.page-about {
  --about-line: rgba(111, 123, 134, 0.28);
  --about-panel: rgba(51, 74, 94, 0.38);
  --about-glow: rgba(47, 227, 208, 0.12);
  color: var(--cream);
}

.page-about p {
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--mist);
  margin: 0 0 16px;
}

.page-about h2 {
  font-family: var(--font-display);
  font-size: var(--fs-h2);
  line-height: 1.24;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--cream);
  margin: 6px 0 18px;
  max-width: 24ch;
}

.page-about h3 {
  font-family: var(--font-display);
  font-size: var(--fs-h3);
  line-height: 1.42;
  font-weight: 700;
  color: var(--cream);
  margin: 0 0 8px;
}

.page-about .about-section {
  padding: var(--space-section) 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(20px, 3vw, 36px) 0 var(--space-section);
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(47, 227, 208, 0.12), transparent 62%),
    radial-gradient(90% 80% at 0% 100%, rgba(255, 158, 61, 0.09), transparent 58%),
    var(--ink);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(90deg, rgba(111, 123, 134, 0.11) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(111, 123, 134, 0.11) 0 1px, transparent 1px 96px);
  mask-image: radial-gradient(120% 100% at 70% 10%, #000 20%, transparent 78%);
  -webkit-mask-image: radial-gradient(120% 100% at 70% 10%, #000 20%, transparent 78%);
}

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

.page-about .hero-shell {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  margin-top: clamp(20px, 3vw, 38px);
}

.page-about .hero-spine {
  display: none;
}

.page-about .hero-copy h1 {
  font-family: var(--font-display);
  font-size: var(--fs-h1);
  line-height: 1.12;
  font-weight: 700;
  letter-spacing: 0.015em;
  color: var(--cream);
  margin: 10px 0 20px;
  max-width: 17ch;
}

.page-about .hero-copy .lead {
  font-size: var(--fs-body);
  line-height: 1.9;
  color: var(--mist);
  max-width: 48ch;
}

.page-about .hero-meta {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 24px 0 0;
  padding: 0;
}

.page-about .hero-meta li {
  font-family: var(--font-label);
  font-size: var(--fs-label);
  letter-spacing: 0.06em;
  color: var(--mist);
  padding: 7px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--about-line);
  background: rgba(51, 74, 94, 0.32);
}

.page-about .hero-index {
  border-radius: var(--radius-lg);
  border: 1px solid var(--about-line);
  background: linear-gradient(158deg, rgba(51, 74, 94, 0.56), rgba(20, 28, 36, 0.78));
  padding: clamp(16px, 2.4vw, 26px);
}

.page-about .hero-index__title {
  font-family: var(--font-label);
  font-size: var(--fs-label);
  letter-spacing: 0.24em;
  color: var(--stone);
  margin: 0 0 12px;
}

.page-about .hero-index ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .hero-index a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 10px;
  border-radius: var(--radius-sm);
  color: var(--mist);
  text-decoration: none;
  font-size: 0.95rem;
  transition: background 160ms ease, transform 160ms ease, color 160ms ease;
}

.page-about .hero-index a:hover {
  background: var(--about-glow);
  color: var(--cream);
  transform: translateX(2px);
}

.page-about .hero-index a:focus-visible {
  outline: var(--ring);
  outline-offset: 2px;
}

.page-about .hero-index .idx {
  font-family: var(--font-label);
  font-size: var(--fs-label);
  letter-spacing: 0.08em;
  color: var(--cyan);
}

/* ---------- 起点 ---------- */
.page-about .origin-section {
  background: linear-gradient(180deg, var(--ink) 0%, var(--graphite) 100%);
}

.page-about .origin-grid {
  display: grid;
  gap: clamp(24px, 4vw, 46px);
  align-items: center;
}

.page-about .about-figure {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--graphite);
  border: 1px solid var(--about-line);
}

