.page-about {
  --about-pad-x: 20px;
  --about-pad-y: 30px;
  display: block;
  background: var(--char);
  color: var(--paper);
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-top: 24px;
  margin-bottom: 18px;
  font-size: 13px;
  color: var(--frost);
}

.page-about .breadcrumb a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .breadcrumb-sep {
  color: var(--frost);
}

/* ---------- 首屏框景 ---------- */
.page-about .about-hero {
  margin-bottom: 32px;
}

.page-about .about-hero__frame {
  display: grid;
  gap: 24px;
  padding: 26px 18px 30px;
  background: var(--indigo);
  border: 1px solid var(--line-strong);
  box-shadow: var(--shadow-1);
}

.page-about .about-hero .eyebrow {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-hero__title {
  margin: 12px 0 0;
  font-size: 38px;
  line-height: 1.08;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero__lede {
  margin: 16px 0 0;
  max-width: 640px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-figures {
  display: grid;
  gap: 0;
  margin: 0;
}

.page-about .about-figure {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding: 12px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-figure:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-figure dt {
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  line-height: 1;
  color: var(--amber);
}

.page-about .about-figure dd {
  margin: 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--frost);
}

/* ---------- 面板堆叠 ---------- */
.page-about .about-stack {
  display: flex;
  flex-direction: column;
  gap: 26px;
}

.page-about .about-panel {
  position: relative;
  padding: var(--about-pad-y) var(--about-pad-x) calc(var(--about-pad-y) + 6px);
  border: 1px solid var(--line);
  background: var(--night);
  color: var(--mist);
}

.page-about .about-panel::before {
  content: "";
  position: absolute;
  left: 0;
  top: 30px;
  width: 14px;
  height: 2px;
  background: var(--orange);
}

.page-about .about-panel--deep {
  background: var(--indigo);
}

.page-about .about-panel--night {
  background: var(--night);
}

.page-about .about-panel--paper {
  background: var(--paper);
  border-color: var(--line-ink);
  color: var(--ink);
  box-shadow: var(--shadow-1);
}

.page-about .about-panel p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.8;
}

.page-about .about-panel p + p {
  margin-top: 14px;
}

/* ---------- 章节标题 ---------- */
.page-about .about-chapter {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 16px;
  margin-bottom: 22px;
}

.page-about .chapter-num {
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--orange);
}

.page-about .chapter-title {
  margin: 0;
  font-size: 23px;
  line-height: 1.25;
  font-weight: 900;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-panel--paper .chapter-title {
  color: var(--char);
}

.page-about .about-chapter__anno {
  display: none;
}

/* ---------- 01 起点 ---------- */
.page-about .about-cols {
  display: grid;
  gap: 24px;
}

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

.page-about .about-marks li {
  display: grid;
  grid-template-columns: 50px minmax(0, 1fr);
  gap: 12px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .about-marks li:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-marks .mono {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.08em;
  color: var(--amber);
}

/* ---------- 02 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 26px;
}

.page-about .about-roles {
  display: grid;
}

.page-about .about-role {
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr);
  gap: 14px;
  padding: 18px 0;
  border-top: 1px solid var(--line-ink);
}

.page-about .about-role:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-role__num {
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--orange);
}

.page-about .about-role__body h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  color: var(--char);
}

.page-about .about-role__body p {
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .about-team__figure {
  margin: 0;
}

.page-about .about-team__figure img {
  display: block;
  width: 100%;
  max-width: 420px;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line-ink);
  background: var(--indigo);
}

.page-about .about-team__figure figcaption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--ink);
  opacity: 0.72;
}

/* ---------- 03 流程 ---------- */
.page-about .about-flow {
  display: grid;
  gap: 26px;
}

.page-about .about-flow__figure {
  margin: 0;
}

.page-about .about-flow__figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line-ink);
  background: var(--indigo);
}

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: about-step;
}

.page-about .about-step {
  position: relative;
  padding: 18px 0 18px 50px;
  border-top: 1px solid var(--line-ink);
}

.page-about .about-step:first-child {
  border-top: 0;
  padding-top: 4px;
}

.page-about .about-step::before {
  counter-increment: about-step;
  content: counter(about-step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 18px;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--orange);
}

.page-about .about-step:first-child::before {
  top: 4px;
}

.page-about .about-step h3 {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 700;
  color: var(--char);
}

.page-about .about-step p {
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .about-flow__note {
  margin-top: 24px !important;
  padding-top: 18px;
  border-top: 1px dashed var(--line-ink);
  font-size: 14px !important;
  line-height: 1.75;
  color: var(--ink);
  opacity: 0.85;
}

/* ---------- 04 里程碑 ---------- */
.page-about .about-timeline {
  display: grid;
  gap: 0;
}

.page-about .milestone {
  border: 0;
  border-left: 1px solid var(--line-strong);
  padding-left: 18px;
}

.page-about .milestone__sum {
  display: grid;
  grid-template-columns: 14px minmax(0, 1fr);
  column-gap: 10px;
  row-gap: 3px;
  padding: 14px 0 14px 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .milestone__dot {
  grid-row: 1 / span 2;
  align-self: start;
  margin-top: 5px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--orange);
  transition: background 240ms var(--ease), box-shadow 240ms var(--ease);
}

.page-about .milestone__year {
  grid-column: 2;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--amber);
}

.page-about .milestone__name {
  grid-column: 2;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
  transition: color 200ms var(--ease);
}

