.page-about {
  --about-edge: 2px solid var(--line);
  --about-gap: clamp(18px, 3vw, 32px);
  display: block;
  position: relative;
  padding-bottom: clamp(56px, 8vw, 112px);
  background:
    radial-gradient(1100px 520px at 8% 0%, rgba(110, 208, 246, .10), transparent 60%),
    radial-gradient(920px 460px at 94% 3%, rgba(232, 180, 74, .09), transparent 58%);
  overflow-x: hidden;
}

.page-about .breadcrumbs {
  padding-top: calc(var(--header-h) + clamp(16px, 3vw, 30px));
  padding-bottom: 4px;
}

.page-about .breadcrumbs-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--mono);
  font-size: .8125rem;
  letter-spacing: .08em;
  color: var(--muted);
}

.page-about .breadcrumbs-list a {
  color: var(--ice);
  text-decoration: none;
}

.page-about .breadcrumbs-list a:hover,
.page-about .breadcrumbs-list a:focus-visible {
  color: var(--gold-soft);
}

.page-about .breadcrumbs-list li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--line);
}

/* ---------- 通用排版 ---------- */
.page-about .about-h2 {
  margin: 0 0 14px;
  font-size: clamp(1.45rem, 2.7vw, 2.1rem);
  line-height: 1.24;
  letter-spacing: -.01em;
  font-weight: 900;
  color: var(--white);
}

.page-about .about-note {
  margin: 0;
  max-width: 70ch;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text);
}

.page-about .section-head {
  margin-bottom: clamp(22px, 3vw, 36px);
}

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

.page-about .media-frame figcaption {
  margin: 0;
  padding: 12px 4px 0;
  font-family: var(--mono);
  font-size: .75rem;
  letter-spacing: .06em;
  color: var(--muted);
}

/* ---------- 开篇 ---------- */
.page-about .about-intro {
  padding: clamp(18px, 3.5vw, 40px) 0 clamp(36px, 5vw, 68px);
}

.page-about .about-intro-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 52px);
  align-items: center;
}

.page-about .about-intro h1 {
  margin: 14px 0 22px;
  font-size: clamp(1.9rem, 4.6vw, 3.3rem);
  line-height: 1.14;
  letter-spacing: -.014em;
  font-weight: 900;
  color: var(--white);
}

.page-about .about-lede-text {
  margin: 0 0 18px;
  padding-left: 16px;
  border-left: 3px solid var(--gold);
  font-size: clamp(1rem, 1.3vw, 1.0938rem);
  line-height: 1.82;
  color: var(--text);
}

.page-about .about-lede-sub {
  margin: 0 0 28px;
  max-width: 54ch;
  font-size: .9688rem;
  line-height: 1.8;
  color: var(--muted);
}

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

.page-about .about-intro-media {
  margin: 0;
  border: var(--about-edge);
  background: var(--panel-2);
  box-shadow: var(--shadow-hard);
  overflow: hidden;
}

.page-about .about-intro-media img {
  aspect-ratio: 16 / 9;
}

@media (min-width: 980px) {
  .page-about .about-intro-grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, .98fr);
  }
}

/* ---------- 内容主线 ---------- */
.page-about .about-lines,
.page-about .about-column,
.page-about .about-versions,
.page-about .about-team,
.page-about .about-coop {
  padding-block: clamp(38px, 5.5vw, 78px);
}

.page-about .about-lines-figure {
  margin: 0 auto clamp(24px, 3.4vw, 40px);
  max-width: 780px;
  border: var(--about-edge);
  background:
    linear-gradient(180deg, rgba(14, 42, 69, .92), rgba(7, 26, 43, .96)),
    repeating-linear-gradient(90deg, rgba(110, 208, 246, .08) 0 1px, transparent 1px 56px);
  box-shadow: var(--shadow-hard);
  overflow: hidden;
}

.page-about .about-lines-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--about-gap);
}

.page-about .about-line-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: clamp(20px, 2.6vw, 30px);
  border: var(--about-edge);
  background: linear-gradient(158deg, var(--panel) 0%, var(--panel-2) 100%);
  box-shadow: var(--shadow-hard);
}

.page-about .about-line-index {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 1.5rem;
  line-height: 1;
  letter-spacing: .04em;
  color: var(--gold);
}

.page-about .about-line-title {
  margin: 0 0 12px;
  font-size: clamp(1.125rem, 1.7vw, 1.375rem);
  font-weight: 800;
  color: var(--white);
}

.page-about .about-line-text {
  margin: 0 0 12px;
  font-size: .9688rem;
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-link {
  display: inline-block;
  margin-top: auto;
  padding-top: 12px;
  font-family: var(--mono);
  font-size: .8125rem;
  letter-spacing: .06em;
  color: var(--ice);
  text-decoration: none;
  border-bottom: 1px solid rgba(110, 208, 246, .38);
  align-self: flex-start;
}

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

.page-about .about-entry {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: auto;
  padding-top: 14px;
  align-self: flex-start;
  text-decoration: none;
  font-weight: 700;
  color: var(--gold-soft);
}

