.page-about {
  --about-rail: 176px;
  --about-pad: clamp(20px, 3.6vw, 40px);
  background: var(--ink-950);
  color: var(--mist);
  font-family: var(--font-body);
  padding-bottom: clamp(48px, 6vw, 96px);
  overflow-x: hidden;
}

/* ---------- 首屏：章节预览 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(26px, 4.6vw, 60px) 0 clamp(32px, 4vw, 56px);
  background:
    linear-gradient(155deg, var(--navy-900) 0%, rgba(11, 46, 79, 0.42) 46%, var(--ink-950) 80%),
    var(--ink-950);
  border-bottom: 1px solid var(--line-strong);
}
.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -25%;
  right: -10%;
  width: min(46vw, 420px);
  height: 160%;
  background: linear-gradient(180deg, rgba(255, 106, 42, 0.3), rgba(255, 106, 42, 0) 72%);
  transform: skewX(-8deg);
  pointer-events: none;
}
.page-about .about-hero > .shell {
  position: relative;
  z-index: 1;
}
.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mute);
  margin-bottom: clamp(18px, 2.6vw, 30px);
}
.page-about .breadcrumb__link {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.page-about .breadcrumb__link:hover,
.page-about .breadcrumb__link:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--orange);
}
.page-about .about-crumb-sep {
  color: var(--mute);
}
.page-about .about-hero h1 {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 6vw, 58px);
  line-height: 1.12;
  letter-spacing: -0.015em;
  color: var(--cream);
  max-width: 18em;
}
.page-about .about-hero__lead {
  margin: clamp(16px, 2.2vw, 24px) 0 0;
  max-width: 62ch;
  font-size: clamp(15px, 1.5vw, 17.5px);
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  margin: clamp(24px, 3.4vw, 40px) 0 0;
  background: var(--line);
  border: 1px solid var(--line);
}
.page-about .about-meta__cell {
  background: rgba(14, 17, 22, 0.76);
  padding: 14px 16px;
}
.page-about .about-meta dt {
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--mute);
}
.page-about .about-meta dd {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 700;
  line-height: 1;
  color: var(--cream);
}
.page-about .about-meta__num {
  color: var(--mint);
}
.page-about .about-meta dd small {
  margin-left: 5px;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 400;
  color: var(--amber);
}

.page-about .about-index-nav {
  margin-top: clamp(22px, 3vw, 34px);
}
.page-about .about-index {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.page-about .about-index li {
  background: rgba(26, 32, 40, 0.88);
}
.page-about .about-index a {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 12px 13px;
  font-size: 13.5px;
  line-height: 1.45;
  color: var(--mist);
  text-decoration: none;
  transition: background 0.2s var(--ease), color 0.2s var(--ease);
}
.page-about .about-index a:hover,
.page-about .about-index a:focus-visible {
  background: var(--navy-600);
  color: var(--cream);
}
.page-about .idx-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--orange);
  flex: none;
}

/* ---------- 主体网格 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 3vw, 40px);
  padding-top: clamp(24px, 3.4vw, 44px);
}

.page-about .about-rail {
  min-width: 0;
}
.page-about .about-rail__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--mute);
}
.page-about .about-rail ul {
  list-style: none;
  display: flex;
  gap: 0;
  margin: 0;
  padding: 0 0 8px;
  overflow-x: auto;
  border-left: 1px solid var(--line);
  scrollbar-width: thin;
}
.page-about .about-rail li {
  flex: none;
}
.page-about .about-rail a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 9px 14px;
  font-size: 13px;
  color: var(--mute);
  text-decoration: none;
  border-left: 2px solid transparent;
  margin-left: -1px;
  white-space: nowrap;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.page-about .about-rail a:hover,
.page-about .about-rail a:focus-visible {
  color: var(--cream);
  border-left-color: var(--orange);
}
.page-about .about-rail__top {
  display: inline-block;
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 3px;
}
.page-about .about-rail__top:hover,
.page-about .about-rail__top:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding: clamp(28px, 4vw, 56px) 0;
  border-top: 1px solid var(--line);
}
.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 0;
}
.page-about .about-sec__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.2vw, 38px);
  line-height: 1.24;
  letter-spacing: -0.012em;
  color: var(--cream);
}
.page-about .about-prose {
  margin-top: 16px;
}
.page-about .about-prose p {
  margin: 0 0 14px;
  font-size: clamp(15px, 1.4vw, 16.5px);
  line-height: 1.9;
  color: var(--mist);
  max-width: 68ch;
}
.page-about .about-prose p:last-child {
  margin-bottom: 0;
}