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

.page-about .about-figure figcaption {
  font-family: var(--font-label);
  font-size: var(--fs-label);
  letter-spacing: 0.06em;
  color: var(--stone);
  padding: 12px 16px 14px;
  background: rgba(8, 24, 38, 0.6);
}

.page-about .origin-list {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .origin-list li {
  position: relative;
  padding-left: 26px;
  font-size: var(--fs-body);
  line-height: 1.72;
  color: var(--mist);
}

.page-about .origin-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 12px;
  height: 2px;
  border-radius: 2px;
  background: var(--amber);
}

/* ---------- 通用分栏 ---------- */
.page-about .split {
  display: grid;
  gap: clamp(22px, 4vw, 48px);
}

.page-about .split__note {
  color: var(--stone);
  font-size: 0.94rem;
  line-height: 1.8;
  max-width: 34ch;
}

/* ---------- 时间线 ---------- */
.page-about .timeline-section {
  background: var(--graphite);
}

.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 30px 30px;
  border-left: 1px solid var(--about-line);
}

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

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 8px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--graphite);
  border: 2px solid var(--stone);
  transition: background 180ms ease, border-color 180ms ease;
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus-within::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .tl-item:focus-visible {
  outline: var(--ring);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

.page-about .tl-year {
  font-family: var(--font-label);
  font-size: var(--fs-label);
  letter-spacing: 0.18em;
  color: var(--amber);
  margin: 0 0 6px;
}

.page-about .tl-main p {
  margin: 0 0 10px;
}

.page-about .tl-detail {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height 240ms ease, opacity 200ms ease, margin 200ms ease;
  color: var(--stone);
  font-size: 0.93rem;
  line-height: 1.78;
  margin: 0;
  padding-left: 12px;
  border-left: 2px solid rgba(47, 227, 208, 0.4);
}

@media (hover: hover) {
  .page-about .tl-item:hover .tl-detail,
  .page-about .tl-item:focus-within .tl-detail {
    max-height: 14rem;
    opacity: 1;
    margin-top: 4px;
  }
}

@media (hover: none) {
  .page-about .tl-detail {
    max-height: none;
    opacity: 1;
    margin-top: 4px;
  }
}

/* ---------- 分类体系 ---------- */
.page-about .taxonomy-section {
  background: linear-gradient(180deg, var(--graphite) 0%, var(--ink) 46%, var(--ink) 100%);
}

.page-about .taxonomy-panel {
  border-radius: var(--radius-lg);
  padding: clamp(20px, 3.4vw, 44px);
  background:
    radial-gradient(110% 90% at 100% 0%, rgba(255, 158, 61, 0.12), transparent 58%),
    linear-gradient(150deg, rgba(51, 74, 94, 0.72), rgba(14, 58, 64, 0.58));
  border: 1px solid var(--about-line);
}

.page-about .taxonomy-head {
  display: grid;
  gap: 16px;
  margin-bottom: clamp(20px, 3vw, 30px);
}

.page-about .taxonomy-intro {
  color: var(--mist);
  max-width: 52ch;
  margin: 0;
}

.page-about .cat-switch {
  position: relative;
}

.page-about .cat-input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.page-about .cat-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 20px;
}

.page-about .cat-tabs label {
  display: inline-flex;
  align-items: center;
  padding: 9px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--about-line);
  background: rgba(8, 24, 38, 0.55);
  color: var(--mist);
  font-size: 0.9rem;
  line-height: 1.2;
  cursor: pointer;
  transition: background 160ms ease, color 160ms ease, transform 160ms ease, border-color 160ms ease;
}

.page-about .cat-tabs label:hover {
  border-color: var(--cyan);
  color: var(--cream);
  transform: translateY(-2px);
}

