.page-about {
  --about-rail-w: 240px;
  --about-gap: clamp(28px, 4.5vw, 88px);
  --about-pad: clamp(56px, 8vw, 118px);
  display: block;
  background: var(--paper);
  color: var(--text-strong);
  overflow-x: clip;
}

.page-about .crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-top: 18px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.page-about .crumbs a {
  color: var(--text-muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .crumbs a:hover {
  color: var(--blue-mid);
  border-bottom-color: var(--cyan-signal);
}

.page-about .inline-link {
  color: var(--blue-mid);
  text-decoration: none;
  border-bottom: 1px solid var(--line-light);
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .inline-link:hover {
  color: var(--orange-volt);
  border-bottom-color: var(--orange-volt);
}

.page-about .chapter--dark .inline-link,
.page-about .chapter--abyss .inline-link,
.page-about .chapter--mid .inline-link {
  color: var(--cyan-signal);
  border-bottom-color: var(--line-dark);
}

.page-about .chapter--dark .inline-link:hover,
.page-about .chapter--abyss .inline-link:hover,
.page-about .chapter--mid .inline-link:hover {
  color: var(--orange-volt);
  border-bottom-color: var(--orange-volt);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(40px, 6vw, 88px) 0 clamp(34px, 5vw, 64px);
  background:
    radial-gradient(120% 150% at 8% 0%, var(--blue-mid) 0%, var(--blue-deep) 44%, var(--ink-abyss) 100%);
  color: var(--text-on-dark);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(94, 196, 255, 0.09) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(94, 196, 255, 0.09) 1px, transparent 1px);
  background-size: 76px 76px;
  -webkit-mask-image: linear-gradient(118deg, #000 0%, rgba(0, 0, 0, 0.25) 46%, transparent 68%);
  mask-image: linear-gradient(118deg, #000 0%, rgba(0, 0, 0, 0.25) 46%, transparent 68%);
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .eyebrow {
  color: var(--cyan-signal);
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  max-width: 15em;
  font-size: clamp(2.1rem, 5.4vw, 3.9rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.025em;
}

.page-about .about-hero .lead {
  margin-top: clamp(16px, 2vw, 24px);
  max-width: 36em;
  font-size: clamp(0.98rem, 1.2vw, 1.08rem);
  line-height: 1.78;
  color: var(--text-on-dark-muted);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: clamp(28px, 4vw, 48px) 0 0;
  padding: 0;
  list-style: none;
  border: 1px solid var(--line-dark);
  border-radius: var(--radius);
  background: var(--blue-glass);
  overflow: hidden;
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 18px;
  border-bottom: 1px solid var(--line-dark);
  border-right: 1px solid var(--line-dark);
}

.page-about .about-stat:nth-child(2n) {
  border-right: 0;
}

.page-about .about-stat:nth-last-child(-n + 2) {
  border-bottom: 0;
}

.page-about .stat-num {
  font-size: clamp(1.35rem, 2.4vw, 1.85rem);
  font-weight: 600;
  line-height: 1;
  color: var(--cyan-signal);
}

.page-about .stat-label {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--text-on-dark-muted);
}

/* ---------- 章节导航 ---------- */

.page-about .about-toc {
  position: relative;
  z-index: 2;
  background: var(--ink-abyss);
  border-bottom: 1px solid var(--line-dark);
}

.page-about .about-toc-inner {
  display: flex;
  align-items: center;
  gap: clamp(16px, 3vw, 34px);
  padding: 13px 0;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-toc-inner::-webkit-scrollbar {
  display: none;
}

.page-about .toc-link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  flex: 0 0 auto;
  padding-bottom: 4px;
  white-space: nowrap;
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-on-dark-muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

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

.page-about .toc-num {
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--orange-volt);
}

/* ---------- 章节骨架 ---------- */

.page-about .chapter {
  padding: var(--about-pad) 0;
  scroll-margin-top: 24px;
}

.page-about .chapter--paper {
  background: var(--paper);
  color: var(--text-strong);
  border-bottom: 1px solid var(--line-light);
}

