.page-about {
  font-family: var(--sans);
  color: var(--ink);
  background: var(--ivory);
}

.page-about a:focus-visible,
.page-about [tabindex]:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 2px;
}

.page-about .breadcrumb {
  margin-top: 22px;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-top: 24px;
}

.page-about .about-hero__frame {
  padding: 28px 20px 30px;
  background: var(--ivory);
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--serif);
  font-weight: 300;
  font-size: clamp(2.3rem, 10vw, 4.4rem);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .about-hero__sub {
  display: block;
  margin-top: 12px;
  font-family: var(--kaiti);
  font-weight: 400;
  font-size: clamp(1rem, 4.2vw, 1.35rem);
  line-height: 1.5;
  letter-spacing: 0.05em;
  color: var(--brown);
}

.page-about .about-hero .lede {
  margin: 22px 0 0;
  max-width: 32em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--brown);
}

.page-about .about-figures {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 30px;
  background: var(--line);
  border-top: 1px solid var(--line);
}

.page-about .about-figure {
  background: var(--ivory);
  padding: 14px 12px 16px;
  min-width: 0;
}

.page-about .about-figure__num {
  display: block;
  font-family: var(--mono);
  font-size: 26px;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--gold);
}

.page-about .about-figure__cap {
  display: block;
  margin-top: 9px;
  font-family: var(--mono);
  font-size: 11px;
  line-height: 1.55;
  letter-spacing: 0.06em;
  color: var(--brown);
}

/* ---------- 主体骨架 ---------- */

.page-about .about-body {
  padding-top: 42px;
}

.page-about .about-index {
  margin-bottom: 30px;
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 8px;
  display: flex;
  gap: 6px;
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
  -webkit-overflow-scrolling: touch;
}

.page-about .about-index__link {
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 6px 9px;
  white-space: nowrap;
  text-decoration: none;
  color: var(--brown);
  border: 1px solid transparent;
  transition: color 160ms var(--ease), border-color 160ms var(--ease), background-color 160ms var(--ease);
}

.page-about .about-index__num {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--mist);
}

.page-about .about-index__label {
  font-size: 13px;
}

.page-about .about-index__link:hover {
  color: var(--cinnabar);
  border-color: var(--line);
  background: var(--paper);
}

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

/* ---------- 段落 ---------- */

.page-about .about-sec {
  position: relative;
  padding: 36px 0 30px;
  border-top: 1px solid var(--line);
  scroll-margin-top: 84px;
}

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

.page-about .about-sec::after {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 46px;
  height: 1px;
  background: var(--cinnabar);
}

.page-about .about-sec:first-child::after {
  display: none;
}

.page-about .about-sec--flush {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec--flush::after {
  display: none;
}

.page-about .about-sec__num {
  display: inline-block;
  padding-bottom: 4px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--cinnabar);
  border-bottom: 1px solid var(--cinnabar);
}

.page-about .about-sec h2 {
  margin: 12px 0 18px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(1.35rem, 5vw, 1.9rem);
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-sec p {
  max-width: 34em;
  margin: 0 0 1.2em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--ink);
}

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

.page-about .about-link {
  color: var(--cinnabar);
  text-decoration-line: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  transition: text-decoration-thickness 160ms var(--ease), color 160ms var(--ease);
}

.page-about .about-link:hover {
  text-decoration-thickness: 2px;
}

/* ---------- 图片 ---------- */

.page-about .about-photo {
  margin: 26px 0 22px;
}

.page-about .about-photo .media__frame {
  overflow: hidden;
  background: var(--paper);
}

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

.page-about .about-photo--band .media__frame img {
  aspect-ratio: 21 / 9;
}

.page-about .about-photo .media__cap {
  margin-top: 9px;
  font-family: var(--mono);
  font-size: 11px;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--brown);
}

/* ---------- 校对环节 ---------- */

.page-about .about-flowmap {
  margin: 26px 0 24px;
  padding: 18px 14px 20px;
  background: var(--paper);
  border: 1px solid var(--line);
}

.page-about .about-flowmap__svg {
  display: block;
  width: 100%;
  height: auto;
  margin-bottom: 12px;
}

.page-about .about-flowmap__path {
  fill: none;
  stroke: var(--bamboo);
  stroke-width: 1.5;
  vector-effect: non-scaling-stroke;
}

.page-about .about-flowmap__node {
  fill: var(--ivory);
  stroke: var(--cinnabar);
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}

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

.page-about .about-flowmap__step {
  position: relative;
  background: var(--paper);
  padding: 14px 12px 16px;
  min-width: 0;
  transition: background-color 160ms var(--ease), box-shadow 160ms var(--ease);
}

.page-about .about-flowmap__step:hover,
.page-about .about-flowmap__step:focus {
  background: var(--ivory);
  box-shadow: inset 2px 0 0 var(--cinnabar);
}