.page-about #cat-desk:checked ~ .cat-tabs [for="cat-desk"],
.page-about #cat-mobile:checked ~ .cat-tabs [for="cat-mobile"],
.page-about #cat-season:checked ~ .cat-tabs [for="cat-season"],
.page-about #cat-login:checked ~ .cat-tabs [for="cat-login"] {
  background: var(--cyan);
  border-color: transparent;
  color: var(--ink);
  font-weight: 700;
}

.page-about #cat-desk:focus-visible ~ .cat-tabs [for="cat-desk"],
.page-about #cat-mobile:focus-visible ~ .cat-tabs [for="cat-mobile"],
.page-about #cat-season:focus-visible ~ .cat-tabs [for="cat-season"],
.page-about #cat-login:focus-visible ~ .cat-tabs [for="cat-login"] {
  outline: var(--ring);
  outline-offset: 3px;
}

.page-about .cat-panel {
  display: none;
  padding: 18px 20px;
  border-radius: var(--radius-md);
  background: rgba(8, 24, 38, 0.55);
  border-left: 3px solid var(--cyan);
}

.page-about #cat-desk:checked ~ .cat-panels .cat-panel--desk,
.page-about #cat-mobile:checked ~ .cat-panels .cat-panel--mobile,
.page-about #cat-season:checked ~ .cat-panels .cat-panel--season,
.page-about #cat-login:checked ~ .cat-panels .cat-panel--login {
  display: block;
  animation: about-panel-in 180ms ease both;
}

.page-about .cat-panel--season {
  border-left-color: var(--amber);
}

.page-about .cat-panel p {
  margin: 0;
}

@keyframes about-panel-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.page-about .status-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--about-line);
}

.page-about .status-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-label);
  font-size: var(--fs-label);
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}

.page-about .dot--cyan {
  background: var(--cyan);
}

.page-about .dot--amber {
  background: var(--amber);
}

.page-about .dot--slate {
  background: var(--slate);
  box-shadow: inset 0 0 0 1px var(--stone);
}

.page-about .taxonomy-figure {
  margin-top: clamp(22px, 3vw, 34px);
}

/* ---------- 多设备 ---------- */
.page-about .devices-section {
  background: linear-gradient(150deg, rgba(14, 58, 64, 0.92), var(--ink) 68%);
}

.page-about .devices-grid {
  display: grid;
  gap: clamp(24px, 4vw, 46px);
  align-items: center;
}

.page-about .device-list {
  list-style: none;
  margin: 20px 0 18px;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .device-list li {
  position: relative;
  padding-left: 20px;
  font-size: var(--fs-body);
  line-height: 1.7;
  color: var(--mist);
}

.page-about .device-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.35em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--cyan);
}

.page-about .device-list strong {
  color: var(--cream);
  font-weight: 700;
  margin-right: 6px;
}

.page-about .devices-note {
  color: var(--stone);
  font-size: 0.94rem;
  margin-bottom: 18px;
}

.page-about .devices-link {
  display: inline-flex;
  align-items: center;
  padding: 11px 20px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--cyan);
  color: var(--cyan);
  text-decoration: none;
  font-size: 0.92rem;
  transition: background 160ms ease, transform 160ms ease, color 160ms ease;
}

.page-about .devices-link:hover {
  background: rgba(47, 227, 208, 0.14);
  color: var(--cream);
  transform: translateY(-2px);
}

.page-about .devices-link:focus-visible {
  outline: var(--ring);
  outline-offset: 3px;
}

/* ---------- 运营 ---------- */
.page-about .ops-section {
  background: var(--graphite);
}

.page-about .ops-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ops-item {
  display: grid;
  gap: 4px 18px;
  padding: 20px 0;
  border-top: 1px solid var(--about-line);
}

.page-about .ops-item:last-child {
  border-bottom: 1px solid var(--about-line);
}

.page-about .ops-item p {
  margin: 0;
  color: var(--stone);
  font-size: 0.95rem;
}

.page-about .ops-num {
  font-family: var(--font-label);
  font-size: 1.35rem;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

