.page-about {
  --about-node: 12px;
  --about-rail-x: 8px;
  --about-indent: 30px;
  --about-card-hi: #1B2F49;
  background: var(--c-ink);
  color: var(--c-paper);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  overflow-x: hidden;
}

.page-about .shell {
  position: relative;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-display);
  font-weight: 900;
  letter-spacing: -0.01em;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: clamp(22px, 4vw, 42px) 0 clamp(34px, 6vw, 70px);
  border-bottom: 1px solid var(--c-line);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -10%;
  top: 0;
  width: 52%;
  height: 100%;
  background: linear-gradient(142deg, transparent 44%, var(--c-cyan-soft) 44.3%, transparent 76%);
  pointer-events: none;
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(20px, 3vw, 34px);
  position: relative;
  z-index: 1;
}

.page-about .about-hero__kicker {
  position: relative;
  z-index: 1;
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.page-about .about-hero__title {
  position: relative;
  z-index: 1;
  margin: 0;
  max-width: 22ch;
  font-size: clamp(30px, 5.6vw, 62px);
  line-height: 1.1;
}

.page-about .about-hero__lead {
  position: relative;
  z-index: 1;
  margin: clamp(18px, 3vw, 26px) 0 0;
  max-width: 64ch;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: rgba(242, 245, 247, 0.78);
}

.page-about .about-hero__stats {
  position: relative;
  z-index: 1;
  list-style: none;
  margin: clamp(28px, 5vw, 48px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .about-stat {
  background: var(--c-ink);
  padding: 16px 18px 18px;
}

.page-about .about-stat__num {
  display: block;
  font-size: clamp(24px, 3.4vw, 34px);
  line-height: 1.1;
  color: var(--c-cyan);
}

.page-about .about-stat:nth-child(1) .about-stat__num {
  color: var(--c-lime);
}

.page-about .about-stat:nth-child(3) .about-stat__num {
  color: var(--c-orange);
}

.page-about .about-stat__desc {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  color: var(--c-grey);
}

/* ---------- 章节公共件 ---------- */

.page-about .about-sec {
  padding: clamp(46px, 8vw, 96px) 0;
  border-bottom: 1px solid var(--c-line);
}

.page-about .about-sec--last {
  border-bottom: 0;
  padding-bottom: clamp(52px, 9vw, 104px);
}

.page-about .sec-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: 8px clamp(12px, 2vw, 22px);
  margin-bottom: clamp(24px, 4vw, 42px);
}

.page-about .sec-head::after {
  content: "";
  grid-column: 1 / -1;
  height: 2px;
  margin-top: 12px;
  background: linear-gradient(90deg, var(--c-cyan) 0%, rgba(37, 216, 232, 0.14) 46%, transparent 72%);
}

.page-about .sec-num {
  font-size: clamp(26px, 4vw, 44px);
  line-height: 1;
  color: rgba(124, 141, 163, 0.42);
}

.page-about .sec-title {
  margin: 0;
  font-size: clamp(21px, 3.4vw, 36px);
  line-height: 1.22;
}

/* ---------- 01 平台定位 ---------- */

.page-about .position-body p {
  margin: 0 0 18px;
  max-width: 74ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: rgba(242, 245, 247, 0.8);
}

.page-about .position-body p:last-child {
  margin-bottom: 0;
  padding-left: 18px;
  border-left: 2px solid var(--c-orange);
  color: rgba(242, 245, 247, 0.92);
}

.page-about .position-body a {
  color: var(--c-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(37, 216, 232, 0.4);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .position-body a:hover {
  color: var(--c-orange);
  border-bottom-color: var(--c-orange);
}

/* ---------- 02 纵向时间线 ---------- */

.page-about .timeline {
  position: relative;
  padding-left: var(--about-indent);
  display: grid;
  gap: clamp(16px, 2.6vw, 28px);
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 12px;
  bottom: 12px;
  width: 2px;
  background: linear-gradient(180deg, var(--c-lime) 0%, rgba(180, 249, 74, 0.26) 52%, rgba(180, 249, 74, 0.05) 100%);
}

