.page-about {
  --about-rail: 176px;
  --about-gutter: clamp(16px, 2.6vw, 40px);
  display: block;
  padding-bottom: clamp(40px, 6vw, 88px);
}

/* ---------- 封面 ---------- */

.page-about .about-cover {
  position: relative;
  overflow: hidden;
  padding-block: clamp(20px, 3vw, 40px) clamp(44px, 5.6vw, 84px);
  background:
    radial-gradient(120% 88% at 90% 4%, rgba(53, 242, 192, .10), transparent 58%),
    radial-gradient(96% 74% at 2% 104%, rgba(255, 122, 47, .07), transparent 62%);
}

.page-about .about-slash {
  position: absolute;
  left: -4%;
  right: -4%;
  bottom: 12px;
  height: 4px;
  background: linear-gradient(90deg, var(--neon-cyan), var(--league-ice) 38%, var(--season-amber) 68%, var(--signal-orange));
  transform: rotate(-0.7deg);
  transform-origin: left center;
  opacity: .8;
  pointer-events: none;
}

.page-about .about-crumb {
  margin-bottom: clamp(18px, 3vw, 34px);
}

.page-about .about-cover-grid {
  display: grid;
  gap: clamp(26px, 3.6vw, 48px);
}

@media (min-width: 880px) {
  .page-about .about-cover-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }
}

.page-about .about-overline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 clamp(14px, 2vw, 22px);
  font-size: 12px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted-sage);
}

.page-about .about-ver {
  padding: 3px 9px;
  border: 1px solid var(--neon-cyan);
  color: var(--neon-cyan);
  font-size: 11px;
  letter-spacing: .08em;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 6px), calc(100% - 6px) 100%, 0 100%);
}

.page-about .about-overline-sep {
  width: 22px;
  height: 1px;
  background: var(--line-chalk);
}

.page-about .about-title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(42px, 9vw, 82px);
  line-height: 1.02;
  letter-spacing: -.022em;
  color: var(--chalk-white);
}

.page-about .about-title-em {
  position: relative;
  display: inline-block;
  color: var(--neon-cyan);
  padding-right: .08em;
}

.page-about .about-title-em::after {
  content: "";
  position: absolute;
  left: 0;
  right: -4%;
  bottom: .06em;
  height: 6px;
  background: var(--signal-orange);
  opacity: .38;
  transform: rotate(-0.9deg);
  transform-origin: left center;
  z-index: -1;
}

.page-about .about-deck {
  max-width: 46ch;
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  font-size: 16.5px;
  line-height: 1.82;
  color: var(--muted-sage);
}

.page-about .about-cover-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  font-size: 13px;
  color: var(--muted-sage);
}

.page-about .about-meta-k {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--league-ice);
}

.page-about .about-meta-div {
  color: var(--line-chalk);
}

.page-about .about-cover-index {
  background: var(--charcoal-panel);
  padding: 20px 22px 20px;
  box-shadow: inset 0 0 0 1px var(--line-chalk);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), calc(100% - 20px) 100%, 0 100%);
}

.page-about .about-index-label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted-sage);
}

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

.page-about .about-toc li {
  border-top: 1px solid var(--line-chalk);
}

.page-about .about-toc a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 2px;
  color: var(--chalk-white);
  text-decoration: none;
  font-size: 14.5px;
  line-height: 1.4;
  border-left: 2px solid transparent;
  padding-left: 10px;
  transition: color .16s var(--ease), border-color .16s var(--ease), padding-left .16s var(--ease);
}

.page-about .about-toc a .mono {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--fog);
  transition: color .16s var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  color: var(--neon-cyan);
  border-left-color: var(--neon-cyan);
  padding-left: 14px;
  outline: none;
}

.page-about .about-toc a:hover .mono,
.page-about .about-toc a:focus-visible .mono {
  color: var(--neon-cyan);
}

.page-about .about-toc a:focus-visible {
  box-shadow: 0 0 0 2px var(--neon-cyan);
}

/* ---------- 章节 ---------- */

.page-about .about-chapter {
  position: relative;
  display: grid;
  gap: clamp(14px, 2.4vw, 36px);
  padding-block: clamp(42px, 5.4vw, 76px);
}

