.page-about {
  --about-rail-w: 236px;
  background: var(--by-ink);
  color: var(--by-text);
  font-family: var(--by-font-body);
  line-height: 1.75;
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(18px, 3.4vw, 34px) 0 clamp(30px, 5.5vw, 64px);
  background:
    radial-gradient(circle at 80% 8%, rgba(199, 255, 61, 0.11), transparent 46%),
    linear-gradient(180deg, var(--by-forest) 0%, var(--by-ink) 100%);
  border-bottom: 1px solid var(--by-line);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(42, 59, 51, 0.55) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(42, 59, 51, 0.55) 1px, transparent 1px);
  background-size: 96px 96px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 86%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 86%);
  pointer-events: none;
}

.page-about .about-hero > .by-shell {
  position: relative;
  z-index: 1;
}

.page-about .by-breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--by-font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
}

.page-about .by-breadcrumb__item + .by-breadcrumb__item::before {
  content: "/";
  margin-right: 6px;
  color: var(--by-dim);
}

.page-about .by-breadcrumb__link {
  color: var(--by-muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--by-ease), border-color 0.16s var(--by-ease);
}

.page-about .by-breadcrumb__link:hover {
  color: var(--by-lime);
  border-bottom-color: var(--by-lime);
}

.page-about .by-breadcrumb__current {
  color: var(--by-text);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(22px, 4vw, 44px);
  margin-top: 20px;
}

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

.page-about .by-eyebrow {
  display: inline-block;
  margin: 0 0 14px;
  padding: 4px 10px;
  border: 1px solid var(--by-line);
  font-family: var(--by-font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--by-lime);
  background: rgba(199, 255, 61, 0.05);
}

.page-about .about-hero__title {
  margin: 0 0 18px;
  font-family: var(--by-font-display);
  font-weight: 800;
  font-size: clamp(32px, 6.2vw, 68px);
  line-height: 1.04;
  letter-spacing: -0.012em;
  color: var(--by-text);
  text-wrap: balance;
  position: relative;
}

.page-about .about-hero__title::after {
  content: "";
  display: block;
  width: 96px;
  height: 3px;
  margin-top: 18px;
  background: linear-gradient(100deg, var(--by-lime) 0%, var(--by-lime) 62%, transparent 62%);
  transform: skewX(-18deg);
}

.page-about .about-hero__lede {
  max-width: 60ch;
  margin: 0 0 22px;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
  color: var(--by-muted);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 24px;
}

.page-about .about-hero__actions .by-btn {
  font-family: var(--by-font-display);
  font-weight: 600;
  letter-spacing: 0.04em;
}

.page-about .about-hero__strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  background: var(--by-line);
  border: 1px solid var(--by-line);
}

.page-about .about-hero__strip-item {
  background: var(--by-panel);
  padding: 12px 12px 14px;
  min-width: 0;
}

.page-about .about-hero__strip-item dt {
  font-size: 12px;
  line-height: 1.5;
  color: var(--by-dim);
  letter-spacing: 0.02em;
}

.page-about .about-hero__strip-item dd {
  margin: 4px 0 0;
  font-family: var(--by-font-mono);
  font-size: clamp(17px, 2.4vw, 23px);
  line-height: 1.2;
  color: var(--by-lime);
}

.page-about .about-hero__media {
  position: relative;
  margin: 0;
  border: 1px solid var(--by-line);
  background: var(--by-panel);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 34px), calc(100% - 34px) 100%, 0 100%);
}

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

.page-about .by-media__tag {
  position: absolute;
  left: 0;
  bottom: 0;
  padding: 6px 12px;
  font-family: var(--by-font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--by-ink);
  background: var(--by-lime);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  padding: clamp(24px, 4.5vw, 56px) 0 clamp(40px, 7vw, 88px);
  background: var(--by-forest);
}

.page-about .about-body__grid {
  display: grid;
  gap: clamp(20px, 3.6vw, 40px);
  align-items: start;
}

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

.page-about .about-toc {
  border-top: 1px solid var(--by-line);
  padding-top: 12px;
}

.page-about .by-toc__title {
  margin: 0 0 10px;
  font-family: var(--by-font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--by-dim);
}

