.page-about {
  --about-rail: 84px;
  --about-cut: 14px;
  --about-ink-mute: #4C5C54;
  --about-rule: rgba(23, 24, 18, .16);
  --about-rule-dark: rgba(143, 167, 156, .22);
  display: block;
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(20px, 3.4vw, 40px) clamp(48px, 7vw, 96px);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 110px;
  background: repeating-linear-gradient(
    -6deg,
    rgba(69, 224, 174, .09) 0 1px,
    transparent 1px 18px
  );
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 52px);
  align-items: start;
  margin-top: clamp(20px, 3vw, 36px);
}

.page-about .about-hero__lead h1 {
  font-family: var(--font-display);
  font-size: clamp(30px, 5.6vw, 64px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  font-weight: 700;
  color: var(--c-paper-hi);
  margin: 12px 0 22px;
  max-width: 11em;
}

.page-about .about-hero__lead .label {
  color: var(--c-mint);
}

.page-about .about-hero__lede {
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: rgba(244, 240, 229, .84);
  max-width: 36em;
  margin: 0 0 30px;
}

.page-about .about-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  max-width: 540px;
  border-top: 1px solid var(--about-rule-dark);
  border-left: 1px solid var(--about-rule-dark);
}

.page-about .about-facts li {
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding: 13px 15px;
  border-right: 1px solid var(--about-rule-dark);
  border-bottom: 1px solid var(--about-rule-dark);
}

.page-about .about-facts .num {
  font-family: var(--font-num);
  font-size: 23px;
  line-height: 1.1;
  color: var(--c-mint);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0;
}

.page-about .about-facts span:last-child {
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--c-mute);
}

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

.page-about .about-hero__media {
  position: relative;
  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 .about-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 21 / 9;
  object-fit: cover;
  filter: saturate(.85) contrast(1.07) brightness(.92);
}

.page-about .about-hero__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(7, 19, 15, 0) 42%, rgba(7, 19, 15, .62) 100%),
    repeating-linear-gradient(0deg, rgba(69, 224, 174, .07) 0 1px, transparent 1px 46px);
  pointer-events: none;
}

.page-about .about-hero__figure .figure__caption {
  margin-top: 12px;
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: .02em;
  color: var(--c-mute);
}

/* ============ 正文画板 ============ */
.page-about .about-body {
  padding-block: clamp(44px, 7vw, 96px);
}

.page-about .about-body__head {
  max-width: 46em;
  margin-bottom: clamp(38px, 5.5vw, 68px);
}

.page-about .about-body .label {
  color: var(--about-ink-mute);
}

.page-about .about-body__head h2 {
  font-family: var(--font-display);
  font-size: clamp(25px, 3.5vw, 38px);
  line-height: 1.18;
  letter-spacing: -0.02em;
  color: var(--c-ink-2);
  margin: 10px 0 16px;
}

.page-about .about-body__head p {
  margin: 0;
  font-size: clamp(15px, 1.5vw, 16.5px);
  line-height: 1.85;
  color: var(--about-ink-mute);
  max-width: 60ch;
}

/* ============ 章节与竖直刻度 ============ */
.page-about .about-chapters {
  position: relative;
}

.page-about .about-chapter {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-bottom: clamp(46px, 6.5vw, 84px);
}

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

.page-about .about-chapter__tick {
  display: flex;
  justify-content: flex-start;
  align-items: flex-start;
}

.page-about .about-chapter__tick .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 40px;
  height: 34px;
  padding-inline: 9px;
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--c-mint);
  background: var(--c-night);
  clip-path: polygon(
    0 0,
    calc(100% - 9px) 0,
    100% 9px,
    100% 100%,
    9px 100%,
    0 calc(100% - 9px)
  );
}

.page-about .about-chapter__body h2 {
  font-family: var(--font-display);
  font-size: clamp(22px, 2.9vw, 33px);
  line-height: 1.2;
  letter-spacing: -0.018em;
  color: var(--c-ink-2);
  margin: 8px 0 18px;
}

