.page-about {
  --about-rule: rgba(11, 42, 74, .14);
  --about-ink-soft: rgba(16, 24, 32, .74);
}

.page-about .breadcrumb {
  padding-top: 18px;
  padding-bottom: 6px;
}

/* ---------- 首屏：深色甲板 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  margin-top: 12px;
  padding: clamp(26px, 5vw, 54px) clamp(20px, 4.4vw, 56px) clamp(30px, 5.4vw, 58px);
  border-radius: var(--radius-xl);
  background: linear-gradient(152deg, var(--navy) 0%, var(--navy) 42%, var(--navy-night) 100%);
  box-shadow: var(--shadow-panel);
  color: var(--paper);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto -18% -46% 34%;
  height: 78%;
  background: radial-gradient(closest-side, rgba(0, 212, 200, .34), transparent 72%);
  pointer-events: none;
}

.page-about .about-kicker {
  position: relative;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .about-hero h1 {
  position: relative;
  margin: 0;
  max-width: 20ch;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(28px, 6vw, 52px);
  line-height: 1.14;
  letter-spacing: -.01em;
}

.page-about .about-hero-lead {
  position: relative;
  margin: 18px 0 0;
  max-width: 62ch;
  font-family: var(--font-body);
  font-size: clamp(15px, 1.6vw, 17.5px);
  line-height: 1.85;
  color: rgba(247, 245, 240, .84);
}

.page-about .hero-facts {
  position: relative;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 30px 0 0;
  padding: 0;
  background: rgba(217, 222, 227, .18);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .hero-fact {
  padding: 14px 16px;
  background: rgba(6, 26, 46, .62);
}

.page-about .hero-fact dt {
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .12em;
  color: rgba(230, 255, 252, .68);
}

.page-about .hero-fact dd {
  margin: 6px 0 0;
  font-family: var(--font-head);
  font-size: 1rem;
  color: var(--paper);
}

.page-about .hero-fact .num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--cyan);
  margin-right: 4px;
}

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin-top: clamp(30px, 5vw, 52px);
}

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

.page-about .index-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .18em;
  color: var(--teal-deep);
}

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

/* ---------- 章节 ---------- */
.page-about .chapter {
  padding: clamp(34px, 5.6vw, 68px) 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .chapter--start {
  border-top: 0;
  padding-top: 0;
}

.page-about .chapter-head {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}

.page-about .big-index {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: clamp(30px, 5.6vw, 62px);
  font-weight: 700;
  line-height: 1;
  color: rgba(11, 42, 74, .16);
  letter-spacing: -.03em;
}

.page-about .chapter-intro {
  min-width: 0;
}

.page-about .chapter-intro .section-title {
  margin: 0 0 14px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(21px, 3.4vw, 32px);
  line-height: 1.3;
  color: var(--navy);
}

.page-about .chapter-intro .lead {
  margin: 0 0 12px;
  font-family: var(--font-body);
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.9;
  color: var(--about-ink-soft);
}

.page-about .chapter-intro p {
  margin: 0 0 12px;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.9;
  color: var(--about-ink-soft);
}

.page-about .chapter-intro p:last-child {
  margin-bottom: 0;
}

.page-about .inline-link {
  color: var(--teal-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .chapter-note {
  margin: 22px 0 0;
  padding-left: 14px;
  border-left: 3px solid var(--cyan);
  font-family: var(--font-body);
  font-size: .95rem;
  line-height: 1.8;
  color: var(--about-ink-soft);
}

/* ---------- 图像容器 ---------- */
.page-about .about-hero-figure {
  margin: clamp(20px, 3.4vw, 34px) 0 0;
}

.page-about .about-method-figure,
.page-about .about-tail-figure {
  margin: clamp(24px, 4vw, 40px) 0 0;
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--about-rule);
  object-fit: cover;
  background: var(--mist);
}

.page-about .about-hero-figure img {
  aspect-ratio: 16 / 8;
}

.page-about .about-method-figure img {
  aspect-ratio: 12 / 7;
}

.page-about .about-tail-figure img {
  aspect-ratio: 10 / 6;
}

.page-about .media-caption {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .04em;
  color: rgba(16, 24, 32, .56);
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  position: relative;
  margin: clamp(22px, 3.6vw, 36px) 0 0;
  padding: 0 0 0 26px;
  list-style: none;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--cyan), var(--navy) 62%, var(--mist));
}

.page-about .timeline-node {
  position: relative;
  margin-bottom: 14px;
}

.page-about .timeline-node:last-child {
  margin-bottom: 0;
}

.page-about .timeline-dot {
  position: absolute;
  left: -26px;
  top: 20px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--cyan);
  box-shadow: 0 0 0 4px rgba(0, 212, 200, .14);
}

.page-about .accordion-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  width: 100%;
  padding: 15px 16px;
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: var(--shadow-paper);
  text-align: left;
  cursor: pointer;
}

.page-about .accordion-trigger:hover {
  border-color: var(--cyan);
}

.page-about .timeline-stage {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.page-about .stage-ver {
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .14em;
  color: var(--teal-deep);
}