.page-about .milestone__sum:hover .milestone__name,
.page-about .milestone__sum:focus-visible .milestone__name {
  color: var(--cyan);
}

.page-about .milestone[open] .milestone__dot {
  background: var(--cyan);
  box-shadow: 0 0 0 5px rgba(53, 214, 200, 0.16);
}

.page-about .milestone__body {
  margin: 0 0 16px;
  padding-left: 24px;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--frost);
}

/* ---------- 05 协作 ---------- */
.page-about .about-partners {
  display: grid;
  gap: 20px;
  margin-bottom: 24px;
}

.page-about .about-partner h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-partner h3 .mono {
  font-family: var(--font-mono);
  font-size: 20px;
  color: var(--amber);
  margin-right: 2px;
}

.page-about .about-partner p {
  font-size: 14px;
  line-height: 1.75;
  color: var(--frost);
}

.page-about .about-network__note {
  margin: 0 !important;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 14.5px !important;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-map {
  margin: 26px 0 0;
}

.page-about .about-map img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

.page-about .about-map figcaption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--frost);
}

/* ---------- 06 合作与加入 ---------- */
.page-about .about-join {
  display: grid;
  gap: 26px;
}

.page-about .about-join__block {
  padding-top: 18px;
  border-top: 1px solid var(--line-ink);
}

.page-about .about-join__block:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-join__block h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  color: var(--char);
}

.page-about .about-join__block p {
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--ink);
}

.page-about .about-brief {
  padding: 22px 18px 24px;
  border: 1px solid var(--line-ink);
  background: rgba(16, 26, 51, 0.045);
}

.page-about .about-brief h3 {
  margin: 0;
  font-size: 15.5px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--char);
}

.page-about .about-checklist {
  list-style: none;
  margin: 16px 0 22px;
  padding: 0;
  display: grid;
  gap: 11px;
}

.page-about .about-checklist li {
  position: relative;
  padding-left: 22px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--ink);
}

.page-about .about-checklist li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 12px;
  height: 2px;
  background: var(--orange);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 收尾条 ---------- */
.page-about .about-tail {
  margin-top: 44px;
  border-top: 1px solid var(--line);
  background: var(--night);
}

.page-about .about-tail__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 26px;
  padding-bottom: 26px;
}

.page-about .about-tail__inner p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-tail__inner a:not(.btn) {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 214, 200, 0.4);
}

.page-about .about-tail__inner a:not(.btn):hover,
.page-about .about-tail__inner a:not(.btn):focus-visible {
  border-bottom-color: var(--cyan);
}

.page-about .about-tail__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 桌面端 ---------- */
@media (min-width: 760px) {
  .page-about .about-partners {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0;
    margin-bottom: 28px;
  }

  .page-about .about-partner {
    padding: 0 22px;
    border-left: 1px solid var(--line);
  }

  .page-about .about-partner:first-child {
    padding-left: 0;
    border-left: 0;
  }

  .page-about .about-timeline {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .milestone {
    border-left: 0;
    border-top: 2px solid var(--line-strong);
    padding-left: 0;
    padding-right: 12px;
  }

  .page-about .milestone:nth-child(1) { margin-top: 0; }
  .page-about .milestone:nth-child(2) { margin-top: 12px; }
  .page-about .milestone:nth-child(3) { margin-top: 24px; }
  .page-about .milestone:nth-child(4) { margin-top: 36px; }
  .page-about .milestone:nth-child(5) { margin-top: 48px; }
  .page-about .milestone:nth-child(6) { margin-top: 60px; }

  .page-about .milestone__body {
    padding-left: 24px;
    padding-right: 4px;
    font-size: 12.5px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    margin-bottom: 44px;
  }

  .page-about .about-hero__frame {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 0.85fr);
    gap: 48px;
    padding: 46px 44px 50px;
    align-items: start;
  }

  .page-about .about-hero__title {
    font-size: 66px;
  }

  .page-about .about-hero__lede {
    font-size: 17px;
  }

  .page-about .about-stack {
    gap: 34px;
  }

  .page-about .about-panel {
    --about-pad-x: 52px;
    --about-pad-y: 44px;
    padding: var(--about-pad-y) var(--about-pad-x) calc(var(--about-pad-y) + 12px);
  }

  .page-about .about-panel--inset {
    margin-inline-start: 5%;
  }

  .page-about .about-panel--offset {
    margin-inline-start: 2%;
    margin-inline-end: 3%;
  }

  .page-about .chapter-num {
    font-size: 40px;
  }

  .page-about .chapter-title {
    font-size: 33px;
  }

  .page-about .about-chapter {
    gap: 12px 20px;
    margin-bottom: 28px;
  }

  .page-about .about-chapter__anno {
    display: inline-block;
    align-self: stretch;
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.3em;
    color: var(--frost);
  }

  .page-about .about-panel--paper .about-chapter__anno {
    color: var(--ink);
    opacity: 0.6;
  }

  .page-about .about-cols {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 0.85fr);
    gap: 52px;
    align-items: start;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .about-team__figure {
    justify-self: end;
    width: 100%;
    max-width: 420px;
  }

  .page-about .about-flow {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
    gap: 48px;
    align-items: center;
  }

  .page-about .about-join {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.85fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .about-brief {
    padding: 26px 24px 28px;
  }

  .page-about .about-tail {
    margin-top: 56px;
  }

  .page-about .about-tail__inner {
    padding-top: 30px;
    padding-bottom: 30px;
  }
}