.page-about {
  background: var(--ink);
  color: var(--paper);
  overflow-x: hidden;
}

.page-about .section--paper {
  color: var(--ink-on-card);
}

.page-about .section--paper .muted,
.page-about .section--paper .lede {
  color: var(--ink-soft);
}

/* 首屏 */
.page-about .about-hero {
  padding-top: clamp(32px, 6vw, 72px);
  padding-bottom: clamp(40px, 6vw, 88px);
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(28px, 5vw, 56px);
}

.page-about .about-hero__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
}

.page-about .about-hero__kicker {
  color: var(--gold);
  margin-bottom: 18px;
}

.page-about .about-hero__title {
  font-size: clamp(38px, 5.6vw, 76px);
  font-weight: 300;
  line-height: 1.12;
  letter-spacing: -0.02em;
  margin: 0 0 24px;
  color: var(--paper);
}

.page-about .about-hero__lede {
  max-width: 32em;
  color: var(--slate);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 16px;
  margin: 36px 0 0;
  padding-top: 24px;
  border-top: 1px solid var(--gold-line);
}

.page-about .about-fact dt {
  color: var(--slate);
  margin-bottom: 6px;
}

.page-about .about-fact dd {
  margin: 0;
  font-size: var(--step-21);
  color: var(--gold-light);
}

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

.page-about .about-hero__media figcaption {
  margin-top: 12px;
  font-size: var(--step-13);
}

.page-about .about-hero__index {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  list-style: none;
  margin: clamp(36px, 5vw, 64px) 0 0;
  padding: 20px 0 0;
  border-top: 1px solid var(--gold-line);
}

.page-about .about-indexlink {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-size: var(--step-13);
  letter-spacing: 0.06em;
  color: var(--slate);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .about-indexlink .mono {
  color: var(--gold);
}

.page-about .about-indexlink:hover,
.page-about .about-indexlink:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--jade);
}

/* 章节通用 */
.page-about .about-chapter__head {
  margin-bottom: clamp(28px, 4vw, 52px);
}

.page-about .about-chapter__head .section-index {
  color: var(--gold);
  margin-bottom: 14px;
}

.page-about .about-chapter__title {
  margin: 0 0 18px;
}

.page-about .about-rule {
  display: block;
  width: 56px;
  height: 2px;
  background: var(--vermilion);
}

.page-about .about-chapter__body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

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

.page-about .about-aside__title {
  color: var(--gold);
  margin-bottom: 14px;
}

.page-about .about-aside__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 18px;
  border-left: 1px solid var(--gold-line);
  display: grid;
  gap: 14px;
}

.page-about .about-aside__item {
  font-size: var(--step-13);
  line-height: 1.7;
  color: var(--slate);
}

.page-about .section--paper .about-aside__item {
  color: var(--ink-soft);
}

.page-about .about-aside__item .mono {
  display: inline-block;
  min-width: 5.4em;
  margin-right: 6px;
  color: var(--gold-deep);
}

.page-about .section--table .about-aside__item .mono,
.page-about .about-chapter:not(.section--paper) .about-aside__item .mono {
  color: var(--gold-light);
}

.page-about .about-figure figcaption {
  margin-top: 12px;
  font-size: var(--step-13);
}

/* 三条原则 */
.page-about .about-principles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .about-principle {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 20px;
  padding: 26px 0;
  border-top: 1px solid var(--gold-line);
}

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

.page-about .about-principle__num {
  font-size: var(--step-21);
  color: var(--vermilion);
  line-height: 1.3;
}

.page-about .about-principle__title {
  margin: 0;
  color: var(--ink-on-card);
}

.page-about .about-principle__text {
  grid-column: 2 / -1;
  margin: 8px 0 0;
  max-width: 34em;
  font-size: var(--step-17);
  line-height: 1.9;
  color: var(--ink-soft);
}

/* 团队分工 */
.page-about .about-roles {
  margin-top: 32px;
}

.page-about .about-roles .site-filter {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
  margin-bottom: 18px;
}

.page-about .about-roles .site-filter__label {
  font-size: var(--step-13);
  letter-spacing: 0.12em;
  color: var(--gold);
}

.page-about .about-roles .site-filter__input {
  flex: 1 1 220px;
  min-width: 0;
  background: var(--table);
  border: 1px solid var(--gold-line);
  border-radius: 0;
  color: var(--paper);
  font-family: var(--font-sans);
  font-size: var(--step-17);
  padding: 10px 12px;
  outline: none;
}

.page-about .about-roles .site-filter__input:focus {
  border-color: var(--jade);
}

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

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

.page-about .about-roles__role {
  font-size: var(--step-21);
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-roles__count {
  color: var(--gold-light);
  font-size: var(--step-15, var(--step-17));
}

