.page-about {
  --about-measure: 40em;
  --about-rail: 3.25rem;
  background: var(--c-pitch-abyss);
  color: var(--c-text);
  padding-bottom: 72px;
}

/* ---------- 首屏 ---------- */
.page-about .crumbs {
  padding: 18px 0 0;
}

.page-about .about-masthead {
  padding: 10px 0 40px;
  border-bottom: var(--line);
}

.page-about .about-masthead__kicker {
  margin: 0 0 18px;
  font-size: var(--fs-12);
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--c-accent-lime);
}

.page-about .about-masthead__title {
  margin: 0 0 26px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(30px, 7vw, 72px);
  line-height: .98;
  letter-spacing: .01em;
  max-width: 13em;
}

.page-about .about-masthead__lede {
  margin: 0 0 32px;
  max-width: var(--about-measure);
  font-size: var(--fs-16);
  line-height: 1.9;
}

.page-about .about-masthead__facts {
  display: flex;
  flex-wrap: wrap;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: var(--line);
  border-bottom: var(--line);
}

.page-about .about-masthead__facts li {
  flex: 1 1 140px;
  padding: 14px 16px 16px 0;
  border-right: var(--line);
  font-size: var(--fs-13);
  letter-spacing: .04em;
  color: var(--c-text-muted);
}

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

.page-about .about-masthead__facts b {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-26);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--c-accent-lime);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  max-width: 56rem;
  padding: 44px 0;
  border-bottom: var(--line);
  scroll-margin-top: calc(var(--header-h) + 16px);
}

.page-about .about-section__body {
  max-width: var(--about-measure);
}

.page-about .about-section__body p {
  margin: 0 0 1em;
  font-size: var(--fs-16);
  line-height: 1.9;
}

.page-about .about-section__body p:last-child {
  margin-bottom: 0;
}

.page-about .about-section__body a {
  color: var(--c-text);
  text-decoration: underline;
  text-decoration-color: var(--c-grid);
  text-underline-offset: 3px;
  transition: color var(--t-fast) var(--ease), text-decoration-color var(--t-fast) var(--ease);
}

.page-about .about-section__body a:hover,
.page-about .about-section__body a:focus-visible {
  color: var(--c-accent-lime);
  text-decoration-color: var(--c-accent-lime);
}

.page-about .about-section .section-head {
  margin-bottom: 22px;
}

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

@media (min-width: 900px) {
  .page-about .about-section {
    grid-template-columns: minmax(0, 1fr) var(--about-rail);
    gap: var(--gap);
    padding: 64px 0;
  }

  .page-about .about-section__rail {
    display: block;
    padding-top: 4px;
  }

  .page-about .about-section__rail-num {
    display: block;
    margin-bottom: 14px;
    font-size: var(--fs-20);
    letter-spacing: .1em;
    color: var(--c-accent-lime);
  }

  .page-about .about-section__rail-note {
    display: block;
    writing-mode: vertical-rl;
    font-size: var(--fs-12);
    letter-spacing: .18em;
    line-height: 1;
    color: var(--c-text-muted);
  }
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 26px;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(.72) brightness(.84) contrast(1.04);
  border: var(--line);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: var(--fs-12);
  letter-spacing: .06em;
  line-height: 1.75;
  color: var(--c-text-muted);
}

.page-about .about-figure--wide {
  margin-top: 4px;
}

/* ---------- 编辑组角色 ---------- */
.page-about .about-roles {
  margin: 22px 0 26px;
  border-top: var(--line);
}

.page-about .about-roles__row {
  display: grid;
  grid-template-columns: 2.8rem minmax(0, 1fr);
  gap: 4px 14px;
  padding: 16px 0;
  border-bottom: var(--line);
  transition: background-color var(--t-fast) var(--ease);
}

.page-about .about-roles__row:hover {
  background: var(--c-panel);
}

.page-about .about-roles__num {
  grid-row: span 2;
  font-size: var(--fs-20);
  font-variant-numeric: tabular-nums;
  color: var(--c-accent-lime);
}

.page-about .about-roles__name {
  font-family: var(--font-display);
  font-size: var(--fs-20);
  line-height: 1.2;
  letter-spacing: .02em;
}

.page-about .about-roles__desc {
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--c-text-muted);
}

/* ---------- 口径手册 ---------- */
.page-about .about-manual {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-bottom: 26px;
}

@media (min-width: 720px) {
  .page-about .about-manual {
    grid-template-columns: minmax(0, 1fr) 200px;
    gap: var(--gap);
    align-items: start;
  }
}

.page-about .about-quote {
  margin: 0 0 14px;
  padding: 14px 16px;
  border-left: 3px solid var(--c-ref-red);
  background: var(--c-panel);
}

.page-about .about-quote:last-child {
  margin-bottom: 0;
}

.page-about .about-quote p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--c-text-muted);
}

.page-about .about-quote strong {
  color: var(--c-text);
  font-weight: 600;
}

.page-about .about-figure--portrait {
  margin-bottom: 0;
}

/* ---------- 版本折叠 ---------- */
.page-about .about-versions {
  margin: 0;
  padding: 0 0 0 1.1em;
  list-style: decimal;
}

.page-about .about-versions li {
  margin-bottom: 10px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--c-text-muted);
}

.page-about .about-versions li:last-child {
  margin-bottom: 0;
}

.page-about .about-versions .mono {
  display: inline-block;
  min-width: 3.4em;
  color: var(--c-accent-lime);
  font-variant-numeric: tabular-nums;
}

/* ---------- 覆盖矩阵 ---------- */
.page-about .about-matrix__wrap {
  margin: 20px 0 22px;
  overflow-x: auto;
  border: var(--line);
  background: var(--c-pitch-900);
  -webkit-overflow-scrolling: touch;
}

