.page-about {
  --about-rail: 132px;
  background: var(--ink);
  color: var(--paper);
  overflow-x: hidden;
}

/* 首屏 */
.page-about .about-hero {
  position: relative;
  padding: 28px 0 64px;
  overflow: hidden;
  background: linear-gradient(180deg, var(--ink-deep), var(--ink) 70%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -20%;
  right: -26%;
  width: 72%;
  height: 138%;
  background: linear-gradient(160deg, rgba(47, 169, 140, 0.10), rgba(214, 177, 92, 0.17) 55%, rgba(226, 101, 30, 0.13));
  border-left: 1px solid var(--line);
  transform: rotate(-7deg);
  pointer-events: none;
}

.page-about .about-hero-inner {
  position: relative;
  display: grid;
  gap: 32px;
}

.page-about .about-hero-copy {
  position: relative;
  z-index: 1;
}

.page-about .about-hero-copy .eyebrow {
  margin: 18px 0 0;
}

.page-about .about-hero-copy h1 {
  margin: 14px 0 0;
  font-family: var(--font-hei);
  font-weight: 800;
  font-size: clamp(2rem, 7.2vw, 3.9rem);
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-hero-copy .lede {
  margin: 20px 0 0;
  max-width: 46ch;
  font-family: var(--font-song);
  font-size: clamp(1rem, 2.2vw, 1.125rem);
  line-height: 1.95;
  color: rgba(253, 249, 241, 0.82);
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero-figure {
  margin: 0;
  position: relative;
  z-index: 1;
}

.page-about .about-hero-figure .media-frame {
  border: 1px solid var(--line-strong);
  background: rgba(253, 249, 241, 0.04);
}

.page-about .about-hero-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-hero-figure .media-caption {
  margin-top: 10px;
}

/* 主体两栏 */
.page-about .about-body {
  display: grid;
  gap: 36px;
  padding-bottom: 64px;
}

.page-about .about-rail {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about .about-rail-title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--sand);
}

.page-about .about-rail-list {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-rail-list a {
  display: block;
  white-space: nowrap;
  font-family: var(--font-hei);
  font-size: 13px;
  line-height: 1.4;
  padding: 8px 12px;
  border: 1px solid var(--line);
  color: var(--mist);
  text-decoration: none;
  transition: color 0.24s ease, border-color 0.24s ease;
}

.page-about .about-rail-list a:hover,
.page-about .about-rail-list a[aria-current="true"] {
  color: var(--sand-pale);
  border-color: var(--line-strong);
}

.page-about .about-rail-scale {
  display: none;
  margin: 0;
}

/* 章节 */
.page-about .about-section {
  padding: 40px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-main > .about-section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-section-head {
  margin-bottom: 22px;
}

.page-about .about-section-head .eyebrow {
  margin: 0;
}

.page-about .about-section-head h2 {
  margin: 12px 0 0;
  font-family: var(--font-hei);
  font-weight: 800;
  font-size: clamp(1.45rem, 4.4vw, 2.125rem);
  line-height: 1.28;
  color: var(--paper);
}

.page-about .about-prose p {
  margin: 0 0 16px;
  font-size: 1rem;
  line-height: 1.9;
  color: rgba(253, 249, 241, 0.82);
}

.page-about .about-prose-single {
  margin: 20px 0 0;
  font-size: 0.9688rem;
  line-height: 1.9;
  color: rgba(253, 249, 241, 0.78);
}

/* 阶梯时间轴 */
.page-about .about-stairs {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-step {
  position: relative;
  padding: 16px 0 18px 24px;
  border-left: 1px solid var(--line);
}

.page-about .about-step:last-child {
  border-left-color: transparent;
}

.page-about .about-step::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 28px;
  width: 11px;
  height: 1px;
  background: var(--sand);
}

.page-about .about-step-year {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--sand);
}

.page-about .about-step-body h3 {
  margin: 6px 0 6px;
  font-family: var(--font-hei);
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-step-body p {
  margin: 0;
  max-width: 48ch;
  font-size: 0.9375rem;
  line-height: 1.82;
  color: rgba(253, 249, 241, 0.74);
}

