.page-about {
  --ab-rail: 40px;
  --ab-board-gap: 40px;
  background-color: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
}

.page-about .crumbs {
  margin: 0 0 4px;
}

/* ---------------- 首屏 ---------------- */
.page-about .about-hero {
  padding-top: 4px;
  padding-bottom: 12px;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 26px;
}

.page-about .about-hero__lead {
  min-width: 0;
}

.page-about .about-hero h1 {
  margin: 12px 0 18px;
  font-size: clamp(28px, 6.2vw, 54px);
  line-height: 1.14;
  letter-spacing: -0.012em;
  font-weight: 900;
  color: var(--blue);
}

.page-about .about-hero__intro {
  margin: 0 0 24px;
  max-width: 62ch;
  font-size: var(--fs-17);
  line-height: 1.85;
  color: var(--slate);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-hero__facts > div {
  min-width: 0;
  padding: 12px 12px 14px;
  background: var(--white);
}

.page-about .about-hero__facts dt {
  margin: 0 0 5px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--slate);
}

.page-about .about-hero__facts dd {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.5;
  font-weight: 600;
  color: var(--blue);
}

.page-about .about-hero__figure {
  margin: 0;
  border-bottom: 3px solid var(--yellow);
}

.page-about .media-frame {
  max-width: 100%;
  overflow: hidden;
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------------- 画板主体 ---------------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  padding: 8px 0 0;
}

.page-about .about-board {
  display: grid;
  grid-template-columns: var(--ab-rail) minmax(0, 1fr);
  gap: 12px;
  padding-bottom: var(--ab-board-gap);
}

.page-about .about-board__rail {
  position: relative;
  padding-top: 13px;
}

.page-about .about-board__rail::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: calc(-1 * var(--ab-board-gap));
  left: 50%;
  width: 1px;
  margin-left: -0.5px;
  background: var(--line-strong);
}

.page-about .about-board:last-child .about-board__rail::before {
  bottom: 0;
}

.page-about .about-board__num {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  margin: 0 auto;
  background: var(--blue);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
}

.page-about .about-board__fold {
  min-width: 0;
}

.page-about .about-board__tab {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 14px;
  list-style: none;
  cursor: pointer;
  background: var(--blue);
  color: var(--white);
  border: 1px solid var(--blue);
  border-bottom: 2px solid var(--yellow);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
}

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

.page-about .about-board__tab::after {
  content: "＋";
  font-size: 13px;
  line-height: 1;
  color: var(--yellow);
}

.page-about .about-board__fold[open] > .about-board__tab::after {
  content: "－";
}

.page-about .about-board__body {
  min-width: 0;
  padding: 22px 16px 24px;
  background: var(--white);
  border: 1px solid var(--line);
  border-top: 0;
}

.page-about .about-board__body h2 {
  margin: 0 0 14px;
  font-size: var(--fs-21);
  line-height: 1.32;
  font-weight: 900;
  letter-spacing: -0.005em;
  color: var(--blue);
}

.page-about .about-board__body p {
  margin: 0 0 1.15em;
  font-size: var(--fs-17);
  line-height: 1.85;
  color: var(--slate);
}

.page-about .about-board__body > p:last-of-type {
  margin-bottom: 0;
}

/* ---------------- 数字条 ---------------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-stats li {
  min-width: 0;
  padding: 14px 8px 0 0;
}

.page-about .about-stats li + li {
  padding-left: 12px;
  border-left: 1px solid var(--line);
}

.page-about .about-stats__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-28);
  line-height: 1.1;
  color: var(--ink);
}

.page-about .about-stats__label {
  display: block;
  margin-top: 5px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--slate);
}

/* ---------------- 三条栏目 ---------------- */
.page-about .about-channels {
  display: grid;
  gap: 1px;
  margin-top: 22px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-channel {
  min-width: 0;
  padding: 18px 16px 20px;
  background: var(--white);
  transition: background var(--t);
}

.page-about .about-channel:hover {
  background: var(--paper);
}

.page-about .about-channel h3 {
  margin: 12px 0 8px;
  font-size: var(--fs-17);
  line-height: 1.45;
  color: var(--blue);
}

.page-about .about-channel p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--slate);
}

/* ---------------- 团队 ---------------- */
.page-about .about-team__figure {
  margin: 20px 0 0;
  border-bottom: 2px solid var(--teal);
}

.page-about .about-teams {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  margin-top: 20px;
}

