.page-about {
  --about-rail: 132px;
  --about-pad: clamp(2.8rem, 7vw, 4.8rem);
  background: var(--ink-900);
  color: var(--paper);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .breadcrumbs {
  padding: 1rem 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--dim);
}

.page-about .crumb-link {
  color: var(--dim);
  text-decoration: none;
}

.page-about .crumb-link:hover,
.page-about .crumb-link:focus-visible {
  color: var(--cyan);
}

.page-about .crumb-sep {
  margin: 0 0.45rem;
  color: rgba(200, 214, 227, 0.4);
}

.page-about .crumb-current {
  color: var(--paper);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 1.6rem 0 clamp(2.6rem, 7vw, 4.4rem);
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -30%;
  right: -16%;
  width: min(72%, 640px);
  height: 158%;
  background: linear-gradient(
    158deg,
    rgba(15, 92, 99, 0.9) 0%,
    rgba(15, 92, 99, 0.9) 52%,
    rgba(14, 42, 68, 0.95) 52.3%,
    rgba(14, 42, 68, 0.95) 100%
  );
  clip-path: polygon(24% 0, 100% 0, 100% 100%, 0 100%);
  opacity: 0.5;
  z-index: 0;
  pointer-events: none;
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 2;
  display: grid;
  gap: 1.8rem;
}

.page-about .hero-copy {
  position: relative;
}

.page-about .about-hero .eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--cyan);
  margin: 0 0 0.9rem;
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.1rem, 7.4vw, 3.5rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0 0 1.1rem;
  color: var(--paper);
}

.page-about .about-hero .lede {
  max-width: 54ch;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(243, 247, 250, 0.88);
  margin: 0 0 0.85rem;
}

.page-about .hero-sub {
  max-width: 52ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--dim);
  margin: 0;
  padding-left: 0.9rem;
  border-left: 2px solid rgba(33, 212, 195, 0.55);
}

.page-about .hero-note {
  display: none;
}

.page-about .hero-plate {
  position: relative;
  background: rgba(14, 42, 68, 0.92);
  border: 1px solid var(--line-strong);
  padding: 1.2rem 1.1rem 1.15rem;
  align-self: start;
}

.page-about .hero-plate::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 68px;
  height: 3px;
  background: var(--cyan);
}

.page-about .plate-title {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--mist);
  margin: 0 0 0.8rem;
}

.page-about .plate-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  padding: 0.66rem 0;
  border-bottom: 1px dashed var(--line);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--dim);
}

.page-about .plate-row strong {
  color: var(--paper);
  font-weight: 500;
  font-size: 13px;
}

.page-about .plate-foot {
  margin: 0.85rem 0 0;
  font-size: 12px;
  line-height: 1.7;
  color: rgba(200, 214, 227, 0.62);
}

/* ---------- 章节索引条 ---------- */
.page-about .chapter-index {
  border-bottom: 1px solid var(--line);
  background: rgba(14, 42, 68, 0.45);
}

.page-about .chapter-index-inner {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding-top: 0.65rem;
  padding-bottom: 0.65rem;
  scrollbar-width: none;
}

.page-about .chapter-index-inner::-webkit-scrollbar {
  display: none;
}

.page-about .chapter-index a {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--dim);
  text-decoration: none;
  padding: 0.32rem 0.6rem;
  border: 1px solid transparent;
  white-space: nowrap;
  transition: color var(--step) var(--ease), border-color var(--step) var(--ease);
}

.page-about .chapter-index a:hover,
.page-about .chapter-index a:focus-visible,
.page-about .chapter-index a[aria-current="true"] {
  color: var(--cyan);
  border-color: rgba(33, 212, 195, 0.45);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  padding: var(--about-pad) 0;
}

.page-about .chapter + .chapter,
.page-about .chapter + .about-figure,
.page-about .about-figure + .chapter {
  border-top: 1px solid var(--line);
}

.page-about .chapter-grid {
  display: grid;
  gap: 1.4rem;
}

.page-about .chapter-rail {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
}

.page-about .chapter-num {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: clamp(1.9rem, 5vw, 2.7rem);
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .chapter-note {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.3em;
  color: var(--dim);
}

.page-about .chapter-body {
  min-width: 0;
}

.page-about .chapter-body h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.55rem, 4.4vw, 2.25rem);
  line-height: 1.24;
  letter-spacing: -0.01em;
  margin: 0 0 1rem;
  color: var(--paper);
}

.page-about .chapter-body p {
  margin: 0 0 0.95rem;
  font-size: 15.5px;
  line-height: 1.85;
  color: rgba(243, 247, 250, 0.84);
}

