.page-about {
  --pa-axis: 118px;
  color: var(--paper);
}

.page-about .crumbs {
  padding-top: 18px;
}

/* ============ 首屏：主题声明 + 三支柱 ============ */
.page-about .about-hero {
  display: grid;
  gap: 30px;
  padding-top: 16px;
  padding-bottom: 40px;
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 48px;
    align-items: end;
    padding-top: 26px;
    padding-bottom: 54px;
  }
}

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

.page-about .about-hero h1 {
  margin: 16px 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.95rem, 5.4vw, 3.25rem);
  line-height: 1.12;
  letter-spacing: -0.015em;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .about-hero__lede {
  margin: 20px 0 0;
  max-width: 62ch;
  font-size: 1rem;
  line-height: 1.88;
  color: var(--paper);
}

.page-about .pillars {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .pillars__item {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .pillars__no {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .pillars__title {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .pillars__item p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.78;
  color: var(--muted);
}

@media (min-width: 760px) {
  .page-about .pillars {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border-bottom: 1px solid var(--line);
  }
  .page-about .pillars__item {
    border-bottom: 0;
    border-right: 1px solid var(--line);
    padding: 20px 22px;
  }
  .page-about .pillars__item:first-child {
    padding-left: 0;
  }
  .page-about .pillars__item:last-child {
    border-right: 0;
    padding-right: 0;
  }
}

.page-about .about-hero__fig {
  margin: 0;
  padding: 6px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 6px 6px 0 rgba(37, 87, 74, 0.45);
}

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

.page-about .media-frame__cap {
  display: block;
  padding: 8px 2px 2px;
}

/* ============ 章节头 ============ */
.page-about .section {
  margin-top: 40px;
  margin-bottom: 40px;
}

@media (min-width: 900px) {
  .page-about .section {
    margin-top: 58px;
    margin-bottom: 58px;
  }
}

.page-about .sec-head {
  padding-bottom: 20px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 26px;
}

.page-about .sec-head h2 {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 3.6vw, 2.45rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--paper);
  max-width: 26ch;
}

.page-about .sec-head__lede {
  margin: 14px 0 0;
  max-width: 70ch;
  font-size: 0.98rem;
  line-height: 1.86;
  color: var(--muted);
}

/* ============ 年份索引与筛选 ============ */
.page-about .year-index {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  margin-bottom: 18px;
}

.page-about .year-index__link {
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}

.page-about .year-index__link:hover {
  color: var(--gold-hi);
}

.page-about .year-index__link.is-current {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.page-about .filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 22px;
}

/* ============ 时间线 ============ */
.page-about .timeline__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .tl-item {
  display: grid;
  gap: 8px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .tl-item[hidden] {
  display: none;
}

@media (min-width: 860px) {
  .page-about .tl-item {
    grid-template-columns: var(--pa-axis) minmax(0, 1fr);
    gap: 34px;
    padding: 26px 0;
  }
}

.page-about .tl-item__year {
  font-size: 1rem;
  color: var(--gold);
  letter-spacing: 0.03em;
}

.page-about .tl-item__year::before {
  content: "";
  display: block;
  width: 22px;
  height: 2px;
  background: var(--gold);
  margin-bottom: 10px;
}

.page-about .tl-item__title {
  margin: 0;
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .tl-item__body p {
  margin: 9px 0 14px;
  max-width: 64ch;
  font-size: 0.96rem;
  line-height: 1.84;
  color: var(--muted);
}

.page-about .aside-fold {
  margin-top: 4px;
  background: var(--panel);
  border-left: 2px solid var(--ice);
  padding: 0 14px;
}

.page-about .aside-fold__sum {
  cursor: pointer;
  padding: 11px 0;
  font-size: 0.84rem;
  letter-spacing: 0.1em;
  color: var(--ice);
  list-style: none;
}

.page-about .aside-fold__sum::-webkit-details-marker {
  display: none;
}

.page-about .aside-fold__body {
  padding-bottom: 13px;
}

.page-about .aside-fold__body p {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ============ 内容体系 ============ */
.page-about .scale-grid {
  display: grid;
  gap: 30px;
}

@media (min-width: 900px) {
  .page-about .scale-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 46px;
    align-items: start;
  }
}

.page-about .scale-grid__main {
  min-width: 0;
}

.page-about .scale-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line);
}

@media (min-width: 700px) {
  .page-about .scale-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .scale-stats .stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 12px 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .stat__num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3.4vw, 2.05rem);
  line-height: 1;
  color: var(--gold);
}

.page-about .stat__label {
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .scale-grid__fig {
  margin: 0;
  padding: 6px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 5px 5px 0 rgba(37, 87, 74, 0.4);
}

