.page-about {
  --about-rail: 224px;
  --about-tight: clamp(1.25rem, 3vw, 1.75rem);
  background: var(--night);
  color: var(--ink);
  overflow-x: clip;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(1.5rem, 4vw, 2.5rem) 0 clamp(2.5rem, 7vw, 4.5rem);
  background:
    radial-gradient(110% 80% at 10% 0%, rgba(43, 232, 165, 0.15), transparent 58%),
    radial-gradient(85% 70% at 100% 100%, rgba(255, 138, 61, 0.12), transparent 60%),
    linear-gradient(180deg, var(--field), var(--night) 82%);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: center;
}

.page-about .about-hero-copy .crumbs {
  margin: 0 0 0.85rem;
}

.page-about .about-hero-copy h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.85rem, 6vw, 3.1rem);
  line-height: 1.14;
  letter-spacing: -0.02em;
  margin: 0.7rem 0 0;
}

.page-about .about-lede {
  margin: clamp(0.9rem, 2.5vw, 1.25rem) 0 0;
  max-width: 46ch;
  font-size: clamp(1rem, 2.4vw, 1.08rem);
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-top: clamp(1.15rem, 3vw, 1.6rem);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.5rem, 4vw, 2.25rem) 0 0;
  padding: 1px 0 0;
  background: var(--rule);
  border-top: 1px solid var(--rule);
}

.page-about .about-fact {
  background: var(--night);
  padding: 0.85rem 0.8rem 1rem;
}

.page-about .about-fact dt {
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
}

.page-about .about-fact dd {
  margin: 0.4rem 0 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.3rem, 4vw, 1.6rem);
  font-weight: 700;
  color: var(--signal);
  line-height: 1.1;
}

.page-about .about-fact-unit {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--ink-soft);
}

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

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  padding-bottom: clamp(2rem, 6vw, 3rem);
}

.page-about .about-shell-grid {
  display: grid;
  gap: clamp(1.75rem, 5vw, 3.5rem);
}

/* ---------- 左侧章节坐标轴 ---------- */
.page-about .about-rail-title {
  margin: 0 0 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  color: var(--ink-soft);
}

.page-about .about-rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.page-about .about-rail-link {
  display: inline-flex;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.5rem 0.7rem;
  border: 1px solid var(--rule);
  color: var(--ink-soft);
  font-size: 0.88rem;
  line-height: 1.4;
  text-decoration: none;
  transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}

.page-about .about-rail-no {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--signal);
}

.page-about .about-rail-link:hover,
.page-about .about-rail-link:focus-visible {
  color: var(--ink);
  border-color: var(--signal);
  background: var(--stand);
}

.page-about .about-rail-link:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec + .about-sec {
  margin-top: clamp(2.25rem, 6vw, 3.5rem);
  padding-top: clamp(2.25rem, 6vw, 3.5rem);
  border-top: 1px solid var(--rule);
}

.page-about .about-sec-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.4rem 1rem;
  margin-bottom: 0.85rem;
}

.page-about .about-sec-no {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.5rem, 4.5vw, 2.3rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--signal);
}

.page-about .about-sec-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.3rem, 4vw, 1.85rem);
  letter-spacing: -0.01em;
  margin: 0;
}

.page-about .about-sec-lede {
  max-width: 62ch;
  margin: 0 0 clamp(1.25rem, 3vw, 1.75rem);
  font-size: 1rem;
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .about-sec-lede--tight {
  margin-top: clamp(1.25rem, 3vw, 1.75rem);
  margin-bottom: 0;
}

.page-about .about-sec-lede a {
  color: var(--signal);
  text-decoration: none;
  border-bottom: 1px solid var(--signal-dim);
}

.page-about .about-sec-lede a:hover,
.page-about .about-sec-lede a:focus-visible {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.page-about .about-media {
  margin: clamp(1.25rem, 3vw, 1.75rem) 0 0;
}

/* ---------- 阶段时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-stage {
  position: relative;
  padding-left: 1.6rem;
}

.page-about .about-stage::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.5rem;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--signal-dim), var(--rule));
}

.page-about .about-stage:last-child::before {
  background: linear-gradient(180deg, var(--signal-dim), transparent);
}

.page-about .about-stage-mark {
  position: absolute;
  left: -5px;
  top: 1.25rem;
  width: 12px;
  height: 12px;
  background: var(--night);
  border: 2px solid var(--signal);
  transform: rotate(45deg);
}

.page-about .about-stage summary {
  list-style: none;
  cursor: pointer;
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.35rem 0.8rem;
  padding: 0.85rem 1.8rem 0.85rem 0;
}

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

.page-about .about-stage summary::after {
  content: "";
  position: absolute;
  right: 0.55rem;
  top: 1.25rem;
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--signal);
  border-bottom: 2px solid var(--signal);
  transform: rotate(45deg);
  transition: transform 0.25s ease;
}

.page-about .about-stage[open] summary::after {
  transform: rotate(225deg);
}

.page-about .about-stage summary:hover .about-stage-title {
  color: var(--signal);
}

.page-about .about-stage summary:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 3px;
}

.page-about .about-stage-year {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .about-stage-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.02rem;
  color: var(--ink);
  transition: color 0.2s ease;
}

.page-about .about-stage-body {
  padding: 0 1.6rem 1rem 0;
  font-size: 0.94rem;
  line-height: 1.74;
  color: var(--ink-soft);
}

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

/* ---------- 团队角色 ---------- */
.page-about .about-roles {
  display: grid;
  gap: 1rem;
}

.page-about .about-role {
  position: relative;
  padding: 1.1rem 1.1rem 1.25rem;
  transition: transform 0.25s ease, background-color 0.25s ease;
}

