.page-about {
  background: var(--porcelain);
  padding-bottom: clamp(3rem, 8vw, 5rem);
}

/* ---------- 首屏 ---------- */
.page-about .about-intro {
  position: relative;
  display: grid;
  gap: clamp(1.75rem, 4vw, 2.5rem);
  padding: clamp(1.5rem, 3.5vw, 2.5rem) 0 clamp(2rem, 5vw, 3.25rem);
  border-bottom: 1px solid var(--ink-24);
}

.page-about .about-intro__title {
  margin: 0.55rem 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2rem, 6.4vw, 3.6rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-intro__lead {
  margin: 1rem 0 0;
  max-width: 33em;
  font-size: clamp(1rem, 2.1vw, 1.1rem);
  line-height: 1.85;
  color: var(--ink-70);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.9rem 1.1rem;
  margin: 1.6rem 0 0;
  padding-top: 1.25rem;
  border-top: 1px dashed var(--ink-24);
}

.page-about .about-facts__item {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  min-width: 0;
}

.page-about .about-facts dt {
  font-size: 0.75rem;
  letter-spacing: 0.09em;
  color: var(--patina);
}

.page-about .about-facts dd {
  margin: 0;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.4;
}

.page-about .about-facts__num {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  letter-spacing: -0.01em;
}

.page-about .about-intro__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  margin-top: 1.6rem;
}

.page-about .about-intro__figure {
  margin: 0;
  align-self: stretch;
}

.page-about .about-intro__figure .media__frame {
  box-shadow: var(--shadow-frame);
  border-top: 3px solid var(--cinnabar);
}

/* ---------- 主体：轨道 + 叙事 ---------- */
.page-about .about-body {
  padding-top: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-rail {
  margin-bottom: 1.75rem;
}

.page-about .about-rail__head {
  margin: 0 0 0.7rem;
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .about-rail__list {
  display: flex;
  gap: 0.5rem;
  margin: 0;
  padding: 0 0 0.35rem;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail__item {
  flex: 0 0 auto;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.42rem 0.75rem;
  border: 1px solid var(--ink-12);
  color: var(--ink-70);
  font-size: 0.85rem;
  line-height: 1.2;
  white-space: nowrap;
  text-decoration: none;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--cinnabar);
  border-color: var(--cinnabar-soft);
  background: var(--light-08);
}

.page-about .about-rail__link.is-active {
  color: var(--cinnabar);
  border-color: var(--cinnabar);
  background: rgba(178, 58, 46, 0.07);
}

.page-about .about-rail__code {
  font-size: 0.72rem;
  color: var(--patina);
}

.page-about .about-rail__link.is-active .about-rail__code {
  color: var(--cinnabar);
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  padding-top: clamp(1.35rem, 3.2vw, 2rem);
  border-top: 1px solid var(--ink-24);
}

.page-about .about-section + .about-section {
  margin-top: clamp(2.25rem, 5vw, 3.5rem);
}

.page-about .about-section__no {
  margin: 0;
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--cinnabar);
}

.page-about .about-section__title {
  margin: 0.6rem 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.45rem, 3.6vw, 2.1rem);
  line-height: 1.28;
  letter-spacing: -0.005em;
  color: var(--ink);
}

.page-about .about-section__lead {
  margin: 0.9rem 0 0;
  font-size: 0.98rem;
  line-height: 1.8;
  color: var(--ink-70);
  max-width: 40em;
}

.page-about .about-section__body {
  margin-top: 1rem;
}

.page-about .about-section__body p {
  margin-bottom: 0.9rem;
}

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

.page-about .about-section__body a {
  color: var(--cinnabar);
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

/* 深墨章节 */
.page-about .about-section--ink {
  border-top: 0;
  padding: clamp(1.6rem, 4vw, 2.6rem);
  background: var(--ink);
  color: var(--porcelain);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
}

.page-about .about-section--ink .about-section__no {
  color: var(--cinnabar-soft);
}

.page-about .about-section--ink .about-section__title {
  color: var(--porcelain);
}

.page-about .about-section--ink .about-section__lead {
  color: var(--light-70);
}

/* ---------- 团队分工 ---------- */
.page-about .team-grid {
  display: grid;
  gap: 0.85rem;
  margin-top: 1.5rem;
}

.page-about .team-card {
  padding: 1.05rem 1.15rem 1.15rem;
  background: var(--light-08);
  border: 1px solid var(--light-22);
  border-top: 3px solid var(--celadon);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%);
}

.page-about .team-card__name {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: 0.02em;
  color: var(--porcelain);
}

.page-about .team-card__desc {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.78;
  color: var(--light-70);
}

/* ---------- 编号方法 ---------- */
.page-about .about-split {
  display: grid;
  gap: 1.5rem;
  margin-top: 1rem;
}

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

.page-about .about-split__aside .media__frame {
  border: 1px solid var(--ink-12);
}