/* 纸张区块：团队 */
.page-about .about-section--paper {
  background: var(--cream);
  color: var(--graphite);
  padding: 26px 20px 30px;
  border: 1px solid rgba(42, 42, 42, 0.14);
  border-top: 3px solid var(--sand);
  box-shadow: 10px 10px 0 rgba(7, 19, 34, 0.55);
}

.page-about .about-section--paper .about-section-head h2 {
  color: var(--ink);
}

.page-about .about-eyebrow-ink {
  color: #8a6a1f;
}

.page-about .about-paper-text {
  margin: 0 0 20px;
  font-size: 0.9688rem;
  line-height: 1.85;
  color: rgba(42, 42, 42, 0.84);
}

.page-about .about-chart {
  display: flex;
  height: 18px;
  border: 1px solid rgba(42, 42, 42, 0.2);
  overflow: hidden;
}

.page-about .about-chart span {
  display: block;
  height: 100%;
}

.page-about .about-chart span:nth-child(1) {
  width: 28%;
  background: var(--sand);
}

.page-about .about-chart span:nth-child(2) {
  width: 37%;
  background: var(--ink-soft);
}

.page-about .about-chart span:nth-child(3) {
  width: 13%;
  background: var(--jade);
}

.page-about .about-chart span:nth-child(4) {
  width: 22%;
  background: var(--poplar);
}

.page-about .about-legend {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: rgba(42, 42, 42, 0.82);
}

.page-about .about-legend li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.page-about .about-legend-key {
  display: inline-block;
  width: 10px;
  height: 10px;
  flex: none;
}

.page-about .about-legend-key--edit {
  background: var(--sand);
}

.page-about .about-legend-key--tech {
  background: var(--ink-soft);
}

.page-about .about-legend-key--serve {
  background: var(--jade);
}

.page-about .about-legend-key--ops {
  background: var(--poplar);
}

.page-about .about-subhead {
  margin: 28px 0 0;
  font-family: var(--font-hei);
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-process {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-process summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 12px 14px;
  background: var(--paper);
  border: 1px solid rgba(42, 42, 42, 0.16);
  border-left: 3px solid var(--sand);
  font-family: var(--font-hei);
  font-size: 0.9688rem;
  font-weight: 700;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
  transition: background 0.2s ease, border-color 0.2s ease;
}

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

.page-about .about-process summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--poplar);
}

.page-about .about-process-item[open] summary {
  background: #ffffff;
  border-left-color: var(--poplar);
}

.page-about .about-process-item[open] summary::after {
  content: "−";
}

.page-about .about-process-item p {
  margin: 10px 0 0;
  padding-left: 14px;
  border-left: 1px solid rgba(42, 42, 42, 0.18);
  font-size: 0.9375rem;
  line-height: 1.82;
  color: rgba(42, 42, 42, 0.82);
}

.page-about .about-figure {
  margin: 24px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid rgba(42, 42, 42, 0.16);
}

.page-about .about-figure .media-caption {
  margin-top: 10px;
  color: rgba(42, 42, 42, 0.72);
}

/* 协作点 */
.page-about .about-map {
  margin: 22px 0 24px;
}

.page-about .about-map img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

.page-about .about-map .media-caption {
  margin-top: 10px;
}

.page-about .about-points {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-point {
  padding: 16px 16px 18px;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(19, 42, 68, 0.92), rgba(14, 30, 51, 0.66));
  transition: border-color 0.24s ease, box-shadow 0.24s ease;
}

.page-about .about-point:hover,
.page-about .about-point:focus-within {
  border-color: var(--line-strong);
  box-shadow: 0 4px 0 rgba(214, 177, 92, 0.16);
}

.page-about .about-point-dot {
  display: block;
  width: 9px;
  height: 9px;
  margin-bottom: 10px;
  border-radius: 50%;
  background: var(--jade);
  box-shadow: 0 0 0 4px rgba(47, 169, 140, 0.16);
  transition: background 0.24s ease, box-shadow 0.24s ease;
}

