 1.06rem);
  line-height: 1.85;
  color: rgba(242, 240, 230, .88);
}

.page-about .about-audience {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .55rem;
}

.page-about .about-audience li {
  position: relative;
  padding-left: 1.2rem;
  font-size: .95rem;
  line-height: 1.72;
  color: var(--barley-soft);
}

.page-about .about-audience li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .8em;
  width: .68rem;
  height: 1px;
  background: var(--barley);
}

/* ---------- 校订链速览 ---------- */

.page-about .about-steps__caption {
  margin: 0 0 .7rem;
  font-family: var(--font-numeric);
  font-size: .76rem;
  letter-spacing: .2em;
  color: var(--wheat);
}

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: var(--hair);
}

.page-about .about-steps li {
  display: grid;
  grid-template-columns: 3.1rem 1fr;
  align-items: baseline;
  gap: .6rem;
  padding: .78rem 0;
  border-bottom: var(--hair);
}

.page-about .about-steps__no {
  font-family: var(--font-numeric);
  font-variant-numeric: tabular-nums;
  font-size: 1.05rem;
  letter-spacing: .04em;
  color: var(--barley);
}

.page-about .about-steps__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.02rem;
  letter-spacing: .01em;
  color: var(--paper);
}

.page-about .about-hero__figure {
  margin: clamp(1.6rem, 4vw, 2.3rem) 0 0;
}

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

.page-about .figure__caption {
  color: var(--wheat);
}

/* ---------- 阅读栏 + 批注栏 ---------- */

.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.8rem, 4vw, 2.6rem);
  align-items: start;
  margin-top: clamp(1rem, 3vw, 2rem);
}

.page-about .about-shell--tail {
  margin-top: clamp(2.4rem, 6vw, 4rem);
}

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

.page-about .about-head {
  margin: 0 0 clamp(1.2rem, 3vw, 1.8rem);
  padding-top: clamp(1rem, 2.4vw, 1.4rem);
  border-top: 2px solid var(--barley);
}

.page-about .section__num {
  margin: 0 0 .55rem;
  font-family: var(--font-numeric);
  font-variant-numeric: tabular-nums;
  font-size: 1.05rem;
  letter-spacing: .18em;
  color: var(--barley);
}

.page-about .section__title {
  margin: 0 0 .7rem;
  font-family: var(--font-display);
  font-weight: 900;
  letter-spacing: -.015em;
  line-height: 1.18;
  font-size: clamp(1.5rem, 3.6vw, 2.1rem);
  color: var(--paper);
}

.page-about .section__lead {
  margin: 0;
  max-width: 36em;
  font-size: .98rem;
  line-height: 1.85;
  color: rgba(242, 240, 230, .8);
}

.page-about .about-chain,
.page-about .about-audit,
.page-about .about-handbook,
.page-about .about-doubts {
  margin-bottom: clamp(2.6rem, 7vw, 4.4rem);
}

/* ---------- 五环节 ---------- */

.page-about .chain {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.1rem;
}

.page-about .chain__item {
  position: relative;
  display: grid;
  grid-template-columns: 2.9rem minmax(0, 1fr);
  gap: .2rem 1rem;
  padding: clamp(1rem, 2.6vw, 1.35rem);
  background: var(--ink-2);
  clip-path: polygon(0 0,
      calc(100% - var(--about-cut)) 0,
      100% var(--about-cut),
      100% 100%,
      var(--about-cut) 100%,
      0 calc(100% - var(--about-cut)));
}

.page-about .chain__no {
  grid-row: 1 / span 2;
  margin: 0;
  font-family: var(--font-numeric);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.5rem, 4.4vw, 2rem);
  line-height: 1;
  color: var(--lake-soft);
  padding-top: .12rem;
}

.page-about .chain__name {
  margin: 0 0 .7rem;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.15rem, 2.6vw, 1.35rem);
  letter-spacing: .01em;
  color: var(--paper);
}

.page-about .chain__io {
  display: grid;
  gap: .5rem;
  margin: 0;
}

.page-about .chain__io > div {
  display: grid;
  grid-template-columns: 4.6rem minmax(0, 1fr);
  gap: .6rem;
  padding-top: .5rem;
  border-top: 1px solid rgba(195, 217, 143, .12);
}

.page-about .chain__io dt {
  font-family: var(--font-numeric);
  font-size: .74rem;
  letter-spacing: .1em;
  color: var(--barley);
  padding-top: .22em;
}

.page-about .chain__io dd {
  margin: 0;
  font-size: .92rem;
  line-height: 1.78;
  color: rgba(242, 240, 230, .84);
}

.page-about .about-breath {
  margin: 0 0 clamp(2.6rem, 7vw, 4.4rem);
}

.page-about .about-breath .figure__media {
  max-width: 30rem;
}

/* ---------- 三层内审 ---------- */

.page-about .audit-layout {
  display: grid;
  gap: clamp(1.4rem, 3.4vw, 2rem);
}

