.page-about {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about [id] {
  scroll-margin-top: 100px;
}

/* 面包屑 */
.page-about .about-crumbs {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(18px, 3vw, 30px) var(--gutter) 0;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--brown);
}

.page-about .about-crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-crumbs li {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
}

.page-about .about-crumbs li + li::before {
  content: "／";
  color: var(--gold);
}

.page-about .about-crumbs a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease);
}

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

.page-about .about-crumbs [aria-current="page"] {
  color: var(--ink);
  font-weight: 700;
}

/* 首屏 */
.page-about .about-hero {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(22px, 3.4vw, 42px) var(--gutter) clamp(34px, 5vw, 72px);
  display: grid;
  gap: clamp(26px, 4vw, 48px);
}

.page-about .about-hero__head .eyebrow {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--teal);
  border: 1px solid var(--teal);
  border-radius: var(--radius-pill);
  padding: 5px 12px;
  margin: 0 0 clamp(14px, 2vw, 20px);
}

.page-about .about-hero h1 {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: clamp(34px, 6.6vw, 74px);
  line-height: 1.04;
  letter-spacing: -0.02em;
  margin: 0 0 clamp(16px, 2.2vw, 24px);
  text-wrap: balance;
}

.page-about .about-hero .lede {
  max-width: 52ch;
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 1.8;
  color: var(--brown);
  margin: 0 0 clamp(18px, 2.4vw, 26px);
}

.page-about .about-hero .button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* 章节索引 */
.page-about .about-index {
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-paper);
  padding: clamp(14px, 2.2vw, 22px);
  align-self: start;
}

.page-about .about-index__label {
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--gold);
  margin: 0 0 10px;
  padding-left: 4px;
}

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

.page-about .about-index__list a {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 10px;
  padding: 9px 10px;
  border-left: 3px solid transparent;
  border-radius: 8px;
  text-decoration: none;
  color: var(--ink);
  transition: background-color 0.24s var(--ease), border-left-color 0.24s var(--ease), transform 0.24s var(--ease);
}

.page-about .about-index__list li:nth-child(2) a { padding-left: 16px; }
.page-about .about-index__list li:nth-child(3) a { padding-left: 22px; }
.page-about .about-index__list li:nth-child(4) a { padding-left: 28px; }
.page-about .about-index__list li:nth-child(5) a { padding-left: 34px; }
.page-about .about-index__list li:nth-child(6) a { padding-left: 40px; }

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  background: var(--paper-warm);
  border-left-color: var(--amber);
  transform: translateX(2px);
  outline: none;
}

.page-about .about-index__num {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--gold);
  letter-spacing: 0.06em;
}

.page-about .about-index__name {
  font-size: 14.5px;
  font-weight: 700;
}

.page-about .about-index__meta {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--teal);
  white-space: nowrap;
}

/* 通用章节 */
.page-about .about-section {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(36px, 5.2vw, 76px) var(--gutter);
  border-top: 1px solid var(--line);
}

.page-about .about-row {
  display: grid;
  gap: clamp(14px, 2vw, 24px);
}

.page-about .about-rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .about-rail__num {
  font-family: var(--font-mono);
  font-size: clamp(28px, 3.6vw, 44px);
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
  letter-spacing: 0.02em;
}

.page-about .about-rail__year {
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--brown);
  border: 1px solid var(--gold);
  border-radius: var(--radius-pill);
  padding: 4px 11px;
  white-space: nowrap;
}

.page-about .about-title {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: clamp(23px, 3.2vw, 36px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin: 0 0 clamp(12px, 1.8vw, 18px);
}

.page-about .about-sub {
  max-width: 60ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--brown);
  margin: 0 0 clamp(18px, 2.4vw, 26px);
}

.page-about .about-body p {
  max-width: 62ch;
  line-height: 1.8;
  margin: 0 0 14px;
}

.page-about .about-split {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}

/* 图文框 */
.page-about .about-figure {
  margin: 0;
  background: var(--paper-warm);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  padding: 10px;
  box-shadow: var(--shadow-paper);
}

.page-about .about-figure--wide {
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border-radius: calc(var(--radius-card) - 8px);
}

.page-about .about-figure figcaption {
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--brown);
  padding: 10px 4px 2px;
}

/* 标签行 */
.page-about .tag-row {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 16px 0 0;
  padding: 0;
}

/* 阶段列表 */
.page-about .about-stage-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-stage {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 14px;
  padding: clamp(14px, 2vw, 20px);
  background: var(--cream);
  border: 1px solid var(--line);
  border-left: 4px solid var(--paper-warm);
  border-radius: 12px;
  transition: transform 0.28s var(--ease), box-shadow 0.28s var(--ease), border-left-color 0.28s var(--ease);
}