.page-about .stage-name {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(15px, 2vw, 18px);
  color: var(--navy);
}

.page-about .accordion-icon {
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1px solid var(--mist);
  position: relative;
}

.page-about .accordion-icon::before,
.page-about .accordion-icon::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  background: var(--navy);
  transform: translate(-50%, -50%);
}

.page-about .accordion-icon::before {
  width: 10px;
  height: 2px;
}

.page-about .accordion-icon::after {
  width: 2px;
  height: 10px;
  transition: transform .22s ease;
}

.page-about .accordion-trigger[aria-expanded="true"] .accordion-icon::after {
  transform: translate(-50%, -50%) scaleY(0);
}

.page-about .accordion-trigger[aria-expanded="true"] {
  border-color: var(--cyan);
  background: var(--pale-cyan);
}

.page-about .accordion-panel {
  overflow: hidden;
}

.page-about .accordion-panel[hidden] {
  display: none;
}

.page-about .accordion-body {
  padding: 14px 16px 4px;
  font-family: var(--font-body);
  font-size: .96rem;
  line-height: 1.9;
  color: var(--about-ink-soft);
}

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

/* ---------- 团队方法 ---------- */
.page-about .method-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(20px, 3.4vw, 34px);
}

.page-about .method-card {
  padding: 20px 20px 22px;
  border: 1px solid var(--about-rule);
  border-top: 4px solid var(--navy);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: var(--shadow-paper);
}

.page-about .method-card:nth-child(2) {
  border-top-color: var(--cyan);
}

.page-about .method-card:nth-child(3) {
  border-top-color: var(--coral);
}

.page-about .method-card:nth-child(4) {
  border-top-color: var(--teal-deep);
}

.page-about .method-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--navy);
}

.page-about .method-card p {
  margin: 0;
  font-family: var(--font-body);
  font-size: .95rem;
  line-height: 1.85;
  color: var(--about-ink-soft);
}

/* ---------- 合作生态 ---------- */
.page-about .chip-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: clamp(18px, 3vw, 28px);
}

.page-about .eco-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin-top: 18px;
}

.page-about .eco-card {
  padding: 16px 18px;
  border: 1px solid var(--about-rule);
  border-left: 4px solid var(--cyan);
  border-radius: var(--radius-sm);
  background: rgba(230, 255, 252, .5);
}

.page-about .eco-card h3 {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: .98rem;
  color: var(--navy);
}

.page-about .eco-card p {
  margin: 0;
  font-family: var(--font-body);
  font-size: .92rem;
  line-height: 1.8;
  color: var(--about-ink-soft);
}

.page-about .coverage-strip {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 22px;
  background: var(--about-rule);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .coverage-cell {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 16px 18px;
  background: var(--navy-night);
}

.page-about .coverage-num {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--cyan);
}

.page-about .coverage-label {
  font-family: var(--font-body);
  font-size: .92rem;
  line-height: 1.6;
  color: rgba(247, 245, 240, .86);
}

/* ---------- 更新节奏 ---------- */
.page-about .cadence-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin-top: clamp(20px, 3.4vw, 32px);
}

.page-about .cadence-item {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 18px;
  border: 1px dashed var(--mist);
  border-radius: var(--radius);
  background: var(--paper);
}

.page-about .cadence-tag {
  align-self: flex-start;
}

.page-about .cadence-item p {
  margin: 0;
  font-family: var(--font-body);
  font-size: .95rem;
  line-height: 1.85;
  color: var(--about-ink-soft);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3.6vw, 34px);
}

.page-about .icp-line {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 22px 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--about-rule);
  font-family: var(--font-mono);
  font-size: .78rem;
  color: rgba(16, 24, 32, .62);
}

.page-about .icp-value {
  color: var(--navy);
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

  .page-about .cadence-item {
    flex-direction: row;
    align-items: flex-start;
    gap: 14px;
  }

  .page-about .cadence-tag {
    flex: 0 0 auto;
  }
}

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: 196px minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-index {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + 24px);
    padding-right: 8px;
    border-right: 1px solid var(--about-rule);
  }

  .page-about .about-index .index-list {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin: 0;
    padding: 0;
    list-style: none;
  }

  .page-about .about-index .index-link {
    display: block;
    padding: 7px 10px;
    border-left: 2px solid transparent;
    font-family: var(--font-mono);
    font-size: .76rem;
    letter-spacing: .04em;
    color: rgba(16, 24, 32, .6);
    text-decoration: none;
    transition: color .2s ease, border-color .2s ease, background-color .2s ease;
  }

  .page-about .about-index .index-link:hover {
    color: var(--navy);
    background: var(--pale-cyan);
  }

  .page-about .about-index .index-link[aria-current="true"] {
    border-left-color: var(--cyan);
    background: var(--pale-cyan);
    color: var(--navy);
    font-weight: 700;
  }

  .page-about .method-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }

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

  .page-about .cadence-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .chapter-intro .lead {
    max-width: 68ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .accordion-icon::after,
  .page-about .about-index .index-link {
    transition: none;
  }
}
</main>