.page-about {
  --about-gap: clamp(20px, 3vw, 36px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding-top: calc(var(--header-offset) + clamp(28px, 6vw, 64px));
  padding-bottom: clamp(48px, 7vw, 88px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -20%;
  right: -18%;
  width: min(640px, 78%);
  height: 140%;
  background: var(--grad-warm);
  transform: skewX(-14deg) rotate(-4deg);
  opacity: .18;
  z-index: -1;
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--grad-track);
  opacity: .55;
}

.page-about .about-hero .breadcrumb {
  margin-bottom: 28px;
  color: rgba(255, 255, 255, .6);
}

.page-about .about-hero .breadcrumb a {
  color: rgba(255, 255, 255, .78);
}

.page-about .about-hero .breadcrumb a:hover {
  color: var(--cyan);
}

.page-about .hero-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .hero-lead .eyebrow {
  color: var(--cyan);
  margin-bottom: 14px;
}

.page-about .hero-lead h1 {
  max-width: 20ch;
  margin-bottom: 20px;
}

.page-about .hero-lead .lede {
  max-width: 56ch;
  color: rgba(255, 255, 255, .82);
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 1px;
  border-radius: var(--r-md);
  background: rgba(255, 255, 255, .14);
  overflow: hidden;
}

.page-about .hero-stat {
  padding: 18px 16px;
  background: rgba(13, 27, 46, .82);
  border-top: 2px solid transparent;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .hero-stat:hover {
  border-top-color: var(--flame);
  background: rgba(29, 51, 82, .92);
}

.page-about .hero-stat .stat-label {
  display: block;
  font-size: 13px;
  color: rgba(255, 255, 255, .58);
  margin-bottom: 8px;
}

.page-about .hero-stat .stat-value {
  display: block;
  font-size: clamp(22px, 3.4vw, 30px);
  font-weight: 700;
  color: var(--paper);
  letter-spacing: .01em;
}

.page-about .hero-stat .stat-value span {
  font-size: 13px;
  font-weight: 500;
  color: var(--cyan);
  margin-left: 6px;
  letter-spacing: 0;
}

/* ---------- 团队分工 ---------- */
.page-about .about-roles .section-head {
  max-width: 66ch;
}

.page-about .roles-grid {
  display: grid;
  gap: var(--about-gap);
  margin-top: 36px;
}

.page-about .role-cards {
  display: grid;
  gap: 16px;
}

.page-about .role-card {
  padding: 22px 20px;
  outline: none;
}

.page-about .role-card:focus-visible {
  border-color: var(--cyan);
  box-shadow: 0 0 0 2px var(--cyan);
}

.page-about .role-card .card-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 12px;
}

.page-about .role-num {
  flex: none;
  font-size: 13px;
  color: var(--flame);
  padding: 3px 8px;
  border: 1px solid rgba(255, 74, 28, .3);
  border-radius: var(--r-pill);
  background: rgba(255, 74, 28, .07);
}

.page-about .role-card .card-title {
  margin: 0;
  font-size: 18px;
}

.page-about .role-card .card-body {
  margin: 0;
  color: var(--gray);
  font-size: 15.5px;
}

.page-about .role-detail {
  overflow: hidden;
  max-height: 14em;
  opacity: 1;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  transition: max-height 240ms var(--ease), opacity 200ms var(--ease), margin-top 200ms var(--ease);
}

.page-about .role-detail p {
  margin: 0;
  font-size: 14.5px;
  color: var(--ink-2);
}

.page-about .roles-figure {
  margin: 0;
}

.page-about .roles-figure .media {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
  box-shadow: var(--shadow-1);
}

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

.page-about .media-cap {
  margin-top: 12px;
  font-size: 13.5px;
  color: var(--gray);
  line-height: 1.6;
}

/* ---------- 工作节奏 tabs ---------- */
.page-about .about-rhythm .section-head {
  max-width: 62ch;
}

