.page-about {
  --ab-rail: 300px;
  --ab-gap: clamp(24px, 4vw, 64px);
  --ab-blue-glow: rgba(43, 240, 196, 0.16);
  --ab-orange-glow: rgba(255, 122, 31, 0.16);
  background: var(--ink);
  color: var(--paper);
  padding-bottom: clamp(72px, 10vw, 128px);
}

.page-about .container {
  padding-top: clamp(24px, 4vw, 48px);
  max-width: 1180px;
}

/* ---------- 面包屑 ---------- */

.page-about .crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mute);
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .crumbs a {
  color: var(--mute);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .crumbs [aria-current="page"] {
  color: var(--paper);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-bottom: clamp(40px, 6vw, 72px);
}

.page-about .about-hero .eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--cyan);
  margin: 0;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.page-about .about-hero .eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: var(--cyan);
}

.page-about .about-hero__title {
  font-size: clamp(30px, 5.4vw, 60px);
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: -0.025em;
  color: var(--paper);
  margin: 18px 0 0;
  max-width: 22ch;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
  margin-top: clamp(28px, 4vw, 48px);
  align-items: start;
}

.page-about .about-hero__lead p {
  margin: 0 0 16px;
  font-size: 17px;
  line-height: 1.8;
  color: var(--paper);
  max-width: 60ch;
}

.page-about .about-hero__lead p:last-child {
  margin-bottom: 0;
  color: var(--mute);
}

.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 20px;
  overflow: hidden;
  margin: clamp(32px, 5vw, 56px) 0 0;
}

.page-about .about-hero__stat {
  background: var(--deck);
  padding: 20px 22px;
  min-width: 0;
}

.page-about .about-hero__stat dt {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--mute);
}

.page-about .about-hero__stat dd {
  margin: 8px 0 0;
  font-family: var(--mono);
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--cyan);
  line-height: 1.1;
}

/* ---------- 图片槽位 ---------- */

.page-about .shot {
  position: relative;
  margin: 0;
  border-radius: 20px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: linear-gradient(155deg, var(--board) 0%, var(--ink) 78%);
}

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

.page-about .shot__cap {
  position: absolute;
  left: 14px;
  bottom: 12px;
  right: 14px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--paper);
  background: rgba(10, 28, 23, 0.72);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 5px 12px;
  max-width: max-content;
  backdrop-filter: blur(4px);
}

/* ---------- 手册主体 ---------- */

.page-about .about-manual {
  display: block;
}

.page-about .about-chapter {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 32px);
  padding-top: clamp(40px, 6vw, 72px);
}

.page-about .about-chapter + .about-chapter {
  margin-top: clamp(40px, 6vw, 72px);
  border-top: 1px solid var(--line);
  padding-top: clamp(48px, 7vw, 88px);
}

.page-about .about-chapter__rail {
  min-width: 0;
}

.page-about .about-chapter__no {
  display: block;
  font-family: var(--mono);
  font-size: clamp(46px, 7vw, 84px);
  font-weight: 800;
  line-height: 0.86;
  letter-spacing: -0.04em;
  color: var(--ab-blue-glow);
  -webkit-text-stroke: 1.5px var(--cyan);
}

.page-about .about-chapter:nth-of-type(even) .about-chapter__no {
  color: var(--ab-orange-glow);
  -webkit-text-stroke-color: var(--orange);
}

.page-about .about-chapter__title {
  font-size: clamp(20px, 2.4vw, 28px);
  font-weight: 800;
  line-height: 1.34;
  letter-spacing: -0.012em;
  color: var(--paper);
  margin: 16px 0 0;
  max-width: 22ch;
}

.page-about .about-chapter__body {
  display: grid;
  gap: clamp(18px, 2.6vw, 28px);
  min-width: 0;
}

.page-about .about-chapter__body p {
  margin: 0;
  font-size: 17px;
  line-height: 1.82;
  color: var(--paper);
  max-width: 68ch;
}

.page-about .about-chapter__body p a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: border-color 160ms ease;
}

.page-about .about-chapter__body p a:hover,
.page-about .about-chapter__body p a:focus-visible {
  border-bottom-color: var(--cyan);
}

.page-about .band {
  display: block;
  grid-column: 1 / -1;
  height: 2px;
  width: 34%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--cyan) 46%, var(--orange) 100%);
  margin-top: clamp(16px, 2vw, 24px);
  transition: width 260ms ease;
}

.page-about .about-chapter.is-in .band {
  width: 100%;
}

/* ---------- 规模数字 ---------- */

.page-about .about-metric-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 20px;
  overflow: hidden;
}

.page-about .about-metric {
  background: var(--board);
  padding: 20px 18px;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-metric__num {
  font-family: var(--mono);
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1;
  color: var(--paper);
}

