.page-about {
  --about-rail: 176px;
  --about-gap: clamp(32px, 5vw, 80px);
  background-color: var(--ink);
  background-image:
    repeating-linear-gradient(90deg, rgba(44, 69, 92, 0.26) 0 1px, transparent 1px 88px),
    repeating-linear-gradient(0deg, rgba(44, 69, 92, 0.14) 0 1px, transparent 1px 88px);
  color: var(--paper);
  padding-bottom: clamp(56px, 9vw, 120px);
}

.page-about a:focus-visible {
  outline: 2px solid var(--amber-soft);
  outline-offset: 3px;
}

.page-about .about-top {
  padding-top: clamp(18px, 3vw, 30px);
}

.page-about .about-top .breadcrumb {
  color: var(--mist);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
}

.page-about .about-top .breadcrumb a {
  color: var(--amber-soft);
  text-decoration: none;
}

.page-about .about-top .breadcrumb a:hover {
  border-bottom: 1px solid var(--amber);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: clamp(26px, 4.5vw, 56px) 0 clamp(30px, 5vw, 64px);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
  align-items: start;
}

.page-about .about-hero-copy .eyebrow {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--amber);
  text-transform: uppercase;
}

.page-about h1 {
  margin: 0.24em 0 0.42em;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2.35rem, 7vw, 4.6rem);
  line-height: 1.1;
  letter-spacing: -0.012em;
  color: var(--paper);
}

.page-about .about-hero-copy .lede {
  margin: 0 0 1.4em;
  max-width: 46ch;
  font-size: clamp(0.9375rem, 1.5vw, 1.0625rem);
  line-height: 1.9;
  color: var(--paper-warm);
}

.page-about .about-hero-copy .meta-line {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5em 0.75em;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .about-hero-figure {
  margin: 0;
}

.page-about .media-frame {
  border: 1px solid var(--wire);
  background: var(--ink-deep);
  overflow: hidden;
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: brightness(0.9) contrast(1.05);
  transition: filter var(--t) ease;
}

.page-about figure:hover .media-frame img {
  filter: brightness(1) contrast(1.05);
}

.page-about .media-caption {
  margin-top: 10px;
  font-size: 0.75rem;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--mist);
  border-left: 1px solid var(--amber);
  padding-left: 10px;
}

/* ---------- 数据条 ---------- */

.page-about .about-stats {
  list-style: none;
  margin: 0;
  padding: 1px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--wire);
  border-top: 1px solid var(--wire);
  border-bottom: 1px solid var(--wire);
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: 0.4em;
  padding: clamp(14px, 2.4vw, 22px) clamp(12px, 2vw, 20px);
  background: var(--ink);
  transition: background var(--t) ease;
}

.page-about .about-stats li:hover {
  background: rgba(201, 151, 74, 0.07);
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: clamp(1.9rem, 4.2vw, 2.7rem);
  font-weight: 500;
  line-height: 1;
  letter-spacing: 0.01em;
  color: var(--amber);
}

.page-about .stat-unit {
  font-size: 0.5em;
  margin-left: 0.12em;
}

.page-about .stat-key {
  font-size: 0.8125rem;
  line-height: 1.5;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ---------- 主体：索引 + 叙事 ---------- */

.page-about .about-body {
  display: grid;
  gap: clamp(22px, 4vw, 44px);
  padding-top: clamp(34px, 6vw, 72px);
}

.page-about .about-rail {
  border-top: 1px solid var(--amber);
  padding-top: 14px;
}

.page-about .rail-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  color: var(--amber);
  text-transform: uppercase;
}

.page-about .rail-nav ol {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .rail-nav a {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  padding: 7px 12px;
  border: 1px solid var(--wire);
  color: var(--paper-warm);
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--t) ease, border-color var(--t) ease, background var(--t) ease;
}

.page-about .rail-nav a span {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--amber-soft);
}

.page-about .rail-nav a:hover,
.page-about .rail-nav a:focus-visible {
  border-color: var(--amber);
  color: var(--paper);
}

.page-about .rail-top {
  display: inline-block;
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  color: var(--amber-soft);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--t) ease;
}

