.page-about {
  --about-soft-light: rgba(237, 231, 218, 0.74);
  --about-soft-ink: rgba(11, 20, 16, 0.68);
  --about-hair-ink: rgba(11, 20, 16, 0.16);
  color: var(--mineral-linen);
  background: var(--bg-pitch);
}

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

.page-about h2 {
  margin: 12px 0 0;
  font-size: clamp(26px, 4.6vw, 44px);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: -0.015em;
  max-width: 24ch;
}

.page-about h3 {
  margin: 0;
  font-size: var(--fs-18);
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -0.005em;
}

.page-about .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

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

.page-about .figure__cap {
  margin-top: 10px;
  font-size: var(--fs-14);
  color: var(--mineral-stone);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: calc(var(--section-y) * 0.85) 0 var(--section-y);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -28%;
  right: -22%;
  width: 62vmax;
  height: 62vmax;
  background: radial-gradient(closest-side, rgba(18, 230, 192, 0.16), rgba(18, 230, 192, 0) 72%);
  pointer-events: none;
}

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

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: clamp(28px, 5vw, 52px);
  font-size: var(--fs-14);
  color: var(--mineral-stone);
}

.page-about .breadcrumb a {
  color: var(--mineral-stone);
  text-decoration: none;
  border-bottom: 1px solid var(--hairline);
  padding-bottom: 2px;
}

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

.page-about .about-sep {
  color: var(--moss-mid);
}

.page-about .about-hero__title {
  margin: 12px 0 0;
  font-size: clamp(34px, 8.4vw, 68px);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -0.02em;
  max-width: 15ch;
}

.page-about .about-hero__lead {
  margin: 22px 0 0;
  max-width: 46ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(34px, 5vw, 60px) 0 0;
  background: var(--hairline);
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

.page-about .about-stat {
  background: var(--bg-pitch);
  padding: 18px 16px 20px;
}

.page-about .about-stat dt {
  font-size: var(--fs-14);
  color: var(--mineral-stone);
  letter-spacing: 0.02em;
}

.page-about .about-stat dd {
  margin: 10px 0 0;
  font-size: clamp(26px, 6vw, 40px);
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-stat__unit {
  margin-left: 6px;
  font-size: var(--fs-14);
  color: var(--mineral-stone);
}

/* ---------- 队伍与历程 ---------- */
.page-about .about-origin {
  padding: var(--section-y) 0;
}

.page-about .about-origin__grid {
  display: grid;
  gap: clamp(28px, 5vw, 56px);
}

.page-about .about-origin__text p {
  margin: 16px 0 0;
  max-width: 62ch;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: var(--about-soft-light);
}

.page-about .about-origin__figure {
  margin: 0;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline-section {
  padding: var(--section-y) 0;
}

.page-about .about-timeline__hint {
  margin: 14px 0 0;
  font-size: var(--fs-14);
  color: var(--mineral-stone);
}

.page-about .about-timeline__figure {
  margin: clamp(24px, 4vw, 40px) 0 0;
}

.page-about .about-timeline {
  list-style: none;
  display: flex;
  gap: 18px;
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: 4px 0 20px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-padding-left: 4px;
  -webkit-overflow-scrolling: touch;
  border-bottom: 1px solid var(--hairline);
}

.page-about .about-timeline__item {
  position: relative;
  flex: 0 0 min(78vw, 300px);
  scroll-snap-align: start;
  padding: 26px 4px 8px;
  border-top: 2px solid var(--hairline);
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  top: -6px;
  left: 4px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--bg-moss);
  border: 2px solid var(--cyan);
}

.page-about .about-timeline__item:hover,
.page-about .about-timeline__item:focus {
  border-top-color: var(--cyan);
}

.page-about .about-timeline__year {
  display: block;
  font-size: clamp(24px, 5vw, 32px);
  line-height: 1;
  color: var(--cyan);
  letter-spacing: 0.02em;
}

.page-about .about-timeline__title {
  margin-top: 12px;
  color: var(--mineral-linen);
}

.page-about .about-timeline__desc {
  margin: 10px 0 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--about-soft-light);
}

/* ---------- 质检工序 ---------- */
.page-about .about-craft {
  padding: var(--section-y) 0;
  color: var(--ink);
}

.page-about .about-craft h2 {
  color: var(--ink);
}

.page-about .about-craft .eyebrow {
  color: var(--mineral-clay);
}

.page-about .about-craft__lead {
  margin: 18px 0 0;
  max-width: 64ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--about-soft-ink);
}

.page-about .about-steps {
  list-style: none;
  margin: clamp(30px, 5vw, 52px) 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-step {
  --stair: 0px;
  position: relative;
  padding: calc(46px + var(--stair)) 4px 22px;
}

.page-about .about-step::before {
  content: "";
  position: absolute;
  left: 4px;
  right: 4px;
  top: var(--stair);
  height: 1px;
  background: var(--about-hair-ink);
  transition: background 0.2s ease, height 0.2s ease;
}

.page-about .about-step:hover::before,
.page-about .about-step:focus::before,
.page-about .about-step:focus-within::before {
  background: var(--cyan);
  height: 2px;
}

.page-about .about-step__idx {
  display: block;
  font-size: var(--fs-14);
  letter-spacing: 0.16em;
  color: var(--mineral-clay);
}