.page-about .about-matrix {
  min-width: 700px;
  width: 100%;
  border-collapse: collapse;
}

.page-about .about-matrix__caption {
  padding: 12px 14px;
  text-align: left;
  font-size: var(--fs-12);
  letter-spacing: .1em;
  color: var(--c-text-muted);
  border-bottom: var(--line);
}

.page-about .about-matrix th,
.page-about .about-matrix td {
  padding: 12px 14px;
  border-bottom: var(--line);
  border-right: var(--line);
  text-align: left;
}

.page-about .about-matrix tr > *:last-child {
  border-right: 0;
}

.page-about .about-matrix tbody tr:last-child > * {
  border-bottom: 0;
}

.page-about .about-matrix tbody th {
  font-family: var(--font-display);
  font-size: var(--fs-14);
  letter-spacing: .03em;
  color: var(--c-text);
  white-space: nowrap;
}

.page-about .about-matrix tbody tr {
  transition: background-color var(--t-fast) var(--ease);
}

.page-about .about-matrix tbody tr:hover {
  background: var(--c-panel);
}

.page-about .about-cell {
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  font-variant-numeric: tabular-nums;
  letter-spacing: .04em;
  text-align: center;
  white-space: nowrap;
}

.page-about .about-cell--full {
  background: rgba(28, 68, 48, .85);
  color: var(--c-text);
}

.page-about .about-cell--round {
  background: rgba(28, 68, 48, .32);
  color: var(--c-away-sand);
}

/* ---------- 时间线带 ---------- */
.page-about .about-band {
  padding: 44px 0;
  border-bottom: var(--line);
  background: linear-gradient(180deg, var(--c-pitch-900) 0%, var(--c-pitch-abyss) 100%);
  scroll-margin-top: calc(var(--header-h) + 16px);
}

@media (min-width: 900px) {
  .page-about .about-band {
    padding: 64px 0 56px;
  }
}

.page-about .about-band .section-head {
  margin-bottom: 20px;
}

.page-about .about-band__lede {
  margin: 0 0 26px;
  max-width: 46em;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--c-text-muted);
}

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

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

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

.page-about .about-tl__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 0;
  border-bottom: var(--line);
  text-decoration: none;
  color: var(--c-text);
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .about-tl__link:hover,
.page-about .about-tl__link:focus-visible {
  color: var(--c-accent-lime);
  border-bottom-color: var(--c-accent-lime);
}

.page-about .about-tl__dot {
  flex: 0 0 auto;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--c-accent-lime);
}

.page-about .about-tl__dot--open {
  background: transparent;
  border: 2px solid var(--c-accent-lime);
}

.page-about .about-tl__label {
  font-size: var(--fs-14);
  line-height: 1.5;
}

.page-about .about-tl__ver {
  margin-left: auto;
  font-size: var(--fs-12);
  letter-spacing: .08em;
  color: var(--c-text-muted);
}

@media (min-width: 768px) {
  .page-about .about-tl {
    padding: 4px 0 0;
  }

  .page-about .about-tl__axis {
    display: block;
    position: absolute;
    top: 9px;
    left: calc(100% / 12);
    right: calc(100% / 12);
    width: auto;
    height: 2px;
  }

  .page-about .about-tl__list {
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 0 12px;
  }

  .page-about .about-tl__link {
    display: block;
    padding: 0;
    border-bottom: 0;
    text-align: center;
  }

  .page-about .about-tl__dot {
    display: block;
    width: 12px;
    height: 12px;
    margin: 3px auto 16px;
  }

  .page-about .about-tl__label {
    display: block;
    font-size: var(--fs-13);
    line-height: 1.5;
  }

  .page-about .about-tl__ver {
    display: block;
    margin: 6px 0 0;
  }
}

/* ---------- 阶段条目 ---------- */
.page-about .about-stages {
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  border-top: var(--line);
}

.page-about .about-stage {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: var(--line);
  scroll-margin-top: calc(var(--header-h) + 24px);
  transition: background-color var(--t-fast) var(--ease), box-shadow var(--t-fast) var(--ease);
}

.page-about .about-stage:hover {
  background: var(--c-panel);
}

@media (min-width: 640px) {
  .page-about .about-stage {
    grid-template-columns: 4.6rem minmax(0, 1fr);
    gap: var(--gap);
    align-items: start;
  }
}

.page-about .about-stage__ver {
  font-size: var(--fs-13);
  letter-spacing: .08em;
  color: var(--c-accent-lime);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stage__text {
  margin: 0;
  max-width: 44em;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--c-text-muted);
}

.page-about .about-stage__text strong {
  color: var(--c-text);
  font-weight: 600;
}

/* ---------- 回到手册 ---------- */
.page-about .about-jump {
  display: inline-block;
  margin-top: 36px;
}

@media (min-width: 1024px) {
  .page-about .about-jump {
    position: fixed;
    right: var(--gutter-right);
    bottom: 28px;
    z-index: 30;
    margin-top: 0;
    background: var(--c-panel);
  }
}

/* ---------- 窄屏收束 ---------- */
@media (max-width: 599px) {
  .page-about .about-masthead__facts li {
    flex: 1 1 100%;
    border-right: 0;
    border-bottom: var(--line);
    padding: 12px 0;
  }

  .page-about .about-masthead__facts li:last-child {
    border-bottom: 0;
  }

  .page-about .about-masthead__facts b {
    display: inline-block;
    margin: 0 10px 0 0;
    font-size: var(--fs-20);
  }

  .page-about .about-band {
    margin: 0 calc(var(--gutter-left) * -1);
    padding-left: var(--gutter-left);
    padding-right: var(--gutter-right);
  }
}
<<<END>>>