.page-about {
  --about-rail-w: 220px;
  --about-stream-gap: clamp(48px, 7vw, 88px);
  background: var(--cream);
  color: var(--ink);
}

/* ---------- 首屏框景 ---------- */
.page-about .about-hero {
  background-color: var(--green);
  background-image: linear-gradient(158deg, var(--green-deep) 0%, var(--green) 58%, #1b4235 100%);
  color: var(--cream);
  padding: calc(var(--header-h) + clamp(24px, 5vw, 56px)) var(--gutter) clamp(44px, 6vw, 80px);
}

.page-about .about-hero-frame {
  position: relative;
  max-width: var(--shell-max);
  margin: 0 auto;
  border: 2px solid rgba(227, 192, 138, 0.5);
  padding: clamp(22px, 3.6vw, 52px);
}

.page-about .about-hero-frame::after {
  content: "";
  position: absolute;
  left: -2px;
  right: -2px;
  bottom: -2px;
  height: 8px;
  background-image: repeating-linear-gradient(90deg, var(--copper) 0 2px, transparent 2px 18px);
  opacity: 0.55;
  pointer-events: none;
}

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

.page-about .about-breadcrumb .breadcrumb-link {
  color: var(--copper-light);
  text-decoration: none;
}

.page-about .about-breadcrumb .breadcrumb-link:hover,
.page-about .about-breadcrumb .breadcrumb-link:focus-visible {
  color: var(--cream);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-about .about-breadcrumb .breadcrumb-current {
  color: rgba(244, 239, 228, 0.7);
}

.page-about .about-hero-eyebrow {
  margin: 16px 0 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--copper-light);
}

.page-about .about-hero h1 {
  margin: 18px 0 0;
  max-width: 22ch;
  font-family: var(--font-display);
  font-size: clamp(30px, 5.2vw, 58px);
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--cream);
}

.page-about .about-hero-lede {
  margin: 20px 0 0;
  max-width: 58ch;
  font-size: clamp(15.5px, 1.6vw, 18px);
  line-height: 1.75;
  color: rgba(244, 239, 228, 0.84);
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(26px, 4vw, 44px) 0 0;
  background: rgba(227, 192, 138, 0.3);
  border: 1px solid rgba(227, 192, 138, 0.3);
}

.page-about .about-stat {
  background: var(--green-deep);
  padding: 16px 18px;
  min-width: 0;
}

.page-about .about-stat dt {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--copper-light);
}

.page-about .about-stat dd {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-size: clamp(19px, 2.4vw, 26px);
  line-height: 1.2;
  color: var(--cream);
}

@media (min-width: 860px) {
  .page-about .about-hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 主体双栏 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(32px, 5vw, 56px);
  padding-top: clamp(40px, 6vw, 72px);
  padding-bottom: clamp(56px, 8vw, 104px);
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: clamp(36px, 5vw, 72px);
    align-items: start;
  }
}

/* ---------- 左栏：档位轴与目录 ---------- */
.page-about .about-rail {
  display: grid;
  gap: 26px;
  min-width: 0;
}

@media (min-width: 1024px) {
  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 20px);
    gap: 34px;
  }
}

.page-about .rail-block {
  min-width: 0;
}

.page-about .rail-label {
  margin: 0;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--green-deep);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--green);
}

.page-about .rail-tiers {
  position: relative;
  list-style: none;
  margin: 12px 0 0;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .rail-tier {
  position: relative;
  flex: 0 0 auto;
  display: flex;
}

.page-about .tier-node {
  display: inline-flex;
  align-items: baseline;
  gap: 3px;
  min-height: 44px;
  padding: 10px 14px;
  background: var(--cream);
  color: var(--ink);
  border: 2px solid var(--green-deep);
  box-shadow: var(--shadow-hard-sm);
  font-family: var(--font-mono);
  font-size: 15px;
  cursor: help;
  transition: transform 160ms var(--ease), background-color 160ms var(--ease);
}

.page-about .tier-node:hover {
  background: var(--copper);
  transform: translate(-1px, -1px);
}

.page-about .tier-node:focus-visible {
  outline: 2px solid var(--copper);
  outline-offset: 2px;
}

.page-about .tier-unit {
  font-size: 11px;
  letter-spacing: 0.04em;
}

.page-about .tier-info {
  display: none;
}

.page-about .rail-index {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 14px;
}

.page-about .rail-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  font-size: 14.5px;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  color: var(--green);
  text-decoration: underline;
  text-decoration-color: var(--copper);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

@media (min-width: 1024px) {
  .page-about .rail-tiers {
    flex-direction: column;
    gap: 16px;
    padding: 6px 0;
    overflow: visible;
  }

  .page-about .rail-tiers::before {
    content: "";
    position: absolute;
    left: 9px;
    top: 16px;
    bottom: 16px;
    width: 2px;
    background: var(--line);
  }

