.page-about {
  --about-cut: 18px;
  display: block;
  background: var(--ink);
  color: var(--silver);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.85;
  overflow-x: clip;
}

.page-about p {
  margin: 0 0 14px;
}

.page-about a {
  color: var(--gold);
  text-decoration: none;
  border-bottom: 1px solid var(--line-gold);
  transition: color var(--dur) ease, border-color var(--dur) ease;
}

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

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

.page-about .stamp {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0;
}

.page-about .part-no {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--gold);
  margin: 0 0 14px;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-serif);
  color: var(--sand);
  margin: 0;
}

.page-about h1 {
  font-size: clamp(30px, 4.4vw, 58px);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: .01em;
  margin: 14px 0 20px;
}

.page-about h2 {
  font-size: clamp(24px, 2.9vw, 38px);
  font-weight: 800;
  line-height: 1.28;
  margin: 0 0 16px;
}

.page-about h3 {
  font-size: clamp(18px, 1.9vw, 22px);
  font-weight: 700;
  line-height: 1.42;
  margin: 0 0 10px;
}

.page-about .about-text {
  font-size: 16px;
  line-height: 1.85;
  color: var(--silver);
  margin: 0 0 14px;
}

/* ---------- 面包屑 ---------- */

.page-about .breadcrumb {
  padding-top: 28px;
  padding-bottom: 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.page-about .breadcrumb a {
  color: var(--muted);
  border-bottom: 0;
}

.page-about .breadcrumb a:hover {
  color: var(--gold-hi);
}

.page-about .breadcrumb span[aria-current="page"] {
  color: var(--gold);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: 32px 0 80px;
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -30%;
  right: -12%;
  width: 72%;
  height: 150%;
  background: linear-gradient(152deg, rgba(201, 162, 75, .16), rgba(110, 31, 38, .12) 44%, transparent 72%);
  clip-path: polygon(20% 0, 100% 0, 100% 100%, 0 58%);
  pointer-events: none;
}

.page-about .about-hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
  gap: 56px;
  align-items: center;
}

.page-about .about-hero-copy {
  max-width: 60ch;
}

.page-about .about-lead {
  font-size: 17px;
  line-height: 1.85;
  color: var(--silver);
  margin: 0;
}

.page-about .about-hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 36px;
  margin-top: 30px;
  padding-top: 20px;
  border-top: 1px solid var(--line-gold);
}

.page-about .about-hero-meta p {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin: 0;
  font-size: 14px;
  color: var(--muted);
}

.page-about .about-meta-num {
  font-family: var(--font-mono);
  font-size: 22px;
  line-height: 1;
  color: var(--gold);
  letter-spacing: .04em;
}

.page-about .about-hero-media {
  position: relative;
  margin: 0;
  filter: drop-shadow(0 26px 52px rgba(0, 0, 0, .6));
}

.page-about .about-hero-media img {
  display: block;
  width: 100%;
  height: auto;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), calc(100% - 28px) 100%, 0 100%);
}

.page-about .about-hero-media::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0;
  width: 28px;
  height: 28px;
  background: var(--crimson);
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
}

/* ---------- 双轨页体 ---------- */

.page-about .page-shell {
  max-width: var(--shell);
  margin-inline: auto;
  padding: 0 20px 96px;
  display: grid;
  grid-template-columns: 196px minmax(0, 1fr);
  gap: 56px;
  align-items: start;
}

.page-about .page-rail {
  position: sticky;
  top: 108px;
  align-self: start;
}

.page-about .rail-title {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 16px;
  padding-left: 14px;
}

.page-about .rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: block;
}

.page-about .rail-list li {
  margin: 0;
}

.page-about .rail-node {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 11px 0 11px 14px;
  border-left: 1px solid var(--line);
  border-bottom: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.4;
  transition: color var(--dur) ease, border-color var(--dur) ease, padding-left var(--dur) ease;
}

.page-about .rail-node:hover,
.page-about .rail-node:focus-visible {
  color: var(--gold-hi);
  border-left-color: var(--gold);
  padding-left: 18px;
}

.page-about .about-node-no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--gold);
  opacity: .8;
}

.page-about .rail-node:hover .about-node-no,
.page-about .rail-node:focus-visible .about-node-no {
  opacity: 1;
  color: var(--gold-hi);
}

/* ---------- 内容块 ---------- */

.page-about .about-block {
  padding: 0 0 72px;
  margin-bottom: 72px;
  border-bottom: 1px solid var(--line);
}