.page-about .about-roles__duty {
  font-size: var(--step-17);
  line-height: 1.8;
  color: var(--slate);
}

.page-about .about-roles .site-filter__empty {
  margin: 20px 0 0;
  color: var(--slate);
}

/* 版本戳 */
.page-about .about-version-stamp {
  margin: 28px 0 18px;
}

.page-about .about-version-stamp .stamp {
  display: inline-block;
  background: var(--vermilion);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: var(--step-13);
  letter-spacing: 0.08em;
  padding: 6px 12px;
  border: 1px solid var(--vermilion);
}

/* 时间线 */
.page-about .about-timeline {
  margin-top: 8px;
}

.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 20px;
  border-left: 1px solid var(--gold-line);
}

.page-about .about-timeline__node {
  position: relative;
  padding: 0 0 8px;
}

.page-about .about-timeline__node::before {
  content: "";
  position: absolute;
  left: -25px;
  top: 12px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 3px var(--table);
}

.page-about .about-timeline__node + .about-timeline__node {
  border-top: 1px solid var(--gold-line);
  padding-top: 8px;
}

.page-about .about-timeline .accordion__item {
  border: 0;
}

.page-about .about-timeline .accordion__trigger {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 18px;
  width: 100%;
  background: none;
  border: 0;
  padding: 16px 0;
  color: inherit;
  font-family: var(--font-sans);
  text-align: left;
  cursor: pointer;
}

.page-about .about-timeline__year {
  font-size: var(--step-26);
  color: var(--gold-light);
  min-width: 4.2em;
}

.page-about .about-timeline__label {
  flex: 1 1 220px;
  font-size: var(--step-21);
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-timeline .accordion__mark {
  margin-left: auto;
  color: var(--jade);
  font-family: var(--font-mono);
  font-size: var(--step-21);
  line-height: 1;
}

.page-about .about-timeline .accordion__mark::after {
  content: "+";
}

.page-about .about-timeline .accordion__item[data-open="true"] .accordion__mark::after {
  content: "–";
}

.page-about .about-timeline .accordion__panel {
  overflow: hidden;
}

.page-about .about-timeline__inner {
  max-width: 34em;
  padding: 0 0 20px;
  font-size: var(--step-17);
  line-height: 1.9;
  color: var(--slate);
}

/* 页尾双入口 */
.page-about .about-next {
  padding-bottom: clamp(56px, 8vw, 96px);
  border-top: 1px solid var(--gold-line);
}

.page-about .about-next .index-label {
  color: var(--gold);
  margin-bottom: 20px;
}

.page-about .about-next__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2px;
}

.page-about .about-next__card {
  display: grid;
  gap: 8px;
  padding: 26px 22px;
  background: var(--table);
  border: 1px solid var(--gold-line);
  border-radius: 0;
  text-decoration: none;
  color: var(--paper);
  transition: border-color 180ms var(--ease), transform 180ms var(--ease);
}

.page-about .about-next__card:hover,
.page-about .about-next__card:focus-visible {
  border-color: var(--jade);
  transform: translateY(-2px);
}

.page-about .about-next__num {
  color: var(--gold);
  font-size: var(--step-13);
}

.page-about .about-next__desc {
  font-size: var(--step-17);
  line-height: 1.8;
  color: var(--slate);
}

.page-about .about-next__go {
  margin-top: 6px;
  font-size: var(--step-17);
  color: var(--jade);
  border-bottom: 1px solid var(--jade);
  justify-self: start;
  padding-bottom: 2px;
}

/* 窄屏与桌面 */
@media (max-width: 640px) {
  .page-about .about-hero__title br {
    display: none;
  }

  .page-about .about-hero__facts {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .about-timeline__list {
    padding-left: 16px;
  }

  .page-about .about-timeline__node::before {
    left: -21px;
  }

  .page-about .about-timeline__label {
    font-size: var(--step-17);
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: 5fr 7fr;
    gap: clamp(32px, 4vw, 64px);
    align-items: start;
  }

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

  .page-about .about-chapter__body {
    grid-template-columns: 7fr 4fr;
    gap: clamp(32px, 4vw, 72px);
  }

  .page-about .about-chapter__body--wide {
    grid-template-columns: 1fr;
  }

  .page-about .about-chapter__aside {
    padding-top: 8px;
  }

  .page-about .about-roles__row {
    grid-template-columns: 9em 6em 1fr;
    align-items: baseline;
    gap: 0 24px;
    row-gap: 0;
  }

  .page-about .about-roles__duty {
    font-size: var(--step-17);
  }

  .page-about .about-next__grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-principle {
    grid-template-columns: 5em 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-next__card {
    transition: none;
  }

  .page-about .about-next__card:hover,
  .page-about .about-next__card:focus-visible {
    transform: none;
  }
}

.page-about {
  --step-15: 1rem;
}