.page-about {
  --about-rail: 200px;
  --about-hairline: rgba(143, 168, 179, 0.45);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-ui);
  padding: 0 0 72px;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about .about-shell {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.page-about .breadcrumb {
  padding: 18px 0 6px;
  font-size: 13px;
}

/* ---------- 封面 ---------- */
.page-about .about-cover {
  position: relative;
  margin-top: 10px;
  padding: 32px 22px 30px;
  border-radius: var(--radius-l) var(--radius-l) var(--radius-l) var(--radius-s);
  overflow: hidden;
  color: var(--paper);
  background-image:
    linear-gradient(to right, rgba(143, 168, 179, 0.12) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(143, 168, 179, 0.12) 1px, transparent 1px),
    radial-gradient(112% 82% at 92% 4%, rgba(242, 163, 58, 0.24), transparent 60%),
    radial-gradient(92% 72% at 2% 100%, rgba(49, 200, 184, 0.18), transparent 64%),
    linear-gradient(155deg, var(--night), var(--night-2));
  background-size: 46px 46px, 46px 46px, cover, cover, cover;
}

.page-about .about-cover__title {
  margin: 14px 0 16px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(26px, 6.4vw, 50px);
  line-height: 1.24;
  letter-spacing: -0.01em;
  max-width: 20em;
}

.page-about .about-cover__lead {
  margin: 0 0 20px;
  max-width: 34em;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--paper-80);
}

.page-about .about-cover__meta {
  margin: 0 0 22px;
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--aqua);
}

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

/* ---------- 框架与章节导视 ---------- */
.page-about .about-frame {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  margin-top: 32px;
}

.page-about .about-rail__title {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 10px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .about-rail__link {
  position: relative;
  display: block;
  padding: 7px 10px 7px 14px;
  border-radius: var(--radius-s);
  font-size: 13px;
  line-height: 1.5;
  color: var(--slate);
  text-decoration: none;
  transition: color var(--t-fast) var(--ease), background var(--t-fast) var(--ease);
}

.page-about .about-rail__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 0;
  border-radius: 2px;
  background: var(--amber);
  transition: height var(--t-fast) var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--ink);
  background: rgba(111, 149, 168, 0.14);
}

.page-about .about-rail__link:hover::before,
.page-about .about-rail__link:focus-visible::before {
  height: 16px;
}

.page-about .about-rail__link:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
}

.page-about .about-rail__num {
  margin-right: 6px;
  font-size: 11px;
  color: var(--mist);
}

/* ---------- 章节基础 ---------- */
.page-about .about-section {
  padding: 30px 0;
  border-top: 1px solid var(--about-hairline);
}

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

.page-about .about-h2 {
  margin: 10px 0 16px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(21px, 4vw, 31px);
  line-height: 1.36;
  color: var(--night);
  max-width: 22em;
}

.page-about .about-h3 {
  margin: 28px 0 12px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 18px;
  color: var(--night);
}

.page-about .about-lead {
  margin: 0 0 20px;
  max-width: 34em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--ink-76);
}

.page-about .about-section p {
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--ink-76);
}

/* ---------- 品牌起点 ---------- */
.page-about .about-origin {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  align-items: start;
}

.page-about .about-origin__text p {
  margin: 0 0 14px;
  max-width: 36em;
}

.page-about .about-origin__media {
  margin: 0;
  overflow: hidden;
  border-radius: var(--radius-l) var(--radius-s) var(--radius-l) var(--radius-l);
  background: var(--night-2);
}

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

.page-about .about-checks {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-checks li {
  position: relative;
  padding-left: 22px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-76);
}

.page-about .about-checks li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.7em;
  width: 11px;
  height: 2px;
  background: var(--aqua);
}

/* ---------- 三条路线 ---------- */
.page-about .about-paths {
  margin: 0;
}

.page-about .about-paths__svg {
  display: block;
  width: 100%;
  height: auto;
  max-height: 160px;
  margin: 0 0 20px;
}

.page-about .path-line {
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-dasharray: 6 9;
}

.page-about .path-line--a { stroke: var(--amber); }
.page-about .path-line--b { stroke: var(--aqua); }
.page-about .path-line--c { stroke: var(--mist); }

.page-about .path-dot--a { fill: var(--amber); }
.page-about .path-dot--b { fill: var(--aqua); }
.page-about .path-dot--c { fill: var(--mist); }

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

.page-about .route-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 18px 16px 16px;
  border-top: 3px solid var(--mist);
  border-radius: var(--radius-l) var(--radius-s) var(--radius-l) var(--radius-l);
  background: rgba(111, 149, 168, 0.08);
  transition: transform var(--t-fast) var(--ease), box-shadow var(--t-fast) var(--ease);
}

