.page-about {
  --about-line: rgba(140, 90, 43, .32);
  --about-shadow: -7px 7px 0 -1px var(--c-gold-soft);
  background: var(--c-base);
  color: var(--c-ink);
  font-family: var(--sans);
  padding-bottom: 96px;
}

/* ---------- 首屏 ---------- */
.page-about .about-head {
  position: relative;
  overflow: hidden;
  background: var(--c-base);
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-head::before {
  content: "";
  position: absolute;
  top: -24%;
  right: -22%;
  width: 78%;
  aspect-ratio: 1 / 1;
  background: linear-gradient(150deg, rgba(224, 160, 32, .95), rgba(246, 223, 174, .28) 74%);
  clip-path: polygon(58% 0, 100% 0, 100% 100%, 0 100%);
  opacity: .42;
  pointer-events: none;
}

.page-about .about-head__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(26px, 4vw, 46px);
  padding-block: clamp(26px, 4.5vw, 54px) clamp(34px, 5vw, 68px);
}

.page-about .about-head__text .eyebrow {
  margin-top: clamp(14px, 2vw, 22px);
}

.page-about .about-head h1 {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.95rem, 5.4vw, 3.3rem);
  line-height: 1.18;
  letter-spacing: -0.02em;
  margin: .3em 0 .55em;
  color: var(--c-green);
}

.page-about .about-head .lede {
  max-width: 46ch;
  line-height: 1.8;
  color: var(--c-ink);
}

.page-about .about-head__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .about-head__figure {
  margin: 0;
  padding: 9px;
  background: var(--c-paper);
  border: 1px solid var(--c-copper);
  box-shadow: var(--about-shadow);
  transform: rotate(-1.2deg);
}

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

@media (min-width: 900px) {
  .page-about .about-head__inner {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    align-items: center;
  }
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  display: grid;
  gap: clamp(28px, 4vw, 48px);
  padding-block: clamp(34px, 5vw, 68px) clamp(28px, 4vw, 44px);
}

/* ---------- 章节目录 ---------- */
.page-about .about-toc {
  background: var(--c-paper);
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--c-gold);
  padding: 16px 18px;
  align-self: start;
}

.page-about .about-toc__label {
  margin: 0 0 12px;
  font-family: var(--serif);
  font-size: 12px;
  letter-spacing: .34em;
  color: var(--c-copper);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 9px 18px;
}

.page-about .about-toc__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-size: 14px;
  line-height: 1.5;
  color: var(--c-green);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
  transition: color .22s var(--ease), border-color .22s var(--ease);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  color: var(--c-red);
  border-bottom-color: var(--c-red);
}

.page-about .about-toc__index {
  font-family: var(--serif);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  color: var(--c-copper);
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: minmax(0, 1fr) 214px;
    align-items: start;
  }

  .page-about .about-toc {
    grid-column: 2;
    grid-row: 1;
    position: sticky;
    top: 24px;
    padding: 20px 18px 22px;
  }

  .page-about .about-chapters {
    grid-column: 1;
    grid-row: 1;
    min-width: 0;
  }

  .page-about .about-toc__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 13px;
  }
}

/* ---------- 章节 ---------- */
.page-about .chapter {
  position: relative;
  padding-bottom: clamp(28px, 4vw, 52px);
  margin-bottom: clamp(28px, 4vw, 52px);
  border-bottom: 1px dashed var(--about-line);
}

.page-about .chapter:last-of-type {
  border-bottom: 0;
  margin-bottom: clamp(24px, 3vw, 36px);
  padding-bottom: 0;
}

.page-about .chapter__head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  margin-bottom: clamp(16px, 2.4vw, 24px);
}

.page-about .chapter__side {
  display: none;
  writing-mode: vertical-rl;
  font-family: var(--serif);
  font-size: 12px;
  letter-spacing: .26em;
  color: var(--c-copper);
  padding-top: 4px;
}

.page-about .chapter__num {
  display: block;
  font-family: var(--serif);
  font-weight: 900;
  font-size: clamp(34px, 6.6vw, 56px);
  line-height: .94;
  letter-spacing: .02em;
  font-variant-numeric: tabular-nums;
  color: var(--c-gold);
  opacity: .52;
  margin-bottom: .1em;
}

.page-about .chapter__title {
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(1.35rem, 3.2vw, 1.95rem);
  line-height: 1.36;
  letter-spacing: -0.01em;
  margin: 0;
  color: var(--c-green);
}

.page-about .chapter p {
  margin: 0 0 1em;
  line-height: 1.82;
}

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

.page-about .chapter a {
  color: var(--c-red);
  text-decoration: underline;
  text-underline-offset: 3px;
}

@media (min-width: 1080px) {
  .page-about .chapter__head {
    grid-template-columns: 32px minmax(0, 1fr);
    column-gap: 20px;
    align-items: start;
  }

  .page-about .chapter__side {
    display: block;
  }
}

/* ---------- 通用图框 ---------- */
.page-about .about-figure {
  margin: 0 0 clamp(20px, 3vw, 32px);
  padding: 8px;
  background: var(--c-paper);
  border: 1px solid var(--c-copper);
  box-shadow: -6px 6px 0 -1px var(--c-gold-soft);
}

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

.page-about .about-figure figcaption {
  font-size: 13px;
  line-height: 1.6;
  color: var(--c-muted);
  padding: 9px 4px 3px;
}

.page-about .about-figure--square {
  margin: 0;
}

/* ---------- 团队分工 ---------- */
.page-about .team-split {
  display: grid;
  gap: clamp(20px, 3vw, 30px);
  margin: clamp(16px, 2.4vw, 24px) 0 1.1em;
}