.page-about .about-chapter::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, var(--line-chalk) 0%, rgba(36, 49, 44, .34) 58%, transparent 100%);
  transform: rotate(-0.32deg);
  transform-origin: left center;
  pointer-events: none;
}

@media (min-width: 940px) {
  .page-about .about-chapter {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gutter);
  }
}

.page-about .about-chapter-rail {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
}

@media (min-width: 940px) {
  .page-about .about-chapter-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    position: sticky;
    top: 28px;
    align-self: start;
    padding-top: 4px;
  }
}

.page-about .about-chapter-num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.6vw, 40px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--neon-cyan);
}

.page-about .about-chapter-tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--chalk-white);
}

.page-about .about-chapter-hint {
  display: none;
  margin: 8px 0 0;
  max-width: 15ch;
  padding-left: 10px;
  border-left: 1px solid var(--line-chalk);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--muted-sage);
}

@media (min-width: 940px) {
  .page-about .about-chapter-hint {
    display: block;
  }
}

.page-about .about-chapter-title {
  margin: 0 0 clamp(16px, 2.2vw, 24px);
  max-width: 24ch;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(27px, 4.2vw, 44px);
  line-height: 1.1;
  letter-spacing: -.014em;
  color: var(--chalk-white);
}

.page-about .about-p {
  margin: 0 0 1.05em;
  max-width: 70ch;
  font-size: 16.5px;
  line-height: 1.84;
  color: var(--chalk-white);
}

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

.page-about .about-p.muted {
  font-size: 15px;
  color: var(--muted-sage);
  border-left: 2px solid var(--line-chalk);
  padding-left: 14px;
  margin-top: clamp(18px, 2.4vw, 26px);
}

/* ---------- 图片 ---------- */

.page-about .about-figure {
  margin: clamp(22px, 3vw, 34px) 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  filter: saturate(.86) contrast(1.06);
}

/* ---------- 覆盖地图 ---------- */

.page-about .about-map {
  margin: clamp(22px, 3vw, 34px) 0;
  background: linear-gradient(160deg, var(--charcoal-panel), rgba(20, 24, 26, .62));
  box-shadow: inset 0 0 0 1px var(--line-chalk);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
  padding: clamp(16px, 2.4vw, 26px);
}

.page-about .about-map-chrome {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.page-about .about-map-title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 19px;
  letter-spacing: .01em;
  color: var(--chalk-white);
}

.page-about .about-map-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .05em;
  color: var(--muted-sage);
}

.page-about .about-map-legend li {
  display: flex;
  align-items: center;
  gap: 6px;
}

.page-about .about-swatch {
  width: 12px;
  height: 12px;
  border-radius: 2px;
  flex: none;
}

.page-about .about-map-scroll {
  overflow-x: auto;
  overscroll-behavior-x: contain;
}

.page-about .about-map-svg {
  display: block;
  width: 100%;
  min-width: 720px;
  height: auto;
}

.page-about .about-map-svg g rect {
  transition: opacity .16s var(--ease);
}

.page-about .about-map-svg g:hover rect {
  opacity: .72;
}

.page-about .about-map-label {
  font-family: var(--font-mono);
  font-size: 21px;
  letter-spacing: .04em;
  fill: #9DB0A8;
}

.page-about .about-map-foot {
  margin: 14px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted-sage);
}

/* ---------- 口径原则 ---------- */

.page-about .about-rules {
  display: grid;
  gap: 12px;
  margin-top: clamp(20px, 2.8vw, 30px);
}

@media (min-width: 760px) {
  .page-about .about-rule:nth-child(2) { margin-left: 20px; }
  .page-about .about-rule:nth-child(3) { margin-left: 40px; }
  .page-about .about-rule:nth-child(4) { margin-left: 60px; }
}

.page-about .about-rule {
  background: linear-gradient(118deg, var(--charcoal-panel), rgba(20, 24, 26, .74));
  box-shadow: inset 0 0 0 1px var(--line-chalk);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
  transition: box-shadow .18s var(--ease);
}

.page-about .about-rule[open] {
  box-shadow: inset 0 0 0 1px rgba(53, 242, 192, .42);
}

