.page-about {
  --about-rail-w: 232px;
  --about-gap: clamp(28px, 4vw, 56px);
  display: block;
}

/* ---------- 首屏 ---------- */
.page-about .about-masthead {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(158deg, var(--c-night) 0%, var(--c-turf) 62%, var(--c-turf-hi) 100%);
  border-bottom: 1px solid var(--line-hair);
}

.page-about .about-masthead::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--line-soft) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line-soft) 1px, transparent 1px);
  background-size: 64px 64px;
  opacity: .55;
  pointer-events: none;
}

.page-about .about-masthead::after {
  content: "";
  position: absolute;
  right: -14%;
  top: -34%;
  width: 54%;
  height: 168%;
  background: linear-gradient(180deg, rgba(255, 92, 36, .17), rgba(255, 92, 36, 0) 72%);
  transform: rotate(18deg);
  pointer-events: none;
}

.page-about .masthead-ghost {
  position: absolute;
  right: -0.04em;
  bottom: -0.2em;
  z-index: 0;
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(120px, 26vw, 300px);
  line-height: .8;
  letter-spacing: -.05em;
  color: rgba(243, 238, 226, .055);
  pointer-events: none;
  user-select: none;
}

.page-about .masthead-inner {
  position: relative;
  z-index: 1;
  max-width: var(--content-max);
  margin: 0 auto;
  padding: clamp(52px, 8vw, 104px) var(--pad-x) clamp(38px, 6vw, 68px);
}

.page-about .about-kicker {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 10px;
  font-family: var(--font-narrow);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .16em;
  color: var(--c-data);
}

.page-about .about-kicker::after {
  content: "";
  width: 26px;
  height: 2px;
  background: var(--c-score);
  flex: none;
}

.page-about .about-kicker--top {
  color: rgba(243, 238, 226, .72);
}

.page-about .masthead-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(38px, 6.6vw, 76px);
  line-height: 1.06;
  letter-spacing: -.012em;
  color: var(--c-lamp);
}

.page-about .masthead-lede {
  margin: 24px 0 0;
  max-width: 46em;
  font-family: var(--font-body);
  font-size: clamp(16px, 1.8vw, 19px);
  line-height: 1.85;
  color: var(--ink-dim);
}

.page-about .masthead-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(30px, 4vw, 44px);
  background: var(--line-hair);
  border: 1px solid var(--line-hair);
}

.page-about .masthead-stat {
  background: var(--c-turf);
  padding: 16px 16px 18px;
}

.page-about .stat-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(22px, 2.6vw, 30px);
  line-height: 1.1;
  color: var(--c-lamp);
}

.page-about .stat-key {
  display: block;
  margin-top: 7px;
  font-family: var(--font-narrow);
  font-size: 13px;
  line-height: 1.5;
  color: var(--ink-faint);
}

/* ---------- 面包屑条 ---------- */
.page-about .about-crumb {
  background: var(--c-turf);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .crumb-inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 13px var(--pad-x);
}

/* ---------- 骨架 ---------- */
.page-about .about-shell {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: clamp(30px, 5vw, 56px) var(--pad-x) clamp(56px, 8vw, 96px);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 44px);
  align-items: start;
}

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

/* ---------- 左侧索引轨 ---------- */
.page-about .about-rail {
  border-top: 1px solid var(--line-hair);
  padding-top: 16px;
}

.page-about .rail-heading {
  margin: 0 0 12px;
  padding-left: 22px;
  font-family: var(--font-narrow);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .2em;
  color: var(--ink-faint);
}

.page-about .timeline-list {
  --tl-x: 5px;
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .timeline-list::before {
  content: "";
  position: absolute;
  left: var(--tl-x);
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--line-grid);
}

.page-about .timeline-item {
  position: relative;
}

.page-about .timeline-list .toc-link {
  position: relative;
  display: block;
  padding: 9px 0 9px 22px;
  text-decoration: none;
  color: var(--ink-faint);
  transition: color .18s ease;
}

.page-about .timeline-list .toc-link::before {
  content: "";
  position: absolute;
  left: calc(var(--tl-x) - 2px);
  top: 17px;
  width: 7px;
  height: 7px;
  background: var(--c-turf);
  border: 1px solid var(--line-strong);
  transform: rotate(45deg);
  transition: background .18s ease, border-color .18s ease, box-shadow .18s ease;
}

.page-about .timeline-list .toc-link:hover {
  color: var(--ink-dim);
}

.page-about .timeline-list .toc-link.is-active {
  color: var(--c-lamp);
}

.page-about .timeline-list .toc-link.is-active::before {
  background: var(--c-score);
  border-color: var(--c-score);
  box-shadow: 0 0 0 3px rgba(255, 92, 36, .18);
}

.page-about .tl-year {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--c-data);
}

.page-about .timeline-list .toc-link.is-active .tl-year {
  color: var(--c-score);
}

.page-about .tl-text {
  display: block;
  margin-top: 3px;
  font-family: var(--font-narrow);
  font-size: 13px;
  line-height: 1.45;
}