.page-about .codestrip {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0.55rem;
  margin: 1.3rem 0;
}

.page-about .codestrip__cell {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.7rem 0.9rem;
  background: var(--linen);
  border-left: 3px solid var(--patina);
}

.page-about .codestrip__k {
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--jiang);
}

.page-about .codestrip__v {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--ink);
}

.page-about .codestrip__sep {
  display: none;
  color: var(--mist);
  font-size: 0.9rem;
}

.page-about .code-notes {
  margin: 0 0 1.1rem;
  padding: 0;
  list-style: none;
  border-top: 1px dashed var(--ink-24);
}

.page-about .code-notes__item {
  padding: 0.7rem 0 0.7rem 0.9rem;
  border-bottom: 1px dashed var(--ink-12);
  border-left: 2px solid var(--celadon);
  font-size: 0.92rem;
  line-height: 1.75;
  color: var(--ink-70);
}

.page-about .code-notes__k {
  display: inline-block;
  margin-right: 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--cinnabar);
}

/* ---------- 内容中心栏目 ---------- */
.page-about .hub-list {
  margin: 1.4rem 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ink-24);
}

.page-about .hub-item {
  display: flex;
  gap: 0.9rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--ink-12);
}

.page-about .hub-item__code {
  flex: 0 0 auto;
  min-width: 1.6rem;
  padding-top: 0.15rem;
  font-size: 0.78rem;
  color: var(--patina);
}

.page-about .hub-item__body {
  min-width: 0;
}

.page-about .hub-item__name {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.08rem;
  color: var(--jiang);
}

.page-about .hub-item__desc {
  margin: 0 0 0.5rem;
  font-size: 0.92rem;
  line-height: 1.78;
  color: var(--ink-70);
}

/* ---------- 服务范围 ---------- */
.page-about .region-figure {
  margin: 1.3rem 0 1.2rem;
  --media-ratio: 8 / 3;
}

.page-about .region-figure .media__frame {
  border-top: 3px solid var(--patina);
  border-bottom: 3px solid var(--patina);
}

/* ---------- 校勘记录 ---------- */
.page-about .rev-list {
  margin-top: 1.35rem;
  border-top: 1px solid var(--ink-24);
}

.page-about .rev {
  border-bottom: 1px solid var(--ink-12);
}

.page-about .rev__summary {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
  padding: 0.9rem 0.2rem;
  cursor: pointer;
  color: var(--ink);
}

.page-about .rev__summary::marker {
  color: var(--cinnabar);
}

.page-about .rev__code {
  flex: 0 0 auto;
  font-size: 0.74rem;
  letter-spacing: 0.06em;
  color: var(--cinnabar);
}

.page-about .rev__title {
  font-size: 0.96rem;
  font-weight: 600;
  line-height: 1.5;
}

.page-about .rev__body {
  padding: 0 0.2rem 1rem 0.2rem;
}

.page-about .rev__body p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--ink-70);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta {
  display: grid;
  gap: 1rem;
  margin-top: clamp(1.75rem, 4vw, 2.5rem);
  padding: 1.25rem 1.3rem;
  background: var(--celadon);
  border-left: 4px solid var(--cinnabar);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .about-cta__text {
  margin: 0;
  font-size: 0.96rem;
  line-height: 1.8;
  color: var(--jiang);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}

/* ---------- 响应式 ---------- */
@media (min-width: 600px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .codestrip {
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr);
    align-items: stretch;
    gap: 0.5rem;
  }

  .page-about .codestrip__sep {
    display: block;
    align-self: center;
  }

  .page-about .codestrip__cell {
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    gap: 0.3rem;
    padding: 0.8rem 0.85rem;
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    padding: 1.4rem 1.6rem;
  }
}

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

@media (min-width: 860px) {
  .page-about .about-intro {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: end;
    gap: clamp(2rem, 5vw, 3.75rem);
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.6fr);
    align-items: start;
    gap: 1.75rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-body {
    display: grid;
    grid-template-columns: 168px minmax(0, 1fr);
    gap: clamp(2rem, 4vw, 3.25rem);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 112px;
    margin-bottom: 0;
  }

  .page-about .about-rail__list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail__item + .about-rail__item {
    margin-top: 0.15rem;
  }

  .page-about .about-rail__link {
    display: flex;
    width: 100%;
    padding: 0.5rem 0.6rem 0.5rem 0.7rem;
    border: 0;
    border-left: 2px solid var(--ink-12);
    background: transparent;
    white-space: normal;
  }

  .page-about .about-rail__link.is-active {
    border-left-color: var(--cinnabar);
    background: linear-gradient(90deg, rgba(178, 58, 46, 0.09), transparent 78%);
  }

  .page-about .about-section__title {
    max-width: 22em;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link {
    transition: none;
  }
}
<<<END>>>