.page-about {
  --about-axis: linear-gradient(180deg, var(--cyan-soft), var(--cyan) 32%, var(--cyan-deep) 68%, var(--sand));
  --about-panel: rgba(255, 255, 255, 0.42);
  padding-bottom: clamp(32px, 6vw, 72px);
}

/* ---------- 面包屑与首屏 ---------- */
.page-about .about-top {
  padding-top: clamp(14px, 3vw, 30px);
}

.page-about .about-hero {
  position: relative;
  margin-top: 16px;
  padding: clamp(22px, 4.4vw, 46px) clamp(18px, 3.6vw, 40px) clamp(18px, 3vw, 30px);
  background: var(--paper);
  border: 1px solid var(--line-strong);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 9px;
  background-image: repeating-linear-gradient(90deg, var(--line-strong) 0 1px, transparent 1px 13px);
  opacity: 0.55;
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 9px;
  background-image: repeating-linear-gradient(180deg, var(--line-strong) 0 1px, transparent 1px 13px);
  opacity: 0.55;
  pointer-events: none;
}

.page-about .about-hero__inner {
  display: grid;
  gap: clamp(20px, 3.4vw, 36px);
}

.page-about .about-hero__copy .label {
  margin-bottom: 14px;
}

.page-about .about-hero h1 {
  margin: 0;
  font-size: var(--fs-hero);
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: var(--ink);
  max-width: 20em;
}

.page-about .about-hero__lede {
  margin: 20px 0 0;
  max-width: 34em;
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .about-hero__cap {
  float: left;
  margin: 4px 10px 0 0;
  font-family: var(--font-serif);
  font-size: 3.1em;
  line-height: 0.86;
  color: var(--cyan-deep);
  font-weight: 600;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.page-about .about-hero__aside {
  position: relative;
}

.page-about .stack {
  position: relative;
  aspect-ratio: 4 / 3;
  max-width: 340px;
  margin-inline: auto;
}

.page-about .stack__layer {
  position: absolute;
  border-radius: 2px;
  border: 1.5px solid var(--cyan);
}

.page-about .stack__layer--back {
  inset: 6% 20% 36% 4%;
  border-color: var(--cyan-soft);
  background: rgba(214, 227, 228, 0.4);
}

.page-about .stack__layer--front {
  inset: 32% 4% 8% 26%;
  border-color: var(--cyan-deep);
  background: rgba(240, 228, 204, 0.55);
}

.page-about .stack__pin {
  position: absolute;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  border: 1.5px solid var(--cyan-deep);
  background: var(--paper);
}

.page-about .stack__pin--a {
  top: 16%;
  left: 14%;
}

.page-about .stack__pin--b {
  top: 52%;
  left: 62%;
  background: var(--sand);
  border-color: var(--flame);
}

.page-about .stack__pin--c {
  top: 78%;
  left: 38%;
}

.page-about .about-hero__aside-note {
  margin: 14px auto 0;
  max-width: 340px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(24px, 4vw, 36px) 0 0;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  background: transparent;
}

.page-about .hero-stats__item {
  padding: 10px 0 4px;
}

.page-about .hero-stats dt {
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .hero-stats dd {
  margin: 4px 0 0;
  font-family: var(--font-num);
  font-size: 30px;
  line-height: 1.1;
  color: var(--ink);
}

.page-about .hero-stats dd small {
  margin-left: 4px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 400;
  color: var(--muted);
}

/* ---------- 主体布局与目录 ---------- */
.page-about .about-body {
  margin-top: clamp(30px, 5vw, 56px);
}

.page-about .about-layout {
  display: grid;
  gap: clamp(22px, 4vw, 44px);
}

.page-about .about-toc {
  border-top: 2px solid var(--ink);
  padding-top: 12px;
}

.page-about .about-toc__title {
  margin: 0 0 10px;
  font-family: var(--font-serif);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--muted);
}