/* ---------- 合作 ---------- */
.page-about .partners-section {
  background: linear-gradient(180deg, var(--graphite) 0%, var(--ink) 40%, var(--ink) 100%);
}

.page-about .partners-head p {
  max-width: 62ch;
}

.page-about .stat-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 16px;
  margin: 30px 0 24px;
}

.page-about .stat {
  padding-top: 14px;
  border-top: 2px solid var(--about-line);
}

.page-about .stat:nth-child(1) {
  border-top-color: var(--amber);
}

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

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

.page-about .stat:nth-child(4) {
  border-top-color: var(--clay);
}

.page-about .stat-num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 1.15rem + 1.4vw, 2.2rem);
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--cream);
  line-height: 1.2;
  margin-bottom: 6px;
}

.page-about .stat-label {
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--stone);
}

.page-about .partners-note {
  color: var(--stone);
  font-size: 0.95rem;
  max-width: 64ch;
  margin: 0;
}

/* ---------- 结尾入口 ---------- */
.page-about .about-next {
  padding: var(--space-section) 0 calc(var(--space-section) + 8px);
  background: var(--ink);
}

.page-about .next-panel {
  border-radius: var(--radius-lg);
  padding: clamp(22px, 4vw, 48px);
  border: 1px solid var(--about-line);
  background:
    radial-gradient(120% 120% at 100% 0%, rgba(255, 158, 61, 0.16), transparent 56%),
    linear-gradient(140deg, rgba(51, 74, 94, 0.6), rgba(8, 24, 38, 0.95));
}

.page-about .next-panel h2 {
  max-width: 22ch;
}

.page-about .next-panel p {
  max-width: 56ch;
}

.page-about .next-links {
  display: grid;
  gap: 10px;
  margin-top: 24px;
}

.page-about .next-links a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 18px;
  border-radius: var(--radius-md);
  border: 1px solid var(--about-line);
  background: rgba(8, 24, 38, 0.6);
  color: var(--cream);
  text-decoration: none;
  font-size: 0.96rem;
  transition: transform 160ms ease, border-color 160ms ease, background 160ms ease;
}

.page-about .next-links a:hover {
  transform: translateY(-2px);
  border-color: var(--cyan);
  background: var(--about-glow);
}

.page-about .next-links a:focus-visible {
  outline: var(--ring);
  outline-offset: 2px;
}

.page-about .next-links span {
  font-family: var(--font-label);
  font-size: var(--fs-label);
  color: var(--amber);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .ops-item {
    grid-template-columns: 64px minmax(0, 1fr);
    align-items: baseline;
  }

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

@media (min-width: 900px) {
  .page-about .origin-grid,
  .page-about .devices-grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
  }

  .page-about .devices-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.04fr);
  }

  .page-about .taxonomy-head {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    align-items: end;
    gap: 32px;
  }

  .page-about .taxonomy-head h2 {
    margin-bottom: 0;
  }

  .page-about .stat-row {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 20px;
  }
}

@media (min-width: 960px) {
  .page-about .hero-shell {
    grid-template-columns: 78px minmax(0, 1fr) minmax(270px, 0.7fr);
    align-items: start;
    gap: clamp(20px, 3vw, 40px);
  }

  .page-about .hero-spine {
    display: block;
    justify-self: center;
    writing-mode: vertical-rl;
    font-family: var(--font-label);
    font-size: var(--fs-label);
    letter-spacing: 0.32em;
    color: var(--stone);
    padding: 6px 0 6px 10px;
    border-left: 1px solid var(--about-line);
    margin: 6px 0 0;
  }

  .page-about .split {
    grid-template-columns: minmax(0, 0.72fr) minmax(0, 1.28fr);
    align-items: start;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .cat-panel,
  .page-about .tl-detail,
  .page-about .hero-index a,
  .page-about .cat-tabs label,
  .page-about .next-links a,
  .page-about .devices-link {
    animation: none;
    transition: none;
  }
}
<<<END>>>