.page-about {
  --about-line: rgba(20, 22, 26, 0.14);
  padding: 26px 0 72px;
}

.page-about .mono {
  font-family: var(--font-mono);
  letter-spacing: 0.01em;
}

.page-about a:focus-visible,
.page-about [tabindex]:focus-visible {
  outline: 2px solid var(--teal-400);
  outline-offset: 2px;
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 24px;
  font-size: var(--fs-12);
  color: var(--stone-700);
}

.page-about .crumbs a {
  color: var(--stone-700);
  text-decoration: none;
  border-bottom: 1px solid var(--rule-strong);
  padding-bottom: 1px;
  transition: color 180ms ease-out, border-color 180ms ease-out;
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--ink-900);
  border-bottom-color: var(--sand-500);
}

.page-about .crumbs [aria-current="page"] {
  color: var(--ink-900);
  font-weight: 600;
}

.page-about .crumbs__sep {
  color: var(--stone-400);
}

/* ---------- 首屏 ---------- */
.page-about .about-masthead {
  display: grid;
  gap: 26px;
  padding-bottom: 30px;
  border-bottom: 1px solid var(--rule-strong);
  scroll-margin-top: calc(var(--bar-h) + 24px);
}

.page-about .about-masthead .eyebrow {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--sand-700);
}

.page-about h1 {
  margin: 0 0 18px;
  font-family: var(--font-heading);
  font-size: var(--fs-34);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.22;
  color: var(--ink-900);
}

.page-about .lede {
  margin: 0;
  max-width: 30em;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--stone-700);
}

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

.page-about .media-frame {
  display: block;
  padding: 6px;
  background: var(--sand-100);
  border: 1px solid var(--rule-strong);
  overflow: hidden;
}

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

.page-about .figure__caption {
  margin-top: 10px;
  font-family: var(--font-serif);
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--stone-700);
}

/* ---------- 参数速查带 ---------- */
.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 26px 0 42px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .about-facts > div {
  padding: 14px 16px;
  background: var(--sand-050);
}

.page-about .about-facts dt {
  margin-bottom: 6px;
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--stone-700);
}

.page-about .about-facts dd {
  display: inline-block;
  margin: 0;
  padding-bottom: 1px;
  font-family: var(--font-mono);
  font-size: var(--fs-16);
  color: var(--ink-900);
  border-bottom: 1px solid rgba(201, 161, 94, 0.55);
}

/* ---------- 侧栏 + 正文骨架 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
}

.page-about .about-rail {
  display: grid;
  gap: 12px;
  align-content: start;
}

.page-about .rail-card {
  padding: 13px 15px;
  background: var(--sand-100);
  border: 1px solid var(--rule);
}

.page-about .rail-card--status {
  background: var(--sand-050);
  border-left: 3px solid var(--sand-500);
}

.page-about .rail-key {
  margin: 0 0 5px;
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--stone-700);
}

.page-about .rail-val {
  margin: 0;
  font-size: var(--fs-20);
  color: var(--ink-900);
}

.page-about .rail-note {
  margin: 5px 0 0;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--stone-700);
}

.page-about .rail-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: 6px;
  border-radius: 50%;
  background: var(--teal-400);
  box-shadow: 0 0 0 3px rgba(47, 211, 176, 0.2);
}

.page-about .rail-nav {
  padding: 13px 15px;
  background: var(--sand-050);
  border: 1px solid var(--rule);
}

.page-about .rail-list {
  display: grid;
  gap: 2px;
  margin: 9px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .rail-list a {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 6px 8px;
  font-size: var(--fs-14);
  color: var(--stone-700);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: background 180ms ease-out, border-color 180ms ease-out, color 180ms ease-out;
}

.page-about .rail-list a:hover,
.page-about .rail-list a:focus-visible {
  background: var(--sand-100);
  border-left-color: var(--sand-500);
  color: var(--ink-900);
}

.page-about .rail-list .mono {
  font-size: var(--fs-12);
  color: var(--sand-700);
}

.page-about .about-body {
  display: grid;
  gap: 52px;
  min-width: 0;
}

.page-about .about-sec {
  padding-top: 22px;
  border-top: 1px solid var(--rule-strong);
  scroll-margin-top: calc(var(--bar-h) + 24px);
}

.page-about .about-sec:first-child {
  border-top: 1px solid var(--rule);
}

/* ---------- 区块标题 ---------- */
.page-about .section-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 6px 14px;
  align-items: baseline;
  margin-bottom: 20px;
}

.page-about .section-head__no {
  padding: 2px 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--sand-700);
  background: rgba(201, 161, 94, 0.16);
  border: 1px solid rgba(138, 106, 51, 0.28);
}

.page-about .section-head__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--fs-26);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.3;
  color: var(--ink-900);
}

.page-about .section-head__note {
  grid-column: 2;
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--stone-700);
}

/* ---------- 正文排布 ---------- */
.page-about .sec-body {
  display: grid;
  gap: 24px;
}

.page-about .prose p {
  max-width: var(--measure);
  margin: 0 0 14px;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--stone-700);
}