/* ============ 编辑部目录式索引 ============ */
.page-about .ledger {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .ledger__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 6px 14px;
  padding: 16px 0;
  border-top: 1px solid var(--line);
  align-items: start;
}

.page-about .ledger__item:last-child {
  border-bottom: 1px solid var(--line);
}

@media (min-width: 640px) {
  .page-about .ledger__item {
    grid-template-columns: 44px minmax(0, 1fr) auto;
    gap: 22px;
    align-items: baseline;
  }
}

.page-about .ledger__idx {
  font-size: 0.84rem;
  color: var(--gold);
}

.page-about .ledger__title {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .ledger__title a {
  color: var(--paper);
  text-decoration: none;
  border-bottom: 1px solid var(--gold);
  padding-bottom: 1px;
}

.page-about .ledger__title a:hover {
  color: var(--gold-hi);
  border-bottom-color: var(--gold-hi);
}

.page-about .ledger__desc {
  margin: 7px 0 0;
  font-size: 0.92rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .ledger__meta {
  grid-column: 2;
  font-size: 0.76rem;
  letter-spacing: 0.12em;
  color: var(--ice);
}

@media (min-width: 640px) {
  .page-about .ledger__meta {
    grid-column: auto;
  }
}

/* ============ 服务节点 ============ */
.page-about .node-grid {
  display: grid;
  gap: 30px;
}

@media (min-width: 900px) {
  .page-about .node-grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    gap: 46px;
    align-items: start;
  }
}

.page-about .roles {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .roles__item {
  display: grid;
  grid-template-columns: 26px minmax(0, 1fr);
  gap: 16px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
}

.page-about .roles__item:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .roles__idx {
  font-size: 0.86rem;
  color: var(--ice);
}

.page-about .roles__title {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .roles__item p {
  margin: 7px 0 0;
  font-size: 0.93rem;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .node-grid__fig {
  margin: 0;
  padding: 6px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 5px 5px 0 rgba(37, 87, 74, 0.4);
}

/* ============ 版本徽标面板 ============ */
.page-about .badge-panel {
  display: grid;
  gap: 26px;
  padding: 26px 20px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 6px 6px 0 rgba(37, 87, 74, 0.5);
}

@media (min-width: 900px) {
  .page-about .badge-panel {
    grid-template-columns: minmax(0, 6fr) minmax(0, 4fr);
    gap: 48px;
    padding: 40px 36px;
    align-items: start;
  }
}

.page-about .badge-panel h2 {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3.4vw, 2.3rem);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--paper);
  max-width: 22ch;
}

.page-about .badge-panel__main > p {
  margin: 14px 0 0;
  max-width: 62ch;
  font-size: 0.96rem;
  line-height: 1.88;
  color: var(--muted);
}

.page-about .badge-panel__side {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
  padding-top: 6px;
  border-top: 1px solid var(--line);
}

@media (min-width: 900px) {
  .page-about .badge-panel__side {
    padding-top: 0;
    border-top: 0;
    border-left: 1px solid var(--line);
    padding-left: 30px;
  }
}

.page-about .badge-panel__side p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .badge-panel__side .btn {
  margin-top: 4px;
}

.page-about .steps {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .steps__item {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.95rem;
  color: var(--paper);
}

.page-about .steps__no {
  font-size: 0.78rem;
  color: var(--gold);
  letter-spacing: 0.06em;
}

@media (min-width: 700px) {
  .page-about .steps {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 34px;
  }
}

/* ============ 长期维护 ============ */
.page-about .upkeep__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .upkeep__item {
  padding: 22px 0;
  border-top: 1px solid var(--line);
}

.page-about .upkeep__item:last-child {
  border-bottom: 1px solid var(--line);
}

@media (min-width: 820px) {
  .page-about .upkeep__list {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border-bottom: 1px solid var(--line);
  }
  .page-about .upkeep__item {
    border-bottom: 0;
    border-right: 1px solid var(--line);
    padding: 26px 24px;
  }
  .page-about .upkeep__item:first-child {
    padding-left: 0;
  }
  .page-about .upkeep__item:last-child {
    border-right: 0;
    padding-right: 0;
  }
}

.page-about .upkeep__when {
  display: inline-block;
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  color: var(--gold-hi);
}

.page-about .upkeep__title {
  margin: 10px 0 0;
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--paper);
}

.page-about .upkeep__item p {
  margin: 9px 0 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ============ 收尾索引 ============ */
.page-about .ledger--links .ledger__item {
  padding: 20px 0;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .year-index__link,
  .page-about .ledger__title a {
    transition: none;
  }
}
<<<END>>>