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

.page-about .about-toc .toc__item {
  margin: 0;
}

.page-about .about-toc .toc__link {
  display: inline-block;
  padding: 5px 10px;
  font-size: 14px;
  line-height: 1.5;
  color: var(--ink);
  text-decoration: none;
  background: var(--sand-soft);
  border-left: 2px solid transparent;
  border-radius: var(--radius);
}

.page-about .about-toc .toc__link[data-active="true"] {
  background: var(--cyan-soft);
  border-left-color: var(--flame);
  color: var(--ink);
}

.page-about .about-toc__home {
  display: inline-block;
  margin-top: 12px;
  font-size: 14px;
  color: var(--cyan-deep);
  text-decoration: none;
  border-bottom: 1px solid var(--cyan);
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  padding: clamp(26px, 4.4vw, 46px) 0;
  border-top: 1px solid var(--line);
}

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

.page-about .about-sec--cyan {
  background: var(--cyan-soft);
  margin-inline: calc(-1 * clamp(10px, 2vw, 22px));
  padding-inline: clamp(10px, 2vw, 22px);
  border-top-color: transparent;
  border-radius: var(--radius);
}

.page-about .about-sec--sand {
  background: var(--sand-soft);
  margin-inline: calc(-1 * clamp(10px, 2vw, 22px));
  padding-inline: clamp(10px, 2vw, 22px);
  border-top-color: transparent;
  border-radius: var(--radius);
}

.page-about .section-head {
  margin-bottom: clamp(18px, 3vw, 28px);
}

.page-about .section-head__title {
  font-size: var(--fs-h2);
  line-height: 1.24;
  letter-spacing: -0.02em;
  margin: 0 0 12px;
  max-width: 22em;
}

.page-about .section-head__note {
  margin: 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .prose p {
  max-width: 34em;
}

.page-about .about-inline-note {
  margin-top: 18px;
  max-width: 36em;
}

.page-about .about-inline-note a {
  color: var(--cyan-deep);
  text-decoration: underline;
  text-decoration-color: var(--cyan);
  text-underline-offset: 3px;
}

/* ---------- 三根支柱 ---------- */
.page-about .pillars {
  display: grid;
  gap: 22px;
  margin-top: clamp(22px, 3.4vw, 32px);
}

.page-about .pillar {
  padding-top: 16px;
  border-top: 2px solid var(--cyan);
}

.page-about .pillar:nth-child(2) {
  border-top-color: var(--cyan-deep);
}

.page-about .pillar:nth-child(3) {
  border-top-color: var(--sand);
}

.page-about .pillar__num {
  margin: 0 0 8px;
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--flame);
}

.page-about .pillar__title {
  margin: 0 0 8px;
  font-size: var(--fs-h3);
  line-height: 1.3;
}

.page-about .pillar__text {
  margin: 0 0 12px;
  font-size: 15px;
  line-height: 1.82;
  color: var(--ink);
}

.page-about .pillar__link {
  display: inline-block;
  font-size: 14px;
  color: var(--cyan-deep);
  text-decoration: none;
  border-bottom: 1px solid var(--cyan);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 clamp(22px, 3.4vw, 32px);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--radius);
  background: var(--sand-soft);
}

.page-about .figure__caption {
  margin-top: 10px;
  padding-left: 12px;
  border-left: 2px solid var(--cyan);
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 时间线 ---------- */
.page-about .tl {
  list-style: none;
  margin: clamp(26px, 4vw, 40px) 0 0;
  padding: 0 0 0 32px;
  position: relative;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  top: 6px;
  bottom: 6px;
  left: 8px;
  width: 3px;
  border-radius: 2px;
  background: var(--about-axis);
  box-shadow: -6px 0 0 var(--line), 6px 0 0 var(--line);
}

.page-about .tl__item {
  position: relative;
  padding: 0 0 clamp(24px, 3.6vw, 34px);
}