  .page-about .rail-tier {
    display: block;
    padding-left: 30px;
  }

  .page-about .rail-tier::before {
    content: "";
    position: absolute;
    left: 4px;
    top: 50%;
    width: 12px;
    height: 12px;
    margin-top: -6px;
    background: var(--copper);
    border: 2px solid var(--green-deep);
  }

  .page-about .tier-node {
    width: 100%;
    justify-content: flex-start;
    box-shadow: none;
  }

  .page-about .tier-info {
    display: block;
    position: absolute;
    left: calc(100% + 10px);
    top: -2px;
    z-index: 6;
    width: 176px;
    padding: 10px 12px;
    background: var(--green-deep);
    color: var(--cream);
    border: 2px solid var(--copper);
    box-shadow: var(--shadow-hard-sm);
    opacity: 0;
    pointer-events: none;
    transition: opacity 160ms var(--ease);
  }

  .page-about .tier-node:hover + .tier-info,
  .page-about .tier-node:focus-visible + .tier-info {
    opacity: 1;
  }

  .page-about .tier-region {
    display: block;
    font-size: 14px;
    letter-spacing: 0.04em;
  }

  .page-about .tier-span {
    display: block;
    margin-top: 4px;
    font-family: var(--font-mono);
    font-size: 12.5px;
    color: var(--copper-light);
  }

  .page-about .rail-index {
    flex-direction: column;
    gap: 0;
  }

  .page-about .rail-link {
    width: 100%;
    border-bottom: 1px solid var(--line);
  }
}

/* ---------- 右栏内容流 ---------- */
.page-about .about-stream {
  display: grid;
  gap: var(--about-stream-gap);
  min-width: 0;
}

.page-about .archive-section {
  min-width: 0;
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .section-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding-top: 18px;
  border-top: 3px solid var(--green-deep);
  margin-bottom: clamp(22px, 3vw, 34px);
}

@media (min-width: 720px) {
  .page-about .section-head {
    grid-template-columns: auto minmax(0, 1fr);
    gap: clamp(18px, 3vw, 34px);
    align-items: start;
  }
}

.page-about .section-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 62px;
  padding: 6px 12px 10px;
  background: var(--green-deep);
  color: var(--copper-light);
  font-family: var(--font-display);
  font-size: clamp(32px, 4.6vw, 52px);
  line-height: 1;
  letter-spacing: -0.02em;
  box-shadow: var(--shadow-hard-sm);
}

.page-about .section-title {
  margin: 0;
  font-size: clamp(21px, 2.8vw, 30px);
  line-height: 1.3;
}

.page-about .section-lede {
  margin: 10px 0 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.75;
}

/* ---------- 01 时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 0 0 clamp(24px, 3vw, 34px);
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

.page-about .timeline-item {
  position: relative;
  padding: 0 0 26px 26px;
  border-left: 2px solid var(--line);
}

.page-about .timeline-item:last-child {
  padding-bottom: 0;
}

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  left: -8px;
  top: 6px;
  width: 12px;
  height: 12px;
  background: var(--copper);
  border: 2px solid var(--green-deep);
}

.page-about .timeline-step {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.08em;
  color: var(--green);
}

.page-about .timeline-title {
  margin: 4px 0 0;
  font-size: 17px;
}

.page-about .timeline-text {
  margin: 6px 0 0;
  font-size: 14.5px;
  line-height: 1.72;
}

@media (min-width: 760px) {
  .page-about .timeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .timeline-item {
    padding: 26px 20px 0 0;
    border-left: 0;
    border-top: 2px solid var(--line);
  }

  .page-about .timeline-item::before {
    left: 0;
    top: -8px;
  }
}

.page-about .about-figure {
  margin: clamp(22px, 3vw, 34px) 0 0;
}

/* ---------- 02 档位表 ---------- */
.page-about .scroll-hint {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--green);
}

@media (min-width: 760px) {
  .page-about .scroll-hint {
    display: none;
  }
}

.page-about .table-scroll {
  overflow-x: auto;
  border: 2px solid var(--green-deep);
  box-shadow: var(--shadow-hard);
  background: var(--cream);
  -webkit-overflow-scrolling: touch;
}

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

.page-about .tier-table th,
.page-about .tier-table td {
  padding: 14px 16px;
  text-align: left;
  vertical-align: top;
  font-size: 14.5px;
  line-height: 1.65;
  border-bottom: 1px solid var(--line);
}

.page-about .tier-table thead th {
  background: var(--green);
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.page-about .tier-table tbody tr:nth-child(even) {
  background: var(--paper);
}

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

.page-about .tier-table .tier-row-num {
  width: 56px;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--green-deep);
}

