.page-about {
  --about-index: 208px;
  --about-measure: 40rem;
  --about-cut: 24px;
  background: var(--paper);
  color: var(--rock);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--ink);
  color: var(--paper);
  padding: 1.25rem 0 2.5rem;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(159, 183, 176, 0.15) 1px, transparent 1px),
    linear-gradient(90deg, rgba(159, 183, 176, 0.15) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

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

.page-about .about-hero .breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  list-style: none;
  margin: 0 0 1.5rem;
  padding: 0;
  font-size: 0.8125rem;
}

.page-about .about-hero .breadcrumbs li:not(:last-child)::after {
  content: "/";
  margin-left: 0.4rem;
  color: rgba(243, 238, 223, 0.45);
}

.page-about .about-hero .breadcrumbs a {
  color: var(--board);
  text-decoration: none;
}

.page-about .about-hero .breadcrumbs a:hover,
.page-about .about-hero .breadcrumbs a:focus-visible {
  color: var(--gold);
}

.page-about .about-hero .breadcrumbs [aria-current="page"] {
  color: rgba(243, 238, 223, 0.72);
}

.page-about .about-hero__grid {
  display: grid;
  gap: 2rem;
}

.page-about .about-hero__kicker {
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.18em;
  color: var(--gold);
}

.page-about .about-hero h1 {
  margin: 0 0 1.25rem;
  font-size: clamp(2rem, 7vw, 3.5rem);
  line-height: 1.08;
  font-weight: 900;
  letter-spacing: -0.02em;
  max-width: 16em;
}

.page-about .about-hero__lead {
  margin: 0 0 1.75rem;
  max-width: 34rem;
  font-size: 1rem;
  line-height: 1.85;
  color: rgba(243, 238, 223, 0.84);
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 0.8125rem;
  color: rgba(243, 238, 223, 0.72);
}

.page-about .about-hero__meta .num {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  color: var(--signal);
  margin-right: 0.3rem;
}

.page-about .about-hero__figure {
  margin: 0;
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  border: 1px solid rgba(159, 183, 176, 0.35);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), calc(100% - 28px) 100%, 0 100%);
}

/* ---------- 外壳：章节索引 + 正文 ---------- */
.page-about .about-shell {
  padding: 2rem 0 4rem;
}

.page-about .about-index {
  margin-bottom: 1.5rem;
}

.page-about .about-index__title {
  margin: 0 0 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: var(--slate);
}

.page-about .about-index__list {
  display: flex;
  gap: 0.5rem;
  list-style: none;
  margin: 0;
  padding: 0 0 0.5rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-index__list a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 0.85rem;
  min-height: 40px;
  white-space: nowrap;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
  background: var(--paper-raise);
  border: 1px solid var(--line-ink-strong);
  border-radius: 999px;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

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

.page-about .about-index__list .num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--clay);
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding: 2.25rem 0 2.5rem;
  border-top: 1px solid var(--line-ink);
  scroll-margin-top: 1.5rem;
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: 0.5rem;
}

.page-about .about-sec__head {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  margin-bottom: 1.15rem;
}

.page-about .about-sec__num {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  letter-spacing: 0.1em;
  color: var(--clay);
}

.page-about .about-sec h2 {
  margin: 0;
  font-size: clamp(1.4rem, 4.8vw, 1.9rem);
  line-height: 1.25;
  letter-spacing: -0.015em;
  font-weight: 800;
  color: var(--ink);
}

.page-about .about-sec p {
  max-width: var(--about-measure);
  margin: 0 0 1.05rem;
  line-height: 1.85;
}

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

.page-about .about-sec a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: var(--clay);
  text-underline-offset: 3px;
}

.page-about .about-sec a:hover,
.page-about .about-sec a:focus-visible {
  text-decoration-thickness: 2px;
  color: var(--clay);
}

/* 原则句切角面板 */
.page-about .about-principle {
  position: relative;
  margin-top: 1.75rem;
  padding: 1.6rem 1.4rem 1.75rem;
  background: var(--ink);
  color: var(--paper);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-cut)), calc(100% - var(--about-cut)) 100%, 0 100%);
}

.page-about .about-principle::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(159, 183, 176, 0.16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(159, 183, 176, 0.16) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
}

.page-about .about-principle__label {
  position: relative;
  margin: 0 0 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--gold);
}

.page-about .about-principle p {
  position: relative;
  max-width: 30rem;
  margin: 0;
  font-size: 1.0625rem;
  font-weight: 700;
  line-height: 1.75;
  color: var(--paper);
}

.page-about .about-principle p span {
  color: var(--gold-soft);
}

/* 场景 */
.page-about .scenes {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
}

.page-about .scenes li {
  display: grid;
  grid-template-columns: 2.2rem minmax(0, 1fr);
  gap: 0.2rem 0.9rem;
  padding: 1.1rem 0;
  border-bottom: 1px dashed var(--line-ink);
}

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

.page-about .scenes__num {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--gold);
  padding-top: 0.15rem;
}

.page-about .scenes h3 {
  margin: 0 0 0.35rem;
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--ink);
}

.page-about .scenes p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
}

/* 流程 */
.page-about .steps {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
}

.page-about .steps li {
  position: relative;
  margin-left: 0.35rem;
  padding: 0 0 1.4rem 1.5rem;
  border-left: 2px solid var(--line-ink);
}

.page-about .steps li:last-child {
  border-left-color: transparent;
  padding-bottom: 0;
}

.page-about .steps li::before {
  content: "";
  position: absolute;
  left: -2px;
  top: 0.45rem;
  width: 0.8rem;
  height: 0.8rem;
  transform: translateX(-50%);
  background: var(--gold);
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
}

