.page-about {
  --about-aside: 150px;
  --about-paper-rule: rgba(10, 22, 34, 0.16);
  --about-dark-rule: rgba(214, 207, 194, 0.2);
  --about-ink-text: #26333F;
  background: var(--ink);
  color: var(--body-dim);
  overflow-x: hidden;
}

/* ---------- 手册封面 ---------- */

.page-about .about-cover {
  position: relative;
  padding: clamp(22px, 4vw, 46px) 0 clamp(44px, 6vw, 90px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(112% 88% at 6% 0%, rgba(61, 242, 208, 0.13), transparent 62%),
    linear-gradient(158deg, #0A1622 0%, #102032 56%, #0A1622 100%);
}

.page-about .about-cover .crumbs {
  margin-bottom: clamp(16px, 2.4vw, 26px);
}

.page-about .about-cover__frame {
  position: relative;
  border: 1px solid var(--line-strong);
  background: rgba(19, 38, 58, 0.5);
  padding: clamp(20px, 4vw, 54px);
  display: grid;
  gap: clamp(16px, 2.6vw, 28px);
}

.page-about .about-cover__frame::before,
.page-about .about-cover__frame::after {
  content: "";
  position: absolute;
  width: 15px;
  height: 15px;
  border: 1px solid var(--cyan);
  opacity: 0.75;
}

.page-about .about-cover__frame::before {
  top: -1px;
  left: -1px;
  border-right: 0;
  border-bottom: 0;
}

.page-about .about-cover__frame::after {
  bottom: -1px;
  right: -1px;
  border-left: 0;
  border-top: 0;
}

.page-about .about-cover__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 18px;
}

.page-about .about-cover__stamp {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-cover .display-1 {
  margin: 0;
  font-size: clamp(34px, 6.6vw, 78px);
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--white);
}

.page-about .about-cover__lede {
  margin: 0;
  max-width: 36em;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: var(--body-dim);
}

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

.page-about .about-cover__stats > .stat {
  background: rgba(10, 22, 34, 0.74);
  padding: 14px 16px 16px;
}

.page-about .about-cover__stats .stat__label {
  display: block;
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-cover__stats .stat__num {
  display: block;
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 3.2vw, 34px);
  font-weight: 600;
  line-height: 1;
  color: var(--white);
}

.page-about .about-cover__stats .stat__num--signal {
  color: var(--signal);
}

.page-about .about-cover__stats .stat__unit {
  margin-left: 4px;
  font-size: 12px;
  font-weight: 400;
  color: var(--cyan);
}

/* ---------- 章节目录带 ---------- */

.page-about .chapter-index {
  position: sticky;
  top: 0;
  z-index: 6;
  display: flex;
  overflow-x: auto;
  background: rgba(10, 22, 34, 0.95);
  border-bottom: 1px solid var(--line);
  scrollbar-width: none;
}

.page-about .chapter-index::-webkit-scrollbar {
  display: none;
}

.page-about .chapter-index a {
  flex: 0 0 auto;
  padding: 13px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  border-right: 1px solid var(--line);
  transition: color var(--t-fast) linear, background-color var(--t-fast) linear;
}

.page-about .chapter-index a:hover,
.page-about .chapter-index a:focus-visible {
  color: var(--cyan);
  background: rgba(61, 242, 208, 0.08);
  outline: none;
}

/* ---------- 章节骨架 ---------- */

.page-about .chapter {
  padding: clamp(50px, 8vw, 108px) 0;
  position: relative;
}

.page-about .chapter--ink {
  background: var(--ink);
  border-bottom: 1px solid var(--line);
}

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

.page-about .chapter__grid {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .chapter__aside {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-top: 10px;
  border-top: 1px solid var(--about-dark-rule);
}

.page-about .chapter--paper .chapter__aside {
  border-top-color: var(--about-paper-rule);
}

.page-about .chapter__num {
  font-size: 22px;
  letter-spacing: 0.08em;
  color: var(--cyan);
  line-height: 1;
}

.page-about .chapter--paper .chapter__num {
  color: var(--teal);
}

.page-about .chapter__tag {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .chapter--paper .chapter__tag {
  color: #6E7C88;
}

.page-about .chapter__body > .display-3 {
  margin: 0 0 18px;
  color: var(--white);
}

.page-about .chapter--paper .chapter__body > .display-3 {
  color: var(--ink);
}

.page-about .chapter .prose {
  margin: 0 0 14px;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--body-dim);
}

.page-about .chapter--paper .prose {
  color: var(--about-ink-text);
}

.page-about .chapter .prose a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(61, 242, 208, 0.5);
}

.page-about .chapter--paper .prose a {
  color: #0B6F63;
  border-bottom-color: rgba(11, 111, 99, 0.4);
}

.page-about .chapter .prose a:hover,
.page-about .chapter .prose a:focus-visible {
  color: var(--white);
  border-bottom-color: var(--white);
}

.page-about .chapter--paper .prose a:hover,
.page-about .chapter--paper .prose a:focus-visible {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

/* ---------- 首个章节的提示块 ---------- */

.page-about .about-note {
  margin: 22px 0 0;
  padding: 16px 18px;
  border-left: 3px solid var(--teal);
  background: rgba(14, 140, 126, 0.07);
  font-size: 15px;
  line-height: 1.8;
  color: #2B3946;
  max-width: 40em;
}

.page-about .about-note__key {
  display: block;
  margin-bottom: 6px;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #0B6F63;
}

