.page-about {
  --about-rail: 206px;
  color: var(--text-100);
  font-family: var(--font-sans);
  overflow-x: hidden;
}

.page-about a {
  color: var(--cyan-200);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 28px 0 34px;
  border-bottom: 1px solid var(--grid-line);
  background:
    radial-gradient(120% 90% at 12% -10%, rgba(47, 227, 232, 0.16), transparent 58%),
    linear-gradient(180deg, #070E22 0%, #0C1633 100%);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--grid-faint) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-faint) 1px, transparent 1px);
  background-size: 48px 48px;
  opacity: 0.32;
  -webkit-mask-image: linear-gradient(180deg, #000 0%, transparent 82%);
  mask-image: linear-gradient(180deg, #000 0%, transparent 82%);
  pointer-events: none;
}

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

.page-about .about-hero .breadcrumb {
  margin-bottom: 18px;
  font-size: 12.5px;
  color: var(--text-400);
}

.page-about .about-hero .eyebrow {
  margin: 0 0 12px;
}

.page-about .about-hero h1 {
  margin: 0 0 16px;
  max-width: 20ch;
  font-size: 28px;
  line-height: 1.28;
  letter-spacing: -0.01em;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .about-hero .lead {
  max-width: 60ch;
  margin: 0 0 22px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-400);
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 26px;
}

.page-about .hero-facts {
  display: grid;
  gap: 1px;
  margin: 0;
  border: 1px solid var(--grid-line);
  background: var(--grid-line);
}

.page-about .hero-facts > div {
  background: rgba(12, 22, 51, 0.86);
  padding: 14px 16px;
}

.page-about .hero-facts dt {
  margin: 0 0 7px;
  font-size: 19px;
  line-height: 1.2;
  color: var(--cyan-200);
}

.page-about .hero-facts dd {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--text-400);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  padding: 30px 0 56px;
}

.page-about .rail-label {
  margin: 0 0 10px;
  font-size: 11.5px;
  letter-spacing: 0.18em;
  color: var(--text-400);
}

.page-about .about-rail .toc-index {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .about-rail .toc-index li {
  flex: 0 0 auto;
}

.page-about .about-rail .toc-index a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 12px;
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  background: rgba(12, 22, 51, 0.6);
  color: var(--text-400);
  font-size: 13px;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--t-fast) ease, border-color var(--t-fast) ease, background var(--t-fast) ease;
}

.page-about .about-rail .toc-index a .mono {
  font-size: 11px;
  color: var(--cyan-400);
}

.page-about .about-rail .toc-index a:hover,
.page-about .about-rail .toc-index a:focus-visible {
  color: var(--text-100);
  border-color: var(--cyan-400);
}

/* ---------- 区块 ---------- */
.page-about .about-block {
  padding: 30px 0 36px;
  border-top: 1px solid var(--grid-line);
}

.page-about .about-block:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-block--last {
  padding-bottom: 0;
}

.page-about .block-head {
  margin-bottom: 22px;
}

.page-about .block-num {
  display: inline-block;
  margin-bottom: 12px;
  padding: 3px 9px;
  border: 1px solid rgba(47, 227, 232, 0.4);
  border-radius: var(--radius);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--cyan-400);
}

.page-about .block-head h2 {
  margin: 0 0 12px;
  font-size: 23px;
  line-height: 1.34;
  letter-spacing: -0.01em;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .block-head .lead {
  max-width: 64ch;
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-400);
}

/* ---------- 01 版本节奏 ---------- */
.page-about .era-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .era-figure {
  margin: 0;
}

.page-about .media {
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--ink-900);
}

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

.page-about .media-caption {
  display: block;
  margin-top: 8px;
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--text-400);
}

.page-about .era-list {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .era-list li {
  position: relative;
  padding: 0 0 22px 24px;
  border-left: 1px solid var(--grid-line);
}

.page-about .era-list li:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .era-list li::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 7px;
  width: 7px;
  height: 7px;
  border: 1px solid var(--cyan-400);
  border-radius: 50%;
  background: var(--ink-950);
}

.page-about .era-year {
  margin: 0 0 5px;
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--cyan-400);
}

.page-about .era-list h3 {
  margin: 0 0 6px;
  font-size: 16px;
  line-height: 1.45;
  font-weight: 600;
  color: var(--text-100);
}

.page-about .era-list p:last-child {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-400);
}

/* ---------- 02 服务对象 ---------- */
.page-about .audience-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .aud-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 9px;
  padding: 18px 18px 20px;
  border: 1px solid var(--grid-line);
  border-left: 2px solid rgba(47, 227, 232, 0.55);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(19, 32, 72, 0.9) 0%, rgba(12, 22, 51, 0.9) 100%);
}

.page-about .aud-num {
  margin: 0;
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--cyan-400);
}

.page-about .aud-card h3 {
  margin: 0;
  font-size: 16.5px;
  font-weight: 600;
  color: var(--cyan-200);
}

.page-about .aud-card p:last-child {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-400);
}

/* ---------- 03 反馈链路 ---------- */
.page-about .flow-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .flow-list li {
  position: relative;
  padding: 18px 16px 20px;
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(19, 32, 72, 0.85) 0%, rgba(7, 14, 34, 0.85) 100%);
}

.page-about .flow-list li::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan-400), rgba(47, 227, 232, 0));
  opacity: 0.55;
}

.page-about .flow-list li.flow-last::after {
  background: linear-gradient(90deg, var(--signal-500), rgba(255, 138, 43, 0));
}

.page-about .flow-step {
  display: block;
  margin-bottom: 10px;
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--cyan-400);
}