.page-about .about-rule-sum {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 15px 18px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 20px;
  letter-spacing: -.005em;
  color: var(--chalk-white);
}

.page-about .about-rule-sum::-webkit-details-marker {
  display: none;
}

.page-about .about-rule-sum:focus-visible {
  outline: 2px solid var(--neon-cyan);
  outline-offset: -2px;
}

.page-about .about-rule-idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--ink-turf);
  background: var(--neon-cyan);
  padding: 3px 7px;
  flex: none;
}

.page-about .about-rule-name {
  flex: 1 1 auto;
  min-width: 0;
}

.page-about .about-rule-caret {
  flex: none;
  width: 10px;
  height: 10px;
  margin-right: 6px;
  border-right: 2px solid var(--neon-cyan);
  border-bottom: 2px solid var(--neon-cyan);
  transform: rotate(45deg);
  transition: transform .2s var(--ease);
}

.page-about .about-rule[open] .about-rule-caret {
  transform: rotate(-135deg);
}

.page-about .about-rule-body {
  padding: 0 18px 20px 18px;
}

.page-about .about-rule-body p {
  margin: 0;
  max-width: 62ch;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--muted-sage);
}

/* ---------- 发展阶段 ---------- */

.page-about .about-phases {
  position: relative;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0 0 0 28px;
  list-style: none;
}

.page-about .about-phases::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 14px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--neon-cyan), var(--league-ice) 40%, var(--season-amber) 76%, var(--signal-orange));
  opacity: .6;
}

.page-about .about-phase {
  position: relative;
  padding-bottom: clamp(24px, 3.2vw, 36px);
}

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

.page-about .about-phase-dot {
  position: absolute;
  left: -27px;
  top: 6px;
  width: 13px;
  height: 13px;
  box-sizing: border-box;
  border: 2px solid var(--neon-cyan);
  background: var(--ink-turf);
  transform: rotate(45deg);
}

.page-about .about-phase-stage {
  margin: 0 0 5px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--season-amber);
}

.page-about .about-phase-title {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(20px, 2.6vw, 26px);
  line-height: 1.2;
  letter-spacing: -.008em;
  color: var(--chalk-white);
}

.page-about .about-phase-text {
  margin: 0 0 12px;
  max-width: 62ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--muted-sage);
}

.page-about .about-phase-fields {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-phase-fields li {
  padding: 4px 10px;
  border: 1px solid var(--line-chalk);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .04em;
  color: var(--league-ice);
  background: rgba(123, 216, 255, .06);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 5px), calc(100% - 5px) 100%, 0 100%);
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  display: grid;
  gap: 12px;
  margin-top: clamp(20px, 2.8vw, 30px);
}

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

.page-about .about-team-card {
  position: relative;
  padding: 20px 20px 22px;
  background: var(--charcoal-panel);
  box-shadow: inset 0 0 0 1px var(--line-chalk);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .about-team-card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 3px;
  height: 46px;
}

.page-about .about-team-card--a::before { background: var(--neon-cyan); }
.page-about .about-team-card--b::before { background: var(--signal-orange); }
.page-about .about-team-card--c::before { background: var(--league-ice); }
.page-about .about-team-card--d::before { background: var(--season-amber); }

.page-about .about-team-head {
  display: flex;
  align-items: baseline;
  gap: 5px;
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--muted-sage);
}

.page-about .about-team-count {
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--chalk-white);
}

.page-about .about-team-name {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 20px;
  line-height: 1.25;
  color: var(--chalk-white);
}

.page-about .about-team-card p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--muted-sage);
}

/* ---------- 协作生态 ---------- */

.page-about .about-partner-list {
  display: grid;
  gap: 10px;
  margin: clamp(20px, 2.8vw, 30px) 0 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 720px) {
  .page-about .about-partner-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-partner:last-child {
    grid-column: 1 / -1;
  }
}

.page-about .about-partner {
  padding: 15px 18px;
  border: 1px solid var(--line-chalk);
  background: rgba(20, 24, 26, .55);
}

.page-about .about-partner-type {
  margin: 0 0 7px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--signal-orange);
}