.page-about .tl-item {
  position: relative;
  padding: clamp(16px, 2.4vw, 24px);
  background: var(--c-panel);
  border-left: 2px solid transparent;
  clip-path: polygon(0 0, calc(100% - var(--cut-sm)) 0, 100% var(--cut-sm), 100% 100%, 0 100%);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 22px;
  width: var(--about-node);
  height: var(--about-node);
  background: var(--c-lime);
  transform: rotate(45deg);
  transition: box-shadow var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .tl-item__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
}

.page-about .tl-item__year {
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--c-lime);
}

.page-about .tl-item__title {
  margin: 0;
  font-size: clamp(17px, 2.2vw, 22px);
  line-height: 1.35;
  color: var(--c-paper);
}

.page-about .tl-item__lead {
  margin: 10px 0 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(242, 245, 247, 0.74);
}

.page-about .tl-item__more {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height var(--dur-slow) var(--ease), opacity var(--dur) var(--ease), margin-top var(--dur) var(--ease);
}

.page-about .tl-item__more p {
  margin: 0;
  padding-left: 12px;
  border-left: 2px solid rgba(180, 249, 74, 0.35);
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--c-grey);
}

.page-about .tl-item__more a {
  color: var(--c-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(37, 216, 232, 0.4);
}

@media (hover: hover) {
  .page-about .tl-item:hover,
  .page-about .tl-item:focus-within {
    background: var(--about-card-hi);
    border-left-color: var(--c-lime);
  }

  .page-about .tl-item:hover::before,
  .page-about .tl-item:focus-within::before {
    box-shadow: 0 0 0 5px rgba(180, 249, 74, 0.16);
  }

  .page-about .tl-item:hover .tl-item__more,
  .page-about .tl-item:focus-within .tl-item__more {
    max-height: 12rem;
    opacity: 1;
    margin-top: 12px;
  }
}

@media (hover: none) {
  .page-about .tl-item__more {
    max-height: none;
    opacity: 1;
    margin-top: 12px;
  }
}

/* ---------- 图片 ---------- */

.page-about .about-figure {
  margin: 0;
  position: relative;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--c-line);
}

.page-about .about-figure--timeline img {
  aspect-ratio: 16 / 9;
}

.page-about .about-figure--team img {
  aspect-ratio: 3 / 2;
  max-height: 420px;
}

.page-about .about-figure--users img {
  aspect-ratio: 3 / 2;
}

.page-about .about-figure__cap {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--c-grey);
}

/* ---------- 03 覆盖范围 ---------- */

.page-about .cover-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .cover-card {
  background: var(--c-ink);
  padding: clamp(18px, 2.6vw, 28px);
  border-top: 3px solid var(--c-cyan);
  transition: background var(--dur) var(--ease);
}

.page-about .cover-card:nth-child(2) {
  border-top-color: var(--c-orange);
}

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

.page-about .cover-card:nth-child(4) {
  border-top-color: var(--c-lime);
}

.page-about .cover-card:hover {
  background: var(--c-panel);
}

.page-about .cover-card__num {
  margin: 0;
  font-size: clamp(30px, 4.4vw, 44px);
  line-height: 1;
  color: var(--c-paper);
}

.page-about .cover-card__label {
  margin: 8px 0 0;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--c-cyan);
}

.page-about .cover-card:nth-child(2) .cover-card__label {
  color: var(--c-orange);
}

.page-about .cover-card:nth-child(3) .cover-card__label {
  color: var(--c-moss);
}

.page-about .cover-card:nth-child(4) .cover-card__label {
  color: var(--c-lime);
}

.page-about .cover-card__note {
  margin: 12px 0 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(242, 245, 247, 0.62);
}

.page-about .cadence {
  margin-top: clamp(22px, 3.4vw, 36px);
  padding: clamp(18px, 2.6vw, 28px);
  background: var(--c-panel);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, 0 100%);
}

.page-about .cadence__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 17px;
}

.page-about .cadence__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--c-line);
}

.page-about .cadence__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 6px 18px;
  padding: 12px 14px;
  background: var(--c-ink);
}

.page-about .cadence__label {
  font-size: 12.5px;
  letter-spacing: 0.08em;
  color: var(--c-grey);
}

