.page-about {
  --about-hair: rgba(44, 71, 65, 0.7);
  --about-tint: rgba(22, 48, 42, 0.72);
}

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

.page-about .container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.page-about .crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-top: clamp(16px, 3vw, 26px);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .crumbs a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
  outline: none;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
  padding-block: clamp(22px, 4vw, 50px) clamp(26px, 4vw, 44px);
}

.page-about .about-hero .eyebrow {
  margin: 0 0 14px;
}

.page-about .about-hero h1 {
  margin: 0;
  font-size: clamp(2.1rem, 8.6vw, 4.5rem);
  line-height: 1.03;
  letter-spacing: -0.028em;
  font-weight: 900;
  color: var(--text);
  text-wrap: balance;
}

.page-about .about-hero .lede {
  margin: 0;
  max-width: 40ch;
  color: var(--muted);
  line-height: 1.85;
}

.page-about .about-banner {
  position: relative;
  margin: 0 0 clamp(36px, 6vw, 76px);
  border-radius: var(--r-xl);
  border: 1px solid var(--line);
  background: linear-gradient(160deg, var(--layer), var(--press));
  overflow: hidden;
}

.page-about .about-banner img {
  display: block;
  width: 100%;
  aspect-ratio: 1400 / 800;
  object-fit: cover;
}

.page-about .about-banner__cap {
  margin: 0;
  padding: 12px 16px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

/* ---------- 通用区块头部 ---------- */
.page-about .section {
  padding-block: clamp(40px, 6.5vw, 78px);
}

.page-about .about-head {
  max-width: 62ch;
  margin-bottom: clamp(24px, 4vw, 42px);
}

.page-about .about-head h2 {
  margin: 10px 0 14px;
  font-size: clamp(1.6rem, 5.2vw, 2.6rem);
  line-height: 1.12;
  letter-spacing: -0.02em;
}

.page-about .about-head .body-text {
  margin: 0;
  color: var(--muted);
  line-height: 1.85;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(44, 71, 65, 0.28) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(44, 71, 65, 0.28) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: radial-gradient(110% 78% at 18% 26%, #000 0%, transparent 72%);
  mask-image: radial-gradient(110% 78% at 18% 26%, #000 0%, transparent 72%);
}

.page-about .about-timeline .container {
  position: relative;
}

.page-about .tl {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 20px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--line) 16%, var(--line) 84%, transparent 100%);
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 clamp(26px, 4vw, 42px) 34px;
  outline: none;
  border-radius: var(--r-md);
}

.page-about .tl-item:last-child {
  padding-bottom: 0;
}

.page-about .tl-item:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 6px;
}

.page-about .tl-dot {
  position: absolute;
  left: 4px;
  top: 9px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 4px rgba(242, 169, 59, 0.12);
  transition: box-shadow var(--t) var(--ease), transform var(--t) var(--ease);
}

.page-about .tl-item:hover .tl-dot,
.page-about .tl-item:focus-visible .tl-dot {
  transform: scale(1.2);
  box-shadow: 0 0 0 7px rgba(242, 169, 59, 0.2);
}

.page-about .tl-year {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .tl-title {
  margin: 0 0 8px;
  font-size: clamp(1.0625rem, 2.6vw, 1.375rem);
  line-height: 1.4;
  letter-spacing: -0.012em;
  font-weight: 700;
  color: var(--text);
}

.page-about .tl-desc {
  margin: 0;
  max-width: 56ch;
  font-size: 0.975rem;
  line-height: 1.88;
  color: var(--muted);
}

.page-about .tl-more {
  margin: 10px 0 0;
  max-width: 56ch;
  padding-left: 12px;
  border-left: 2px solid var(--about-hair);
  font-size: 0.875rem;
  line-height: 1.78;
  color: rgba(159, 184, 176, 0.86);
}

/* 桌面端把补充说明收起，悬停或键盘聚焦展开 */
@media (hover: hover) and (min-width: 760px) {
  .page-about .tl-more {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    border-left-color: transparent;
    transition:
      max-height var(--t) var(--ease),
      opacity var(--t) var(--ease),
      margin-top var(--t) var(--ease),
      border-color var(--t) var(--ease);
  }

  .page-about .tl-item:hover .tl-more,
  .page-about .tl-item:focus-visible .tl-more {
    max-height: 12em;
    margin-top: 10px;
    opacity: 1;
    border-left-color: var(--about-hair);
  }
}

/* ---------- 三条标准 ---------- */
.page-about .principles {
  display: grid;
  gap: 14px;
  max-width: 80ch;
}

.page-about .principle {
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--layer);
  overflow: hidden;
  transition: border-color var(--t) var(--ease), background-color var(--t) var(--ease);
}

.page-about .principle:hover {
  border-color: rgba(43, 227, 192, 0.4);
}

.page-about .principle[open] {
  border-color: rgba(43, 227, 192, 0.5);
  background: rgba(22, 48, 42, 0.94);
}

.page-about .principle__head {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 20px;
  cursor: pointer;
  list-style: none;
  color: var(--text);
}

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

.page-about .principle__head:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -4px;
  border-radius: var(--r-lg);
}

.page-about .principle__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-about .principle__title {
  flex: 1 1 auto;
  font-size: clamp(1rem, 2.4vw, 1.1875rem);
  font-weight: 700;
  line-height: 1.45;
}