.page-about .by-toc__list {
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .by-toc__item {
  flex: none;
}

.page-about .by-toc__link {
  display: block;
  white-space: nowrap;
  padding: 7px 12px;
  font-family: var(--by-font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--by-muted);
  text-decoration: none;
  border: 1px solid var(--by-line);
  transition: color 0.16s var(--by-ease), border-color 0.16s var(--by-ease), background 0.16s var(--by-ease);
}

.page-about .by-toc__link:hover,
.page-about .by-toc__link:focus-visible {
  color: var(--by-lime);
  border-color: var(--by-lime);
  background: rgba(199, 255, 61, 0.06);
}

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

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  padding: clamp(22px, 3.2vw, 34px) 0 clamp(26px, 3.6vw, 40px);
  border-top: 1px solid var(--by-line-soft);
}

.page-about .about-chapter:first-child {
  border-top: none;
  padding-top: 0;
}

.page-about .about-chapter__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 16px;
}

.page-about .about-chapter__index {
  flex: none;
  font-family: var(--by-font-mono);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--by-lime);
  padding-top: 5px;
}

.page-about .about-chapter__title {
  margin: 0;
  font-family: var(--by-font-display);
  font-weight: 700;
  font-size: clamp(23px, 3.4vw, 36px);
  line-height: 1.14;
  letter-spacing: -0.005em;
  color: var(--by-text);
}

.page-about .about-chapter__lead {
  max-width: 68ch;
  margin: 0 0 20px;
  font-size: clamp(15px, 1.5vw, 16px);
  line-height: 1.8;
  color: var(--by-muted);
}

.page-about .about-chapter__prose p {
  max-width: 68ch;
  margin: 0 0 14px;
  font-size: clamp(15px, 1.5vw, 16px);
  line-height: 1.8;
  color: var(--by-muted);
}

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

.page-about .about-chapter__prose strong {
  color: var(--by-text);
  font-weight: 600;
  padding-bottom: 1px;
  box-shadow: inset 0 -1px 0 rgba(199, 255, 61, 0.5);
}

.page-about .about-chapter__aside {
  max-width: 68ch;
  margin: 18px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--by-dim);
}

.page-about .by-link {
  color: var(--by-lime);
  text-decoration: none;
  border-bottom: 1px solid rgba(199, 255, 61, 0.45);
  transition: border-color 0.16s var(--by-ease), color 0.16s var(--by-ease);
}

.page-about .by-link:hover,
.page-about .by-link:focus-visible {
  color: var(--by-focus);
  border-bottom-color: var(--by-focus);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 4px 0 0;
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 24px 26px;
  border-left: 1px solid var(--by-line);
}

.page-about .about-timeline__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -4.5px;
  top: 7px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--by-ink);
  border: 1px solid var(--by-line);
}

.page-about .about-timeline__item:first-child::before {
  background: var(--by-lime);
  border-color: var(--by-lime);
}

.page-about .about-timeline__label {
  margin: 0 0 6px;
  font-family: var(--by-font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--by-ember);
}

.page-about .about-timeline__text {
  max-width: 64ch;
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--by-muted);
}

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

.page-about .about-figure {
  background: var(--by-panel);
  padding: 15px 14px 16px;
  min-width: 0;
}

.page-about .about-figure__num {
  display: block;
  margin: 0;
  font-family: var(--by-font-mono);
  font-size: clamp(25px, 4vw, 36px);
  line-height: 1.1;
  color: var(--by-lime);
  letter-spacing: -0.02em;
}

.page-about .about-figure__unit {
  font-size: 0.62em;
  color: var(--by-focus);
}

.page-about .about-figure__label {
  display: block;
  margin-top: 7px;
  font-size: 12.5px;
  line-height: 1.55;
  color: var(--by-muted);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 12px;
}

.page-about .about-team__card {
  position: relative;
  padding: 16px 16px 18px;
  background: var(--by-panel);
  border: 1px solid var(--by-line);
  transition: border-color 0.18s var(--by-ease), transform 0.18s var(--by-ease), background 0.18s var(--by-ease);
}