.page-about .about-metric__unit {
  font-size: 0.46em;
  font-weight: 700;
  color: var(--orange);
  margin-left: 3px;
  letter-spacing: 0;
}

.page-about .about-metric__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--mute);
}

/* ---------- 校准步骤 ---------- */

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .about-step {
  position: relative;
  background: var(--deck);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 24px 22px 26px;
  min-width: 0;
  transition: border-color 180ms ease, transform 180ms ease, box-shadow 180ms ease;
}

.page-about .about-step::before {
  content: "";
  position: absolute;
  left: 22px;
  top: 0;
  width: 44px;
  height: 2px;
  background: var(--orange);
  border-radius: 0 0 2px 2px;
}

.page-about .about-step:hover {
  border-color: var(--cyan);
  transform: translateY(-3px);
  box-shadow: 0 18px 34px -24px rgba(43, 240, 196, 0.55);
}

.page-about .about-step__no {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--orange);
  border: 1px solid var(--ab-orange-glow);
  border-radius: 999px;
  padding: 4px 11px;
}

.page-about .about-step__title {
  margin: 16px 0 10px;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-step p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--mute);
}

/* ---------- 团队角色 ---------- */

.page-about .about-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-role {
  background: var(--board);
  border-left: 2px solid var(--line);
  border-radius: 0 20px 20px 0;
  padding: 20px 22px;
  min-width: 0;
  transition: border-left-color 180ms ease, background 180ms ease;
}

.page-about .about-role:hover {
  border-left-color: var(--cyan);
  background: var(--deck);
}

.page-about .about-role p {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--mute);
  max-width: 62ch;
}

/* ---------- 选择理由 ---------- */

.page-about .about-reasons {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 20px;
  overflow: hidden;
}

.page-about .about-reason {
  background: var(--deck);
  padding: 22px 22px 24px;
  min-width: 0;
}

.page-about .about-reason__key {
  display: block;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--cyan);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-reason:nth-child(even) .about-reason__key {
  color: var(--orange);
}

.page-about .about-reason p {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--mute);
}

/* ---------- 结尾行动区 ---------- */

.page-about .about-cta {
  margin-top: clamp(56px, 8vw, 104px);
  border: 1px solid var(--line);
  border-radius: 24px;
  background:
    radial-gradient(120% 160% at 100% 0%, rgba(43, 240, 196, 0.12) 0%, transparent 58%),
    linear-gradient(160deg, var(--deck) 0%, var(--ink) 100%);
  padding: clamp(28px, 4vw, 48px);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3vw, 36px);
  align-items: center;
}

.page-about .about-cta__title {
  margin: 0;
  font-size: clamp(22px, 3vw, 34px);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: -0.02em;
  color: var(--paper);
  max-width: 24ch;
}

.page-about .about-cta__copy p {
  margin: 14px 0 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--mute);
  max-width: 56ch;
}

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

.page-about .about-cta__actions .btn {
  min-height: 46px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 24px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 700;
  text-decoration: none;
  transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease;
}

.page-about .about-cta__actions .btn--primary {
  background: var(--orange);
  color: var(--ink);
}

.page-about .about-cta__actions .btn--primary:hover,
.page-about .about-cta__actions .btn--primary:focus-visible {
  box-shadow: inset 0 0 0 3px rgba(10, 28, 23, 0.24);
  transform: translateY(-2px);
}

.page-about .about-cta__actions .btn--ghost {
  border: 1px solid var(--line);
  color: var(--paper);
  background: transparent;
}

.page-about .about-cta__actions .btn--ghost:hover,
.page-about .about-cta__actions .btn--ghost:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  transform: translateY(-2px);
}

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

/* ---------- 平板 ---------- */

@media (min-width: 700px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .about-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

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

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  }

  .page-about .about-cta__actions {
    justify-content: flex-end;
  }
}

/* ---------- 桌面：手册双栏 ---------- */

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    gap: var(--ab-gap);
  }

  .page-about .about-chapter {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: var(--ab-gap);
    align-items: start;
  }

  .page-about .about-chapter__rail {
    position: sticky;
    top: calc(var(--bar) + 32px);
    align-self: start;
  }

  .page-about .about-chapter__body {
    padding-top: 4px;
  }

  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1px;
    background: var(--line);
    border: 1px solid var(--line);
    border-radius: 20px;
    overflow: hidden;
  }

  .page-about .about-role {
    border-left: 0;
    border-radius: 0;
    padding: 24px 22px;
  }

  .page-about .about-role:hover {
    background: var(--deck);
  }
}

@media (min-width: 1180px) {
  .page-about {
    --ab-rail: 340px;
  }
}

/* ---------- 动效降级 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }

  .page-about .band {
    width: 100%;
  }
}