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

.page-about .about-block--sand {
  background: var(--sand);
  color: var(--ink-2);
  padding: 56px clamp(22px, 3.6vw, 44px);
  margin-bottom: 72px;
  border-bottom: 0;
  clip-path: polygon(
    var(--about-cut) 0,
    100% 0,
    100% calc(100% - var(--about-cut)),
    calc(100% - var(--about-cut)) 100%,
    0 100%,
    0 var(--about-cut)
  );
}

.page-about .about-block--sand:last-child {
  margin-bottom: 0;
}

.page-about .about-block-head {
  max-width: 62ch;
  margin-bottom: 36px;
}

.page-about .about-block--sand .part-no {
  color: var(--crimson);
}

.page-about .about-block--sand h2,
.page-about .about-block--sand h3 {
  color: var(--ink);
}

.page-about .about-block--sand .about-text {
  color: #3B3F45;
}

.page-about .about-block--sand a {
  color: #7A2028;
  border-bottom-color: rgba(110, 31, 38, .4);
}

.page-about .about-block--sand a:hover,
.page-about .about-block--sand a:focus-visible {
  color: var(--crimson);
  border-bottom-color: var(--crimson);
}

/* ---------- 阶段 ---------- */

.page-about .about-paper {
  margin: 0 0 44px;
  border-top: 1px solid var(--line-gold);
  border-bottom: 1px solid var(--line-gold);
  overflow: hidden;
}

.page-about .about-paper img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  opacity: .72;
}

.page-about .about-stage-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-stage {
  display: grid;
  grid-template-columns: 104px minmax(0, 1fr);
  gap: 32px;
  padding: 32px 0;
  border-top: 1px solid var(--line);
}

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

.page-about .about-stage-idx {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-start;
}

.page-about .about-stage-num {
  font-family: var(--font-mono);
  font-size: 30px;
  line-height: 1;
  letter-spacing: .06em;
  color: var(--gold);
  text-shadow: 0 0 22px rgba(201, 162, 75, .35);
}

.page-about .about-stage-body {
  max-width: 60ch;
}

.page-about .about-stage-body .about-text {
  margin-bottom: 0;
}

/* ---------- 团队 ---------- */

.page-about .about-team-media {
  margin: 0 0 36px;
  overflow: hidden;
  border-top: 1px solid rgba(11, 12, 14, .16);
  border-bottom: 1px solid rgba(11, 12, 14, .16);
}

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

.page-about .about-team-list {
  margin: 0;
  display: grid;
  gap: 0;
}

.page-about .about-team-row {
  display: grid;
  grid-template-columns: minmax(0, 220px) minmax(0, 1fr);
  gap: 28px;
  padding: 22px 0;
  border-top: 1px solid rgba(11, 12, 14, .14);
}

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

.page-about .about-team-term {
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 18px;
  color: var(--ink);
  line-height: 1.4;
}

.page-about .about-team-count {
  font-family: var(--font-mono);
  font-size: 24px;
  line-height: 1;
  color: var(--crimson);
  letter-spacing: .04em;
}

.page-about .about-team-row dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: #3B3F45;
  max-width: 62ch;
}

/* ---------- 版本序号 ---------- */

.page-about .about-version-list {
  display: grid;
  gap: 0;
}

.page-about .about-version-row {
  display: grid;
  grid-template-columns: 128px minmax(0, 1fr);
  gap: 32px;
  align-items: start;
  padding: 30px 0;
  border-top: 1px solid var(--line);
}

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

.page-about .about-version-row:nth-child(2) {
  padding-left: 24px;
}

.page-about .about-version-row:nth-child(3) {
  padding-left: 48px;
}

.page-about .about-version-no {
  font-family: var(--font-mono);
  font-size: clamp(38px, 4.4vw, 56px);
  line-height: 1;
  letter-spacing: .04em;
  color: var(--gold);
  margin: 0;
  text-shadow: 0 0 26px rgba(201, 162, 75, .3);
}

.page-about .about-version-body {
  max-width: 60ch;
}

.page-about .about-version-use {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
  margin: 0;
  padding-top: 10px;
  border-top: 1px dashed var(--line-gold);
}

.page-about .about-tail-note {
  margin-top: 30px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 15px;
  color: var(--muted);
}

.page-about .about-block--sand .about-tail-note {
  border-top-color: rgba(11, 12, 14, .14);
  color: #4A4E54;
}