.page-about .about-team__card:hover,
.page-about .about-team__card:focus-within {
  border-color: var(--by-lime);
  background: var(--by-panel-2);
  transform: translateY(-2px);
}

.page-about .about-team__no {
  margin: 0 0 8px;
  font-family: var(--by-font-mono);
  font-size: 22px;
  line-height: 1;
  color: var(--by-lime);
  letter-spacing: 0.04em;
}

.page-about .about-team__title {
  margin: 0 0 8px;
  font-family: var(--by-font-display);
  font-weight: 600;
  font-size: 18px;
  line-height: 1.3;
  color: var(--by-text);
}

.page-about .about-team__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--by-muted);
}

.page-about .about-team__media,
.page-about .about-partners__media {
  margin: 18px 0 0;
  border: 1px solid var(--by-line);
  background: var(--by-panel);
  position: relative;
}

.page-about .about-team__media img,
.page-about .about-partners__media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

/* ---------- 合作生态 ---------- */
.page-about .about-partners__list {
  display: grid;
  gap: 1px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
  background: var(--by-line);
  border: 1px solid var(--by-line);
}

.page-about .about-partners__item {
  background: var(--by-panel);
  padding: 15px 16px 16px;
  border-left: 2px solid transparent;
  transition: border-color 0.18s var(--by-ease);
}

.page-about .about-partners__item:hover {
  border-left-color: var(--by-lime);
}

.page-about .about-partners__name {
  margin: 0 0 6px;
  font-family: var(--by-font-display);
  font-weight: 600;
  font-size: 17px;
  line-height: 1.3;
  color: var(--by-text);
}

.page-about .about-partners__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--by-muted);
}

/* ---------- 服务与联系 ---------- */
.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 20px 0 22px;
}

.page-about .about-actions .by-btn {
  font-family: var(--by-font-display);
  font-weight: 600;
  letter-spacing: 0.04em;
}

.page-about .about-contact {
  padding: 18px 18px 20px;
  border: 1px solid var(--by-line);
  background: var(--by-glass);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

.page-about .about-contact__title {
  margin: 0 0 14px;
  font-family: var(--by-font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--by-lime);
}

.page-about .about-contact__list {
  display: grid;
  gap: 10px;
  margin: 0;
}

.page-about .about-contact__row {
  display: grid;
  gap: 2px;
}

.page-about .about-contact__row dt {
  font-family: var(--by-font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--by-dim);
}

.page-about .about-contact__row dd {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.65;
  color: var(--by-text);
  word-break: break-word;
}

.page-about .about-contact__note {
  margin: 14px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--by-ember);
  font-size: 13px;
  line-height: 1.7;
  color: var(--by-muted);
}

/* ---------- 焦点可见性 ---------- */
.page-about a:focus-visible,
.page-about .by-btn:focus-visible {
  outline: 2px solid var(--by-focus);
  outline-offset: 3px;
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .about-partners__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-contact__row {
    grid-template-columns: 96px minmax(0, 1fr);
    align-items: baseline;
    gap: 12px;
  }
}

@media (min-width: 760px) {
  .page-about .about-figures {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .about-timeline__item {
    padding-left: 32px;
  }
}

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

  .page-about .about-hero__media {
    margin-top: 8px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body__grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--by-header-h) + 22px);
  }

  .page-about .about-toc {
    border-top: 1px solid var(--by-line);
    border-left: 1px solid var(--by-line);
    padding: 14px 0 14px 0;
  }

  .page-about .by-toc__title {
    padding-left: 14px;
  }

  .page-about .by-toc__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .by-toc__item {
    flex: none;
  }

  .page-about .by-toc__link {
    white-space: normal;
    border: none;
    border-left: 2px solid transparent;
    padding: 8px 14px;
    font-size: 12.5px;
    line-height: 1.5;
  }

  .page-about .by-toc__link:hover,
  .page-about .by-toc__link:focus-visible {
    border-left-color: var(--by-lime);
    background: rgba(199, 255, 61, 0.06);
  }

  .page-about .about-chapter__head {
    gap: 16px;
    margin-bottom: 20px;
  }

  .page-about .about-chapter__prose p,
  .page-about .about-chapter__lead {
    font-size: 16.5px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-team {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-partners__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

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