.page-about .about-flowmap__num {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cinnabar);
}

.page-about .about-flowmap__name {
  display: block;
  margin-top: 7px;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-flowmap__role {
  display: block;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin-top: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--brown);
  transition: max-height 200ms var(--ease), opacity 200ms var(--ease), margin-top 200ms var(--ease);
}

.page-about .about-flowmap__step:hover .about-flowmap__role,
.page-about .about-flowmap__step:focus .about-flowmap__role {
  max-height: 14em;
  opacity: 1;
  margin-top: 9px;
}

/* ---------- 服务范围 ---------- */

.page-about .about-scope {
  margin-top: 16px;
  padding: 40px 0 42px;
  background: var(--paper);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 84px;
}

/* ---------- 版本留痕 ---------- */

.page-about .about-rhythm {
  margin-top: 44px;
  padding: 48px 0 54px;
  background: var(--deepgreen);
  color: var(--ivory);
  scroll-margin-top: 84px;
}

.page-about .about-rhythm__num {
  display: inline-block;
  margin: 0;
  padding-bottom: 4px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--gold);
  border-bottom: 1px solid var(--gold);
}

.page-about .about-rhythm h2 {
  margin: 14px 0 16px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(1.45rem, 5.4vw, 2.1rem);
  line-height: 1.28;
  letter-spacing: -0.01em;
  color: var(--ivory);
}

.page-about .about-rhythm__lede {
  max-width: 34em;
  margin: 0 0 8px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ivory);
  opacity: 0.78;
}

.page-about .about-timeline {
  list-style: none;
  position: relative;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: var(--line-light);
}

.page-about .about-timeline__item {
  position: relative;
  padding-left: 34px;
}

.page-about .about-timeline .fold {
  border-bottom: 1px solid var(--line-light);
}

.page-about .about-timeline .fold__summary {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 15px 0;
  list-style: none;
  cursor: pointer;
  color: var(--ivory);
  transition: color 160ms var(--ease);
}

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

.page-about .about-timeline .fold__summary::before {
  content: "";
  position: absolute;
  left: -34px;
  top: 23px;
  width: 20px;
  height: 1px;
  background: var(--gold);
  transition: width 160ms var(--ease);
}

.page-about .about-timeline .fold[open] > .fold__summary::before,
.page-about .about-timeline .fold__summary:hover::before {
  width: 28px;
}

.page-about .about-timeline .fold__summary:hover {
  color: var(--gold);
}

.page-about .about-timeline__round {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .about-timeline__label {
  font-size: 15px;
  line-height: 1.5;
}

.page-about .about-rhythm .fold__body {
  padding: 0 0 18px;
  max-width: 46em;
  font-size: 14px;
  line-height: 1.85;
  color: var(--ivory);
  opacity: 0.78;
}

.page-about .about-rhythm__more {
  max-width: 40em;
  margin: 30px 0 0;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--ivory);
  opacity: 0.85;
}

.page-about .about-rhythm .about-link {
  color: var(--gold);
}

.page-about .about-rhythm a:focus-visible,
.page-about .about-rhythm summary:focus-visible {
  outline-color: var(--gold);
}

/* ---------- 窄屏之上的调整 ---------- */

@media (min-width: 600px) {
  .page-about .about-figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .about-flowmap__steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 700px) {
  .page-about .about-sec__split {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 208px;
    column-gap: 32px;
    align-items: start;
  }
  .page-about .about-sec__split .about-photo {
    margin-top: 4px;
    margin-bottom: 0;
  }
  .page-about .about-flowmap__steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .about-flowmap {
    padding: 20px 18px 22px;
  }
}

@media (hover: none) {
  .page-about .about-flowmap__role {
    max-height: 14em;
    opacity: 1;
    margin-top: 9px;
  }
}

@media (min-width: 961px) {
  .page-about .about-hero__frame {
    padding: 52px 48px 56px;
  }
  .page-about .about-body {
    display: grid;
    grid-template-columns: 112px minmax(0, 1fr);
    column-gap: 52px;
    align-items: start;
    padding-top: 52px;
  }
  .page-about .about-index {
    position: sticky;
    top: 30px;
    margin-bottom: 0;
  }
  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
    border-bottom: 0;
    border-left: 1px solid var(--line);
  }
  .page-about .about-index__link {
    flex-direction: column;
    align-items: flex-start;
    gap: 3px;
    margin-left: -1px;
    padding: 10px 0 10px 14px;
    border: 0;
    border-left: 2px solid transparent;
  }
  .page-about .about-index__link:hover {
    background: transparent;
    border-left-color: var(--cinnabar);
  }
  .page-about .about-flow {
    max-width: 860px;
  }
  .page-about .about-sec {
    padding: 44px 0 38px;
  }
  .page-about .about-rhythm {
    padding: 64px 0 72px;
  }
}
<<<END>>>