/* ---------- 纸张章节 ---------- */
.page-about .about-paper {
  position: relative;
  margin: clamp(18px, 3vw, 34px) 0;
  padding: var(--about-pad);
  background: var(--cream);
  color: var(--brown);
  border: 1px solid rgba(42, 29, 23, 0.28);
  box-shadow: 10px 10px 0 -1px rgba(242, 233, 216, 0.2);
}
.page-about .about-paper::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 68px;
  height: 4px;
  background: var(--orange);
}
.page-about .about-paper .section-label {
  color: var(--brown);
}
.page-about .about-paper .about-sec__title {
  color: var(--brown);
}
.page-about .about-paper .about-prose p {
  color: rgba(42, 29, 23, 0.88);
}
.page-about .about-paper .about-figure {
  border-color: rgba(42, 29, 23, 0.3);
  background: rgba(42, 29, 23, 0.08);
}
.page-about .about-paper .about-figure__cap {
  color: rgba(42, 29, 23, 0.72);
  border-top-color: rgba(42, 29, 23, 0.2);
}

.page-about .about-origin {
  display: grid;
  gap: clamp(18px, 3vw, 32px);
  margin-top: 16px;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--line-strong);
  background: var(--ink-800);
  overflow: hidden;
}
.page-about .about-figure__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .about-figure__cap {
  display: block;
  padding: 10px 13px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--mute);
  border-top: 1px solid var(--line);
}
.page-about .about-figure--wide,
.page-about .about-figure--tall {
  margin-top: 4px;
}

/* ---------- 赛区列表 ---------- */
.page-about .about-zones {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}
.page-about .about-zone {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 5px;
  padding: 15px 0 15px 14px;
  border-bottom: 1px solid var(--line);
  border-left: 2px solid transparent;
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease);
}
.page-about .about-zone:hover {
  border-left-color: var(--orange);
  background: rgba(26, 32, 40, 0.6);
}
.page-about .about-zone__name {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--amber);
}
.page-about .about-zone__desc {
  font-size: 15px;
  color: var(--cream);
  line-height: 1.6;
}
.page-about .about-zone__note {
  font-size: 13.5px;
  color: var(--mute);
  line-height: 1.7;
}

.page-about .about-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 1px;
  margin-top: 24px;
  background: var(--line);
  border: 1px solid var(--line);
}
.page-about .about-strip div {
  background: var(--ink-800);
  padding: 15px 16px;
}
.page-about .about-strip b {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 2.6vw, 27px);
  font-weight: 700;
  color: var(--mint);
}
.page-about .about-strip span {
  display: block;
  margin-top: 6px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--mute);
}

/* ---------- 维护流程 ---------- */
.page-about .about-maintain {
  margin-top: 22px;
  display: grid;
  gap: clamp(18px, 3vw, 28px);
}
.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}
.page-about .about-step {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 12px;
  padding: 15px 16px;
  background: var(--ink-800);
  border-left: 3px solid var(--orange);
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.page-about .about-step:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 0 1px var(--orange) inset;
}
.page-about .about-step__num {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
  color: var(--orange);
  line-height: 1.3;
}
.page-about .about-step h3 {
  margin: 0 0 7px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16.5px;
  line-height: 1.4;
  color: var(--cream);
}
.page-about .about-step p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 团队分工条 ---------- */
.page-about .about-bars {
  margin-top: 24px;
  display: grid;
  gap: 6px;
}
.page-about .about-bar {
  padding: 13px 0;
  border-bottom: 1px dashed var(--line);
}
.page-about .about-bar__head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
}
.page-about .about-bar__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  color: var(--cream);
}
.page-about .about-bar__num {
  font-family: var(--font-mono);
  font-size: 19px;
  font-weight: 700;
  color: var(--amber);
}
.page-about .about-bar__track {
  display: block;
  height: 6px;
  margin: 10px 0 9px;
  background: rgba(124, 139, 153, 0.18);
  overflow: hidden;
}
.page-about .about-bar__fill {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--navy-600), var(--mint));
  transition: background 0.25s var(--ease);
}
.page-about .about-bar--a .about-bar__fill { width: 39%; }
.page-about .about-bar--b .about-bar__fill { width: 30%; }
.page-about .about-bar--c .about-bar__fill { width: 20%; }
.page-about .about-bar--d .about-bar__fill { width: 11%; }
.page-about .about-bar__duty {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--mute);
  transition: color 0.2s var(--ease);
}
.page-about .about-bar:hover .about-bar__fill {
  background: linear-gradient(90deg, var(--orange), var(--amber));
}
.page-about .about-bar:hover .about-bar__duty {
  color: var(--mist);
}