.page-about .about-step__title {
  margin-top: 8px;
  font-size: var(--fs-24);
  color: var(--ink);
}

.page-about .about-step__desc {
  margin: 10px 0 0;
  max-width: 42ch;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--about-soft-ink);
}

.page-about .about-step__note {
  margin: 14px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--moss-mid);
  max-width: 42ch;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--ink);
  overflow: hidden;
  max-height: 260px;
  opacity: 1;
  transition: max-height 0.25s ease, opacity 0.25s ease, margin-top 0.25s ease;
}

/* ---------- 多端资料库 ---------- */
.page-about .about-devices {
  padding: var(--section-y) 0;
}

.page-about .about-devices__lead {
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-devices__grid {
  display: grid;
  gap: 1px;
  margin: clamp(28px, 4vw, 44px) 0 0;
  background: var(--hairline);
  border: 1px solid var(--hairline);
}

.page-about .about-device {
  background: var(--glass);
  padding: 22px 20px;
  transition: background 0.2s ease, transform 0.2s ease;
}

.page-about .about-device--ios {
  border-left: 2px solid var(--cyan);
}

.page-about .about-device:hover {
  background: var(--glass-strong);
  transform: translateY(-4px);
}

.page-about .about-device__tag {
  margin: 0;
  font-size: var(--fs-14);
  letter-spacing: 0.14em;
  text-transform: none;
  color: var(--cyan);
}

.page-about .about-device--ios .about-device__tag {
  color: var(--orange);
}

.page-about .about-device__list {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
}

.page-about .about-device__list li {
  position: relative;
  padding-left: 18px;
  margin-top: 12px;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-device__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.7em;
  width: 8px;
  height: 1px;
  background: var(--moss-mid);
}

.page-about .about-devices__figure {
  margin: clamp(30px, 5vw, 48px) 0 0;
  max-width: 420px;
}

.page-about .about-devices__cta {
  margin: clamp(24px, 4vw, 36px) 0 0;
}

/* ---------- 合作生态 ---------- */
.page-about .about-partners {
  padding: var(--section-y) 0;
}

.page-about .about-partners__lead {
  margin: 18px 0 0;
  max-width: 64ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-partners__list {
  list-style: none;
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hairline);
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

.page-about .about-partner {
  background: var(--bg-moss);
  padding: 22px 20px;
}

.page-about .about-partner__title {
  color: var(--mineral-linen);
}

.page-about .about-partner__desc {
  margin: 10px 0 0;
  max-width: 46ch;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-partners__link {
  margin: clamp(22px, 3vw, 32px) 0 0;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-partners__link a {
  color: var(--blue);
  text-decoration: none;
  border-bottom: 1px solid rgba(59, 130, 246, 0.5);
  padding-bottom: 1px;
}

.page-about .about-partners__link a:hover {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* ---------- 版本路线图 ---------- */
.page-about .about-roadmap {
  padding: var(--section-y) 0;
}

.page-about .about-roadmap__lead {
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-roadmap__list {
  list-style: none;
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: 0;
  display: grid;
  gap: 24px;
}

.page-about .about-roadmap__item {
  padding-top: 18px;
  border-top: 1px solid var(--hairline);
}

.page-about .about-roadmap__ver {
  display: inline-block;
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--mineral-clay);
  border: 1px solid rgba(192, 102, 74, 0.5);
  padding: 4px 10px;
  border-radius: var(--radius);
}

.page-about .about-roadmap__title {
  margin-top: 14px;
  color: var(--mineral-linen);
}

.page-about .about-roadmap__desc {
  margin: 10px 0 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--about-soft-light);
}

/* ---------- 开始使用 ---------- */
.page-about .about-start {
  padding: var(--section-y) 0;
  border-top: 1px solid var(--hairline-cyan);
}

.page-about .about-start__lead {
  margin: 18px 0 0;
  max-width: 60ch;
  font-size: var(--fs-17);
  line-height: 1.75;
  color: var(--about-soft-light);
}

.page-about .about-start__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(24px, 4vw, 36px);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 920px) {
  .page-about .about-origin__grid {
    grid-template-columns: 1.05fr 0.95fr;
    align-items: center;
  }

  .page-about .about-timeline__item {
    flex: 0 0 340px;
  }

  .page-about .about-steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    column-gap: 28px;
  }

  .page-about .about-step {
    padding-left: 0;
    padding-right: 0;
    padding-bottom: 28px;
  }

  .page-about .about-step::before {
    left: 0;
    right: 12px;
  }

  .page-about .about-step:nth-child(2) { --stair: 34px; }
  .page-about .about-step:nth-child(3) { --stair: 68px; }
  .page-about .about-step:nth-child(4) { --stair: 102px; }

  .page-about .about-devices__figure {
    max-width: 380px;
  }

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

  .page-about .about-roadmap__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 32px;
  }
}

@media (hover: hover) and (pointer: fine) {
  .page-about .about-step__note {
    max-height: 0;
    opacity: 0;
    margin-top: 0;
  }

  .page-about .about-step:hover .about-step__note,
  .page-about .about-step:focus .about-step__note,
  .page-about .about-step:focus-within .about-step__note {
    max-height: 260px;
    opacity: 1;
    margin-top: 14px;
  }
}

@media (max-width: 480px) {
  .page-about .about-device,
  .page-about .about-partner {
    padding: 18px 16px;
  }
}