.page-about .about-chapter__body h3 {
  font-family: var(--font-display);
  font-size: clamp(16px, 1.8vw, 19px);
  letter-spacing: -0.01em;
  line-height: 1.3;
  color: var(--c-ink-2);
  margin: 0;
}

.page-about .about-chapter__body > p {
  margin: 0 0 16px;
  font-size: clamp(15px, 1.55vw, 16.5px);
  line-height: 1.88;
  color: var(--c-ink-2);
  max-width: 66ch;
}

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

.page-about .about-slash {
  width: 76px;
  height: 8px;
  margin: 28px 0 4px;
  background: repeating-linear-gradient(
    115deg,
    var(--c-mint-deep) 0 2px,
    transparent 2px 11px
  );
  opacity: .65;
}

.page-about .term {
  cursor: help;
  text-decoration: underline;
  text-decoration-color: var(--c-mint-deep);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

/* ============ 图组 ============ */
.page-about .about-figure {
  margin: 26px 0 28px;
}

.page-about .about-media {
  position: relative;
  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 .about-media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  filter: saturate(.82) contrast(1.06) brightness(.9);
}

.page-about .about-figure--wide .about-media img {
  aspect-ratio: 3 / 2;
}

.page-about .about-media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(90deg, rgba(69, 224, 174, .07) 0 1px, transparent 1px 44px);
  pointer-events: none;
}

.page-about .about-figure .figure__caption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: .02em;
  color: var(--about-ink-mute);
}

/* ============ 切角数据板 ============ */
.page-about .about-board {
  position: relative;
  margin: 28px 0;
  padding: clamp(18px, 2.6vw, 28px);
  background: var(--c-paper-hi);
  color: var(--c-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 .about-board::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--c-mint);
}

.page-about .about-board .label {
  color: var(--about-ink-mute);
  margin: 0 0 14px;
}

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 13px;
}

.page-about .about-steps li {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--c-ink-2);
}

.page-about .about-steps li .num {
  font-family: var(--font-num);
  font-size: 12.5px;
  line-height: 2;
  color: var(--c-mint-deep);
  font-variant-numeric: tabular-nums;
  letter-spacing: .06em;
}

/* 深色数据板变体 */
.page-about .about-board--night {
  background: var(--c-turf);
  color: var(--c-paper-hi);
}

.page-about .about-board--night::after {
  background: var(--c-mint);
}

.page-about .about-board--night .label {
  color: var(--c-mute);
}

.page-about .about-cadence {
  margin: 0;
  display: grid;
  gap: 18px;
}

.page-about .about-cadence > div {
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.page-about .about-cadence dt {
  margin: 0;
  font-family: var(--font-num);
  font-size: 27px;
  line-height: 1;
  color: var(--c-mint);
  font-variant-numeric: tabular-nums;
}

.page-about .about-cadence .about-unit {
  font-family: var(--font-body);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--c-mute);
  margin-left: 5px;
}

.page-about .about-cadence dd {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(244, 240, 229, .86);
}

.page-about .about-board__note {
  margin: 20px 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--about-rule-dark);
  font-size: 13px;
  line-height: 1.7;
  color: var(--c-mute);
}

/* ============ 改版时间线 ============ */
.page-about .about-revisions {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-revision {
  padding: 22px 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-revision:last-child {
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-revision__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 14px;
  margin-bottom: 10px;
}

.page-about .about-revision__no {
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--c-mint-deep);
}

.page-about .about-revision__head .label {
  color: var(--about-ink-mute);
  margin-left: auto;
}

.page-about .about-revision > p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.82;
  color: var(--c-ink-2);
  max-width: 64ch;
}

.page-about .about-details {
  border-left: 2px solid var(--c-mint);
  padding-left: 14px;
}

.page-about .about-details summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 3px 0;
  font-size: 13.5px;
  letter-spacing: .04em;
  color: var(--c-mint-deep);
}

