.page-about {
  --about-rail: clamp(58px, 11vw, 112px);
  --about-flow-gap: clamp(14px, 2.4vw, 22px);
  padding-top: clamp(18px, 3vw, 30px);
  padding-bottom: clamp(16px, 3vw, 32px);
  overflow-x: clip;
}

.page-about .breadcrumbs {
  margin-bottom: clamp(16px, 2.6vw, 28px);
}

/* ============ 首屏框景 ============ */
.page-about .about-hero {
  position: relative;
  border: 2px solid var(--line);
  background:
    linear-gradient(180deg, rgba(0, 229, 208, 0.07), rgba(0, 229, 208, 0) 46%),
    var(--panel);
  padding: clamp(22px, 4vw, 54px);
  box-shadow: var(--shadow-hard);
}

.page-about .about-hero::before,
.page-about .about-hero::after {
  content: "";
  position: absolute;
  width: 20px;
  height: 20px;
  border: 2px solid var(--cyan);
  pointer-events: none;
}

.page-about .about-hero::before {
  top: -2px;
  left: -2px;
  border-right-color: transparent;
  border-bottom-color: transparent;
}

.page-about .about-hero::after {
  bottom: -2px;
  right: -2px;
  border-left-color: transparent;
  border-top-color: transparent;
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(26px, 4vw, 48px);
  align-items: end;
}

.page-about .about-hero h1 {
  margin: 0 0 clamp(14px, 2vw, 20px);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: var(--fs-display);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--white);
  max-width: 22ch;
}

.page-about .about-hero-lede {
  margin: 0 0 14px;
  font-family: var(--font-serif);
  font-size: clamp(1.02rem, 1.6vw, 1.26rem);
  line-height: 1.75;
  color: var(--text);
  max-width: 46ch;
}

.page-about .about-hero-note {
  margin: 0 0 clamp(18px, 2.6vw, 26px);
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--muted);
  max-width: 50ch;
}

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

.page-about .about-hero-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line);
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
  padding: clamp(14px, 2.2vw, 20px);
  background: var(--bg-deep);
}

.page-about .about-stat-key {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .about-stat-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: clamp(1.5rem, 3.4vw, 2.1rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

/* ============ 章节标题行 ============ */
.page-about .about-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: clamp(12px, 2vw, 32px);
  margin-bottom: clamp(22px, 3.4vw, 38px);
  padding-bottom: clamp(14px, 2vw, 20px);
  border-bottom: 1px solid var(--line);
}

.page-about .about-head-main {
  min-width: 0;
  flex: 1 1 320px;
}

.page-about .about-head h2 {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-h2);
  line-height: 1.2;
  letter-spacing: -0.015em;
  color: var(--white);
}

.page-about .about-head-note {
  flex: 0 1 44ch;
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .section {
  padding-block: clamp(44px, 7vw, 84px);
}

.page-about .section:first-of-type {
  padding-top: clamp(28px, 4.5vw, 56px);
}

/* ============ 沿革时间轴 ============ */
.page-about .about-history-figure,
.page-about .about-process-figure {
  margin: 0 0 clamp(26px, 4vw, 46px);
}

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

.page-about .about-timeline-item {
  position: relative;
  display: grid;
  grid-template-columns: var(--about-rail) minmax(0, 1fr);
  column-gap: clamp(14px, 2.6vw, 34px);
  padding-bottom: clamp(18px, 3vw, 32px);
}

.page-about .about-timeline-item::before {
  content: "";
  position: absolute;
  top: 14px;
  bottom: 0;
  left: calc(var(--about-rail) - 1px);
  border-left: 1px dashed var(--line);
  pointer-events: none;
}

.page-about .about-timeline-item:last-child::before {
  display: none;
}

.page-about .about-timeline-item::after {
  content: "";
  position: absolute;
  top: 8px;
  left: calc(var(--about-rail) - 5px);
  width: 10px;
  height: 10px;
  box-sizing: border-box;
  background: var(--cyan);
  border: 1px solid var(--bg);
  pointer-events: none;
}

.page-about .about-tl-marker {
  padding-right: 16px;
  text-align: right;
}

.page-about .about-tl-year {
  display: inline-block;
  padding-top: 2px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(0.76rem, 1.15vw, 0.86rem);
  letter-spacing: 0.06em;
  color: var(--muted);
  white-space: nowrap;
}

.page-about .about-tl-card {
  min-width: 0;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: clamp(16px, 2.6vw, 26px);
  transition: transform 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-tl-card:hover,
.page-about .about-tl-card:focus-within {
  transform: translateY(-3px);
  border-color: var(--cyan);
}

.page-about .about-tl-card h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-h3);
  line-height: 1.35;
  color: var(--white);
}

.page-about .about-tl-card p {
  margin: 0 0 12px;
  font-size: var(--fs-body);
  line-height: 1.8;
  color: var(--text);
}

.page-about .about-tl-card p:last-of-type {
  margin-bottom: 0;
}

/* ============ 复核流程 ============ */
.page-about .about-flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--about-flow-gap);
}

.page-about .about-flow-step {
  position: relative;
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: clamp(18px, 2.6vw, 26px);
  border: 1px solid var(--line);
  border-top: 3px solid var(--cyan);
  background: var(--panel-2);
}

.page-about .about-flow-step:nth-child(2) {
  border-top-color: var(--blue);
}

.page-about .about-flow-step:nth-child(3) {
  border-top-color: var(--orange);
}

.page-about .about-flow-no {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .about-flow-step h3 {
  margin: 10px 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.35rem, 2.4vw, 1.7rem);
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .about-flow-step p {
  margin: 0;
  font-size: var(--fs-body);
  line-height: 1.8;
  color: var(--text);
}