.page-about .principle__chev {
  flex: 0 0 auto;
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--muted);
  border-bottom: 2px solid var(--muted);
  transform: rotate(45deg) translate(-2px, -2px);
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
}

.page-about .principle[open] .principle__chev {
  transform: rotate(-135deg) translate(-2px, -2px);
  border-color: var(--cyan);
}

.page-about .principle__body {
  padding: 0 20px 20px;
  font-size: 0.975rem;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .principle__body p {
  margin: 0 0 10px;
  max-width: 58ch;
}

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

.page-about .principle__body a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(43, 227, 192, 0.35);
  transition: border-color var(--t-fast) var(--ease);
}

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

/* ---------- 团队 ---------- */
.page-about .about-team__grid {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
}

.page-about .about-team h2 {
  margin: 10px 0 16px;
  font-size: clamp(1.6rem, 5.2vw, 2.6rem);
  line-height: 1.12;
  letter-spacing: -0.02em;
}

.page-about .about-team__copy .body-text {
  margin: 0;
  max-width: 52ch;
  color: var(--muted);
  line-height: 1.85;
}

.page-about .role-list {
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .role {
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.page-about .role dt {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 6px;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
}

.page-about .role__num {
  font-family: var(--font-mono);
  font-size: 1.375rem;
  line-height: 1;
  color: var(--cyan);
}

.page-about .role dd {
  margin: 0;
  max-width: 52ch;
  font-size: 0.9625rem;
  line-height: 1.82;
  color: var(--muted);
}

.page-about .about-team__figure {
  margin: 0;
  align-self: start;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  background: var(--layer);
  overflow: hidden;
}

.page-about .about-team__figure img {
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.page-about .about-team__cap {
  padding: 12px 16px;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

/* ---------- 覆盖范围 ---------- */
.page-about .coverage-grid {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
}

.page-about .coverage-stats {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .coverage-stats li {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--about-tint);
  transition: border-color var(--t) var(--ease), transform var(--t) var(--ease);
}

.page-about .coverage-stats li:hover {
  transform: translateY(-2px);
  border-color: rgba(43, 227, 192, 0.42);
}

.page-about .coverage-stats__num {
  font-family: var(--font-mono);
  font-size: clamp(1.65rem, 7vw, 2.75rem);
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan);
  word-break: break-word;
}

.page-about .coverage-stats__unit {
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--muted);
}

.page-about .coverage-figure {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  overflow: hidden;
  background: var(--press);
}

.page-about .coverage-figure img {
  display: block;
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
}

.page-about .cadence {
  margin: clamp(28px, 4vw, 48px) 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .cadence__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .cadence__row dt {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .cadence__row dd {
  margin: 0;
  max-width: 64ch;
  font-size: 0.95rem;
  line-height: 1.82;
  color: var(--muted);
}

/* ---------- 语言 ---------- */
.page-about .about-language__inner {
  max-width: 70ch;
  padding: clamp(22px, 4vw, 42px);
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  background: linear-gradient(140deg, var(--layer), rgba(16, 32, 28, 0.55));
}

.page-about .about-language h2 {
  margin: 10px 0 16px;
  font-size: clamp(1.5rem, 4.8vw, 2.35rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.page-about .about-language .body-text {
  margin: 0;
  max-width: 62ch;
  color: var(--muted);
  line-height: 1.88;
}

.page-about .about-language .body-text + .body-text {
  margin-top: 14px;
}

/* ---------- 下一步 ---------- */
.page-about .next-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .next-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 22px;
  text-decoration: none;
  color: inherit;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--layer);
  transition:
    transform var(--t) var(--ease),
    border-color var(--t) var(--ease),
    background-color var(--t) var(--ease);
}

.page-about .next-card:hover,
.page-about .next-card:focus-visible {
  transform: translateY(-2px);
  border-color: var(--cyan);
  background: rgba(22, 48, 42, 0.96);
  outline: none;
}

.page-about .next-card:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .next-card__desc {
  font-size: 0.9125rem;
  line-height: 1.78;
  color: var(--muted);
}

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

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

  .page-about .cadence__row {
    grid-template-columns: 180px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }

  .page-about .about-banner__cap {
    position: absolute;
    left: 16px;
    bottom: 16px;
    width: fit-content;
    max-width: calc(100% - 32px);
    padding: 8px 16px;
    border: 1px solid var(--line);
    border-radius: var(--r-pill);
    background: rgba(4, 16, 14, 0.78);
    color: var(--text);
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.22fr) minmax(0, 0.78fr);
    align-items: end;
    gap: clamp(32px, 5vw, 72px);
  }

  .page-about .about-hero__lead {
    margin-left: -0.045em;
  }

  .page-about .about-hero h1 {
    max-width: 14ch;
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: start;
  }

  .page-about .coverage-grid {
    grid-template-columns: minmax(0, 1.32fr) minmax(0, 0.68fr);
    align-items: start;
  }

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

  .page-about .tl-item {
    padding-left: 40px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-more,
  .page-about .tl-dot,
  .page-about .principle,
  .page-about .principle__chev,
  .page-about .coverage-stats li,
  .page-about .next-card {
    transition: none;
  }
}