.page-about .about-details summary::-webkit-details-marker {
  display: none;
}

.page-about .about-details summary::before {
  content: "+";
  font-family: var(--font-num);
  font-size: 15px;
  line-height: 1;
  color: var(--c-mint-deep);
}

.page-about .about-details[open] summary::before {
  content: "\2212";
}

.page-about .about-details ul {
  margin: 10px 0 2px;
  padding-left: 18px;
  display: grid;
  gap: 7px;
}

.page-about .about-details li {
  font-size: 13.5px;
  line-height: 1.75;
  color: #3A423C;
}

/* ============ 团队分工 ============ */
.page-about .about-team {
  list-style: none;
  margin: 22px 0 20px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-rule);
  border: 1px solid var(--about-rule);
}

.page-about .about-team li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 14px 15px;
  background: var(--c-paper);
}

.page-about .about-team li .num {
  font-family: var(--font-num);
  font-size: 21px;
  line-height: 1;
  color: var(--c-ink-2);
  font-variant-numeric: tabular-nums;
}

.page-about .about-team li span:last-child {
  font-size: 13px;
  letter-spacing: .05em;
  color: var(--about-ink-mute);
}

.page-about .about-team__note {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--about-ink-mute);
  max-width: 62ch;
}

/* ============ 继续阅读 ============ */
.page-about .about-next {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-next__card {
  display: flex;
  flex-direction: column;
  gap: 7px;
  padding: 20px 22px;
  background: var(--c-paper-hi);
  color: var(--c-ink-2);
  text-decoration: none;
  clip-path: polygon(
    0 0,
    calc(100% - 12px) 0,
    100% 12px,
    100% 100%,
    12px 100%,
    0 calc(100% - 12px)
  );
  transition: transform .18s ease, background-color .18s ease;
}

.page-about .about-next__card .label {
  color: var(--about-ink-mute);
}

.page-about .about-next__card strong {
  font-family: var(--font-display);
  font-size: 19px;
  letter-spacing: -0.01em;
  color: var(--c-ink-2);
}

.page-about .about-next__card > span:nth-of-type(2) {
  font-size: 13.5px;
  line-height: 1.72;
  color: #3A423C;
}

.page-about .about-next__go {
  margin-top: 4px;
  font-family: var(--font-num);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--c-mint-deep);
  transition: transform .18s ease;
}

.page-about .about-next__card:hover {
  transform: translateY(-2px);
  background: #FBF7EC;
}

.page-about .about-next__card:hover .about-next__go {
  transform: translateX(4px);
}

/* ============ 焦点 ============ */
.page-about a:focus-visible,
.page-about summary:focus-visible,
.page-about .term:focus-visible {
  outline: 2px solid var(--c-mint);
  outline-offset: 2px;
}

/* ============ 断点 ============ */
@media (min-width: 620px) {
  .page-about .about-cadence {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
  }
}

@media (min-width: 700px) {
  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-next {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-chapters::before {
    content: "";
    position: absolute;
    top: 6px;
    bottom: 6px;
    left: var(--about-rail);
    width: 1px;
    background: linear-gradient(
      180deg,
      rgba(69, 224, 174, .5) 0%,
      rgba(143, 167, 156, .3) 32%,
      rgba(143, 167, 156, .14) 100%
    );
    pointer-events: none;
  }

  .page-about .about-chapter {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 0;
  }

  .page-about .about-chapter__tick {
    justify-content: center;
  }

  .page-about .about-chapter__body {
    padding-left: clamp(22px, 3vw, 46px);
    padding-top: 4px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }
}

@media (min-width: 1100px) {
  .page-about {
    --about-rail: 96px;
  }

  .page-about .about-chapter__body > p {
    max-width: 62ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-next__card,
  .page-about .about-next__go {
    transition: none;
  }

  .page-about .about-next__card:hover {
    transform: none;
  }
}
</main>