.page-about .about-stage:hover,
.page-about .about-stage:focus {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lift);
  border-left-color: var(--amber);
  outline: none;
}

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

.page-about .about-stage__num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--gold);
  letter-spacing: 0.08em;
  padding-top: 3px;
}

.page-about .about-stage__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 12px;
  margin: 0 0 6px;
}

.page-about .about-stage__name {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.4;
}

.page-about .about-stage__when {
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--teal);
  border-bottom: 1px dashed var(--teal-light);
}

.page-about .about-stage__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--brown);
  max-width: 62ch;
}

/* 数字卡片 */
.page-about .about-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  background: var(--cream);
  border: 1px solid var(--gold);
  border-radius: var(--radius-card);
  padding: clamp(16px, 2.2vw, 24px);
  transition: transform 0.28s var(--ease), box-shadow 0.28s var(--ease), background-color 0.28s var(--ease);
}

.page-about .about-stat:hover,
.page-about .about-stat:focus {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lift);
  background: var(--paper);
  outline: none;
}

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

.page-about .about-stat__figure {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin: 0;
}

.page-about .about-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(32px, 4.4vw, 48px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stat__unit {
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--gold);
}

.page-about .about-stat__label {
  margin: 0;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--teal);
}

.page-about .about-stat__desc {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--brown);
}

/* 协作原则 */
.page-about .about-principles {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: none;
}

.page-about .about-principle {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 16px;
  padding: clamp(16px, 2.2vw, 24px) 0;
  border-top: 1px solid var(--line);
}

.page-about .about-principle:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-principle__no {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--teal);
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  margin-top: 2px;
}

.page-about .about-principle__name {
  margin: 0 0 6px;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.45;
}

.page-about .about-principle__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--brown);
  max-width: 64ch;
}

/* 生态 */
.page-about .about-eco-grid {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}

.page-about .about-nodes {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0 0;
  padding: 0;
}

.page-about .about-node {
  font-size: 13px;
  letter-spacing: 0.02em;
  padding: 7px 14px;
  border: 1px solid var(--teal);
  border-radius: var(--radius-pill);
  color: var(--teal);
  background: transparent;
  transition: background-color 0.24s var(--ease), color 0.24s var(--ease), transform 0.24s var(--ease);
}

.page-about .about-node:hover,
.page-about .about-node:focus {
  background: var(--teal);
  color: var(--cream);
  transform: translateY(-2px);
  outline: none;
}

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

/* 备案条带 */
.page-about .about-stamp {
  background: var(--brown);
  color: var(--paper);
}

.page-about .about-stamp__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(32px, 4.6vw, 62px) var(--gutter);
  display: grid;
  gap: clamp(22px, 3.4vw, 44px);
}

.page-about .about-stamp__eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--teal-light);
  margin: 0 0 12px;
}

.page-about .about-stamp__title {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: clamp(22px, 3vw, 34px);
  line-height: 1.24;
  margin: 0 0 14px;
  color: var(--cream);
}

.page-about .about-stamp__text {
  max-width: 56ch;
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(244, 235, 221, 0.86);
}

.page-about .about-stamp__panel {
  border: 1px solid var(--line-light);
  border-radius: var(--radius-card);
  padding: clamp(16px, 2.4vw, 24px);
  background: rgba(244, 235, 221, 0.06);
}

.page-about .about-stamp__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 6px 16px;
  margin: 0;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line-light);
}

.page-about .about-stamp__key {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--teal-light);
}

.page-about .about-stamp__val {
  font-size: 14.5px;
  font-weight: 700;
  color: var(--cream);
  word-break: break-word;
}

.page-about .about-stamp__panel .button {
  margin-top: 16px;
}

/* 结尾行动 */
.page-about .about-cta {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(30px, 4.4vw, 60px) var(--gutter) clamp(40px, 5vw, 72px);
  display: grid;
  gap: clamp(16px, 2vw, 22px);
}

.page-about .about-cta__text {
  max-width: 62ch;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--brown);
}

.page-about .about-cta .button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* 桌面布局 */
@media (min-width: 880px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.8fr);
    align-items: end;
  }

  .page-about .about-row {
    grid-template-columns: minmax(0, 156px) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 60px);
  }

  .page-about .about-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    position: sticky;
    top: 104px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: start;
  }

  .page-about .about-eco-grid {
    grid-template-columns: minmax(0, 1.06fr) minmax(0, 0.94fr);
    align-items: center;
  }

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

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 0.72fr);
  }
}
<<<END>>>