.page-about .audit-stack {
  display: grid;
  gap: 1.05rem;
  position: relative;
}

.page-about .audit-card {
  position: relative;
  padding: clamp(1rem, 2.6vw, 1.35rem);
  background: var(--ink-2);
  border-left: 2px dashed var(--barley);
  clip-path: polygon(0 0,
      calc(100% - var(--about-cut)) 0,
      100% var(--about-cut),
      100% 100%,
      var(--about-cut) 100%,
      0 calc(100% - var(--about-cut)));
}

.page-about .audit-card--wide {
  background: linear-gradient(135deg, rgba(30, 110, 140, .3), rgba(22, 48, 42, .95) 68%);
}

.page-about .audit-card__layer {
  margin: 0 0 .45rem;
  font-family: var(--font-numeric);
  font-size: .74rem;
  letter-spacing: .18em;
  color: var(--lake-soft);
}

.page-about .audit-card__name {
  margin: 0 0 .5rem;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.12rem;
  color: var(--paper);
}

.page-about .audit-card__desc {
  margin: 0;
  font-size: .92rem;
  line-height: 1.8;
  color: rgba(242, 240, 230, .82);
}

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

/* ---------- 口径手册 ---------- */

.page-about .handbook-grid {
  display: grid;
  gap: 1rem;
}

.page-about .handbook-card {
  padding: clamp(1rem, 2.6vw, 1.3rem);
  background: var(--ink-2);
  border-top: 2px solid var(--lake);
}

.page-about .handbook-card__name {
  margin: 0 0 .55rem;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.06rem;
  color: var(--lake-soft);
}

.page-about .handbook-card p {
  margin: 0;
  font-size: .92rem;
  line-height: 1.82;
  color: rgba(242, 240, 230, .82);
}

.page-about .handbook-card a,
.page-about .qa__a a {
  color: var(--lake-soft);
  text-decoration: underline;
  text-decoration-color: rgba(127, 182, 204, .45);
  text-underline-offset: .22em;
}

.page-about .handbook-card a:hover,
.page-about .handbook-card a:focus-visible,
.page-about .qa__a a:hover,
.page-about .qa__a a:focus-visible {
  color: var(--gold);
  text-decoration-color: var(--gold);
}

.page-about .handbook-version {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .7rem;
  margin: clamp(1.2rem, 3vw, 1.7rem) 0 0;
  padding-top: clamp(.9rem, 2.4vw, 1.2rem);
  border-top: var(--hair);
}

.page-about .handbook-version__text {
  flex: 1 1 16rem;
  font-size: .9rem;
  line-height: 1.8;
  color: var(--wheat);
}

/* ---------- 侧栏 ---------- */

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

.page-about .about-rail__title {
  margin: 0 0 .7rem;
  font-family: var(--font-numeric);
  font-size: .72rem;
  letter-spacing: .2em;
  color: var(--wheat);
}

.page-about .side-timeline__list {
  list-style: none;
  margin: 0 0 1.4rem;
  padding: 0;
  display: grid;
  gap: .3rem;
}

.page-about .side-timeline__item {
  margin: 0;
  padding: 0;
}

.page-about .side-timeline__label {
  display: block;
  padding: .38rem 0 .38rem .85rem;
  border-left: 1px solid var(--about-line);
  font-family: var(--font-numeric);
  font-size: .78rem;
  letter-spacing: .04em;
  color: var(--wheat);
  text-decoration: none;
  transition: color .18s ease, border-color .18s ease;
}

.page-about .side-timeline__label:hover,
.page-about .side-timeline__label:focus-visible {
  color: var(--barley-soft);
  border-left-color: var(--barley);
}

.page-about .about-rail__notes {
  display: grid;
  gap: .7rem;
}

.page-about .about-rail__note {
  margin: 0;
  font-size: .82rem;
  line-height: 1.7;
}

/* ---------- 简史条款带 ---------- */

.page-about .about-history {
  margin-top: clamp(1rem, 3vw, 2rem);
}

.page-about .about-history__hint {
  margin: .75rem 0 0;
  font-family: var(--font-hand);
  font-size: .88rem;
  color: var(--saffron-soft);
  transform: rotate(-1.2deg);
  transform-origin: left center;
}

.page-about .band {
  overflow-x: auto;
  overscroll-behavior-x: contain;
  scroll-snap-type: x proximity;
  padding-bottom: .9rem;
  border-top: var(--hair);
  border-bottom: var(--hair);
  scrollbar-width: thin;
  scrollbar-color: var(--barley) rgba(195, 217, 143, .12);
}

