.page-about {
  position: relative;
  isolation: isolate;
  background-color: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
}

.page-about::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(43, 69, 92, 0.34) 1px, transparent 1px),
    linear-gradient(90deg, rgba(43, 69, 92, 0.34) 1px, transparent 1px);
  background-size: 64px 64px;
  opacity: 0.5;
  -webkit-mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.35) 55%, transparent 100%);
  mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.35) 55%, transparent 100%);
}

.page-about .page-shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.page-about .crumbs {
  padding-block: 18px 6px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--mist);
}

.page-about .crumbs a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--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);
}

.page-about .crumbs__sep {
  margin-inline: 8px;
  color: var(--line);
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-title);
  font-weight: 800;
  letter-spacing: -0.015em;
  color: var(--paper);
}

.page-about .lede {
  color: var(--mist);
  font-size: 16px;
  line-height: 1.75;
  margin: 14px 0 0;
}

.page-about .kicker {
  margin: 0 0 10px;
}

/* ---------- 首屏 ---------- */

.about-hero {
  padding-block: 8px 48px;
}

.about-hero__grid {
  display: grid;
  gap: 26px;
}

.about-hero h1 {
  margin: 0;
  font-size: clamp(34px, 8.6vw, 74px);
  line-height: 1.02;
  letter-spacing: -0.025em;
}

.about-hero h1 em {
  display: block;
  font-style: normal;
  color: var(--orange);
}

.about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.about-seal {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--archive);
  background-image: linear-gradient(150deg, rgba(21, 50, 77, 0.9), rgba(14, 34, 58, 0.6));
  padding: 20px;
}

.about-seal__no {
  margin: 8px 0 14px;
  font-family: var(--font-title);
  font-weight: 800;
  font-size: clamp(64px, 20vw, 118px);
  line-height: 0.84;
  letter-spacing: -0.05em;
  color: rgba(56, 224, 208, 0.16);
  text-shadow: 0 0 0 transparent;
  user-select: none;
}

.about-seal__facts {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px 16px;
  margin: 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.about-seal__fact dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.about-seal__fact dd {
  margin: 4px 0 0;
  font-size: 17px;
  font-weight: 600;
  color: var(--paper);
}

.about-band {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
  margin-top: 30px;
  padding-block: 12px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(255, 106, 42, 0.12), rgba(21, 50, 77, 0.55) 45%, rgba(56, 224, 208, 0.12));
  font-size: 12.5px;
  color: var(--paper);
}

.about-band .mono {
  font-size: 12.5px;
  letter-spacing: 0.03em;
}

.about-band__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--orange);
  flex: 0 0 auto;
}

.about-cover {
  margin: 30px 0 0;
}

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

.about-cover img {
  aspect-ratio: 3 / 2;
  filter: saturate(0.9) contrast(1.03);
}

.about-cover figcaption,
.about-figure figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 通用章节 ---------- */

.about-section {
  padding-block: 52px;
}

.about-section + .about-section {
  border-top: 1px solid rgba(43, 69, 92, 0.7);
}

.about-head h2,
.about-who__head h2,
.about-cta h2 {
  margin: 0;
  font-size: clamp(26px, 5.6vw, 44px);
  line-height: 1.08;
}

.about-figure {
  margin: 24px 0 0;
}

.about-figure--track img {
  aspect-ratio: 5 / 3;
}

/* ---------- 版本长卷 ---------- */

.stage-track {
  position: relative;
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
}

.stage-track::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 4px;
  bottom: 4px;
  width: 2px;
  background: linear-gradient(180deg, var(--orange), var(--console) 55%, var(--cyan));
  opacity: 0.55;
}

.stage {
  position: relative;
  padding-left: 40px;
  margin-bottom: 16px;
}

.stage:last-child {
  margin-bottom: 0;
}

.stage::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 22px;
  width: 12px;
  height: 12px;
  box-sizing: content-box;
  border: 2px solid var(--orange);
  border-radius: 50%;
  background: var(--ink);
  box-shadow: 0 0 0 4px rgba(255, 106, 42, 0.1);
}

.stage__box {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--archive);
  transition: border-color 0.22s var(--ease), background-color 0.22s var(--ease);
}

.stage__box:hover {
  border-color: var(--console);
}

.stage__box[open] {
  background-color: var(--console);
  border-color: rgba(56, 224, 208, 0.4);
}

.stage__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
}

.stage__summary::-webkit-details-marker {
  display: none;
}

.stage__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--cyan);
  transition: transform 0.2s var(--ease);
}

.stage__box[open] .stage__summary::after {
  content: "–";
}

.stage__no {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--orange);
  border: 1px solid var(--line);
  border-radius: var(--pill);
  padding: 3px 10px;
}