.page-about .about-flow-rule {
  margin-top: 14px !important;
  padding-left: 12px;
  border-left: 2px solid var(--line);
  font-family: var(--font-mono);
  font-size: 13px !important;
  line-height: 1.7 !important;
  color: var(--muted) !important;
  transition: border-color 0.18s var(--ease), color 0.18s var(--ease);
}

.page-about .about-flow-step:hover .about-flow-rule,
.page-about .about-flow-step:focus-within .about-flow-rule {
  border-left-color: var(--cyan);
  color: var(--text) !important;
}

/* ============ 口径维护 ============ */
.page-about .about-rulebook-grid {
  margin-bottom: clamp(20px, 3vw, 30px);
}

.page-about .about-rule-card {
  min-width: 0;
  padding: clamp(18px, 2.6vw, 26px);
  border: 1px solid var(--line);
  background: var(--panel);
  transition: transform 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .about-rule-card:hover {
  transform: translateY(-3px);
  border-color: var(--blue);
}

.page-about .about-rule-code {
  display: inline-block;
  padding: 3px 10px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--blue);
}

.page-about .about-rule-card h3 {
  margin: 14px 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-h3);
  line-height: 1.4;
  color: var(--white);
}

.page-about .about-rule-card p {
  margin: 0;
  font-size: var(--fs-body);
  line-height: 1.8;
  color: var(--text);
}

.page-about .about-legend {
  flex-wrap: wrap;
  gap: 10px 22px;
  padding-top: clamp(14px, 2vw, 20px);
  border-top: 1px solid var(--line-soft);
}

/* ============ 团队分工 ============ */
.page-about .about-team-grid {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
}

.page-about .about-team-figure {
  margin: 0;
  min-width: 0;
}

.page-about .about-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line);
}

.page-about .about-role {
  position: relative;
  min-width: 0;
  padding: clamp(16px, 2.4vw, 22px) clamp(16px, 2.4vw, 24px);
  background: var(--bg-deep);
  transition: background-color 0.18s var(--ease);
}

.page-about .about-role::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 3px;
  background: transparent;
  transition: background-color 0.15s var(--ease);
}

.page-about .about-role:hover,
.page-about .about-role:focus-within {
  background: var(--panel-2);
}

.page-about .about-role:hover::before,
.page-about .about-role:focus-within::before {
  background: var(--cyan);
}

.page-about .about-role-code {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .about-role h3 {
  margin: 8px 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.12rem;
  color: var(--white);
}

.page-about .about-role p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

/* ============ 合作与参与 ============ */
.page-about .about-coop-grid {
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
}

.page-about .about-coop-main {
  min-width: 0;
  padding-left: clamp(14px, 2vw, 22px);
  border-left: 2px solid var(--orange);
}

.page-about .about-coop-main p {
  margin: 0 0 16px;
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--text);
}

.page-about .about-coop-main p:last-child {
  margin-bottom: 0;
  font-family: var(--font-serif);
  color: var(--muted);
}

.page-about .about-coop-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-coop-list li {
  position: relative;
  padding-left: 20px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-coop-list li::before {
  content: "";
  position: absolute;
  top: 9px;
  left: 0;
  width: 9px;
  height: 2px;
  background: var(--cyan);
}

/* ============ 结尾窄栏 ============ */
.page-about .about-closing {
  max-width: 62ch;
  margin-top: clamp(24px, 4vw, 44px);
  padding: clamp(20px, 3.2vw, 34px);
  border: 2px solid var(--line);
  border-left: 4px solid var(--cyan);
  background: var(--bg-deep);
}

.page-about .about-closing h2 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-h2);
  line-height: 1.2;
  color: var(--white);
}

.page-about .about-closing p {
  margin: 0 0 clamp(18px, 2.6vw, 24px);
  font-size: var(--fs-body);
  line-height: 1.85;
  color: var(--text);
}

.page-about .about-closing-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ============ 窄屏 ============ */
@media (max-width: 560px) {
  .page-about .about-hero {
    box-shadow: 6px 6px 0 0 rgba(0, 0, 0, 0.45);
  }

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

  .page-about .about-hero h1 {
    max-width: none;
  }

  .page-about .about-tl-marker {
    padding-right: 12px;
  }

  .page-about .about-head-note {
    flex-basis: 100%;
  }
}

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

  .page-about .about-coop-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    align-items: start;
  }
}

@media (min-width: 880px) {
  .page-about .about-flow {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-flow-step:not(:last-child)::after {
    content: "";
    position: absolute;
    top: 54px;
    right: calc(-1 * var(--about-flow-gap));
    width: var(--about-flow-gap);
    height: 1px;
    background: var(--line);
  }

  .page-about .about-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 920px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
  }

  .page-about .about-team-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    align-items: start;
  }
}

@media (min-width: 1024px) {
  .page-about .about-timeline-item:nth-child(1) .about-tl-card {
    width: 82%;
  }

  .page-about .about-timeline-item:nth-child(2) .about-tl-card {
    width: 87%;
  }

  .page-about .about-timeline-item:nth-child(3) .about-tl-card {
    width: 92%;
  }

  .page-about .about-timeline-item:nth-child(4) .about-tl-card {
    width: 96%;
  }

  .page-about .about-timeline-item:nth-child(5) .about-tl-card {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-tl-card,
  .page-about .about-rule-card,
  .page-about .about-role,
  .page-about .about-flow-rule,
  .page-about .about-role::before {
    transition: none !important;
  }

  .page-about .about-tl-card:hover,
  .page-about .about-rule-card:hover,
  .page-about .about-role:hover {
    transform: none;
  }
}