.page-about {
  --about-toc-w: 224px;
}

.page-about p {
  line-height: 1.75;
}

.page-about .breadcrumb-wrap {
  padding: 22px 0 4px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 28px;
  padding: 18px 0 10px;
  align-items: center;
}

.page-about .about-hero h1 {
  margin: 12px 0 0;
  font-size: clamp(30px, 5.6vw, 52px);
  line-height: 1.14;
  letter-spacing: -0.02em;
}

.page-about .about-hero .lede {
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: 16.5px;
  color: var(--body);
}

.page-about .about-hero-actions {
  margin-top: 26px;
  gap: 12px;
}

.page-about .about-hero-media {
  margin: 0;
}

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  display: grid;
  gap: 26px;
  padding: 34px 0 70px;
}

.page-about .about-toc {
  display: none;
}

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

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  padding: 36px 0 10px;
  border-top: 1px solid var(--line);
}

.page-about .about-chapter:first-of-type {
  border-top: 0;
  padding-top: 6px;
}

.page-about .about-chapter-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
}

.page-about .about-chapter-idx {
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .about-chapter h2 {
  margin: 0;
  font-size: clamp(22px, 3.4vw, 31px);
  line-height: 1.28;
  letter-spacing: -0.015em;
}

.page-about .about-chapter-body {
  margin-top: 14px;
}

.page-about .about-chapter-body p {
  margin: 0;
  color: var(--mist);
  font-size: 16px;
  max-width: 74ch;
}

/* ---------- 三条主线 ---------- */
.page-about .about-lanes {
  display: grid;
  gap: 14px;
  margin-top: 26px;
}

.page-about .about-lane {
  position: relative;
  padding: 22px 20px 24px;
  background: var(--midnight);
  border: 1px solid var(--line);
  clip-path: var(--notch);
}

.page-about .about-lane::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--amber), rgba(217, 164, 65, 0));
}

.page-about .about-lane h3 {
  margin: 14px 0 8px;
  font-size: 18px;
  letter-spacing: -0.01em;
}

.page-about .about-lane p {
  margin: 0;
  font-size: 15px;
  color: var(--mist);
}

/* ---------- 关键数字 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-stats .stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--celadon);
  background: rgba(18, 40, 61, 0.55);
}

.page-about .about-stats .stat-value {
  font-family: var(--font-mono);
  font-size: 21px;
  color: var(--amber-soft);
  letter-spacing: 0.01em;
}

.page-about .about-stats .stat-label {
  font-size: 13px;
  color: var(--mist);
}

/* ---------- 入口对照 ---------- */
.page-about .about-split {
  display: grid;
  gap: 22px;
  margin-top: 24px;
  align-items: start;
}

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-step {
  border: 1px solid var(--line);
  background: rgba(18, 40, 61, 0.62);
  clip-path: var(--notch);
  transition: border-color 0.24s var(--ease), background 0.24s var(--ease);
}

.page-about .about-step:hover,
.page-about .about-step[open] {
  border-color: var(--line-strong);
  background: var(--midnight);
}

.page-about .about-step summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 15px 18px;
  cursor: pointer;
  list-style: none;
  font-size: 15.5px;
  font-weight: 600;
  color: var(--body);
}

.page-about .about-step summary::-webkit-details-marker {
  display: none;
}

.page-about .about-step summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--mist);
  transition: color 0.2s var(--ease), transform 0.2s var(--ease);
}

.page-about .about-step[open] summary::after {
  content: "–";
  color: var(--amber);
}

.page-about .about-step[open] summary {
  color: var(--amber-soft);
}

.page-about .about-step-num {
  font-size: 12.5px;
  color: var(--amber);
  letter-spacing: 0.06em;
}

.page-about .about-step-body {
  padding: 0 18px 18px 45px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .about-entry-media {
  margin: 0;
}

.page-about .about-entry-cta {
  margin: 24px 0 0;
}

/* ---------- 三条路径 ---------- */
.page-about .about-paths {
  display: grid;
  gap: 16px;
  margin-top: 24px;
}

.page-about .about-path {
  position: relative;
  padding: 24px 22px 26px 26px;
  background: linear-gradient(115deg, rgba(217, 164, 65, 0.09), rgba(11, 28, 44, 0) 58%), var(--midnight);
  border: 1px solid var(--line);
  clip-path: var(--notch);
}

.page-about .about-path::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(180deg, var(--amber), var(--celadon));
}

.page-about .about-path-tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--celadon-soft);
}

.page-about .about-path h3 {
  margin: 12px 0 10px;
  font-size: 19px;
  letter-spacing: -0.01em;
}

.page-about .about-path p {
  margin: 0;
  font-size: 15px;
  color: var(--mist);
}