.page-about .rail-top:hover {
  border-bottom-color: var(--amber);
}

/* ---------- 章节 ---------- */

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

.page-about .about-chapter {
  padding-top: clamp(26px, 4vw, 44px);
  margin-bottom: clamp(40px, 6vw, 76px);
  border-top: 1px solid var(--wire);
}

.page-about .about-chapter:first-child {
  padding-top: 0;
  border-top: 0;
}

.page-about .chapter-head {
  display: flex;
  align-items: baseline;
  gap: clamp(12px, 2vw, 20px);
  margin-bottom: clamp(16px, 2.6vw, 26px);
}

.page-about .chapter-idx {
  flex: none;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .chapter-head h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(1.55rem, 3.6vw, 2.3rem);
  line-height: 1.24;
  letter-spacing: -0.005em;
  color: var(--paper);
}

.page-about .chapter-body p {
  max-width: 62ch;
  margin: 0 0 1.15em;
  font-size: clamp(0.9375rem, 1.35vw, 1.0625rem);
  line-height: 1.95;
  color: var(--paper-warm);
}

/* ---------- 时间轴 ---------- */

.page-about .year-axis {
  display: block;
  width: 100%;
  height: auto;
  margin: clamp(18px, 3vw, 30px) 0 14px;
}

.page-about .year-list {
  list-style: none;
  margin: 0;
  padding: 1px;
  display: grid;
  gap: 1px;
  background: var(--wire);
  border: 1px solid var(--wire);
}

.page-about .year-list li {
  display: grid;
  gap: 4px;
  padding: 12px 14px;
  background: var(--ink);
}

.page-about .year-mark {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .year-text {
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--paper-warm);
}

/* ---------- 空间数据条 ---------- */

.page-about .space-bars {
  list-style: none;
  margin: 0 0 clamp(20px, 3vw, 32px);
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--wire);
  border: 1px solid var(--wire);
}

.page-about .space-bar {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 14px;
  padding: 14px 16px;
  background: var(--ink);
  border-left: 2px solid transparent;
  transition: border-color var(--t) ease, background var(--t) ease;
}

.page-about .space-bar:hover {
  border-left-color: var(--amber);
  background: rgba(201, 151, 74, 0.07);
}

.page-about .bar-idx {
  grid-column: 1;
  grid-row: 1;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--amber-soft);
}

.page-about .bar-name {
  grid-column: 2;
  grid-row: 1;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  letter-spacing: 0.01em;
  color: var(--paper);
}

.page-about .bar-note {
  grid-column: 2;
  grid-row: 2;
  font-size: 0.875rem;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 表格 ---------- */

.page-about .table-scroll {
  max-width: 100%;
  overflow-x: auto;
  margin: 0 0 clamp(20px, 3vw, 32px);
  border: 1px solid var(--wire);
}

.page-about .space-table {
  width: 100%;
  min-width: 520px;
  border-collapse: collapse;
  font-size: 0.875rem;
  color: var(--paper-warm);
}

.page-about .space-table caption {
  padding: 12px 14px 10px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  color: var(--amber-soft);
  background: var(--ink-deep);
}

.page-about .space-table th,
.page-about .space-table td {
  padding: 11px 14px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--wire);
}

.page-about .space-table thead th {
  font-weight: 400;
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  color: var(--mist);
  border-bottom-color: var(--amber);
}

.page-about .space-table tbody th {
  font-weight: 400;
  color: var(--paper);
  white-space: nowrap;
}

.page-about .space-table tbody tr:last-child th,
.page-about .space-table tbody tr:last-child td {
  border-bottom: 0;
}

/* ---------- 五步流程 ---------- */

.page-about .flow-steps {
  list-style: none;
  margin: 0 0 clamp(18px, 3vw, 28px);
  padding: 1px;
  display: grid;
  gap: 1px;
  background: var(--wire);
  border: 1px solid var(--wire);
}

.page-about .flow-steps li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 3px 16px;
  padding: 15px 16px;
  background: var(--ink);
  transition: background var(--t) ease;
}

.page-about .flow-steps li:hover {
  background: rgba(18, 42, 64, 0.55);
}

.page-about .step-idx {
  grid-column: 1;
  grid-row: 1;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .flow-steps h3 {
  grid-column: 2;
  grid-row: 1;
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  color: var(--paper);
}

