.page-about {
  --about-gap: 20px;
  --about-radius: 6px;
  background: var(--sand);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  overflow-x: hidden;
}

.page-about .kicker {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--clay);
  margin: 0 0 10px;
}

.page-about a {
  color: var(--tide);
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-display);
  color: var(--tide);
  margin: 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: 24px clamp(36px, 7vw, 76px);
}

.page-about .about-hero__inner {
  display: grid;
  gap: 24px;
  padding: clamp(20px, 4vw, 40px);
  background:
    linear-gradient(118deg, var(--cream) 0%, var(--cream) 48%, var(--sand-2) 48%, var(--sand-2) 100%);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
}

.page-about .about-hero h1 {
  font-size: clamp(2rem, 5.4vw, 3.5rem);
  font-weight: 300;
  letter-spacing: -0.02em;
  line-height: 1.14;
  max-width: 20ch;
}

.page-about .about-hero__intro {
  margin: 18px 0 0;
  max-width: 42ch;
  font-size: 16px;
  line-height: 1.8;
}

.page-about .about-hero__note {
  margin: 14px 0 0;
  max-width: 44ch;
  font-size: 13px;
  font-family: var(--font-mono);
  line-height: 1.7;
  color: var(--moss);
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.page-about .about-hero__facts {
  display: grid;
  gap: 12px;
  padding: 18px;
  background: rgba(255, 253, 248, 0.66);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  align-self: start;
}

.page-about .fact {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(201, 207, 210, 0.9);
}

.page-about .fact:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .fact__num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  letter-spacing: 0.02em;
  color: var(--coral);
  line-height: 1;
}

.page-about .fact__label {
  font-size: 13px;
  color: var(--moss);
  font-family: var(--font-mono);
}

/* ---------- 章节索引 ---------- */
.page-about .about-toc {
  margin-top: 22px;
}

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

.page-about .about-toc a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  font-size: 14px;
  text-decoration: none;
  color: var(--ink);
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: 999px;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  transform: translateY(-2px);
  border-color: var(--coral);
  box-shadow: var(--shadow-2);
}

.page-about .about-toc a:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 2px;
}

.page-about .about-toc__n {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--coral);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  position: relative;
  padding-bottom: clamp(32px, 6vw, 72px);
}

.page-about .chapter--sand {
  background: var(--sand-2);
}

.page-about .chapter--dark {
  background: var(--ink);
  color: var(--cream);
}

.page-about .chapter__band {
  padding-block: clamp(14px, 3vw, 22px);
  border-top: 1px solid var(--line);
}

.page-about .chapter--dark .chapter__band {
  border-top-color: rgba(255, 253, 248, 0.18);
}

.page-about .chapter__bandinner {
  display: flex;
  align-items: baseline;
  gap: 16px;
}

.page-about .chapter__num {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 6vw, 3.1rem);
  line-height: 0.9;
  letter-spacing: 0.04em;
  color: var(--coral);
}

.page-about .chapter__eyebrow {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--moss);
}

.page-about .chapter--dark .chapter__eyebrow {
  color: var(--mint);
}

.page-about .chapter__grid {
  padding-top: clamp(20px, 4vw, 36px);
  display: grid;
  gap: var(--about-gap);
}

.page-about .chapter__title {
  font-size: clamp(1.45rem, 3.4vw, 2rem);
  font-weight: 400;
  line-height: 1.3;
  letter-spacing: -0.01em;
  max-width: 24ch;
}

.page-about .chapter--dark .chapter__title {
  color: var(--cream);
}

.page-about .chapter__lede {
  margin: 0;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .chapter--dark .chapter__lede {
  color: rgba(255, 253, 248, 0.86);
}

.page-about .chapter__foot {
  margin: 4px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--mint);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--moss);
  max-width: 62ch;
}

.page-about .prose p {
  margin: 0 0 14px;
  max-width: 52ch;
}

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

.page-about .pullquote {
  margin: 18px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--coral);
  font-size: 1.15rem;
  line-height: 1.6;
  color: var(--tide);
  max-width: 24ch;
}

.page-about .chapter__link {
  margin: 20px 0 0;
}

.page-about .split {
  display: grid;
  gap: 24px;
}

/* ---------- 覆盖 ---------- */
.page-about .cover-grid {
  display: grid;
  gap: 14px;
}