/* ---------- 索引分区 ---------- */

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

.page-about .about-index-item {
  display: grid;
  grid-template-columns: 96px minmax(140px, 200px) minmax(0, 1fr);
  gap: 20px;
  align-items: baseline;
  padding: 20px 0;
  border-top: 1px solid rgba(11, 12, 14, .14);
}

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

.page-about .about-index-item h3 {
  font-size: 19px;
  margin: 0;
  color: var(--ink);
}

.page-about .about-index-item .about-text {
  margin: 0;
  font-size: 15px;
  color: #3B3F45;
}

.page-about .plate-tag {
  display: inline-block;
  align-self: start;
  justify-self: start;
  background: var(--crimson);
  color: var(--sand);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  padding: 4px 12px 4px 10px;
  clip-path: polygon(0 0, 100% 0, calc(100% - 8px) 100%, 0 100%);
}

/* ---------- 长期积累 ---------- */

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

.page-about .about-claim {
  padding: 20px 0;
  border-top: 1px solid var(--line);
  transition: background var(--dur) ease;
}

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

.page-about .about-claim-main {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(17px, 1.8vw, 21px);
  line-height: 1.45;
  color: var(--sand);
}

.page-about .about-claim-num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 2.6vw, 34px);
  line-height: 1;
  letter-spacing: .03em;
  color: var(--gold);
  flex: none;
}

.page-about .about-claim-note {
  margin: 0 0 0 0;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
  transition: max-height var(--dur) ease, opacity var(--dur) ease, margin var(--dur) ease;
}

.page-about .about-claim:hover .about-claim-note,
.page-about .about-claim:focus-within .about-claim-note,
.page-about .about-claim:focus .about-claim-note {
  max-height: 8em;
  opacity: 1;
  margin-top: 10px;
}

.page-about .about-claim:hover .about-claim-main,
.page-about .about-claim:focus-visible .about-claim-main {
  color: var(--gold-hi);
}

/* ---------- 备案与信息 ---------- */

.page-about .about-filing-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 40px;
}

.page-about .about-filing-item {
  padding: 16px 0;
  border-top: 1px solid rgba(11, 12, 14, .14);
}

.page-about .about-filing-key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--crimson);
  margin: 0 0 6px;
}

.page-about .about-filing-val {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink);
  word-break: break-word;
}

.page-about .about-filing-val.mono {
  font-family: var(--font-mono);
  letter-spacing: .02em;
  font-size: 14px;
}

/* ---------- 反转动效 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .page-about .rail-node,
  .page-about .about-claim-note,
  .page-about a {
    transition: none;
  }
}

/* ---------- 响应式 ---------- */

@media (max-width: 1024px) {
  .page-about .page-shell {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding-bottom: 72px;
  }

  .page-about .page-rail {
    position: static;
    top: auto;
  }

  .page-about .rail-title {
    padding-left: 0;
  }

  .page-about .rail-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 18px;
  }

  .page-about .rail-node {
    border-left: 0;
    border-bottom: 1px solid var(--line);
    padding: 6px 0;
  }

  .page-about .rail-node:hover,
  .page-about .rail-node:focus-visible {
    border-left-color: transparent;
    border-bottom-color: var(--gold);
    padding-left: 0;
  }
}

@media (max-width: 860px) {
  .page-about .about-hero {
    padding-bottom: 56px;
  }

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

  .page-about .about-hero::before {
    width: 100%;
    right: -30%;
    opacity: .7;
  }

  .page-about .about-block {
    padding-bottom: 52px;
    margin-bottom: 52px;
  }

  .page-about .about-block--sand {
    padding: 40px 22px;
    margin-bottom: 52px;
  }

  .page-about .about-stage {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
    padding: 26px 0;
  }

  .page-about .about-stage-idx {
    flex-direction: row;
    align-items: baseline;
    gap: 14px;
  }

  .page-about .about-stage-num {
    font-size: 22px;
  }

  .page-about .about-team-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
  }

  .page-about .about-version-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .page-about .about-version-row:nth-child(2),
  .page-about .about-version-row:nth-child(3) {
    padding-left: 0;
  }

  .page-about .about-index-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
  }

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

  .page-about .about-claim-main {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .page-about .about-claim-note {
    max-height: none;
    opacity: 1;
    margin-top: 10px;
  }
}

@media (max-width: 520px) {
  .page-about h1 {
    font-size: 28px;
  }

  .page-about .about-hero-meta {
    gap: 12px 22px;
  }

  .page-about .about-meta-num {
    font-size: 18px;
  }
}