.stage__title {
  flex: 1 1 60%;
  font-family: var(--font-title);
  font-size: 21px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--paper);
}

.stage__year {
  font-size: 12px;
  color: var(--mist);
}

.stage__body {
  padding: 4px 18px 20px;
  border-top: 1px dashed var(--line);
}

.stage__body p {
  margin: 14px 0 0;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--paper);
}

.stage__list {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
}

.stage__list li {
  position: relative;
  padding-left: 18px;
  margin-bottom: 8px;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--mist);
}

.stage__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 7px;
  height: 2px;
  background: var(--orange);
}

.stage__more {
  margin-top: 14px;
}

.stage__more a,
.who__go a {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(56, 224, 208, 0.45);
  padding-bottom: 2px;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.stage__more a:hover,
.stage__more a:focus-visible,
.who__go a:hover,
.who__go a:focus-visible {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

/* ---------- 回访场景 ---------- */

.about-who__head {
  display: grid;
  gap: 22px;
}

.who {
  display: grid;
  gap: 16px;
  margin-top: 26px;
}

.who__card {
  border: 1px solid var(--line);
  border-left: 3px solid var(--orange);
  border-radius: var(--radius-s);
  background-color: var(--archive);
  padding: 20px;
}

.who__tag {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  border: 1px solid rgba(56, 224, 208, 0.35);
  border-radius: var(--pill);
  padding: 3px 10px;
}

.who__card h3 {
  margin: 12px 0 8px;
  font-size: 20px;
  line-height: 1.28;
}

.who__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--mist);
}

.who__go {
  margin-top: 14px;
}

/* ---------- 维护巡检 ---------- */

.upkeep {
  display: grid;
  gap: 16px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.upkeep__item {
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

.upkeep__no {
  display: block;
  font-size: 12.5px;
  letter-spacing: 0.08em;
  color: var(--orange);
}

.upkeep__item h3 {
  margin: 8px 0 8px;
  font-size: 19px;
  line-height: 1.3;
}

.upkeep__item p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--mist);
}

.about-upkeep__note {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 24px 0 0;
  padding: 14px 16px;
  border: 1px dashed var(--line);
  border-radius: var(--radius-s);
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 联络支持 ---------- */

.about-support {
  padding-block: 52px 72px;
}

.about-cta {
  display: grid;
  gap: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--console);
  background-image: linear-gradient(120deg, rgba(255, 106, 42, 0.14), rgba(21, 50, 77, 0) 55%);
  padding: 24px;
}

.about-cta__copy p {
  margin: 12px 0 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--paper);
}

.about-cta__label {
  margin: 0;
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.about-cta__value {
  margin: 4px 0 12px;
  font-size: 16px;
  color: var(--paper);
  word-break: break-word;
}

.about-cta__note {
  margin: 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--mist);
}

.about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: start;
}

@media (min-width: 760px) {
  .about-hero {
    padding-block: 12px 64px;
  }

  .about-seal {
    padding: 24px;
  }

  .about-figure {
    margin-top: 28px;
  }

  .who {
    grid-template-columns: 1fr 1fr;
    gap: 18px;
  }

  .who__card--wide {
    grid-column: 1 / -1;
  }

  .upkeep {
    grid-template-columns: 1fr 1fr;
    gap: 22px 28px;
  }

  .about-cta {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    align-items: start;
    padding: 30px;
  }

  .about-cta__actions {
    grid-column: 1 / -1;
  }
}

@media (min-width: 900px) {
  .about-hero__grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    align-items: end;
    gap: 46px;
  }

  .about-hero__copy {
    padding-bottom: 6px;
  }

  .about-band {
    margin-top: 38px;
  }

  .about-cover img {
    aspect-ratio: 21 / 9;
  }

  .about-section {
    padding-block: 76px;
  }

  .about-who__head {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
    align-items: end;
    gap: 40px;
  }

  .about-who__head .about-figure {
    margin-top: 0;
  }

  .stage {
    padding-left: 48px;
  }

  .stage-track::before {
    left: 10px;
  }

  .stage::before {
    left: 4px;
  }

  .stage__summary {
    padding: 18px 22px;
  }

  .stage__title {
    flex: 1 1 auto;
    font-size: 23px;
  }

  .stage__body {
    padding: 4px 22px 22px;
  }

  .stage__body p {
    max-width: 62ch;
  }

  .about-cta {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.85fr) minmax(0, 0.55fr);
    gap: 26px 34px;
    padding: 38px;
  }

  .about-cta__actions {
    grid-column: auto;
    flex-direction: column;
    align-items: stretch;
  }

  .about-cta__actions .btn {
    text-align: center;
  }
}

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