.page-about .chapter-body p:last-child {
  margin-bottom: 0;
}

.page-about .origin-plate {
  margin-top: 1.4rem;
  padding: 1.05rem 1.1rem 1.1rem;
  background: rgba(14, 42, 68, 0.85);
  border: 1px solid var(--line-strong);
  border-left: 3px solid var(--cyan);
}

.page-about .origin-plate .tag {
  margin: 0 0 0.55rem;
}

.page-about .origin-plate p:last-child {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(243, 247, 250, 0.86);
}

/* ---------- 浅色章节：内容方法 ---------- */
.page-about .chapter--paper {
  background: var(--paper);
  color: var(--ink-900);
}

.page-about .chapter--paper .chapter-num {
  color: var(--teal);
}

.page-about .chapter--paper .chapter-note {
  color: rgba(8, 24, 38, 0.55);
}

.page-about .chapter--paper h2 {
  color: var(--ink-900);
}

.page-about .chapter--paper .chapter-body p {
  color: #2b4557;
}

.page-about .flow {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  border-top: 1px solid rgba(8, 24, 38, 0.16);
}

.page-about .flow-step {
  display: grid;
  grid-template-columns: 2.4rem minmax(0, 1fr);
  gap: 0.85rem;
  padding: 1rem 0;
  border-bottom: 1px solid rgba(8, 24, 38, 0.16);
}

.page-about .step-num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--teal);
  padding-top: 0.25rem;
}

.page-about .step-title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  margin: 0 0 0.3rem;
  color: var(--ink-900);
}

.page-about .step-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: #35505f;
}

/* ---------- 流程图 ---------- */
.page-about .about-figure {
  margin: 0 auto;
  padding: var(--about-pad) 0;
  width: 100%;
  max-width: var(--wrap);
  padding-left: var(--gutter);
  padding-right: var(--gutter);
}

.page-about .about-figure .media-frame {
  border: 1px solid var(--line-strong);
  aspect-ratio: 7 / 4;
  overflow: hidden;
  background: linear-gradient(140deg, var(--ink-800), var(--teal));
}

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

.page-about .about-figure .figure-caption {
  margin-top: 0.7rem;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  line-height: 1.7;
  color: var(--dim);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: 0.9rem;
  margin-top: 1.4rem;
}

.page-about .team-card {
  position: relative;
  padding: 1.35rem 1.05rem 1.1rem;
  background: linear-gradient(180deg, rgba(14, 42, 68, 0.92), rgba(8, 24, 38, 0.92));
  border: 1px solid var(--line-strong);
  outline: none;
}

.page-about .team-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--cyan);
}

.page-about .team-card:nth-child(2)::before {
  background: var(--amber);
}

.page-about .team-card:nth-child(3)::before {
  background: var(--rose);
}

.page-about .team-card:nth-child(4)::before {
  background: var(--orange);
}

.page-about .team-card:focus-visible {
  border-color: var(--cyan);
}

.page-about .team-tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--dim);
  margin: 0 0 0.45rem;
}

.page-about .team-name {
  font-family: var(--font-display);
  font-size: 1.12rem;
  font-weight: 700;
  margin: 0 0 0.45rem;
  color: var(--paper);
}

.page-about .team-line {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: rgba(243, 247, 250, 0.8);
}

.page-about .team-detail {
  margin: 0.55rem 0 0;
  padding-top: 0.55rem;
  border-top: 1px dashed var(--line);
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--dim);
}

/* ---------- 版本演进 ---------- */
.page-about .chapter--timeline {
  background: linear-gradient(180deg, rgba(14, 42, 68, 0.55), rgba(8, 24, 38, 0));
}

.page-about .timeline-grid {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.4rem;
}

.page-about .timeline-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line-strong);
  background: var(--ink-800);
}

.page-about .ver-index {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 1rem;
}

.page-about .ver-index a {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--dim);
  text-decoration: none;
  border: 1px solid var(--line-strong);
  padding: 0.3rem 0.55rem;
  transition: background var(--step) var(--ease), color var(--step) var(--ease),
    border-color var(--step) var(--ease);
}

.page-about .ver-index a:hover,
.page-about .ver-index a:focus-visible {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink-900);
}

.page-about .ver-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.75rem;
}

.page-about .ver-item {
  position: relative;
  padding: 0.95rem 1rem 1rem 1.35rem;
  border-left: 1px solid var(--line-strong);
  background: rgba(14, 42, 68, 0.4);
  scroll-margin-top: 6rem;
  transition: background var(--step) var(--ease), border-color var(--step) var(--ease);
}

.page-about .ver-item::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 1.35rem;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--ink-700);
  transition: background var(--step) var(--ease);
}

.page-about .ver-item:target {
  background: rgba(33, 212, 195, 0.09);
  border-left-color: var(--cyan);
}