.page-about .chapter--alt {
  background: var(--paper-alt);
  color: var(--text-strong);
  border-bottom: 1px solid var(--line-light);
}

.page-about .chapter--dark {
  background: linear-gradient(180deg, var(--blue-deep) 0%, #092746 100%);
  color: var(--text-on-dark);
}

.page-about .chapter--abyss {
  background: var(--ink-abyss);
  color: var(--text-on-dark);
}

.page-about .chapter--mid {
  background: var(--blue-mid);
  color: var(--text-on-dark);
}

.page-about .chapter-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3vw, 34px);
}

.page-about .chapter-rail {
  padding-top: 16px;
  border-top: 1px solid var(--line-light);
}

.page-about .chapter--dark .chapter-rail,
.page-about .chapter--abyss .chapter-rail,
.page-about .chapter--mid .chapter-rail {
  border-top-color: var(--line-dark);
}

.page-about .chapter-num {
  display: block;
  font-size: 0.76rem;
  letter-spacing: 0.2em;
  color: var(--orange-volt);
}

.page-about .chapter-line {
  margin: 10px 0 0;
  max-width: 20em;
  font-size: 1.02rem;
  font-weight: 800;
  line-height: 1.5;
  letter-spacing: -0.01em;
}

.page-about .chapter--dark .chapter-line,
.page-about .chapter--abyss .chapter-line,
.page-about .chapter--mid .chapter-line {
  color: var(--text-on-dark);
}

.page-about .chapter-body {
  display: flex;
  flex-direction: column;
  gap: clamp(16px, 2.4vw, 26px);
  min-width: 0;
}

.page-about .chapter-body h2 {
  margin: 0;
  max-width: 20em;
  font-size: clamp(1.5rem, 2.7vw, 2.15rem);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: -0.022em;
}

.page-about .chapter-body p {
  margin: 0;
  max-width: 38em;
  font-size: 1rem;
  line-height: 1.78;
  color: var(--text-muted);
}

.page-about .chapter--dark .chapter-body p,
.page-about .chapter--abyss .chapter-body p,
.page-about .chapter--mid .chapter-body p {
  color: var(--text-on-dark-muted);
}

/* ---------- 01 日常三条线 ---------- */

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

.page-about .task-list li {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line-light);
}

.page-about .task-key {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--blue-mid);
}

.page-about .task-text {
  max-width: 44em;
  font-size: 0.96rem;
  line-height: 1.72;
  color: var(--text-muted);
}

/* ---------- 02 角色卡 ---------- */

.page-about .role-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .role-card {
  display: flex;
  flex-direction: column;
  padding: 20px 18px;
  border: 1px solid var(--line-dark);
  border-radius: var(--radius);
  background: var(--blue-glass);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  transition: transform 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .role-card:hover {
  transform: translateY(-2px);
  border-color: var(--cyan-signal);
}

.page-about .role-count {
  font-size: 1.7rem;
  font-weight: 600;
  line-height: 1;
  color: var(--cyan-signal);
}

.page-about .role-name {
  margin-top: 10px;
  font-size: 0.95rem;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--text-on-dark);
}

.page-about .role-desc {
  margin: 8px 0 0;
  max-width: none;
  font-size: 0.85rem;
  line-height: 1.66;
  color: var(--text-on-dark-muted);
}

.page-about .chapter-media-right {
  width: 100%;
  max-width: 560px;
  margin: 4px 0 0;
}

/* ---------- 03 三个环节 ---------- */

.page-about .flow-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: flow;
  border-top: 1px solid var(--line-light);
}

.page-about .flow-step {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line-light);
}

.page-about .flow-index {
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: var(--orange-volt);
}

.page-about .flow-step h3 {
  margin: 0;
  font-size: 1.06rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--text-strong);
}

.page-about .flow-step p {
  margin: 0;
  max-width: 34em;
  font-size: 0.94rem;
  line-height: 1.72;
  color: var(--text-muted);
}