.page-about .about-point:hover .about-point-dot,
.page-about .about-point:focus-within .about-point-dot {
  background: var(--poplar);
  box-shadow: 0 0 0 5px rgba(226, 101, 30, 0.2);
}

.page-about .about-point h3 {
  margin: 0 0 6px;
  font-family: var(--font-hei);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--sand-pale);
}

.page-about .about-point p {
  margin: 0;
  font-size: 0.9063rem;
  line-height: 1.78;
  color: rgba(253, 249, 241, 0.74);
}

/* 资料可靠性 */
.page-about .about-quote {
  margin: 0 0 24px;
  padding-left: 18px;
  border-left: 2px solid var(--sand);
  font-family: var(--font-song);
  font-size: clamp(1.0625rem, 3.4vw, 1.375rem);
  line-height: 1.9;
  color: var(--sand-pale);
}

.page-about .about-facts {
  display: grid;
  gap: 18px;
}

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

.page-about .about-fact strong {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--sand);
}

.page-about .about-fact p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.82;
  color: rgba(253, 249, 241, 0.78);
}

.page-about .about-callout {
  margin-top: 24px;
}

.page-about .about-callout p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.82;
}

.page-about .about-callout a {
  color: var(--jade);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* 资质 */
.page-about .about-cred {
  margin: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-cred > div {
  display: grid;
  gap: 6px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-cred dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--sand);
}

.page-about .about-cred dd {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.82;
  color: rgba(253, 249, 241, 0.84);
}

/* 尾部引导 */
.page-about .about-cta {
  padding: 36px 0 56px;
  background: var(--ink-deep);
  border-top: 1px solid var(--line-strong);
}

.page-about .about-cta-inner {
  display: grid;
  gap: 22px;
}

.page-about .about-cta h2 {
  margin: 0 0 10px;
  font-family: var(--font-hei);
  font-weight: 800;
  font-size: clamp(1.35rem, 4vw, 1.875rem);
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-cta p {
  margin: 0;
  max-width: 52ch;
  font-size: 0.9688rem;
  line-height: 1.85;
  color: rgba(253, 249, 241, 0.76);
}

.page-about .about-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* 中等屏 */
@media (min-width: 720px) {
  .page-about .about-step:nth-child(2) {
    margin-left: 28px;
  }

  .page-about .about-step:nth-child(3) {
    margin-left: 56px;
  }

  .page-about .about-step:nth-child(4) {
    margin-left: 84px;
  }

  .page-about .about-step:nth-child(5) {
    margin-left: 112px;
  }

  .page-about .about-step:nth-child(6) {
    margin-left: 140px;
  }

  .page-about .about-section--paper {
    padding: 32px 28px 34px;
  }

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

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

  .page-about .about-facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .about-cred > div {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }

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

/* 桌面：左栏跟随 + 宽幅叙事 */
@media (min-width: 1024px) {
  .page-about .about-hero {
    padding: 40px 0 88px;
  }

  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: end;
    gap: 56px;
  }

  .page-about .about-hero-figure {
    margin-top: -12px;
  }

  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 56px;
    align-items: start;
    padding-bottom: 80px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
  }

  .page-about .about-rail-list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding: 0;
  }

  .page-about .about-rail-list a {
    padding: 7px 0 7px 12px;
    border: 0;
    border-left: 1px solid var(--line);
    font-size: 12.5px;
    line-height: 1.55;
    white-space: normal;
  }

  .page-about .about-rail-list a[aria-current="true"] {
    border-left: 2px solid var(--sand);
    color: var(--sand-pale);
  }

  .page-about .about-rail-scale {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: 172px;
    margin-top: 18px;
    padding-left: 12px;
    border-left: 1px solid var(--line);
    font-family: var(--font-mono);
    font-size: 10px;
    letter-spacing: 0.12em;
    color: var(--mist);
  }

  .page-about .about-section {
    padding: 48px 0;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail-list a,
  .page-about .about-point,
  .page-about .about-point-dot,
  .page-about .about-process summary {
    transition: none;
  }
}
<<<END>>>