.page-about .cover-card {
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  padding: 20px;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .cover-card:hover {
  transform: translateY(-2px);
  border-color: var(--coral);
  box-shadow: var(--shadow-2);
}

.page-about .cover-card__title {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  padding-bottom: 10px;
  margin-bottom: 10px;
  border-bottom: 1px solid var(--rock);
}

.page-about .cover-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 9px;
  font-size: 15px;
  line-height: 1.7;
}

.page-about .cover-list li {
  padding-left: 16px;
  position: relative;
}

.page-about .cover-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.66em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--clay);
}

/* ---------- 小屏优先级 ---------- */
.page-about .priority {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .priority__item {
  display: grid;
  gap: 4px;
  padding: 14px 16px;
  background: var(--cream);
  border: 1px solid var(--line);
  border-left: 3px solid var(--rock);
  border-radius: 0 var(--about-radius) var(--about-radius) 0;
}

.page-about .priority__item:first-child {
  border-left-color: var(--coral);
}

.page-about .priority__item:nth-child(2) {
  border-left-color: var(--tide);
}

.page-about .priority__item:nth-child(3) {
  border-left-color: var(--mint);
}

.page-about .priority__n {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--moss);
}

.page-about .priority__text {
  font-size: 15px;
  line-height: 1.7;
}

/* ---------- 团队 ---------- */
.page-about .team-banner {
  margin: 0;
}

.page-about .team-grid {
  display: grid;
  gap: 14px;
}

.page-about .persona {
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  padding: 20px;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .persona:hover {
  transform: translateY(-2px);
  border-color: var(--coral);
  box-shadow: var(--shadow-2);
}

.page-about .persona__title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.page-about .persona__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
}

.page-about .persona__meta {
  margin: 12px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--rock);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  color: var(--moss);
}

/* ---------- 流程 ---------- */
.page-about .flow {
  display: grid;
  gap: 16px;
}

.page-about .flow__line {
  width: 100%;
  height: 52px;
  display: block;
}

.page-about .flow__line polyline {
  stroke: var(--coral);
  stroke-width: 2;
  stroke-dasharray: 6 6;
  opacity: 0.85;
}

.page-about .flow__line circle {
  fill: var(--coral);
}

.page-about .steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .step details {
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .step details:hover {
  border-color: var(--coral);
}

.page-about .step details[open] {
  border-color: var(--tide);
  box-shadow: var(--shadow-1);
}

.page-about .step summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

.page-about .step summary::-webkit-details-marker {
  display: none;
}

.page-about .step summary:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 2px;
}

.page-about .step__n {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--coral);
}

.page-about .step__title {
  font-family: var(--font-display);
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--tide);
}

.page-about .step__hint {
  font-size: 13px;
  color: var(--moss);
  font-family: var(--font-mono);
}

.page-about .step__body {
  padding: 0 16px 16px;
  border-top: 1px solid var(--rock);
  padding-top: 12px;
}

.page-about .step__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
}

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

/* ---------- 时间线 ---------- */
.page-about .timeline-wrap {
  display: grid;
  gap: 24px;
}

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

.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0 0 0 28px;
  position: relative;
}

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

.page-about .tl__item {
  position: relative;
  padding-bottom: 22px;
  border-radius: var(--about-radius);
  transition: background-color var(--dur) var(--ease);
}

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

.page-about .tl__item::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 8px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--coral);
  box-shadow: 0 0 0 4px var(--sand-2);
  transition: transform var(--dur) var(--ease);
}

.page-about .tl__item--now::before {
  background: var(--mint);
}

.page-about .tl__item:hover::before,
.page-about .tl__item:focus-within::before,
.page-about .tl__item:focus::before {
  transform: scale(1.35);
}

.page-about .tl__item:focus-visible,
.page-about .tl__item:focus {
  outline: 2px solid var(--coral);
  outline-offset: 4px;
}

.page-about .tl__year {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--clay);
}

.page-about .tl__title {
  font-size: 1.08rem;
  font-weight: 700;
  margin: 4px 0 0;
  line-height: 1.45;
}