.page-about .route-card--a {
  border-top-color: var(--amber);
  background: linear-gradient(165deg, rgba(242, 163, 58, 0.15), rgba(242, 163, 58, 0.03));
}

.page-about .route-card--b {
  border-top-color: var(--aqua);
  background: linear-gradient(165deg, rgba(49, 200, 184, 0.15), rgba(49, 200, 184, 0.03));
}

.page-about .route-card--c {
  border-top-color: var(--mist);
  background: linear-gradient(165deg, rgba(111, 149, 168, 0.2), rgba(111, 149, 168, 0.05));
}

.page-about .route-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 22px rgba(11, 31, 42, 0.1);
}

.page-about .route-card__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 18px;
  line-height: 1.42;
  color: var(--night);
}

.page-about .route-card__text {
  margin: 0;
  flex: 1;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-76);
}

.page-about .route-card__link {
  align-self: flex-start;
  padding-bottom: 2px;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--night);
  text-decoration: none;
  border-bottom: 2px solid var(--amber);
}

.page-about .route-card__link:hover,
.page-about .route-card__link:focus-visible {
  color: var(--slate);
  border-bottom-color: var(--aqua);
}

.page-about .route-card__link:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

/* ---------- 时间线 ---------- */
.page-about .about-tl {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-tl__item {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 18px 16px 22px;
  border-left: 2px solid rgba(143, 168, 179, 0.6);
  border-radius: 0 var(--radius-m) var(--radius-m) 0;
  background: rgba(111, 149, 168, 0.07);
  outline: none;
  transition: background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .about-tl__item::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 22px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--mist);
}

.page-about .about-tl__item:hover,
.page-about .about-tl__item:focus {
  background: rgba(242, 163, 58, 0.1);
  border-left-color: var(--amber);
}

.page-about .about-tl__item:hover::before,
.page-about .about-tl__item:focus::before {
  border-color: var(--amber);
  background: var(--amber-soft);
}

.page-about .about-tl__item:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
  box-shadow: inset 0 0 0 2px rgba(49, 200, 184, 0.28);
}

.page-about .about-tl__year {
  font-size: 30px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--night);
}

.page-about .about-tl__title {
  margin: 2px 0 0;
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 15.5px;
  line-height: 1.5;
  color: var(--night);
}

.page-about .about-tl__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--ink-76);
}

.page-about .about-tl__note {
  margin: 0;
  font-size: 13px;
  line-height: 1.72;
  color: var(--ink-58);
  opacity: 0.82;
  transition: opacity var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .about-tl__item:hover .about-tl__note,
.page-about .about-tl__item:focus .about-tl__note {
  opacity: 1;
  color: var(--slate);
}

.page-about .about-tl__media {
  margin: 24px 0 0;
  overflow: hidden;
  border-radius: var(--radius-s) var(--radius-l) var(--radius-l) var(--radius-l);
}

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

.page-about .about-inline-link {
  margin: 18px 0 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--ink-76);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  align-items: start;
}

.page-about .about-roles {
  display: grid;
  gap: 8px;
}

.page-about .role {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  align-items: baseline;
  gap: 2px 12px;
  padding: 12px 14px;
  border-left: 3px solid var(--mist);
  border-radius: var(--radius-m) var(--radius-s) var(--radius-m) var(--radius-m);
  background: rgba(111, 149, 168, 0.1);
  outline: none;
  transition: background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}

.page-about .role:hover,
.page-about .role:focus {
  background: rgba(49, 200, 184, 0.16);
  border-left-color: var(--aqua);
  transform: translateY(-2px);
}

.page-about .role:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
  box-shadow: inset 0 0 0 2px rgba(49, 200, 184, 0.28);
}

.page-about .role__num {
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--night);
}

.page-about .role__name {
  font-size: 15px;
  font-weight: 700;
  color: var(--night);
}

.page-about .role__note {
  grid-column: 2;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--ink-58);
  opacity: 0.82;
  transition: opacity var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .role:hover .role__note,
.page-about .role:focus .role__note {
  opacity: 1;
  color: var(--slate);
}

.page-about .about-team__media {
  margin: 0;
  overflow: hidden;
  border-radius: var(--radius-s) var(--radius-l) var(--radius-l) var(--radius-s);
}

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

.page-about .about-review {
  margin-top: 4px;
}

/* ---------- 协作网络 ---------- */
.page-about .about-stats {
  list-style: none;
  margin: 6px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .stat {
  display: grid;
  grid-template-columns: auto auto;
  justify-content: start;
  align-items: baseline;
  gap: 0 8px;
  padding: 16px 18px;
  border-radius: var(--radius-s) var(--radius-l) var(--radius-l) var(--radius-l);
  background: linear-gradient(110deg, rgba(11, 31, 42, 0.07), rgba(111, 149, 168, 0.14));
}