.page-about .flow-list h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .flow-list p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-400);
}

.page-about .flow-note {
  margin: 20px 0 0;
  padding: 14px 16px;
  border: 1px dashed rgba(255, 138, 43, 0.42);
  border-radius: var(--radius);
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-400);
  background: rgba(255, 138, 43, 0.06);
}

/* ---------- 04 团队分工 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .team-right {
  min-width: 0;
}

.page-about .team-bar {
  display: flex;
  gap: 3px;
  height: 8px;
  margin: 0 0 20px;
}

.page-about .team-bar .tb {
  display: block;
  border-radius: 1px;
}

.page-about .tb-1 { flex: 14 1 0; background: var(--cyan-400); }
.page-about .tb-2 { flex: 22 1 0; background: rgba(47, 227, 232, 0.42); }
.page-about .tb-3 { flex: 9 1 0; background: var(--cyan-200); }
.page-about .tb-4 { flex: 11 1 0; background: var(--grid-line); }

.page-about .team-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .team-item {
  padding: 16px;
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  background: rgba(12, 22, 51, 0.75);
}

.page-about .team-count {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 20px;
  letter-spacing: 0.02em;
  color: var(--cyan-200);
}

.page-about .team-name {
  margin: 0;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-100);
}

.page-about .team-item p:last-child {
  margin: 8px 0 0;
  font-size: 13.5px;
  line-height: 1.78;
  color: var(--text-400);
}

/* ---------- 05 覆盖与适配 ---------- */
.page-about .cover-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
}

.page-about .cover-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--grid-line);
}

.page-about .cover-list li {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--grid-line);
}

.page-about .cover-key {
  display: block;
  font-size: 17px;
  letter-spacing: 0.02em;
  color: var(--cyan-400);
}

.page-about .cover-body h3 {
  margin: 0 0 5px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-100);
}

.page-about .cover-body p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.78;
  color: var(--text-400);
}

/* ---------- 06 协作伙伴 ---------- */
.page-about .partner-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .partner-card {
  padding: 18px;
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  background: var(--ink-900);
}

.page-about .partner-num {
  margin: 0 0 8px;
  font-size: 26px;
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--cyan-400);
}

.page-about .partner-card h3 {
  margin: 0 0 9px;
  font-size: 16.5px;
  font-weight: 600;
  color: var(--text-100);
}

.page-about .partner-card p:last-child {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-400);
}

.page-about .partner-card--wide {
  border-left: 2px solid var(--signal-500);
  background: linear-gradient(180deg, rgba(19, 32, 72, 0.92) 0%, rgba(12, 22, 51, 0.92) 100%);
}

.page-about .partner-card--wide .partner-num {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--signal-200);
}

/* ---------- 07 继续查看 ---------- */
.page-about .next-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .next-tile {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px;
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  background: rgba(12, 22, 51, 0.7);
  text-decoration: none;
  transition: border-color var(--t-base) ease, background var(--t-base) ease, transform var(--t-base) ease;
}

.page-about .next-tile:hover,
.page-about .next-tile:focus-visible {
  border-color: var(--cyan-400);
  background: linear-gradient(180deg, rgba(47, 227, 232, 0.12) 0%, rgba(12, 22, 51, 0.9) 100%);
}

.page-about .tile-num {
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--cyan-400);
}

.page-about .next-tile h3 {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .next-tile p {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--text-400);
}

.page-about .tile-go {
  margin-top: 4px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--cyan-200);
}

.page-about .next-foot {
  margin: 20px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--text-400);
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .about-hero {
    padding: 36px 0 42px;
  }

  .page-about .about-hero h1 {
    font-size: 34px;
  }

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

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

  .page-about .partner-card--wide {
    grid-column: 1 / -1;
  }

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

@media (min-width: 860px) {
  .page-about .block-head h2 {
    font-size: 28px;
  }

  .page-about .about-hero h1 {
    font-size: 38px;
  }

  .page-about .era-grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
    gap: 28px;
    align-items: start;
  }

  .page-about .team-grid {
    grid-template-columns: 300px minmax(0, 1fr);
    gap: 28px;
    align-items: start;
  }

  .page-about .cover-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 28px;
    align-items: start;
  }

  .page-about .cover-list li {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }

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

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

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 46px;
    padding: 42px 0 72px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
    align-self: start;
  }

  .page-about .about-rail .toc-index {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
    border-left: 1px solid var(--grid-line);
  }

  .page-about .about-rail .toc-index a {
    display: flex;
    width: 100%;
    padding: 9px 10px 9px 14px;
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
    background: none;
    font-size: 13.5px;
  }

  .page-about .about-rail .toc-index a:hover,
  .page-about .about-rail .toc-index a:focus-visible {
    color: var(--cyan-200);
    background: linear-gradient(90deg, rgba(47, 227, 232, 0.1), transparent 78%);
  }

  .page-about .about-rail .toc-index a[aria-current="true"] {
    border-left-color: var(--cyan-400);
    color: var(--cyan-200);
    background: linear-gradient(90deg, rgba(47, 227, 232, 0.16), transparent 78%);
  }

  .page-about .about-block {
    padding: 42px 0 48px;
  }

  .page-about .about-block:first-child {
    padding-top: 4px;
  }
}

@media (min-width: 1240px) {
  .page-about .about-hero h1 {
    font-size: 42px;
  }

  .page-about .block-head h2 {
    font-size: 30px;
  }

  .page-about .block-head .lead,
  .page-about .about-hero .lead {
    font-size: 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .next-tile {
    transition: none;
  }
}