.page-about .about-path-link {
  display: inline-block;
  margin-top: 14px;
  font-size: 14px;
  color: var(--amber-soft);
  text-decoration: none;
  border-bottom: 1px solid rgba(240, 201, 120, 0.4);
  padding-bottom: 2px;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-path-link:hover,
.page-about .about-path-link:focus-visible {
  color: var(--paper);
  border-color: var(--amber);
}

/* ---------- 移动端 ---------- */
.page-about .about-mobile-list {
  margin-top: 22px;
}

.page-about .about-mobile-list li {
  font-size: 15px;
  color: var(--mist);
}

.page-about .about-quote {
  margin: 26px 0 0;
  padding: 22px 22px 22px 24px;
  border-left: 3px solid var(--amber);
  background: linear-gradient(115deg, rgba(217, 164, 65, 0.12), rgba(95, 169, 138, 0.07));
  font-size: 17px;
  line-height: 1.7;
  color: var(--body);
}

/* ---------- 维护记录 ---------- */
.page-about .about-filter {
  margin-top: 24px;
  flex-wrap: wrap;
}

.page-about .about-filter-count {
  display: inline-flex;
  align-items: baseline;
  gap: 5px;
  font-size: 13px;
}

.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 24px 0 0;
  padding: 0 0 0 24px;
  display: grid;
  gap: 14px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(180deg, var(--amber), var(--celadon), rgba(95, 169, 138, 0));
}

.page-about .about-tl-item {
  position: relative;
  padding: 16px 18px 18px;
  background: var(--midnight);
  border: 1px solid var(--line);
  transition: border-color 0.24s var(--ease), transform 0.24s var(--ease);
}

.page-about .about-tl-item::before {
  content: "";
  position: absolute;
  left: -24px;
  top: 24px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--amber);
}

.page-about .about-tl-item:hover {
  border-color: var(--line-strong);
}

.page-about .about-tl-meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--celadon-soft);
}

.page-about .about-tl-item h3 {
  margin: 9px 0 7px;
  font-size: 16.5px;
  letter-spacing: -0.01em;
}

.page-about .about-tl-item p:last-child {
  margin: 0;
  font-size: 14.8px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-update-note {
  margin: 22px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--line-strong);
  font-size: 14.5px;
  color: var(--mist);
}

/* ---------- 底部行动区 ---------- */
.page-about .about-cta {
  margin-top: 44px;
  border: 1px solid var(--line);
  background: var(--midnight);
  clip-path: var(--notch);
  overflow: hidden;
}

.page-about .about-cta-media {
  margin: 0;
}

.page-about .about-cta-media img {
  opacity: 0.6;
}

.page-about .about-cta-body {
  padding: 26px 22px 30px;
}

.page-about .about-cta-body h2 {
  margin: 0;
  font-size: clamp(20px, 2.8vw, 26px);
  line-height: 1.35;
  letter-spacing: -0.012em;
}

.page-about .about-cta-body p {
  margin: 14px 0 0;
  max-width: 62ch;
  font-size: 15.5px;
  color: var(--mist);
}

.page-about .about-cta-actions {
  margin-top: 22px;
  gap: 12px;
}

/* ---------- 桌面 ---------- */
@media (min-width: 720px) {
  .page-about .about-lanes {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .about-paths {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .about-timeline {
    gap: 16px;
  }

  .page-about .about-cta-body {
    padding: 32px 34px 38px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 44px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 32px;
  }

  .page-about .about-chapter {
    padding-top: 46px;
  }

  .page-about .about-chapter-body p {
    font-size: 16.5px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-toc-w) minmax(0, 1fr);
    gap: 56px;
  }

  .page-about .about-toc {
    display: block;
    align-self: start;
    position: sticky;
    top: calc(var(--bar-h) + 28px);
    padding: 16px 0 16px 2px;
  }

  .page-about .about-toc-title {
    margin: 0 0 12px;
    font-family: var(--font-mono);
    font-size: 12px;
    letter-spacing: 0.14em;
    color: var(--mist);
  }

  .page-about .about-toc-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 2px;
    border-left: 1px solid var(--line);
  }

  .page-about .about-toc-link {
    display: flex;
    gap: 10px;
    padding: 9px 12px;
    font-size: 14px;
    line-height: 1.5;
    color: var(--mist);
    text-decoration: none;
    border-left: 2px solid transparent;
    margin-left: -2px;
    transition: color 0.22s var(--ease), border-color 0.22s var(--ease), background 0.22s var(--ease);
  }

  .page-about .about-toc-link:hover,
  .page-about .about-toc-link:focus-visible {
    color: var(--body);
    border-left-color: var(--amber);
    background: rgba(217, 164, 65, 0.07);
  }

  .page-about .about-toc-idx {
    font-size: 12px;
    color: var(--amber);
    letter-spacing: 0.06em;
  }

  .page-about .about-chapter {
    scroll-margin-top: calc(var(--bar-h) + 24px);
  }
}

@media (min-width: 1200px) {
  .page-about .about-cta-media img {
    max-height: 260px;
    object-fit: cover;
  }
}
</final>
</answer>