.page-about .stat__num {
  grid-column: 1;
  font-size: clamp(24px, 5vw, 32px);
  font-weight: 700;
  line-height: 1;
  color: var(--night);
}

.page-about .stat__unit {
  grid-column: 2;
  font-size: 13px;
  color: var(--slate);
}

.page-about .stat__label {
  grid-column: 1 / -1;
  margin-top: 8px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink-76);
}

/* ---------- 设计语言 ---------- */
.page-about .about-design {
  display: grid;
  gap: 14px;
}

.page-about .design-card {
  padding: 20px 18px;
  border-radius: var(--radius-l);
}

.page-about .design-card--1 {
  border-radius: var(--radius-l) var(--radius-s) var(--radius-l) var(--radius-l);
  background: linear-gradient(150deg, var(--night), var(--night-2));
  color: var(--paper);
}

.page-about .design-card--2 {
  border-radius: var(--radius-l) var(--radius-l) var(--radius-s) var(--radius-l);
  background: rgba(49, 200, 184, 0.16);
}

.page-about .design-card--3 {
  border-radius: var(--radius-s) var(--radius-l) var(--radius-l) var(--radius-l);
  background: rgba(242, 163, 58, 0.18);
}

.page-about .design-card__kicker {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--slate);
}

.page-about .design-card--1 .design-card__kicker {
  color: var(--aqua);
}

.page-about .design-card__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 19px;
  line-height: 1.4;
  color: var(--night);
}

.page-about .design-card--1 .design-card__title {
  color: var(--paper);
}

.page-about .design-card__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.82;
  color: var(--ink-76);
}

.page-about .design-card--1 .design-card__text {
  color: var(--paper-80);
}

/* ---------- 结尾行动 ---------- */
.page-about .about-cta {
  margin-top: 34px;
  padding: 26px 22px 28px;
  border-radius: var(--radius-l) var(--radius-l) var(--radius-s) var(--radius-l);
  background-image:
    radial-gradient(100% 80% at 96% 0%, rgba(242, 163, 58, 0.22), transparent 62%),
    linear-gradient(140deg, var(--night-2), var(--night));
  color: var(--paper);
}

.page-about .about-cta__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(20px, 3.6vw, 27px);
  line-height: 1.4;
}

.page-about .about-cta__text {
  margin: 0 0 20px;
  max-width: 34em;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--paper-80);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 680px) {
  .page-about .about-shell {
    padding: 0 28px;
  }

  .page-about .about-cover {
    padding: 44px 36px 40px;
  }

  .page-about .about-cover__lead {
    font-size: 16px;
  }

  .page-about .about-section {
    padding: 38px 0;
  }

  .page-about .about-origin {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 26px;
  }

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

  .page-about .about-tl__item {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 2px 20px;
    padding: 18px 20px 18px 24px;
  }

  .page-about .about-tl__year {
    grid-column: 1;
    grid-row: 1 / span 3;
    align-self: start;
    font-size: 36px;
  }

  .page-about .about-tl__title,
  .page-about .about-tl__text,
  .page-about .about-tl__note {
    grid-column: 2;
  }

  .page-about .about-tl__item:nth-child(even) {
    margin-left: 40px;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: 24px;
  }

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

  .page-about .stat:nth-child(2) {
    margin-left: 18px;
  }

  .page-about .stat:nth-child(3) {
    margin-right: 18px;
  }

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

  .page-about .design-card--2 {
    margin-top: 22px;
  }

  .page-about .design-card--3 {
    margin-top: 44px;
  }

  .page-about .about-cta {
    padding: 34px 32px 36px;
  }
}

@media (min-width: 960px) {
  .page-about .about-frame {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 48px;
    align-items: start;
    margin-top: 40px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 88px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 2px;
    margin-top: 12px;
  }

  .page-about .about-rail__link {
    padding: 9px 12px 9px 16px;
  }

  .page-about .about-cover__title {
    max-width: 16em;
  }

  .page-about .about-section {
    padding: 44px 0;
  }

  .page-about .about-tl__item:nth-child(even) {
    margin-left: 64px;
  }

  .page-about .about-stats {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .page-about .stat:nth-child(2) {
    margin-left: 44px;
    margin-right: 0;
  }

  .page-about .stat:nth-child(3) {
    margin-left: 18px;
    margin-right: 26px;
  }

  .page-about .stat:nth-child(4) {
    margin-left: 56px;
    margin-right: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .route-card,
  .page-about .role,
  .page-about .about-tl__item,
  .page-about .about-rail__link,
  .page-about .about-tl__note,
  .page-about .role__note {
    transition: none;
  }

  .page-about .route-card:hover,
  .page-about .role:hover,
  .page-about .role:focus {
    transform: none;
  }
}