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

.page-about .sec-lede {
  max-width: var(--measure);
  margin: 0 0 22px;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--stone-700);
}

.page-about .note {
  max-width: var(--measure);
  margin: 0;
  font-size: var(--fs-12);
  line-height: 1.75;
  color: var(--stone-700);
}

.page-about a.text-link {
  color: var(--verdigris-700);
  text-decoration: none;
  border-bottom: 1px solid rgba(36, 95, 82, 0.35);
  transition: border-color 180ms ease-out;
}

.page-about a.text-link:hover,
.page-about a.text-link:focus-visible {
  border-bottom-color: var(--verdigris-700);
}

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

.page-about .note-list li {
  display: flex;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--rule);
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--stone-700);
}

.page-about .note-list .mono {
  flex: 0 0 44px;
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--sand-700);
}

/* ---------- 分类树 ---------- */
.page-about .tree {
  margin: 0 0 26px;
  padding: 18px 18px 20px;
  background: var(--sand-100);
  border: 1px solid var(--rule);
}

.page-about .tree-root {
  display: inline-block;
  margin: 0 0 14px;
  padding: 4px 12px;
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--sand-050);
  background: var(--ink-900);
}

.page-about .tree-branches {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .tree-branch {
  position: relative;
  padding: 14px 16px 16px 20px;
  background: var(--sand-050);
  border: 1px solid var(--rule);
}

.page-about .tree-branch::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 5px;
}

.page-about .tree-branch--chem::before {
  background: var(--cobalt-700);
}

.page-about .tree-branch--renew::before {
  background: var(--verdigris-700);
}

.page-about .tree-head {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--fs-16);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .tree-leaves {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin: 11px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .tree-leaves li {
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--stone-700);
  background: var(--sand-100);
  border: 1px solid var(--rule);
}

/* ---------- 双分类卡片 ---------- */
.page-about .split-grid {
  display: grid;
  gap: 22px;
}

.page-about .stock-card {
  position: relative;
  padding: 16px 16px 20px;
  background: var(--sand-050);
  border: 1px solid var(--rule-strong);
  box-shadow: 6px 6px 0 rgba(20, 22, 26, 0.07);
  transition: transform 180ms ease-out, box-shadow 180ms ease-out;
}

.page-about .stock-card::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 64px;
  transition: height 180ms ease-out;
}

.page-about .stock-card:hover {
  transform: translateY(-2px);
  box-shadow: 8px 8px 0 rgba(20, 22, 26, 0.11);
}

.page-about .stock-card:hover::after {
  height: 96px;
}

.page-about .stock-card--chem::after {
  background: var(--cobalt-700);
}

.page-about .stock-card--renew::after {
  background: var(--verdigris-700);
}

.page-about .stock-flag {
  margin: 14px 0 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
}

.page-about .stock-card--chem .stock-flag {
  color: var(--cobalt-700);
}

.page-about .stock-card--renew .stock-flag {
  color: var(--verdigris-700);
}

.page-about .stock-title {
  margin: 0 0 10px;
  font-family: var(--font-heading);
  font-size: var(--fs-20);
  font-weight: 600;
  letter-spacing: -0.015em;
  color: var(--ink-900);
}

.page-about .stock-text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--stone-700);
}

.page-about .stock-points {
  display: grid;
  gap: 7px;
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .stock-points li {
  position: relative;
  padding-left: 16px;
  font-size: var(--fs-14);
  line-height: 1.65;
  color: var(--stone-700);
}

.page-about .stock-points li::before {
  content: "";
  position: absolute;
  top: 0.75em;
  left: 0;
  width: 8px;
  height: 1px;
  background: var(--sand-500);
}

/* ---------- 版本时间线 ---------- */
.page-about .timeline {
  position: relative;
  margin: 0;
  padding: 0 0 0 28px;
  list-style: none;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 6px;
  width: 1px;
  background: var(--rule-strong);
}

.page-about .tl-item {
  position: relative;
  padding-bottom: 26px;
}

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

.page-about .tl-node {
  position: absolute;
  top: 5px;
  left: -28px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--violet-700);
  box-shadow: 0 0 0 3px var(--sand-050);
  transition: transform 180ms ease-out, box-shadow 180ms ease-out;
}

.page-about .tl-item:hover .tl-node,
.page-about .tl-item:focus-within .tl-node {
  transform: scale(1.2);
  box-shadow: 0 0 0 5px rgba(91, 75, 138, 0.16);
}

.page-about .tl-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 10px;
  margin-bottom: 8px;
}

.page-about .tl-ver {
  padding: 3px 9px;
  font-size: var(--fs-12);
  color: var(--violet-700);
  background: rgba(91, 75, 138, 0.1);
  border: 1px solid rgba(91, 75, 138, 0.4);
  border-radius: 999px;
}

.page-about .tl-ver--current {
  color: var(--sand-050);
  background: var(--violet-700);
  border-color: var(--violet-700);
}

.page-about .tl-year {
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--stone-700);
}

.page-about .tl-title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--fs-20);
  font-weight: 600;
  letter-spacing: -0.015em;
  color: var(--ink-900);
}