.page-about .about-rhythm .tabs {
  margin-top: 32px;
}

.page-about .about-rhythm .tab-list {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 4px;
  scrollbar-width: thin;
}

.page-about .about-rhythm .tab {
  flex: none;
  cursor: pointer;
  font: inherit;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-2);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  padding: 10px 20px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-rhythm .tab:hover {
  border-color: var(--flame);
  color: var(--flame);
}

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

.page-about .about-rhythm .tab[aria-selected="true"] {
  background: var(--grad-warm);
  border-color: transparent;
  color: var(--paper);
}

.page-about .about-rhythm .tab-panel {
  margin-top: 24px;
  padding: 8px 18px 14px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-1);
}

.page-about .about-rhythm .tab-panel[hidden] {
  display: none;
}

.page-about .about-rhythm .index-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-rhythm .index-item:last-child {
  border-bottom: 0;
}

.page-about .about-rhythm .index-num {
  font-size: 13px;
  color: var(--flame);
  letter-spacing: .04em;
}

.page-about .about-rhythm .index-label {
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-rhythm .index-value {
  color: var(--gray);
  font-size: 15px;
}

/* ---------- 发展时间轴 ---------- */
.page-about .about-timeline {
  position: relative;
  overflow: hidden;
}

.page-about .timeline-visual {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 260px;
  margin: 0;
  opacity: .3;
  pointer-events: none;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, .9) 0%, rgba(0, 0, 0, 0) 100%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, .9) 0%, rgba(0, 0, 0, 0) 100%);
}

.page-about .timeline-visual img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .about-timeline .wrap {
  position: relative;
  z-index: 1;
}

.page-about .about-timeline .section-head {
  max-width: 64ch;
}

.page-about .timeline-grid {
  display: grid;
  gap: var(--about-gap);
  margin-top: 40px;
}

.page-about .timeline-index {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding-bottom: 6px;
}

.page-about .tl-year {
  flex: none;
  font-size: 14px;
  font-weight: 700;
  color: rgba(255, 255, 255, .62);
  padding: 6px 14px;
  border: 1px solid rgba(255, 255, 255, .18);
  border-radius: var(--r-pill);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .tl-year:hover,
.page-about .tl-year:focus-visible {
  color: var(--paper);
  border-color: var(--cyan);
  background: rgba(20, 210, 194, .12);
  outline: none;
}

.page-about .timeline-body {
  position: relative;
  padding-left: 26px;
}

.page-about .timeline-body::before {
  content: "";
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 5px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, rgba(255, 74, 28, .7) 55%, rgba(255, 255, 255, .12) 100%);
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 34px;
}

.page-about .tl-item:last-child {
  padding-bottom: 0;
}

.page-about .tl-dot {
  position: absolute;
  left: -26px;
  top: 8px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(20, 210, 194, .16);
}

.page-about .tl-year-mono,
.page-about .tl-year {
  font-family: var(--font-mono);
}

.page-about .tl-item .tl-year {
  display: inline-block;
  margin: 0 0 10px;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: none;
  font-size: 15px;
  font-weight: 700;
  color: var(--amber);
  letter-spacing: .12em;
}

.page-about .tl-title {
  margin: 0 0 10px;
  font-size: clamp(18px, 2.4vw, 22px);
  color: var(--paper);
}

.page-about .tl-text {
  margin: 0;
  max-width: 60ch;
  color: rgba(255, 255, 255, .74);
  font-size: 15.5px;
}

/* ---------- 服务覆盖 ---------- */
.page-about .reach-grid {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .reach-copy .eyebrow {
  color: var(--flame);
  margin-bottom: 12px;
}

.page-about .reach-copy p {
  color: var(--gray);
  max-width: 56ch;
  margin: 16px 0 0;
}

.page-about .reach-copy .index-list {
  margin-top: 26px;
  border-top: 1px solid var(--line);
}

.page-about .reach-copy .index-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  align-items: baseline;
}

.page-about .reach-copy .index-num {
  grid-row: span 2;
  font-size: 13px;
  color: var(--flame);
}