.page-about .about-partner-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted-sage);
}

/* ---------- 边界 ---------- */

.page-about .about-limits {
  display: grid;
  gap: 0;
  margin: clamp(20px, 2.8vw, 30px) 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-chalk);
}

.page-about .about-limit {
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr);
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line-chalk);
}

.page-about .about-limit-mark {
  width: 11px;
  height: 11px;
  margin-top: 6px;
  border: 2px solid var(--whistle-red);
  transform: rotate(45deg);
}

.page-about .about-limit-name {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 19px;
  line-height: 1.3;
  color: var(--chalk-white);
}

.page-about .about-limit p {
  margin: 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--muted-sage);
}

/* ---------- 结尾索引 ---------- */

.page-about .about-outro {
  margin-top: clamp(48px, 6.5vw, 90px);
  padding: clamp(24px, 3.4vw, 40px) clamp(18px, 2.8vw, 34px);
  background: linear-gradient(150deg, rgba(53, 242, 192, .07), rgba(255, 122, 47, .05) 62%, transparent);
  box-shadow: inset 0 0 0 1px var(--line-chalk);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 24px), calc(100% - 24px) 100%, 0 100%);
}

.page-about .about-outro-title {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(24px, 3.4vw, 34px);
  line-height: 1.1;
  letter-spacing: -.012em;
  color: var(--chalk-white);
}

.page-about .about-outro-lead {
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  max-width: 60ch;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--muted-sage);
}

.page-about .about-outro-links {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 780px) {
  .page-about .about-outro-links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-outro-link {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 15px 16px;
  text-decoration: none;
  border: 1px solid var(--line-chalk);
  background: rgba(7, 19, 15, .45);
  transition: border-color .16s var(--ease), transform .16s var(--ease), background-color .16s var(--ease);
}

.page-about .about-outro-link:hover,
.page-about .about-outro-link:focus-visible {
  border-color: var(--neon-cyan);
  background: rgba(53, 242, 192, .07);
  transform: translateY(-2px);
  outline: none;
}

.page-about .about-outro-link:focus-visible {
  box-shadow: 0 0 0 2px var(--neon-cyan);
}

.page-about .about-outro-num {
  flex: none;
  padding-top: 2px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--neon-cyan);
}

.page-about .about-outro-text {
  display: block;
  min-width: 0;
}

.page-about .about-outro-text strong {
  display: block;
  margin-bottom: 5px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -.004em;
  color: var(--chalk-white);
}

.page-about .about-outro-text em {
  display: block;
  font-style: normal;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted-sage);
}

.page-about .about-outro-note {
  margin: clamp(16px, 2.2vw, 22px) 0 0;
  font-size: 14px;
  color: var(--muted-sage);
}

.page-about .about-outro-note a {
  color: var(--neon-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 242, 192, .38);
  transition: border-color .16s var(--ease);
}

.page-about .about-outro-note a:hover,
.page-about .about-outro-note a:focus-visible {
  border-bottom-color: var(--neon-cyan);
  outline: none;
}

/* ---------- 窄屏收口 ---------- */

@media (max-width: 620px) {
  .page-about .about-cover-index {
    padding: 16px 16px 18px;
  }

  .page-about .about-toc a {
    font-size: 14px;
    padding: 9px 2px 9px 8px;
  }

  .page-about .about-map-legend {
    gap: 10px;
    font-size: 11px;
  }

  .page-about .about-rule-sum {
    font-size: 17px;
    gap: 10px;
    padding: 13px 14px;
  }

  .page-about .about-rule-body {
    padding: 0 14px 16px;
  }

  .page-about .about-phases {
    padding-left: 22px;
  }

  .page-about .about-phase-dot {
    left: -21px;
  }

  .page-about .about-limit {
    grid-template-columns: 14px minmax(0, 1fr);
    gap: 12px;
  }

  .page-about .about-limit-mark {
    width: 9px;
    height: 9px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc a,
  .page-about .about-rule,
  .page-about .about-rule-caret,
  .page-about .about-outro-link,
  .page-about .about-map-svg g rect {
    transition: none;
  }

  .page-about .about-outro-link:hover {
    transform: none;
  }
}