.page-about .flow-steps p {
  grid-column: 2;
  grid-row: 2;
  margin: 0;
  max-width: 52ch;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .aside-note {
  margin: 0;
  max-width: 56ch;
  padding: 12px 16px;
  border-left: 2px solid var(--amber);
  background: rgba(201, 151, 74, 0.06);
  font-size: 0.875rem !important;
  line-height: 1.8;
  color: var(--paper-warm) !important;
}

/* ---------- 活动与合作 ---------- */

.page-about .activity-split {
  display: grid;
  gap: clamp(22px, 3.5vw, 40px);
}

.page-about .chapter-figure {
  margin: clamp(20px, 3vw, 34px) 0 0;
}

.page-about .activity-split .chapter-figure {
  margin-top: 0;
}

.page-about .tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 4px;
}

.page-about .tag {
  padding: 5px 11px;
  border: 1px solid var(--wire);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--paper-warm);
  background: rgba(18, 42, 64, 0.5);
}

.page-about .tag--amber {
  border-color: var(--amber);
  color: var(--amber-soft);
}

.page-about .tag--celadon {
  border-color: var(--celadon);
  color: #9dbfb0;
}

/* ---------- 门户版本 ---------- */

.page-about .version-list {
  list-style: none;
  margin: 0 0 clamp(18px, 3vw, 28px);
  padding: 0;
  display: grid;
  gap: clamp(12px, 2vw, 18px);
  counter-reset: none;
}

.page-about .version-list li {
  padding-left: 14px;
  border-left: 1px solid var(--wire);
  transition: border-color var(--t) ease;
}

.page-about .version-list li:hover {
  border-left-color: var(--amber);
}

.page-about .ver-idx {
  display: block;
  margin-bottom: 3px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--amber-soft);
}

.page-about .version-list p {
  margin: 0;
  max-width: 58ch;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--paper-warm);
}

/* ---------- 到馆下一步 ---------- */

.page-about .about-next {
  border-top: 1px solid var(--amber);
}

.page-about .next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: clamp(16px, 2.6vw, 26px) 0 16px;
}

.page-about .next-links .btn {
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  text-decoration: none;
  transition: background var(--t) ease, color var(--t) ease, border-color var(--t) ease;
}

.page-about .next-links .btn--solid {
  background: var(--amber);
  border: 1px solid var(--amber);
  color: var(--ink);
}

.page-about .next-links .btn--solid:hover {
  background: var(--amber-soft);
  border-color: var(--amber-soft);
}

.page-about .next-links .btn--ghost {
  border: 1px solid var(--amber);
  color: var(--amber-soft);
  background: transparent;
}

.page-about .next-links .btn--ghost:hover {
  background: rgba(201, 151, 74, 0.12);
  color: var(--paper);
}

.page-about .next-links .btn--quiet {
  border: 1px solid var(--wire);
  color: var(--mist);
  background: transparent;
}

.page-about .next-links .btn--quiet:hover {
  border-color: var(--amber);
  color: var(--paper);
}

.page-about .next-note {
  margin: 0 !important;
  font-size: 0.8125rem !important;
  line-height: 1.8;
  color: var(--mist) !important;
}

/* ---------- 媒体查询 ---------- */

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

  .page-about .year-list li {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }

  .page-about .activity-split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: start;
  }
}

@media (min-width: 940px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: clamp(40px, 5vw, 88px);
  }

  .page-about .about-hero-figure {
    margin-top: clamp(36px, 6vw, 96px);
  }

  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
    align-self: start;
  }

  .page-about .rail-nav ol {
    display: grid;
    gap: 0;
    overflow: visible;
    padding: 0;
  }

  .page-about .rail-nav a {
    border: 0;
    border-left: 2px solid transparent;
    padding: 9px 0 9px 12px;
  }

  .page-about .rail-nav a:hover,
  .page-about .rail-nav a:focus-visible {
    border-left-color: var(--amber);
    background: rgba(201, 151, 74, 0.08);
  }

  .page-about .activity-split .chapter-figure {
    margin-top: clamp(16px, 3vw, 40px);
  }
}