.page-about .cadence__value {
  font-size: 15px;
  color: var(--c-lime);
}

.page-about .cadence__note {
  margin: 16px 0 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: rgba(242, 245, 247, 0.66);
}

/* ---------- 04 团队 ---------- */

.page-about .crew-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .crew-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-height: 176px;
  padding: clamp(16px, 2vw, 22px);
  background: var(--c-panel);
  border-left: 2px solid var(--c-cyan);
  clip-path: polygon(0 0, calc(100% - var(--cut-sm)) 0, 100% var(--cut-sm), 100% 100%, 0 100%);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .crew-card:hover {
  background: var(--about-card-hi);
  border-left-color: var(--c-orange);
}

.page-about .crew-card__idx {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--c-grey);
}

.page-about .crew-card__name {
  margin: 0;
  font-size: 17px;
  line-height: 1.35;
}

.page-about .crew-card__desc {
  flex: 1;
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: rgba(242, 245, 247, 0.7);
}

.page-about .crew-card__tag {
  align-self: flex-start;
  padding: 4px 9px;
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--c-cyan);
  border: 1px solid var(--c-cyan);
  clip-path: polygon(0 0, calc(100% - 6px) 0, 100% 6px, 100% 100%, 0 100%);
  opacity: 0;
  transform: translateY(6px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
}

@media (hover: hover) {
  .page-about .crew-card:hover .crew-card__tag,
  .page-about .crew-card:focus-within .crew-card__tag {
    opacity: 1;
    transform: none;
  }
}

@media (hover: none) {
  .page-about .crew-card__tag {
    opacity: 1;
    transform: none;
  }
}

.page-about .crew-process {
  margin-top: clamp(22px, 3.4vw, 34px);
  padding: clamp(18px, 2.6vw, 26px);
  border: 1px solid var(--c-line);
  border-left: 3px solid var(--c-lime);
  background: linear-gradient(100deg, rgba(180, 249, 74, 0.06) 0%, transparent 58%);
}

.page-about .crew-process__lead {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(17px, 2.2vw, 21px);
}

.page-about .crew-process__note {
  margin: 0;
  max-width: 78ch;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(242, 245, 247, 0.72);
}

.page-about .about-figure--team {
  margin-top: clamp(24px, 4vw, 42px);
}

/* ---------- 05 用户结构 ---------- */

.page-about .users-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
  align-items: start;
}

.page-about .users-copy p {
  margin: 0 0 18px;
  max-width: 68ch;
  font-size: clamp(15px, 1.5vw, 16.5px);
  line-height: 1.85;
  color: rgba(242, 245, 247, 0.8);
}

.page-about .users-copy p:last-child {
  margin-bottom: 0;
  color: rgba(242, 245, 247, 0.92);
}

/* ---------- 06 合作 ---------- */

.page-about .coop-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
}

.page-about .coop-item {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: clamp(18px, 2.6vw, 28px);
  background: var(--c-ink);
  transition: background var(--dur) var(--ease);
}

.page-about .coop-item:hover {
  background: var(--c-panel);
}

.page-about .coop-item h3 {
  margin: 0;
  font-size: 18px;
  line-height: 1.35;
}

.page-about .coop-item p {
  flex: 1;
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(242, 245, 247, 0.72);
}

.page-about .coop-item .btn {
  align-self: flex-start;
}

.page-about .about-cta {
  margin-top: clamp(24px, 4vw, 40px);
  padding: clamp(22px, 3.4vw, 36px);
  display: grid;
  gap: 20px;
  background: var(--c-panel);
  border-top: 3px solid var(--c-orange);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, 0 100%);
}

.page-about .about-cta__text {
  margin: 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.7vw, 17px);
  line-height: 1.8;
  color: rgba(242, 245, 247, 0.86);
}

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

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .crew-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-figure--timeline {
    padding-left: 0;
  }
}

@media (min-width: 768px) {
  .page-about .cover-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

@media (min-width: 960px) {
  .page-about .timeline {
    padding-left: 40px;
  }

  .page-about .timeline::before {
    left: 9px;
  }

  .page-about .tl-item::before {
    left: -37px;
  }

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

@media (min-width: 1080px) {
  .page-about .cover-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .crew-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
  }
}