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

.page-about .tl__node {
  position: absolute;
  left: -32px;
  top: 6px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--cyan);
  box-sizing: border-box;
}

.page-about .tl__item--milestone .tl__node {
  background: var(--sand);
  border-color: var(--flame);
}

.page-about .tl__stage {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin: 0 0 6px;
  font-family: var(--font-serif);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .tl__num {
  font-family: var(--font-num);
  letter-spacing: 0.04em;
  color: var(--cyan-deep);
}

.page-about .tl__title {
  margin: 0 0 8px;
  font-size: var(--fs-h3);
  line-height: 1.28;
  letter-spacing: -0.01em;
}

.page-about .tl__text {
  margin: 0;
  max-width: 32em;
  font-size: 15px;
  line-height: 1.82;
  color: var(--ink);
}

.page-about .tl__more {
  margin-top: 10px;
  max-width: 32em;
  border-left: 2px solid var(--sand);
  padding-left: 12px;
}

.page-about .tl__summary {
  cursor: pointer;
  font-size: 14px;
  color: var(--cyan-deep);
  list-style: none;
}

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

.page-about .tl__summary::before {
  content: "＋ ";
  font-family: var(--font-num);
}

.page-about .tl__more[open] .tl__summary::before {
  content: "－ ";
}

.page-about .tl__more p {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 旧版对照 ---------- */
.page-about .cmp {
  display: grid;
  gap: 18px;
  margin: clamp(20px, 3vw, 28px) 0;
}

.page-about .cmp__pane {
  position: relative;
}

.page-about .cmp__tag {
  margin: 0 0 8px;
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .cmp__tag--new {
  color: var(--cyan-deep);
}

.page-about .mock {
  display: grid;
  gap: 8px;
  padding: 12px;
  aspect-ratio: 4 / 3;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--about-panel);
}

.page-about .mock__head {
  height: 14px;
  border-radius: 2px;
  background: rgba(42, 37, 32, 0.2);
}

.page-about .mock--new .mock__head {
  background: var(--cyan);
}

.page-about .mock__row {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 8px;
  flex: 1;
  min-height: 0;
}

.page-about .mock--old .mock__row {
  grid-template-columns: 2fr 1fr;
}

.page-about .mock__col {
  border-radius: 2px;
  background: rgba(42, 37, 32, 0.12);
}

.page-about .mock__col--wide {
  background: rgba(42, 37, 32, 0.18);
}

.page-about .mock--new .mock__col {
  background: var(--cyan-soft);
}

.page-about .mock--new .mock__col--wide {
  background: var(--sand);
}

.page-about .mock__line {
  height: 8px;
  border-radius: 2px;
  background: rgba(42, 37, 32, 0.14);
}

.page-about .mock--new .mock__line {
  background: rgba(74, 112, 118, 0.32);
}

.page-about .mock__line--short {
  width: 62%;
}

.page-about .mock__badge {
  position: absolute;
  right: 10px;
  bottom: 10px;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--flame);
  opacity: 0.85;
}

.page-about .diff-list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .diff-list__item {
  padding-left: 14px;
  border-left: 2px solid var(--cyan);
}

.page-about .diff-list__item:nth-child(2) {
  border-left-color: var(--cyan-deep);
}

.page-about .diff-list__item:nth-child(3) {
  border-left-color: var(--flame);
}

.page-about .diff-list__title {
  margin: 0 0 4px;
  font-size: 17px;
  line-height: 1.4;
}

.page-about .diff-list__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink);
}

/* ---------- 更新节奏 ---------- */
.page-about .steps {
  list-style: none;
  margin: clamp(18px, 3vw, 26px) 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .steps__item {
  position: relative;
  padding-top: 12px;
  border-top: 1px solid var(--line-strong);
}

.page-about .steps__num {
  display: block;
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--flame);
  margin-bottom: 6px;
}