.page-about .bars {
  list-style: none;
  margin: 0 0 1.1em;
  padding: 0;
  display: grid;
  gap: 15px;
}

.page-about .bar__head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 4px 12px;
  font-size: 14px;
  font-weight: 500;
  margin-bottom: 6px;
  color: var(--c-green);
}

.page-about .bar__head .num {
  font-size: 13px;
  color: var(--c-copper);
  letter-spacing: .01em;
}

.page-about .bar__track {
  display: block;
  height: 12px;
  background: var(--c-gold-soft);
  border: 1px solid rgba(140, 90, 43, .38);
}

.page-about .bar__fill {
  display: block;
  height: 100%;
  transition: width .5s var(--ease);
}

.page-about .bar--product .bar__fill { width: 17%; }
.page-about .bar--eng .bar__fill { width: 45%; }
.page-about .bar--cs .bar__fill { width: 19%; }
.page-about .bar--content .bar__fill { width: 19%; }

.page-about .bar__fill--gold { background: var(--c-gold); }
.page-about .bar__fill--green { background: var(--c-green); }
.page-about .bar__fill--red { background: var(--c-red); }
.page-about .bar__fill--copper { background: var(--c-copper); }

@media (min-width: 900px) {
  .page-about .team-split {
    grid-template-columns: minmax(0, 1fr) 282px;
    align-items: start;
  }
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  position: relative;
  display: grid;
  gap: 18px;
  margin-top: clamp(18px, 3vw, 34px);
  padding-top: 0;
}

.page-about .timeline::before {
  content: none;
}

.page-about .tl-item {
  position: relative;
  background: var(--c-paper);
  border: 1px solid rgba(140, 90, 43, .55);
  padding: clamp(20px, 3vw, 26px) clamp(18px, 2.6vw, 24px);
  box-shadow: var(--about-shadow);
  transition: transform .28s var(--ease), border-color .28s var(--ease), box-shadow .28s var(--ease);
}

.page-about .tl-item:hover {
  transform: translateY(-6px);
  border-color: var(--c-red);
  box-shadow: -8px 12px 0 -1px var(--c-gold-soft);
}

.page-about .tl-item__dot {
  position: absolute;
  top: -7px;
  left: 22px;
  width: 13px;
  height: 13px;
  background: var(--c-red);
  border-radius: 50%;
  border: 2px solid var(--c-paper);
}

.page-about .tl-item:nth-child(2) .tl-item__dot { background: var(--c-gold); }
.page-about .tl-item:nth-child(3) .tl-item__dot { background: var(--c-green); }

.page-about .tl-item__range {
  margin: 0 0 .5em;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .06em;
  color: var(--c-copper);
}

.page-about .tl-item__title {
  margin: 0 0 .55em;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.14rem;
  line-height: 1.42;
  color: var(--c-green);
}

.page-about .tl-item__text {
  margin: 0 0 .9em;
  font-size: 15px;
  line-height: 1.78;
}

.page-about .tl-item__key {
  margin: 0;
  padding-top: .8em;
  border-top: 1px solid var(--about-line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--c-red);
  letter-spacing: .01em;
}

@media (min-width: 820px) {
  .page-about .timeline {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 26px;
    padding-top: 26px;
  }

  .page-about .timeline::before {
    content: "";
    position: absolute;
    top: 8px;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--c-copper);
    opacity: .55;
  }

  .page-about .tl-item:nth-child(2) { margin-top: 42px; }
  .page-about .tl-item:nth-child(3) { margin-top: 16px; }
}

/* ---------- 归档流程 ---------- */
.page-about .flow {
  list-style: none;
  margin: clamp(18px, 2.6vw, 26px) 0 1.2em;
  padding: 0;
  display: grid;
  gap: 20px;
  counter-reset: flow;
}

.page-about .flow__item {
  position: relative;
  padding-left: 54px;
}

.page-about .flow__item::before {
  counter-increment: flow;
  content: counter(flow, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 1px;
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 14px;
  font-variant-numeric: tabular-nums;
  color: var(--c-paper);
  background: var(--c-green);
}

.page-about .flow__item h3 {
  margin: 0 0 .35em;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.03rem;
  line-height: 1.45;
  color: var(--c-ink);
}

.page-about .flow__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
}

/* ---------- 工作准则 ---------- */
.page-about .rules {
  list-style: none;
  margin: clamp(14px, 2vw, 20px) 0 0;
  padding: 0;
  border-top: 1px solid var(--about-line);
}

.page-about .rules__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 20px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .rules__key {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.06rem;
  color: var(--c-red);
  letter-spacing: .02em;
  position: relative;
  padding-left: 16px;
}

.page-about .rules__key::before {
  content: "";
  position: absolute;
  left: 0;
  top: .46em;
  width: 7px;
  height: 7px;
  background: var(--c-gold);
}

.page-about .rules__value {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
}

@media (min-width: 720px) {
  .page-about .rules__item {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 28px;
    align-items: baseline;
    padding: 22px 0;
  }

  .page-about .rules__value {
    padding-left: 6px;
  }
}

/* ---------- 结尾导航块 ---------- */
.page-about .about-next {
  display: grid;
  gap: 18px;
  padding: clamp(24px, 4vw, 40px);
  background: var(--c-green);
  color: var(--c-paper);
  border-top: 4px solid var(--c-red);
}

.page-about .about-next__title {
  margin: 0 0 .4em;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: .04em;
}

.page-about .about-next__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--c-gold-soft);
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

@media (min-width: 800px) {
  .page-about .about-next {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 26px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-item,
  .page-about .bar__fill {
    transition: none;
  }

  .page-about .tl-item:hover {
    transform: none;
  }
}
<<<END>>>