.page-about .tier-table tbody td {
  color: var(--ink);
}

/* ---------- 03 交付与产区 ---------- */
.page-about .delivery-list {
  display: grid;
  gap: 20px;
  margin: 0 0 clamp(20px, 3vw, 28px);
}

.page-about .delivery-list .meter-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 13.5px;
  color: var(--green-deep);
}

.page-about .delivery-list .meter-track {
  height: 16px;
  background: var(--copper-light);
  border: 2px solid var(--green-deep);
  overflow: hidden;
}

.page-about .delivery-list .meter-fill {
  width: calc(var(--meter-value, 0) * 100%);
  height: 100%;
  background: var(--copper);
  transition: width 220ms var(--ease);
}

.page-about .about-note {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin: 0 0 clamp(26px, 4vw, 40px);
  padding: 14px 16px;
  background: var(--cream);
  border: 2px solid var(--clay);
  box-shadow: 3px 3px 0 var(--clay);
  font-size: 14.5px;
  line-height: 1.7;
}

.page-about .note-mark {
  flex: 0 0 auto;
  padding: 3px 8px;
  background: var(--clay);
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
}

.page-about .origin-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 32px);
  align-items: start;
}

@media (min-width: 800px) {
  .page-about .origin-split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }
}

.page-about .origin-title {
  margin: 0 0 10px;
  font-size: 18px;
}

.page-about .origin-copy p {
  margin: 0 0 12px;
  max-width: 54ch;
  font-size: 15px;
  line-height: 1.75;
}

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

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

/* ---------- 04 团队与合作生态 ---------- */
.page-about .team-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .team-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 4px 18px;
  align-items: baseline;
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .team-role {
  font-weight: 600;
}

.page-about .team-count {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--green-deep);
  text-align: right;
}

.page-about .team-desc {
  grid-column: 1 / -1;
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
}

@media (min-width: 760px) {
  .page-about .team-row {
    grid-template-columns: 150px 90px minmax(0, 1fr);
  }

  .page-about .team-count {
    text-align: left;
  }

  .page-about .team-desc {
    grid-column: auto;
  }
}

.page-about .team-total {
  margin: 18px 0 0;
  padding-top: 14px;
  border-top: 2px solid var(--green-deep);
  font-family: var(--font-display);
  font-size: 20px;
  color: var(--green-deep);
}

.page-about .eco-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .eco-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 18px;
  background: var(--paper);
  border: 2px solid var(--green-deep);
}

@media (min-width: 520px) {
  .page-about .eco-row {
    grid-template-columns: 96px minmax(0, 1fr);
    align-items: baseline;
  }
}

.page-about .eco-head {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 26px;
  line-height: 1;
  color: var(--green-deep);
}

.page-about .eco-unit {
  font-size: 13px;
  color: var(--green);
}

.page-about .eco-desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
}

/* ---------- 05 维护节奏 ---------- */
.page-about .archive-section--slab {
  padding: clamp(20px, 3vw, 36px);
  background: var(--paper);
  border: 2px solid var(--green-deep);
  box-shadow: var(--shadow-hard);
}

.page-about .archive-section--slab .section-head {
  border-top: 0;
  padding-top: 0;
}

.page-about .maintain-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border-top: 2px solid var(--green-deep);
}

.page-about .maintain-item {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

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

  .page-about .maintain-item:nth-child(odd) {
    padding-right: 24px;
    border-right: 1px solid var(--line);
  }

  .page-about .maintain-item:nth-child(even) {
    padding-left: 24px;
  }

  .page-about .maintain-item:last-child,
  .page-about .maintain-item:nth-last-child(2) {
    border-bottom: 0;
  }
}

.page-about .maintain-title {
  margin: 0;
  font-size: 17px;
}

.page-about .maintain-text {
  margin: 8px 0 0;
  font-size: 14.5px;
  line-height: 1.72;
}

/* ---------- 06 下一步路径 ---------- */
.page-about .next-paths {
  list-style: none;
  margin: 0 0 clamp(26px, 4vw, 36px);
  padding: 0;
  border-top: 2px solid var(--line);
}

.page-about .next-path {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .path-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--green-deep);
  color: var(--copper-light);
  font-family: var(--font-mono);
  font-size: 16px;
}

.page-about .path-title {
  margin: 0;
  font-size: 18px;
  line-height: 1.45;
}

.page-about .path-link {
  color: var(--green-deep);
  text-decoration: none;
  border-bottom: 2px solid var(--copper);
}

.page-about .path-link:hover,
.page-about .path-link:focus-visible {
  background: var(--copper-light);
}

.page-about .path-text {
  margin: 8px 0 0;
  font-size: 14.5px;
  line-height: 1.72;
}

.page-about .next-foot {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin: 0;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tier-node,
  .page-about .tier-info,
  .page-about .delivery-list .meter-fill {
    transition: none;
  }
}

.page-about {
  --meter-value: 1rem;
}