/* ---------- 时间轴 ---------- */
.page-about .about-section--timeline {
  position: relative;
}
.page-about .about-timeline-wrap {
  display: grid;
  gap: clamp(20px, 3vw, 40px);
  margin-top: 22px;
}
.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 4px 0 0 28px;
  position: relative;
}
.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(180deg, var(--orange), rgba(255, 106, 42, 0.12));
}
.page-about .about-tl {
  position: relative;
  padding: 0 0 24px;
}
.page-about .about-tl:last-child {
  padding-bottom: 0;
}
.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 7px;
  width: 10px;
  height: 10px;
  background: var(--ink-950);
  border: 2px solid var(--orange);
  transform: rotate(45deg);
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease);
}
.page-about .about-tl:hover::before {
  background: var(--orange);
  border-color: var(--amber);
}
.page-about .about-tl__year {
  display: block;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--orange);
}
.page-about .about-tl h3 {
  margin: 6px 0 6px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16.5px;
  line-height: 1.4;
  color: var(--cream);
}
.page-about .about-tl p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
  max-width: 46ch;
}

/* ---------- 合作生态 ---------- */
.page-about .about-partners {
  display: grid;
  gap: 12px;
  margin-top: 22px;
}
.page-about .about-partner {
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-top: 3px solid var(--orange);
  padding: 18px 17px;
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.page-about .about-partner:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 0 1px var(--orange) inset;
}
.page-about .about-partner b {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 700;
  line-height: 1;
  color: var(--cream);
}
.page-about .about-partner span {
  display: block;
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--amber);
}
.page-about .about-partner p {
  margin: 12px 0 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-prose--after {
  margin-top: 22px;
}
.page-about .about-modules {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.page-about .about-module {
  background: var(--ink-950);
  padding: 13px 16px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--mist);
}
.page-about .about-module span {
  display: inline-block;
  margin-right: 10px;
  padding: 2px 9px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--ink-950);
  background: var(--mint);
}

.page-about .about-inline-link {
  margin: 20px 0 0;
}
.page-about .about-link {
  display: inline-block;
  font-size: 14.5px;
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 3px;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* ---------- 价值点 ---------- */
.page-about .about-why {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.page-about .about-why li {
  position: relative;
  background: var(--ink-800);
  padding: 18px 18px 18px 22px;
}
.page-about .about-why li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 20px;
  bottom: 20px;
  width: 3px;
  background: var(--mint);
}
.page-about .about-why h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16.5px;
  line-height: 1.4;
  color: var(--cream);
}
.page-about .about-why p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 合作入口 ---------- */
.page-about .about-cta {
  position: relative;
  overflow: hidden;
  background: linear-gradient(140deg, var(--navy-900), var(--ink-800) 86%);
  border: 1px solid var(--line-strong);
  border-top: 1px solid var(--line-strong);
  padding: clamp(24px, 4vw, 48px);
}
.page-about .about-cta::after {
  content: "";
  position: absolute;
  right: -8%;
  bottom: -60%;
  width: 46%;
  height: 170%;
  background: linear-gradient(180deg, rgba(56, 242, 200, 0.14), rgba(56, 242, 200, 0));
  transform: skewX(-8deg);
  pointer-events: none;
}
.page-about .about-cta > * {
  position: relative;
  z-index: 1;
}
.page-about .about-cta .about-prose p {
  color: var(--mist);
}
.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 560px) {
  .page-about .about-index {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-zone {
    grid-template-columns: 132px minmax(0, 1fr);
    align-items: baseline;
    column-gap: 18px;
  }
  .page-about .about-zone__note {
    grid-column: 2;
  }
  .page-about .about-partners {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-modules {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-index {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .about-origin {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
  }
  .page-about .about-maintain {
    grid-template-columns: minmax(0, 1fr);
  }
  .page-about .about-why {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-partners {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-timeline-wrap {
    grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.18fr);
    align-items: start;
  }
  .page-about .about-figure--tall {
    position: sticky;
    top: calc(var(--strip-h) + 24px);
  }
  .page-about .about-maintain {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
    align-items: start;
  }
  .page-about .about-figure--wide {
    margin-top: 0;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
  }
  .page-about .about-rail {
    position: sticky;
    top: calc(var(--strip-h) + 18px);
  }
  .page-about .about-rail ul {
    flex-direction: column;
    overflow: visible;
    padding-bottom: 0;
  }
  .page-about .about-rail a {
    display: flex;
    white-space: normal;
    padding: 9px 0 9px 14px;
  }
  .page-about .about-tl:nth-child(even) {
    padding-left: 30px;
  }
  .page-about .about-flow .about-paper {
    margin-right: -8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-step,
  .page-about .about-partner,
  .page-about .about-bar__fill,
  .page-about .about-tl::before {
    transition: none;
  }
  .page-about .about-step:hover,
  .page-about .about-partner:hover {
    transform: none;
  }
}