.page-about .steps h3 {
  margin: 0 0 0.3rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--ink);
}

.page-about .steps p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
}

/* 配图 */
.page-about .about-figure {
  margin: 1.75rem 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
}

.page-about .about-figure figcaption {
  margin-top: 0.65rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  line-height: 1.7;
  letter-spacing: 0.03em;
  color: var(--slate);
}

/* 演进轴 */
.page-about .about-axis {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 1.5rem;
  color: var(--board);
}

.page-about .about-axis-cap {
  margin: 0.35rem 0 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  line-height: 1.8;
  letter-spacing: 0.03em;
  color: var(--slate);
}

/* 分段切换 */
.page-about .about-tabs {
  margin-top: 1.6rem;
}

.page-about .about-tabs .tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.page-about .about-tabs .tab {
  appearance: none;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.55rem 0.95rem;
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--ink);
  background: var(--paper-raise);
  border: 1px solid var(--line-ink-strong);
  cursor: pointer;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%);
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-tabs .tab:hover {
  border-color: var(--gold);
}

.page-about .about-tabs .tab[aria-selected="true"] {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

.page-about .about-tabs .tab:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
}

.page-about .about-tabs .tabpanel {
  margin-top: 1rem;
  padding: 1.25rem 1.25rem 1.35rem;
  background: var(--paper-raise);
  border: 1px solid var(--line-ink);
  border-top: 3px solid var(--gold);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .about-tabs .tabpanel p {
  margin: 0;
  max-width: 36rem;
  font-size: 0.9375rem;
  line-height: 1.85;
}

.page-about .about-tabs .tabpanel[hidden] {
  display: none;
}

/* 团队规模 */
.page-about .metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.5rem 1.1rem;
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
}

.page-about .metric {
  min-width: 0;
}

.page-about .metric--lead {
  grid-column: 1 / -1;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--line-ink);
}

.page-about .metric__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.9rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .metric--lead .metric__num {
  font-size: clamp(2.75rem, 13vw, 4rem);
}

.page-about .metric--accent .metric__num {
  color: var(--signal);
}

.page-about .metric__label {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--ink);
}

.page-about .metric__note {
  display: block;
  margin-top: 0.3rem;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--slate);
  transition: color var(--dur) var(--ease);
}

.page-about .metric:hover .metric__note,
.page-about .metric:focus-within .metric__note {
  color: var(--clay);
}

/* 联系 */
.page-about .about-reach {
  margin-top: 1.5rem;
  padding: 1.6rem 1.35rem 1.75rem;
  background: var(--ink-deep);
  color: var(--paper);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-cut)), calc(100% - var(--about-cut)) 100%, 0 100%);
}

.page-about .about-reach__title {
  margin: 0 0 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--gold);
}

.page-about .about-contact {
  display: grid;
  gap: 0.85rem;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 0.9375rem;
}

.page-about .about-contact li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.2rem 0.85rem;
  padding-top: 0.85rem;
  border-top: 1px solid rgba(159, 183, 176, 0.24);
}

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

.page-about .about-contact__label {
  min-width: 3.75rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--board);
}

.page-about .about-contact__value {
  font-family: var(--font-mono);
  color: var(--paper);
  word-break: break-word;
}

.page-about .about-reach__cta {
  margin: 1.5rem 0 0;
}

.page-about .about-reach a:not(.btn) {
  color: var(--gold-soft);
  text-decoration-color: currentColor;
}

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 1.5rem 0 3.25rem;
  }

  .page-about .about-hero__lead {
    font-size: 1.0625rem;
  }

  .page-about .about-shell {
    padding-top: 2.75rem;
  }

  .page-about .about-sec {
    padding: 2.75rem 0 3rem;
  }

  .page-about .about-principle {
    padding: 1.9rem 2rem 2rem;
  }

  .page-about .about-principle p {
    font-size: 1.1875rem;
  }

  .page-about .about-tabs .tabpanel {
    padding: 1.5rem 1.6rem 1.6rem;
  }

  .page-about .about-reach {
    padding: 2rem 1.9rem 2.1rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: end;
    gap: 3rem;
  }

  .page-about .metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 2rem 1.75rem;
  }

  .page-about .metric--lead {
    grid-column: span 2;
  }
}

@media (min-width: 960px) {
  .page-about .about-shell {
    display: grid;
    grid-template-columns: var(--about-index) minmax(0, 1fr);
    gap: 3.5rem;
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: 1.75rem;
    margin-bottom: 0;
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding: 0;
    border-left: 2px solid var(--line-ink);
  }

  .page-about .about-index__list a {
    display: grid;
    grid-template-columns: 2rem minmax(0, 1fr);
    align-items: baseline;
    min-height: 0;
    margin-left: -2px;
    padding: 0.55rem 0 0.55rem 0.9rem;
    white-space: normal;
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
    background: transparent;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--rock);
  }

  .page-about .about-index__list a:hover,
  .page-about .about-index__list a:focus-visible {
    border-left-color: var(--gold);
    color: var(--ink);
    font-weight: 700;
  }

  .page-about .about-sec {
    scroll-margin-top: 2rem;
  }

  .page-about .about-sec p {
    font-size: 1.0625rem;
  }
}

@media (min-width: 1100px) {
  .page-about .about-hero h1 {
    max-width: 14em;
  }

  .page-about .about-body {
    max-width: 46rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__list a,
  .page-about .about-tabs .tab,
  .page-about .metric__note {
    transition: none;
  }
}
<<<END>>>