.page-about .steps__title {
  margin: 0 0 6px;
  font-size: 17px;
  line-height: 1.4;
}

.page-about .steps__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink);
}

/* ---------- 团队 ---------- */
.page-about .team-bar {
  display: flex;
  gap: 6px;
  margin: clamp(18px, 3vw, 26px) 0 6px;
}

.page-about .team-bar__seg {
  height: 54px;
  border-radius: 2px;
}

.page-about .team-bar__seg--a {
  flex: 8 1 0;
  background: var(--cyan);
}

.page-about .team-bar__seg--b {
  flex: 6 1 0;
  background: var(--cyan-deep);
}

.page-about .team-bar__seg--c {
  flex: 4 1 0;
  background: var(--sand);
}

.page-about .team-list {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .team-list__item {
  padding-top: 12px;
  border-top: 1px solid var(--line);
}

.page-about .team-list__count {
  margin: 0 0 4px;
  font-size: 13px;
  color: var(--muted);
}

.page-about .team-list__num {
  font-family: var(--font-num);
  font-size: 22px;
  color: var(--ink);
}

.page-about .team-list__title {
  margin: 0 0 6px;
  font-size: 17px;
  line-height: 1.4;
}

.page-about .team-list__item p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .team-list + .about-figure {
  margin-top: clamp(22px, 3.4vw, 32px);
}

/* ---------- 收束 ---------- */
.page-about .about-close {
  margin-top: clamp(30px, 5vw, 52px);
  padding-top: clamp(20px, 3vw, 30px);
  border-top: 2px solid var(--ink);
}

.page-about .about-figure--wide img {
  aspect-ratio: 16 / 9;
}

.page-about .about-close__inner {
  margin-top: 6px;
}

.page-about .about-close__title {
  margin: 0 0 10px;
  font-size: var(--fs-h3);
  line-height: 1.35;
  max-width: 24em;
}

.page-about .about-close__text {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.82;
  color: var(--muted);
}

.page-about .about-close__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 600px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .pillars {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 26px;
  }

  .page-about .steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px 26px;
  }

  .page-about .cmp {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0;
    align-items: start;
  }

  .page-about .cmp__pane {
    padding: 0 16px;
  }

  .page-about .cmp__pane:first-child {
    padding-left: 0;
    border-right: 1px solid var(--line);
  }

  .page-about .cmp__pane:last-child {
    padding-right: 0;
  }
}

@media (min-width: 860px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
    align-items: center;
  }

  .page-about .stack {
    margin-inline: 0 0;
  }

  .page-about .about-hero__aside-note {
    margin-inline: 0;
  }

  .page-about .steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .team-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .tl {
    padding-left: 0;
  }

  .page-about .tl::before {
    left: 50%;
    transform: translateX(-50%);
  }

  .page-about .tl__item {
    width: 50%;
    padding-right: 40px;
    box-sizing: border-box;
  }

  .page-about .tl__item:nth-child(even) {
    margin-left: 50%;
    padding-right: 0;
    padding-left: 40px;
  }

  .page-about .tl__node {
    left: auto;
    right: -9px;
    top: 8px;
  }

  .page-about .tl__item:nth-child(even) .tl__node {
    left: -9px;
    right: auto;
  }
}

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: 208px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 20px;
  }

  .page-about .about-toc .toc__list {
    display: block;
  }

  .page-about .about-toc .toc__item {
    margin-bottom: 4px;
  }

  .page-about .about-toc .toc__link {
    display: block;
    background: transparent;
    padding: 6px 0 6px 12px;
    border-left: 2px solid var(--line);
    border-radius: 0;
    font-size: 14px;
    line-height: 1.5;
  }

  .page-about .about-toc .toc__link[data-active="true"] {
    background: transparent;
    border-left-color: var(--flame);
    color: var(--ink);
    font-weight: 500;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc .toc__link {
    transition: none;
  }
}
<<<END>>>