/* ---------- 图像 ---------- */

.page-about .about-figure {
  margin: clamp(22px, 3.4vw, 36px) 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line-strong);
  background: var(--ink-2);
}

.page-about .chapter--paper .about-figure img {
  border-color: var(--about-paper-rule);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .chapter--paper .about-figure figcaption {
  color: #6E7C88;
}

/* ---------- 岗位矩阵 ---------- */

.page-about .role-matrix {
  list-style: none;
  margin: clamp(24px, 3.6vw, 40px) 0 0;
  padding: 0;
  border-top: 1px solid var(--about-dark-rule);
}

.page-about .role-matrix__row {
  display: grid;
  gap: 10px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .role-matrix__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .role-matrix__idx {
  font-size: 13px;
  color: var(--signal);
}

.page-about .role-matrix__name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .role-matrix__count {
  margin-left: auto;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--cyan);
}

/* ---------- 可展开组 ---------- */

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

.page-about .disclosure__btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 4px 0;
  background: none;
  border: 0;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--cyan);
  transition: color var(--t-fast) linear;
}

.page-about .chapter--paper .disclosure__btn {
  color: #0B6F63;
}

.page-about .disclosure__btn:hover {
  color: var(--white);
}

.page-about .chapter--paper .disclosure__btn:hover {
  color: var(--ink);
}

.page-about .disclosure__btn:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .disclosure__panel {
  margin-top: 10px;
  padding: 14px 16px;
  border-left: 2px solid var(--teal);
  background: rgba(19, 38, 58, 0.6);
  font-size: 15px;
  line-height: 1.8;
  color: var(--body-dim);
  max-width: 38em;
}

.page-about .chapter--paper .disclosure__panel {
  background: rgba(255, 255, 255, 0.72);
  color: var(--about-ink-text);
}

/* ---------- 时间轴 ---------- */

.page-about .timeline {
  list-style: none;
  margin: clamp(24px, 3.6vw, 40px) 0 0;
  padding: 0;
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 28px 26px;
  border-left: 1px solid var(--about-paper-rule);
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 7px;
  width: 9px;
  height: 9px;
  background: var(--paper);
  border: 2px solid var(--teal);
  box-sizing: border-box;
}

.page-about .timeline__item:last-child::before {
  border-color: var(--signal);
}

.page-about .timeline__year {
  margin: 0 0 4px;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: #0B6F63;
}

.page-about .timeline__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: clamp(19px, 2.2vw, 24px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink);
}

/* ---------- 暖纸记录条 ---------- */

.page-about .paper-record {
  margin: clamp(24px, 3.6vw, 38px) 0 0;
  border-top: 1px solid var(--about-paper-rule);
}

.page-about .paper-record__row {
  display: grid;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--about-paper-rule);
}

.page-about .paper-record__label {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #0B6F63;
}

.page-about .paper-record__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-ink-text);
  max-width: 40em;
}

/* ---------- 合作生态卡 ---------- */

.page-about .partner-grid {
  display: grid;
  gap: 14px;
  margin: clamp(24px, 3.6vw, 40px) 0;
}

.page-about .partner-card {
  position: relative;
  padding: 22px 20px 24px;
  border: 1px solid var(--line-strong);
  background: linear-gradient(180deg, rgba(19, 38, 58, 0.9), rgba(10, 22, 34, 0.9));
}

.page-about .partner-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 3px;
  height: 100%;
  background: var(--teal);
}

.page-about .partner-card__num {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(34px, 4.4vw, 46px);
  font-weight: 600;
  line-height: 1;
  color: var(--cyan);
}

.page-about .partner-card__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .partner-card__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--body-dim);
}

/* ---------- 合作路径 ---------- */

.page-about .route-grid {
  display: grid;
  gap: 1px;
  margin: clamp(20px, 3vw, 32px) 0 clamp(24px, 3.4vw, 36px);
  background: var(--about-paper-rule);
  border: 1px solid var(--about-paper-rule);
}

.page-about .route-card {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 24px 22px 26px;
  background: #FFFFFF;
}

.page-about .route-card__idx {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: #6E7C88;
}

.page-about .route-card__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(20px, 2.4vw, 26px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .route-card__text {
  margin: 0;
  flex: 1 1 auto;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-ink-text);
}

.page-about .chapter--paper .btn {
  align-self: flex-start;
  color: var(--ink);
  border-color: rgba(10, 22, 34, 0.36);
}

.page-about .chapter--paper .btn:hover,
.page-about .chapter--paper .btn:focus-visible {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.page-about .chapter--paper .btn--solid {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.page-about .chapter--paper .btn--solid:hover,
.page-about .chapter--paper .btn--solid:focus-visible {
  background: var(--signal);
  border-color: var(--signal);
  color: var(--white);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-cover__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .paper-record__row {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: baseline;
    gap: 20px;
  }
}

@media (min-width: 760px) {
  .page-about .role-matrix__row {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
    gap: 28px;
    align-items: start;
  }

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

  .page-about .partner-card {
    border: 0;
  }

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

@media (min-width: 900px) {
  .page-about .chapter__grid {
    grid-template-columns: var(--about-aside) minmax(0, 1fr);
    gap: clamp(30px, 5vw, 76px);
  }

  .page-about .chapter__aside {
    position: sticky;
    top: 78px;
    align-self: start;
  }

  .page-about .timeline__item {
    padding-left: 34px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-figure--wide {
    margin-right: calc(-1 * clamp(0px, 4vw, 90px));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .chapter-index a,
  .page-about .disclosure__btn {
    transition: none;
  }
}