.page-about .about-entry-cue {
  font-family: var(--mono);
  font-size: .75rem;
  font-weight: 500;
  letter-spacing: .06em;
  color: var(--ice);
  transition: opacity .25s var(--ease);
}

@media (min-width: 940px) {
  .page-about .about-lines-grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    align-items: stretch;
  }

  .page-about .about-lines-grid > :nth-child(1) { grid-column: span 7; }
  .page-about .about-lines-grid > :nth-child(2) { grid-column: span 5; }
  .page-about .about-lines-grid > :nth-child(3) { grid-column: span 5; }
  .page-about .about-lines-grid > :nth-child(4) { grid-column: span 7; }

  .page-about .about-entry-cue {
    opacity: 0;
  }

  .page-about .about-entry:hover .about-entry-cue,
  .page-about .about-entry:focus-visible .about-entry-cue {
    opacity: 1;
  }
}

/* ---------- 会员中心专栏 ---------- */
.page-about .about-head-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px 40px;
}

@media (min-width: 900px) {
  .page-about .about-head-split {
    grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr);
    align-items: end;
  }

  .page-about .about-head-split .about-note {
    padding-bottom: 4px;
  }
}

.page-about .filter-bar {
  margin-bottom: clamp(18px, 2.4vw, 28px);
}

.page-about .filter-btn.is-active {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--ink);
}

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

.page-about .about-column-item {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  border: var(--about-edge);
  background: var(--panel);
  transition: transform .28s var(--ease), border-color .28s var(--ease);
}

.page-about .about-column-item:hover {
  transform: translateY(-4px);
  border-color: var(--gold);
}

.page-about .about-column-item .tag {
  align-self: flex-start;
}

.page-about .about-column-title {
  margin: 0;
  font-size: 1.0625rem;
  line-height: 1.45;
  font-weight: 800;
  color: var(--white);
}

.page-about .about-column-text {
  margin: 0;
  font-size: .9063rem;
  line-height: 1.75;
  color: var(--text);
}

@media (min-width: 700px) {
  .page-about .about-column-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1080px) {
  .page-about .about-column-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 版本演进 ---------- */
.page-about .about-version-track {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: var(--about-edge);
  box-shadow: var(--shadow-hard);
}

.page-about .about-version-node {
  min-width: 0;
  background: var(--navy);
}

.page-about .about-version-details {
  height: 100%;
}

.page-about .about-version-summary {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 18px 18px 14px;
  border-top: 3px solid var(--gold);
  cursor: pointer;
  list-style: none;
}

.page-about .about-version-summary::-webkit-details-marker {
  display: none;
}

.page-about .about-version-summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--mono);
  font-size: 1rem;
  color: var(--ice);
}

.page-about .about-version-details[open] .about-version-summary::after {
  content: "–";
  color: var(--gold);
}

.page-about .about-version-summary:focus-visible {
  outline: 2px solid var(--ice);
  outline-offset: -2px;
}

.page-about .about-version-num {
  font-size: 1.5rem;
  line-height: 1;
  letter-spacing: .04em;
  color: var(--gold);
}

.page-about .about-version-name {
  font-size: .9063rem;
  font-weight: 700;
  color: var(--white);
}

.page-about .about-version-body {
  margin: 0;
  padding: 0 18px 20px;
  font-size: .9063rem;
  line-height: 1.72;
  color: var(--text);
}

.page-about .about-version-figure {
  margin: clamp(20px, 3vw, 32px) 0 0;
  border: var(--about-edge);
  background: var(--panel-2);
  box-shadow: var(--shadow-hard);
  overflow: hidden;
}

@media (min-width: 900px) {
  .page-about .about-version-track {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 内容团队 ---------- */
.page-about .about-team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.4vw, 46px);
}

.page-about .about-team-copy .about-note + .about-note {
  margin-top: 16px;
}

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

.page-about .about-team-item {
  padding: 20px 20px 22px;
  border: var(--about-edge);
  border-left: 4px solid var(--gold);
  background: var(--panel-2);
}

.page-about .about-team-index {
  display: block;
  margin-bottom: 10px;
  font-family: var(--mono);
  font-size: .75rem;
  letter-spacing: .16em;
  color: var(--ice);
}

.page-about .about-team-title {
  margin: 0 0 8px;
  font-size: 1.0625rem;
  font-weight: 800;
  color: var(--white);
}

.page-about .about-team-text {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--text);
}

@media (min-width: 940px) {
  .page-about .about-team-grid {
    grid-template-columns: minmax(0, .92fr) minmax(0, 1.08fr);
    align-items: start;
  }

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

/* ---------- 内容共建 ---------- */
.page-about .about-coop-panel {
  padding: clamp(24px, 3.4vw, 42px);
  border: var(--about-edge);
  background:
    linear-gradient(150deg, rgba(232, 180, 74, .10), rgba(14, 42, 69, .96) 46%),
    var(--panel);
  box-shadow: var(--shadow-hard);
}

.page-about .about-coop-copy {
  max-width: 74ch;
}

.page-about .about-coop-copy .about-note {
  margin-top: 4px;
}

.page-about .about-coop-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}