/* ---------- 04 准则 ---------- */

.page-about .rail-figure {
  margin: 22px 0 0;
}

.page-about .rule-list {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .rule-list li {
  position: relative;
  max-width: 42em;
  padding: 2px 0 2px 18px;
  border-left: 3px solid var(--orange-volt);
  font-size: 0.97rem;
  line-height: 1.72;
  color: var(--text-strong);
}

/* ---------- 05 时间线 ---------- */

.page-about .timeline {
  position: relative;
  display: grid;
  gap: 22px;
  margin: 6px 0 0;
  padding: 0 0 0 22px;
  list-style: none;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  top: 6px;
  bottom: 6px;
  left: 4px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan-signal) 0%, rgba(53, 240, 208, 0.18) 62%, transparent 100%);
}

.page-about .timeline-item {
  position: relative;
}

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  top: 7px;
  left: -22px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-abyss);
  border: 2px solid var(--cyan-signal);
  transition: background 160ms var(--ease);
}

.page-about .timeline-item:hover::before {
  background: var(--orange-volt);
  border-color: var(--orange-volt);
}

.page-about .timeline-phase {
  display: block;
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: var(--cyan-signal);
}

.page-about .timeline-item p {
  margin: 6px 0 0;
  max-width: 36em;
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--text-on-dark-muted);
}

.page-about .chapter-media-band {
  width: 100%;
  margin: 10px 0 0;
}

/* ---------- 06 使用场景 ---------- */

.page-about .audience-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .audience-item {
  padding: 20px 18px;
  border: 1px solid var(--line-light);
  border-radius: var(--radius);
  background: var(--paper);
  transition: transform 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .audience-item:hover {
  transform: translateY(-2px);
  border-color: var(--blue-mid);
}

.page-about .audience-item h3 {
  margin: 0;
  font-size: 1rem;
  font-weight: 800;
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--text-strong);
}

.page-about .audience-item p {
  margin: 10px 0 0;
  max-width: none;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--text-muted);
}

/* ---------- 07 共建 ---------- */

.page-about .join-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 4px;
}

.page-about .join-contact {
  margin: 4px 0 0;
  max-width: 40em;
  font-size: 0.86rem;
  line-height: 1.7;
  color: var(--text-on-dark-muted);
  overflow-wrap: anywhere;
}

/* ---------- 图片容器微调 ---------- */

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

.page-about .rail-figure img {
  border-radius: var(--radius);
}

/* ---------- 响应式 ---------- */

@media (min-width: 560px) {
  .page-about .task-list li {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
  }

  .page-about .role-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .audience-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
  }
}

@media (min-width: 900px) {
  .page-about .chapter-grid {
    grid-template-columns: minmax(180px, var(--about-rail-w)) minmax(0, 1fr);
    gap: var(--about-gap);
  }

  .page-about .chapter-rail {
    position: relative;
    padding-top: 18px;
  }

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

  .page-about .about-stat {
    border-right: 1px solid var(--line-dark);
    border-bottom: 0;
  }

  .page-about .about-stat:nth-child(2n) {
    border-right: 1px solid var(--line-dark);
  }

  .page-about .about-stat:nth-last-child(-n + 2) {
    border-bottom: 0;
  }

  .page-about .about-stat:last-child {
    border-right: 0;
  }

  .page-about .role-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .flow-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0 28px;
    border-top: 1px solid var(--line-light);
  }

  .page-about .flow-step {
    border-bottom: 0;
    padding: 18px 0 0;
  }

  .page-about .audience-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .timeline {
    padding-left: 26px;
  }

  .page-about .timeline-item::before {
    left: -26px;
  }
}

@media (min-width: 1180px) {
  .page-about {
    --about-rail-w: 262px;
  }

  .page-about .chapter-media-right {
    max-width: 620px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .role-card,
  .page-about .audience-item,
  .page-about .timeline-item::before,
  .page-about .toc-link,
  .page-about .inline-link {
    transition: none;
  }
}
<<<END>>>