.page-about {
  --about-shadow: 0 18px 44px rgba(0, 0, 0, 0.35);
  background:
    radial-gradient(90% 48% at 86% 0%, rgba(198, 255, 61, 0.07), transparent 62%),
    radial-gradient(70% 42% at 0% 34%, rgba(30, 74, 60, 0.42), transparent 72%),
    var(--pitch);
  color: var(--frost);
  font-family: var(--sans);
  padding-block: clamp(18px, 3vw, 32px) clamp(48px, 8vw, 96px);
}

.page-about .about-shell {
  width: 100%;
  max-width: var(--page-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
  overflow-x: clip;
}

/* 面包屑 */
.page-about .about-crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--grid-line);
  padding-block: 6px 0;
}

.page-about .about-crumb .crumb-link {
  color: var(--mist);
  text-decoration: none;
  transition: color 0.18s var(--ease);
}

.page-about .about-crumb .crumb-link:hover,
.page-about .about-crumb .crumb-link:focus-visible {
  color: var(--acid);
}

.page-about .about-crumb .crumb-current {
  color: var(--frost);
}

/* 首屏 */
.page-about .about-hero {
  position: relative;
  padding-block: clamp(24px, 5vw, 52px) clamp(30px, 5vw, 60px);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: min(38%, 320px);
  height: 2px;
  background: linear-gradient(90deg, var(--acid), rgba(198, 255, 61, 0));
  pointer-events: none;
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(38px, 8vw, 86px);
  line-height: 0.94;
  letter-spacing: 0.01em;
  color: var(--frost);
  text-wrap: balance;
}

.page-about .about-hero__accent {
  color: var(--acid);
}

.page-about .about-hero__lede {
  margin: clamp(16px, 2.4vw, 22px) 0 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-hero__meta {
  margin: 14px 0 0;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--grid-line);
}

.page-about .about-hero__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 30px);
}

/* 主体框架 */
.page-about .about-body {
  display: block;
  padding-top: clamp(26px, 4vw, 46px);
}

/* 章节索引 */
.page-about .about-rail {
  position: relative;
  margin-bottom: clamp(28px, 5vw, 44px);
  padding-block: 10px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-rail__label {
  display: none;
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--grid-line);
}

.page-about .about-rail__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 2px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  color: var(--mist);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-about .about-rail__link span {
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  color: var(--acid);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--frost);
  border-color: var(--acid);
  background: rgba(198, 255, 61, 0.08);
}

/* 章节流 */
.page-about .about-flow {
  display: grid;
  gap: clamp(44px, 7vw, 92px);
  min-width: 0;
}

.page-about .chapter {
  min-width: 0;
  scroll-margin-top: 108px;
}

.page-about .chapter__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: clamp(16px, 2.4vw, 26px);
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.page-about .chapter__num {
  flex: none;
  font-family: var(--mono);
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--acid);
}

.page-about .chapter__title {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(22px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: 0.01em;
  color: var(--frost);
}

.page-about .chapter__lede {
  margin: 0 0 clamp(18px, 3vw, 28px);
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .chapter__cols {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  align-items: start;
}

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

.page-about .chapter__main > p {
  margin: 0;
  font-size: 15px;
  line-height: 1.74;
  color: var(--mist);
}

.page-about .chapter__main > p + p {
  margin-top: 14px;
}

/* 图片容器 */
.page-about .about-figure {
  position: relative;
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--night);
  overflow: hidden;
  box-shadow: var(--about-shadow);
  transform: rotate(-1.1deg);
  transition: transform 0.32s var(--ease), border-color 0.32s var(--ease);
}

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

.page-about .about-figure:hover,
.page-about .about-figure:focus-within {
  transform: rotate(0deg) translateY(-2px);
  border-color: var(--acid);
}

.page-about .about-banner {
  position: relative;
  margin: 0 0 clamp(24px, 3.4vw, 36px);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--night);
  overflow: hidden;
}

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

/* 时间线 */
.page-about .timeline {
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 24px 26px;
  border-left: 1px solid var(--line);
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -6.5px;
  top: 5px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--night);
  border: 2px solid var(--acid);
  transition: box-shadow 0.22s var(--ease), background-color 0.22s var(--ease);
}

.page-about .timeline__item:hover::before,
.page-about .timeline__item:focus-within::before {
  background: var(--acid);
  box-shadow: 0 0 0 6px rgba(198, 255, 61, 0.16);
}

.page-about .timeline__item--now::before {
  border-color: var(--flare);
}

.page-about .timeline__item--now:hover::before {
  background: var(--flare);
  box-shadow: 0 0 0 6px rgba(255, 90, 42, 0.18);
}

.page-about .timeline__year {
  margin: 0 0 4px;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--acid);
}

.page-about .timeline__item--now .timeline__year {
  font-size: 17px;
  color: var(--flare);
}

.page-about .timeline__title {
  margin: 0 0 4px;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--frost);
}

.page-about .timeline__note {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.66;
  color: var(--mist);
  opacity: 0.82;
  transition: opacity 0.22s var(--ease);
}

.page-about .timeline__item:hover .timeline__note,
.page-about .timeline__item:focus-within .timeline__note {
  opacity: 1;
}