.page-about .ver-item:target::before {
  background: var(--cyan);
}

.page-about .ver-tag {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--amber);
  margin: 0 0 0.3rem;
}

.page-about .ver-item:target .ver-tag {
  color: var(--cyan);
}

.page-about .ver-title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0 0 0.35rem;
  color: var(--paper);
}

.page-about .ver-item p:last-child {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: rgba(243, 247, 250, 0.8);
}

/* ---------- 服务覆盖 ---------- */
.page-about .coverage {
  position: relative;
  overflow: hidden;
  padding: var(--about-pad) 0;
  background: linear-gradient(158deg, var(--teal) 0%, var(--ink-800) 58%, var(--ink-900) 100%);
  border-top: 1px solid var(--line);
}

.page-about .coverage-texture {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.16;
  pointer-events: none;
}

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

.page-about .coverage .eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--cyan);
  margin: 0 0 0.8rem;
}

.page-about .coverage h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.5rem, 4.2vw, 2.15rem);
  line-height: 1.26;
  letter-spacing: -0.01em;
  margin: 0 0 1rem;
  color: var(--paper);
  max-width: 26ch;
}

.page-about .coverage-inner > p {
  max-width: 60ch;
  margin: 0 0 1rem;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(243, 247, 250, 0.85);
}

.page-about .cov-stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line-strong);
  border: 1px solid var(--line-strong);
  margin: 1.6rem 0 1.1rem;
}

.page-about .cov-stat {
  background: rgba(8, 24, 38, 0.66);
  padding: 0.95rem 1rem;
}

.page-about .cov-num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 1.35rem;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .cov-label {
  margin: 0.3rem 0 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--dim);
}

.page-about .cov-foot {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: rgba(200, 214, 227, 0.72);
  max-width: 58ch;
}

/* ---------- 尾段导航 ---------- */
.page-about .next-band {
  padding: var(--about-pad) 0 calc(var(--about-pad) * 1.15);
  border-top: 1px solid var(--line);
}

.page-about .next-band .eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--cyan);
  margin: 0 0 0.7rem;
}

.page-about .next-band h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.4rem, 4vw, 1.95rem);
  line-height: 1.3;
  margin: 0 0 1.2rem;
  color: var(--paper);
}

.page-about .next-links {
  display: grid;
  gap: 0.6rem;
}

.page-about .next-link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 0.85rem;
  padding: 0.85rem 0.95rem;
  border: 1px solid var(--line-strong);
  text-decoration: none;
  color: var(--paper);
  transition: border-color var(--step) var(--ease), background var(--step) var(--ease);
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  border-color: var(--cyan);
  background: rgba(33, 212, 195, 0.08);
}

.page-about .next-link .num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .next-text {
  display: block;
  font-size: 15px;
  font-weight: 500;
  line-height: 1.5;
}

.page-about .next-text em {
  display: block;
  margin-top: 0.25rem;
  font-style: normal;
  font-size: 13px;
  line-height: 1.65;
  color: var(--dim);
}

.page-about .next-link .arrow {
  font-size: 15px;
  color: var(--orange);
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

@media (min-width: 860px) {
  .page-about .chapter-grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(1.6rem, 4vw, 3rem);
    align-items: start;
  }

  .page-about .chapter-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
    position: sticky;
    top: 6rem;
  }

  .page-about .chapter-note {
    writing-mode: vertical-rl;
    letter-spacing: 0.42em;
  }

  .page-about .chapter--paper .flow-step {
    grid-template-columns: 3rem minmax(0, 1fr);
    gap: 1.2rem;
  }
}

@media (min-width: 900px) {
  .page-about .timeline-grid {
    grid-template-columns: minmax(0, 0.68fr) minmax(0, 1fr);
    gap: 2.2rem;
    align-items: start;
  }

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

@media (min-width: 980px) {
  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.82fr);
    align-items: end;
    gap: 3rem;
  }

  .page-about .hero-copy {
    padding-right: 2.6rem;
  }

  .page-about .hero-note {
    display: block;
    position: absolute;
    top: 0.3rem;
    right: 0;
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 11.5px;
    letter-spacing: 0.34em;
    color: rgba(200, 214, 227, 0.6);
  }

  .page-about .team-card .team-detail {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    padding-top: 0;
    border-top-color: transparent;
    transition: max-height var(--step) var(--ease), opacity var(--step) var(--ease),
      padding-top var(--step) var(--ease);
  }

  .page-about .team-card:hover .team-detail,
  .page-about .team-card:focus-within .team-detail,
  .page-about .team-card:focus .team-detail {
    max-height: 10rem;
    opacity: 1;
    padding-top: 0.55rem;
    border-top-color: var(--line);
  }
}

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