.page-about .about-team {
  min-width: 0;
  padding: 16px 0 18px;
  border-top: 1px solid var(--line);
  transition: background var(--t);
}

.page-about .about-team h3 {
  margin: 0 0 8px;
  font-size: var(--fs-17);
  color: var(--blue);
}

.page-about .about-team p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--slate);
}

/* ---------------- 协作 ---------------- */
.page-about .about-collab__figure {
  margin: 22px 0 0;
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
  padding-top: 12px;
}

/* ---------------- 阶段轴 ---------------- */
.page-about .about-stages {
  position: relative;
  margin: 22px 0 0;
  padding: 0 0 0 22px;
  list-style: none;
  border-left: 1px solid var(--line-strong);
}

.page-about .about-stage {
  position: relative;
  padding: 0 0 24px;
  opacity: 0.62;
  transition: opacity var(--t-slow);
}

.page-about .about-stage:last-child {
  padding-bottom: 2px;
}

.page-about .about-stage::before {
  content: "";
  position: absolute;
  top: 5px;
  left: -27px;
  width: 9px;
  height: 9px;
  background: var(--paper);
  border: 1px solid var(--line-strong);
  transition: background var(--t-slow), border-color var(--t-slow);
}

.page-about .about-stage[data-lit] {
  opacity: 1;
}

.page-about .about-stage[data-lit]::before {
  background: var(--yellow);
  border-color: var(--yellow);
}

.page-about .about-stage__step {
  display: block;
  margin-bottom: 5px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--teal);
}

.page-about .about-stage__title {
  margin: 0 0 6px;
  font-size: var(--fs-17);
  line-height: 1.45;
  color: var(--blue);
}

.page-about .about-stage__desc {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--slate);
}

/* ---------------- 强调块 ---------------- */
.page-about .about-note {
  margin-top: 22px;
  padding: 16px 16px 16px 18px;
  background: var(--paper);
  border-left: 3px solid var(--teal);
}

.page-about .about-note p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--ink);
}

/* ---------------- 荣誉 ---------------- */
.page-about .about-honors {
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-honors li {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 12px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-honors__no {
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--teal);
}

.page-about .about-honors__text {
  font-size: var(--fs-15);
  line-height: 1.78;
  color: var(--slate);
}

/* ---------------- 收束 ---------------- */
.page-about .about-cta {
  padding-top: 8px;
  padding-bottom: 64px;
}

.page-about .about-cta__panel {
  padding: 30px 20px 32px;
  background: var(--blue);
  border-bottom: 3px solid var(--yellow);
}

.page-about .about-cta__copy h2 {
  margin: 0 0 12px;
  font-size: var(--fs-21);
  line-height: 1.3;
  font-weight: 900;
  color: var(--white);
}

.page-about .about-cta__copy p {
  margin: 0 0 22px;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: rgba(244, 247, 250, 0.78);
}

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

.page-about .about-cta__panel .btn--ghost {
  color: var(--white);
  border-color: rgba(244, 247, 250, 0.45);
}

/* ---------------- 断点 ---------------- */
@media (min-width: 768px) {
  .page-about {
    --ab-rail: 56px;
    --ab-board-gap: 48px;
  }

  .page-about .about-board__body {
    padding: 28px 28px 30px;
  }

  .page-about .about-board__body h2 {
    font-size: var(--fs-28);
    margin-bottom: 16px;
  }

  .page-about .about-board__num {
    width: 36px;
    height: 36px;
    font-size: 13px;
  }

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

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

  .page-about .about-team {
    padding: 18px 18px 18px 0;
  }

  .page-about .about-team + .about-team {
    padding-left: 18px;
    border-left: 1px solid var(--line);
  }

  .page-about .about-team:hover {
    background: rgba(11, 44, 74, 0.04);
  }

  .page-about .about-cta__panel {
    padding: 44px 40px 46px;
  }

  .page-about .about-cta__copy h2 {
    font-size: var(--fs-40);
  }

  .page-about .about-cta__panel {
    display: grid;
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: 36px;
    align-items: center;
  }
}

@media (min-width: 980px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.06fr) minmax(0, 1fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .about-hero {
    padding-bottom: 24px;
  }

  .page-about .about-collab__figure {
    margin-top: 26px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-board--narrow .about-board__fold {
    max-width: 76%;
  }

  .page-about .about-stage {
    padding-bottom: 26px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stage,
  .page-about .about-stage::before,
  .page-about .about-channel,
  .page-about .about-team {
    transition: none;
  }
}