/* 流程步骤 */
.page-about .flow {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .flow__step {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--panel);
  transition: transform 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .flow__step:hover {
  transform: translateY(-2px);
  border-color: rgba(198, 255, 61, 0.5);
}

.page-about .flow__no {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: var(--radius-pill);
  background: rgba(198, 255, 61, 0.12);
  color: var(--acid);
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 700;
}

.page-about .flow__step p {
  margin: 0;
  font-size: 14px;
  line-height: 1.68;
  color: var(--mist);
}

.page-about .flow__step .flow__name {
  margin-bottom: 4px;
  font-size: 15px;
  font-weight: 700;
  color: var(--frost);
}

/* 数字面板 */
.page-about .numgrid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--line);
  overflow: hidden;
}

.page-about .numgrid__cell {
  display: flex;
  flex-direction: column;
  gap: 7px;
  padding: 18px 16px;
  background: var(--panel);
  transition: background-color 0.2s var(--ease);
}

.page-about .numgrid__cell:hover {
  background: #17402F;
}

.page-about .numgrid__value {
  font-family: var(--mono);
  font-size: clamp(22px, 3.6vw, 32px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--acid);
  font-variant-numeric: tabular-nums;
}

.page-about .numgrid__unit {
  margin-left: 2px;
  font-size: 0.52em;
  letter-spacing: 0.02em;
}

.page-about .numgrid__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--mist);
}

.page-about .about-note {
  display: grid;
  gap: 10px;
  margin-top: clamp(18px, 3vw, 26px);
  padding-left: 16px;
  border-left: 2px solid var(--line);
}

.page-about .about-note p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mist);
}

/* 服务对象 */
.page-about .who {
  display: grid;
  gap: 16px;
}

.page-about .who__card {
  padding: clamp(18px, 2.4vw, 26px);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--panel);
  transition: transform 0.22s var(--ease), border-color 0.22s var(--ease);
}

.page-about .who__card:hover {
  transform: translateY(-3px);
  border-color: rgba(198, 255, 61, 0.45);
}

.page-about .who__card h3 {
  margin: 12px 0 8px;
  font-family: var(--display);
  font-size: clamp(19px, 2vw, 24px);
  font-weight: 700;
  line-height: 1.2;
  color: var(--frost);
}

.page-about .who__card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mist);
}

/* 维护节奏 */
.page-about .keep-list {
  display: grid;
  gap: 10px;
  margin: clamp(16px, 2.4vw, 22px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .keep-list li {
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr);
  gap: 14px;
  padding: 12px 0;
  border-bottom: 1px dashed var(--line);
  font-size: 14px;
  line-height: 1.68;
  color: var(--mist);
}

.page-about .keep-list__k {
  padding-top: 2px;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--acid);
}

.page-about .about-side {
  display: grid;
  gap: 12px;
  padding: clamp(18px, 2.4vw, 26px);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--panel);
}

.page-about .about-side p.about-side__label {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--grid-line);
}

.page-about .about-side p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-side .btn {
  justify-self: start;
}

/* 收口 */
.page-about .about-cta {
  display: grid;
  gap: 14px;
  padding: clamp(24px, 4vw, 40px);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: linear-gradient(118deg, rgba(198, 255, 61, 0.13), rgba(18, 53, 43, 0.92) 58%);
}

.page-about .about-cta h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(24px, 3.4vw, 38px);
  font-weight: 700;
  line-height: 1.12;
  color: var(--frost);
  text-wrap: balance;
}

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

.page-about .about-cta__links a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(7, 19, 15, 0.55);
  color: var(--frost);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-decoration: none;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-about .about-cta__links a:hover,
.page-about .about-cta__links a:focus-visible {
  color: var(--acid);
  border-color: var(--acid);
  background: rgba(198, 255, 61, 0.1);
}

/* 中等屏 */
@media (min-width: 640px) {
  .page-about .numgrid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* 宽屏：左栏索引 + 右侧长卷 */
@media (min-width: 1024px) {
  .page-about .about-body {
    display: grid;
    grid-template-columns: 176px minmax(0, 1fr);
    gap: clamp(28px, 4vw, 64px);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 108px;
    margin-bottom: 0;
    padding-block: 0;
    border-top: 0;
    border-bottom: 0;
  }

  .page-about .about-rail__label {
    display: block;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 6px;
    overflow: visible;
  }

  .page-about .about-rail__link {
    width: 100%;
    justify-content: flex-start;
    border-color: transparent;
    border-radius: var(--radius-sm);
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible {
    border-color: var(--line);
  }
}

@media (min-width: 860px) {
  .page-about .chapter__cols {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }

  .page-about .chapter__cols--flip {
    grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
  }

  .page-about .chapter__cols > .about-figure {
    margin-top: 18px;
  }
}

@media (min-width: 900px) {
  .page-about .who {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
    align-items: start;
  }

  .page-about .who__card:nth-child(2) {
    margin-top: 32px;
  }

  .page-about .who__card:nth-child(3) {
    margin-top: 64px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-figure,
  .page-about .who__card,
  .page-about .flow__step,
  .page-about .timeline__item::before {
    transition: none;
    transform: none;
  }
}
<<<END>>>