/* ---------- 纵向模块 ---------- */
.page-about .about-section {
  padding-bottom: clamp(34px, 5vw, 60px);
  margin-bottom: clamp(34px, 5vw, 60px);
  border-bottom: 1px solid var(--line-hair);
  scroll-margin-top: var(--stick-top);
}

.page-about .about-section:last-of-type {
  border-bottom: 0;
}

.page-about .about-heading {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(26px, 3.6vw, 44px);
  line-height: 1.16;
  letter-spacing: -.004em;
  color: var(--c-lamp);
}

.page-about .about-heading--sm {
  font-size: clamp(22px, 2.6vw, 30px);
  margin-bottom: 14px;
}

.page-about .about-copy > p {
  margin: 0 0 18px;
  font-family: var(--font-body);
  font-size: clamp(16px, 1.55vw, 17px);
  line-height: 1.85;
  color: var(--ink-dim);
}

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

.page-about .about-copy--tight > p {
  margin-top: 22px;
}

/* ---------- 版本横带 ---------- */
.page-about .version-strip {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 26px 0 0;
  background: var(--line-hair);
  border: 1px solid var(--line-hair);
}

.page-about .version-item {
  background: var(--c-turf);
  padding: 18px 16px 20px;
  border-left: 2px solid transparent;
  transition: border-color .18s ease, background .18s ease;
}

.page-about .version-item:hover {
  background: var(--c-turf-hi);
  border-left-color: var(--c-score);
}

.page-about .v-year {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 22px;
  line-height: 1.1;
  letter-spacing: .02em;
  color: var(--c-data);
}

.page-about .v-text {
  display: block;
  margin-top: 9px;
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.65;
  color: var(--ink-dim);
}

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

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

.page-about .about-media figcaption {
  margin-top: 10px;
  padding-left: 10px;
  border-left: 1px solid var(--line-hair);
  font-family: var(--font-narrow);
  font-size: 13px;
  line-height: 1.6;
  color: var(--ink-faint);
}

/* ---------- 靛蓝主题带 ---------- */
.page-about .about-band {
  margin: 0 0 clamp(34px, 5vw, 60px);
  padding: clamp(24px, 3.6vw, 40px);
  background: linear-gradient(140deg, var(--c-indigo) 0%, var(--c-night) 100%);
  border: 1px solid var(--line-hair);
  scroll-margin-top: var(--stick-top);
}

.page-about .about-band .about-kicker {
  color: rgba(243, 238, 226, .74);
}

.page-about .about-band .about-copy > p {
  color: rgba(243, 238, 226, .8);
}

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

.page-about .duty-list li {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding: 15px 0;
  border-bottom: 1px solid var(--line-hair);
}

.page-about .duty-key {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--c-score);
}

.page-about .duty-text {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.75;
  color: rgba(243, 238, 226, .78);
}

.page-about .duty-text b {
  color: var(--c-lamp);
  font-weight: 600;
}

/* ---------- 引文块 ---------- */
.page-about .about-quote {
  margin: 26px 0;
  padding: clamp(20px, 3vw, 30px);
  background: var(--c-wine);
  border-left: 2px solid var(--c-score);
}

.page-about .about-quote p {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(18px, 2.1vw, 22px);
  line-height: 1.6;
  color: var(--c-lamp);
}

/* ---------- 地域收束 ---------- */
.page-about .about-section--region {
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-section--region .about-heading {
  color: rgba(243, 238, 226, .88);
}

/* ---------- 底部导流 ---------- */
.page-about .about-next {
  margin-top: clamp(20px, 3vw, 34px);
  padding-top: clamp(24px, 3vw, 34px);
  border-top: 1px solid var(--line-strong);
}

.page-about .next-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  background: var(--line-hair);
  border: 1px solid var(--line-hair);
}

.page-about .next-link {
  display: block;
  height: 100%;
  padding: 20px 18px 22px;
  background: var(--c-turf);
  text-decoration: none;
  transition: background .18s ease;
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  background: var(--c-turf-hi);
}

.page-about .next-link:focus-visible {
  outline: 2px solid var(--c-data);
  outline-offset: -2px;
}

.page-about .next-key {
  display: block;
  margin-bottom: 9px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--c-data);
}

.page-about .next-title {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 20px;
  line-height: 1.3;
  color: var(--c-lamp);
}

.page-about .next-desc {
  display: block;
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.65;
  color: var(--ink-faint);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .masthead-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
  }

  .page-about .about-rail {
    position: sticky;
    top: var(--stick-top);
    align-self: start;
    max-height: calc(100vh - var(--stick-top) - 48px);
    overflow-y: auto;
    border-top: 0;
    padding-top: 4px;
  }
}

@media (max-width: 719px) {
  .page-about .masthead-ghost {
    font-size: 34vw;
    bottom: -0.14em;
  }

  .page-about .about-band {
    padding: 22px 18px 26px;
  }

  .page-about .about-quote {
    padding: 20px 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .timeline-list .toc-link,
  .page-about .version-item,
  .page-about .next-link {
    transition: none;
  }
}