.page-about .tl-text {
  max-width: var(--measure);
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--stone-700);
}

.page-about .tl-detail {
  max-width: var(--measure);
  margin: 8px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--sand-500);
  font-size: var(--fs-12);
  line-height: 1.75;
  color: var(--stone-700);
}

/* ---------- 校订节奏 ---------- */
.page-about .cadence-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  margin: 0 0 10px;
  padding: 0;
  list-style: none;
}

.page-about .cadence-strip li {
  padding: 12px 6px 10px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--ink-900);
  background: rgba(201, 161, 94, 0.16);
  border: 1px solid rgba(138, 106, 51, 0.32);
  border-bottom: 3px solid var(--sand-500);
}

.page-about .cadence-cap {
  margin: 0 0 24px;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--stone-700);
}

.page-about .cycle-grid {
  display: grid;
  gap: 18px;
  margin-bottom: 22px;
}

.page-about .cycle-panel {
  padding: 18px;
  background: var(--sand-100);
  border: 1px solid var(--rule);
}

.page-about .cycle-panel h3 {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  font-size: var(--fs-16);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .cycle-panel p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--stone-700);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: 1px;
  margin-bottom: 20px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .team-cell {
  padding: 18px 16px;
  background: var(--sand-050);
}

.page-about .team-cell .stat__value {
  display: block;
  margin-bottom: 8px;
  padding-bottom: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-34);
  line-height: 1;
  color: var(--ink-900);
  border-bottom: 1px solid rgba(201, 161, 94, 0.55);
}

.page-about .team-cell .stat__label {
  display: block;
  margin-bottom: 8px;
  font-size: var(--fs-14);
  font-weight: 600;
  color: var(--ink-900);
}

.page-about .team-cell p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--stone-700);
}

/* ---------- 资质与协作 ---------- */
.page-about .asset-list {
  display: grid;
  gap: 16px;
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
}

.page-about .asset-list li {
  padding: 18px 18px 20px;
  background: var(--sand-100);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--sand-700);
}

.page-about .asset-tag {
  display: inline-block;
  margin-bottom: 10px;
  padding: 2px 9px;
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--sand-050);
  background: var(--ink-900);
}

.page-about .asset-list h3 {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  font-size: var(--fs-16);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .asset-list p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--stone-700);
}

/* ---------- 备案与核对 ---------- */
.page-about .reg-list {
  margin: 0 0 22px;
  border-top: 1px solid var(--rule);
}

.page-about .reg-list > div {
  display: grid;
  gap: 4px;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
}

.page-about .reg-list dt {
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--stone-700);
}

.page-about .reg-list dd {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--ink-900);
  overflow-wrap: break-word;
  word-break: break-word;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .tree-branches {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .reg-list > div {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
  }
}

@media (min-width: 720px) {
  .page-about .about-facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .sec-body {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 36px;
    align-items: start;
  }

  .page-about .split-grid,
  .page-about .asset-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .cycle-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }

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

@media (min-width: 860px) {
  .page-about .about-masthead {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    align-items: end;
    gap: 44px;
  }

  .page-about h1 {
    font-size: var(--fs-46);
  }

  .page-about .lede {
    font-size: var(--fs-20);
  }
}

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: minmax(210px, 3fr) minmax(0, 9fr);
    gap: 52px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--bar-h) + 18px);
    max-height: calc(100vh - var(--bar-h) - 40px);
    overflow-y: auto;
  }
}

@media (min-width: 1080px) {
  .page-about .about-facts {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }
}

@media (max-width: 480px) {
  .page-about {
    padding-bottom: 56px;
  }

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

  .page-about .cadence-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .section-head {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .section-head__note {
    grid-column: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .stock-card,
  .page-about .stock-card::after,
  .page-about .tl-node,
  .page-about .rail-list a,
  .page-about .crumbs a {
    transition: none;
  }

  .page-about .stock-card:hover {
    transform: none;
  }

  .page-about .tl-item:hover .tl-node,
  .page-about .tl-item:focus-within .tl-node {
    transform: none;
  }
}
```
### 档案叙事与响应式布局解析

整个页面像一本可以翻阅的台账，左侧索引和右侧内容配合得很自然。

- **左侧常驻索引**：档案编号、现行版本、章节索引和校订状态都固定在窄栏里，滚动时保持可见，方便随时跳回某个段落。
- **时间线版本演进**：v1.0 到 v5.0 用竖向节点串起来，每个节点对应一个年份和一条变更要点；鼠标悬停或键盘聚焦时，节点会有轻微的放大和光晕反馈。
- **双分类视觉区分**：基础化工料和再生料用不同颜色的左侧竖条和标签来标识，避免混淆，也让对比更直观。
- **响应式编排**：窄屏下侧栏收进正文上方，关键参数带和分类卡片从单列逐步过渡到多列，保持阅读节奏不乱。
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**优化建议：** 页面中的图片用了 `{zhanqunpic:h:900w:1600}` 这类占位符，您可以替换为实际的台账照片或分类样本图（如批号特写、再生颗粒对比），保持宽高比即可直接生效。