.page-about .band:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 4px;
}

.page-about .band::-webkit-scrollbar {
  height: 6px;
}

.page-about .band::-webkit-scrollbar-track {
  background: rgba(195, 217, 143, .12);
}

.page-about .band::-webkit-scrollbar-thumb {
  background: var(--barley);
}

.page-about .band__track {
  display: flex;
  gap: clamp(.85rem, 2vw, 1.15rem);
  width: max-content;
  margin: 0;
  padding: clamp(1.1rem, 3vw, 1.5rem) 0;
  list-style: none;
}

.page-about .band__item {
  flex: 0 0 auto;
  width: min(17.5rem, 76vw);
  scroll-snap-align: start;
  padding: clamp(.95rem, 2.4vw, 1.25rem);
  background: var(--ink-2);
  clip-path: polygon(0 0,
      calc(100% - var(--about-cut)) 0,
      100% var(--about-cut),
      100% 100%,
      var(--about-cut) 100%,
      0 calc(100% - var(--about-cut)));
}

.page-about .band__no {
  margin: 0 0 .5rem;
  font-family: var(--font-numeric);
  font-variant-numeric: tabular-nums;
  font-size: 1.28rem;
  letter-spacing: .05em;
  color: var(--barley);
}

.page-about .band__title {
  margin: 0 0 .9rem;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.02rem;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .band__stats {
  display: grid;
  gap: .45rem;
  margin: 0;
}

.page-about .band__stat {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: baseline;
  gap: .5rem;
  padding-top: .42rem;
  border-top: 1px solid rgba(195, 217, 143, .14);
}

.page-about .band__stat dt {
  font-size: .8rem;
  color: var(--wheat);
}

.page-about .band__stat dd {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: .18rem;
}

.page-about .band__stat .stat__value {
  font-family: var(--font-numeric);
  font-variant-numeric: tabular-nums;
  font-size: 1.14rem;
  color: var(--gold);
}

.page-about .band__stat .stat__unit {
  font-size: .74rem;
  color: var(--wheat);
}

.page-about .about-history__foot {
  margin: clamp(1rem, 3vw, 1.5rem) 0 0;
  font-size: .9rem;
  line-height: 1.8;
  color: var(--wheat);
}

/* ---------- 常见质疑 ---------- */

.page-about .qa {
  display: grid;
  gap: 1rem;
}

.page-about .qa__item {
  padding-top: clamp(.85rem, 2.4vw, 1.15rem);
  border-top: 1px solid var(--about-line-strong);
}

.page-about .qa__q {
  margin: 0 0 .6rem;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.05rem, 2.4vw, 1.2rem);
  line-height: 1.45;
  color: var(--barley-soft);
}

.page-about .qa__a {
  margin: 0;
  font-size: .95rem;
  line-height: 1.88;
  color: rgba(242, 240, 230, .84);
}

/* ---------- 收束 ---------- */

.page-about .about-end {
  margin-top: clamp(1rem, 3vw, 1.6rem);
  padding-top: clamp(1.1rem, 3vw, 1.6rem);
  border-top: 2px solid var(--lake);
}

.page-about .about-end__statement {
  margin: 0 0 1.1rem;
  max-width: 34em;
  font-size: .93rem;
  line-height: 1.85;
  color: var(--wheat);
}

.page-about .about-end__links {
  display: flex;
  flex-wrap: wrap;
  gap: .6rem;
}

/* ---------- 响应式 ---------- */

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

  .page-about .handbook-card:last-child {
    grid-column: 1 / -1;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.06fr) minmax(0, .94fr);
    gap: clamp(2rem, 4vw, 3.4rem);
  }

  .page-about .audit-layout {
    grid-template-columns: minmax(0, 1.14fr) minmax(0, .86fr);
    align-items: start;
  }

  .page-about .handbook-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .handbook-card:last-child {
    grid-column: auto;
  }

  .page-about .chain__item {
    grid-template-columns: 3.4rem minmax(0, 1fr);
  }
}

@media (min-width: 1000px) {
  .page-about .about-shell {
    grid-template-columns: minmax(0, 42rem) var(--about-rail-w);
    justify-content: space-between;
    gap: clamp(1.6rem, 3.4vw, 3rem);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--nav-h) + 1.6rem);
    align-self: start;
  }

  .page-about .about-rail--tail {
    position: static;
  }

  .page-about .about-history .about-head {
    max-width: 42rem;
  }
}

@media (min-width: 1240px) {
  .page-about .about-shell {
    grid-template-columns: minmax(0, 44rem) var(--about-rail-w);
  }

  .page-about .about-history .about-head {
    max-width: 44rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .side-timeline__label {
    transition: none;
  }

  .page-about .about-history__hint,
  .page-about .note {
    transform: none;
  }

  .page-about .band {
    scroll-behavior: auto;
  }
}