.page-about .about-role::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--signal), transparent 72%);
  opacity: 0.55;
  transition: opacity 0.25s ease, background 0.25s ease;
}

.page-about .about-role:hover,
.page-about .about-role:focus-within {
  transform: translateY(-2px);
}

.page-about .about-role:hover::after,
.page-about .about-role:focus-within::after {
  opacity: 1;
  background: linear-gradient(90deg, var(--amber), transparent 72%);
}

.page-about .about-role-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem;
}

.page-about .about-role-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  margin: 0;
}

.page-about .about-role-count {
  font-size: 0.8rem;
  color: var(--signal);
}

.page-about .about-role-list {
  list-style: none;
  margin: 0.85rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.45rem;
  font-size: 0.9rem;
  line-height: 1.62;
  color: var(--ink-soft);
}

.page-about .about-role-list li {
  position: relative;
  padding-left: 0.95rem;
}

.page-about .about-role-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 5px;
  height: 5px;
  background: var(--signal-dim);
  transform: rotate(45deg);
}

/* ---------- 比赛日流程 ---------- */
.page-about .about-flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.75rem;
}

.page-about .about-flow-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1rem 1.15rem 1.1rem;
  background: var(--field);
  border-left: 3px solid var(--signal-dim);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, 0 100%);
  transition: border-color 0.25s ease, background-color 0.25s ease;
}

.page-about .about-flow-item:hover {
  border-left-color: var(--amber);
  background: var(--stand);
}

.page-about .about-flow-no {
  flex: 0 0 auto;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--amber);
  line-height: 1.25;
}

.page-about .about-flow-body {
  min-width: 0;
}

.page-about .about-flow-time {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--signal);
}

.page-about .about-flow-text {
  margin: 0.4rem 0 0;
  font-size: 0.94rem;
  line-height: 1.72;
  color: var(--ink-soft);
}

/* ---------- 数据整理 ---------- */
.page-about .about-data-path {
  list-style: none;
  margin: 0 0 clamp(1.5rem, 4vw, 2rem);
  padding: 1px;
  display: grid;
  gap: 1px;
  background: var(--rule);
}

.page-about .about-data-step {
  background: var(--night);
  padding: 1rem 1rem 1.15rem;
}

.page-about .about-data-step-no {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .about-data-step h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1rem;
  margin: 0.5rem 0 0.35rem;
}

.page-about .about-data-step p {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--ink-soft);
}

.page-about .about-data-grid {
  display: grid;
  gap: 0.75rem;
  margin-bottom: clamp(1.25rem, 3vw, 1.75rem);
}

.page-about .about-data-cell {
  padding: 1rem 1rem 1.1rem;
  background: var(--stand);
  clip-path: polygon(0 0, calc(100% - var(--cut)) 0, 100% var(--cut), 100% 100%, 0 100%);
}

.page-about .about-data-cell h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.98rem;
  margin: 0 0 0.4rem;
  color: var(--ink);
}

.page-about .about-data-cell p {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.68;
  color: var(--ink-soft);
}

.page-about .about-views {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.page-about .about-views-label {
  font-size: 0.85rem;
  color: var(--ink-soft);
}

/* ---------- 本地服务 ---------- */
.page-about .about-local {
  display: grid;
  gap: 1.25rem;
}

.page-about .about-local-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.95rem;
}

.page-about .about-local-list li {
  position: relative;
  padding-left: 1.4rem;
  font-size: 0.95rem;
  line-height: 1.72;
  color: var(--ink-soft);
}

.page-about .about-local-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55rem;
  width: 9px;
  height: 9px;
  border: 2px solid var(--signal);
  transform: rotate(45deg);
}

.page-about .about-local-panel {
  padding: 1.25rem 1.25rem 1.4rem;
  background: linear-gradient(150deg, var(--stand), var(--field));
  border-left: 3px solid var(--amber);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
}

.page-about .about-local-panel-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
}

.page-about .about-local-panel-text {
  margin: 0.6rem 0 1.1rem;
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--ink-soft);
}

/* ---------- 页尾引导带 ---------- */
.page-about .about-next {
  margin-top: clamp(2.5rem, 7vw, 4rem);
  padding: clamp(2rem, 6vw, 3.25rem) 0;
  border-top: 1px solid var(--rule);
  background: linear-gradient(140deg, var(--field), var(--night));
}

.page-about .about-next-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.4rem, 4.5vw, 2rem);
  letter-spacing: -0.01em;
  margin: 0 0 0.7rem;
}

.page-about .about-next-lede {
  max-width: 56ch;
  margin: 0 0 clamp(1.25rem, 3vw, 1.75rem);
  font-size: 1rem;
  line-height: 1.75;
  color: var(--ink-soft);
}

.page-about .about-next .route-list {
  margin: 0;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .about-data-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }

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

  .page-about .about-rail-inner {
    position: sticky;
    top: 6rem;
  }

  .page-about .about-rail-list {
    display: grid;
    gap: 0.1rem;
  }

  .page-about .about-rail-link {
    border: 0;
    border-left: 2px solid var(--rule);
    padding: 0.55rem 0.4rem 0.55rem 0.95rem;
    background: none;
  }

  .page-about .about-rail-link:hover,
  .page-about .about-rail-link:focus-visible {
    background: none;
    border-left-color: var(--signal);
  }

  .page-about .about-local {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
  }
}

@media (min-width: 1080px) {
  .page-about .about-data-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-role,
  .page-about .about-flow-item,
  .page-about .about-stage summary::after {
    transition: none;
  }

  .page-about .about-role:hover,
  .page-about .about-role:focus-within {
    transform: none;
  }
}