.page-about .tl__more {
  display: block;
  margin: 0;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
  transition: max-height 220ms var(--ease), opacity 180ms var(--ease), margin-top 220ms var(--ease);
}

.page-about .tl__item:hover .tl__more,
.page-about .tl__item:focus .tl__more,
.page-about .tl__item:focus-within .tl__more {
  max-height: 10em;
  opacity: 1;
  margin-top: 6px;
}

/* ---------- 标准 ---------- */
.page-about .standards {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: rgba(255, 253, 248, 0.16);
  border: 1px solid rgba(255, 253, 248, 0.18);
  border-radius: var(--about-radius);
  overflow: hidden;
}

.page-about .standard {
  background: var(--ink);
  padding: 18px 18px 20px;
  display: grid;
  gap: 6px;
  transition: background-color var(--dur) var(--ease);
}

.page-about .standard:hover {
  background: #123A56;
}

.page-about .standard__n {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--mint);
}

.page-about .standard__title {
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--cream);
  line-height: 1.45;
}

.page-about .standard__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(255, 253, 248, 0.82);
}

.page-about .closing {
  margin-top: 8px;
  padding-top: 22px;
  border-top: 1px solid rgba(255, 253, 248, 0.22);
  display: grid;
  gap: 16px;
}

.page-about .closing__text {
  margin: 0;
  max-width: 44ch;
  font-size: 1.05rem;
  line-height: 1.7;
  color: var(--cream);
}

.page-about .closing__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .closing__actions .btn {
  text-decoration: none;
}

.page-about .closing__actions .btn--ghost {
  color: var(--cream);
  border-color: rgba(255, 253, 248, 0.45);
}

.page-about .closing__actions .btn:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 2px;
}

/* ---------- 图片基座补充 ---------- */
.page-about .media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--about-radius);
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 760px) {
  .page-about {
    --about-gap: 26px;
  }

  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 0.9fr);
    align-items: end;
  }

  .page-about .cover-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

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

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

/* ---------- 桌面叙事长卷 ---------- */
@media (min-width: 1000px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.75fr) minmax(0, 0.85fr);
    padding: clamp(32px, 4vw, 52px);
  }

  .page-about .chapter__band {
    padding-block: 26px;
  }

  .page-about .chapter__bandinner {
    max-width: var(--maxw);
  }

  .page-about .chapter__grid {
    display: grid;
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: 32px;
    row-gap: 24px;
    align-items: start;
  }

  .page-about .chapter__grid > * {
    grid-column: 2 / span 10;
  }

  .page-about .chapter__title {
    grid-column: 2 / span 7;
  }

  .page-about .chapter__lede {
    grid-column: 2 / span 7;
  }

  .page-about .chapter__foot {
    grid-column: 2 / span 8;
  }

  .page-about .split {
    grid-column: 2 / span 10;
    grid-template-columns: minmax(0, 4.2fr) minmax(0, 5.8fr);
    column-gap: clamp(32px, 6vw, 72px);
    align-items: start;
  }

  .page-about .cover-grid {
    grid-column: 2 / span 10;
  }

  .page-about .team-banner {
    grid-column: 2 / span 10;
  }

  .page-about .team-grid {
    grid-column: 2 / span 10;
  }

  .page-about .flow {
    grid-column: 2 / span 6;
  }

  .page-about .flow-figure {
    grid-column: 8 / span 4;
    align-self: start;
  }

  .page-about .timeline-wrap {
    grid-column: 2 / span 10;
    grid-template-columns: minmax(0, 4fr) minmax(0, 6fr);
    column-gap: clamp(32px, 6vw, 64px);
    align-items: start;
  }

  .page-about .timeline-figure {
    position: sticky;
    top: 96px;
    opacity: 0.94;
  }

  .page-about .standards {
    grid-column: 2 / span 10;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .closing {
    grid-column: 2 / span 8;
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .priority {
    margin-top: 8px;
  }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .cover-card:hover,
  .page-about .persona:hover,
  .page-about .about-toc a:hover {
    transform: none;
  }

  .page-about .tl__more {
    transition: none;
  }

  .page-about .tl__item:hover::before,
  .page-about .tl__item:focus::before,
  .page-about .tl__item:focus-within::before {
    transform: none;
  }
}
<<<END>>>