.page-about .reach-copy .index-label {
  font-weight: 700;
  color: var(--ink);
}

.page-about .reach-copy .index-value {
  color: var(--gray);
  font-size: 15px;
}

.page-about .reach-figure {
  margin: 0;
}

.page-about .reach-figure .media {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
  box-shadow: var(--shadow-1);
}

/* ---------- 资质与协作 ---------- */
.page-about .about-assurance .section-head {
  max-width: 64ch;
}

.page-about .assure-grid {
  display: grid;
  gap: 18px;
  margin-top: 36px;
}

.page-about .assure-card {
  padding: 24px 22px;
  border-top: 3px solid var(--flame);
}

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

.page-about .assure-code {
  margin: 0 0 12px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--ink-2);
}

.page-about .assure-card .card-title {
  margin: 0 0 10px;
  font-size: 18px;
}

.page-about .assure-card .card-body {
  margin: 0;
  color: var(--gray);
  font-size: 15.5px;
}

/* ---------- 对外承诺 ---------- */
.page-about .about-promise .section-head {
  max-width: 62ch;
}

.page-about .promise-grid {
  display: grid;
  gap: 1px;
  margin-top: 36px;
  padding: 1px;
  background: rgba(255, 255, 255, .14);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .promise-item {
  padding: 26px 22px;
  background: rgba(13, 27, 46, .9);
  transition: background var(--dur) var(--ease);
}

.page-about .promise-item:hover {
  background: var(--ink-2);
}

.page-about .promise-num {
  margin: 0 0 14px;
  font-size: 13px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .promise-title {
  margin: 0 0 12px;
  font-size: clamp(18px, 2.2vw, 21px);
  color: var(--paper);
}

.page-about .promise-text {
  margin: 0 0 16px;
  font-size: 15px;
  color: rgba(255, 255, 255, .74);
}

.page-about .promise-item .link-arrow {
  color: var(--cyan);
}

.page-about .promise-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-top: 26px;
}

.page-about .promise-note {
  margin: 0;
  font-size: 14px;
  color: rgba(255, 255, 255, .62);
}

.page-about .promise-foot .btn {
  cursor: pointer;
}

/* ---------- 媒体查询 ---------- */
@media (min-width: 720px) {
  .page-about .role-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .role-card:nth-child(even) {
    margin-top: 24px;
  }

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

  .page-about .about-rhythm .index-item {
    grid-template-columns: 128px 1fr minmax(0, 1.4fr);
    align-items: baseline;
    gap: 18px;
  }

  .page-about .about-rhythm .index-num {
    text-align: left;
  }
}

@media (min-width: 1000px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    align-items: end;
    gap: clamp(32px, 5vw, 64px);
  }

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

  .page-about .roles-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .roles-figure {
    position: sticky;
    top: calc(var(--header-offset) + 28px);
  }

  .page-about .timeline-grid {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .timeline-index {
    position: sticky;
    top: calc(var(--header-offset) + 28px);
    flex-direction: column;
    gap: 10px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .tl-year {
    text-align: center;
  }

  .page-about .reach-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    gap: clamp(32px, 5vw, 64px);
  }

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

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

  .page-about .role-detail {
    max-height: 0;
    opacity: 0;
    margin-top: 0;
    padding-top: 0;
    border-top-color: transparent;
  }

  .page-about .role-card:hover .role-detail,
  .page-about .role-card:focus-within .role-detail,
  .page-about .role-card:focus-visible .role-detail {
    max-height: 14em;
    opacity: 1;
    margin-top: 14px;
    padding-top: 14px;
    border-top-color: var(--line);
  }
}

@media (min-width: 1280px) {
  .page-about .timeline-grid {
    grid-template-columns: 180px minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .role-detail,
  .page-about .hero-stat,
  .page-about .promise-item,
  .page-about .tab,
  .page-about .tl-year {
    transition: opacity var(--dur) linear;
  }
}