/* ===== 品牌故事 · page-about ===== */
.page-about {
  --about-surface: linear-gradient(168deg, rgba(31, 58, 95, 0.42) 0%, rgba(6, 16, 32, 0.34) 100%);
  --about-rule: rgba(168, 230, 207, 0.14);
  color: var(--fg);
}

.page-about section[id] {
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-copy {
  margin: 0 0 18px;
  color: var(--fg-muted);
  font-size: 0.98rem;
  line-height: 1.86;
}

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

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  margin-bottom: clamp(24px, 4.5vw, 46px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding-top: calc(var(--header-h) + clamp(14px, 3.5vw, 38px));
  padding-bottom: clamp(40px, 7vw, 78px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -28%;
  right: -24%;
  width: min(740px, 98vw);
  height: min(740px, 98vw);
  background: radial-gradient(circle at 42% 42%, rgba(255, 140, 66, 0.24), transparent 62%);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  z-index: -1;
  bottom: -42%;
  left: -22%;
  width: min(560px, 84vw);
  height: min(560px, 84vw);
  background: radial-gradient(circle at 50% 50%, rgba(58, 175, 169, 0.18), transparent 64%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(30px, 5vw, 54px);
  align-items: start;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(2.05rem, 6.6vw, 3.95rem);
  line-height: 1.05;
  letter-spacing: 0.01em;
  color: var(--cream);
  text-wrap: balance;
}

.page-about .about-hero .lede {
  margin: 20px 0 0;
  max-width: 62ch;
  color: var(--fg-muted);
  font-size: clamp(0.98rem, 1.6vw, 1.08rem);
  line-height: 1.88;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

/* 章节索引 */
.page-about .about-index {
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: var(--about-surface);
  padding: clamp(18px, 3vw, 26px);
  box-shadow: var(--shadow);
}

.page-about .about-index__head {
  margin: 0 0 14px;
  font-size: 0.7rem;
  letter-spacing: 0.24em;
  color: var(--fg-dim);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .about-index__list a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 12px;
  font-size: 0.94rem;
  color: var(--fg-muted);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color var(--speed) ease, border-color var(--speed) ease, background var(--speed) ease;
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--cream);
  border-left-color: var(--amber);
  background: rgba(255, 140, 66, 0.07);
}

.page-about .about-index__num {
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  color: var(--jade);
}

/* ---------- 通用图卡 ---------- */
.page-about .about-figure {
  position: relative;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: var(--surface-2);
  box-shadow: var(--shadow);
}

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

.page-about .about-figure__caption {
  display: block;
  padding: 12px 16px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--fg-dim);
  border-top: 1px solid var(--about-rule);
  background: rgba(6, 16, 32, 0.4);
}

/* ---------- 01 品牌起源 ---------- */
.page-about .about-origin__grid {
  display: grid;
  gap: clamp(26px, 4.5vw, 52px);
  align-items: start;
}

.page-about .about-origin .section-head {
  margin-bottom: 22px;
}

.page-about .about-pillars {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-pillars li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-size: 0.94rem;
  color: var(--fg-muted);
  line-height: 1.7;
}

.page-about .about-pillars__dot {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 4px rgba(255, 140, 66, 0.14);
  transform: translateY(-2px);
}

.page-about .about-pillars__dot--jade {
  background: var(--jade);
  box-shadow: 0 0 0 4px rgba(58, 175, 169, 0.16);
}

.page-about .about-pillars__dot--gold {
  background: var(--gold);
  box-shadow: 0 0 0 4px rgba(255, 209, 102, 0.16);
}

/* ---------- 02 版本迭代 ---------- */
.page-about .about-versions__head {
  margin-bottom: clamp(22px, 3.5vw, 34px);
}

.page-about .about-versions__head .lede {
  max-width: 64ch;
  color: var(--fg-muted);
  line-height: 1.86;
}

.page-about .about-versions__filter {
  margin-bottom: clamp(26px, 4vw, 42px);
}

.page-about .about-versions__grid {
  display: grid;
  gap: clamp(28px, 5vw, 56px);
  align-items: start;
}

/* 时间轴 */
.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 10px;
  bottom: 26px;
  width: 1px;
  background: linear-gradient(180deg, var(--amber) 0%, var(--jade) 46%, rgba(58, 175, 169, 0.06) 100%);
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 clamp(28px, 4.4vw, 46px) clamp(28px, 4vw, 44px);
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 17px;
  height: 17px;
  border-radius: 50%;
  background: var(--ink-deep);
  border: 2px solid var(--amber-deep);
  box-shadow: 0 0 0 5px rgba(255, 140, 66, 0.1);
  transition: border-color var(--speed) ease, box-shadow var(--speed) ease, transform var(--speed) ease;
}

.page-about .timeline__item:hover::before,
.page-about .timeline__item:focus-within::before {
  border-color: var(--jade);
  box-shadow: 0 0 0 8px rgba(58, 175, 169, 0.16);
  transform: scale(1.1);
}

.page-about .timeline__top {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 4px;
}

.page-about .timeline__year {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(2.2rem, 7vw, 3.5rem);
  line-height: 0.94;
  letter-spacing: 0.03em;
  color: var(--gold);
}

.page-about .timeline__title {
  margin: 6px 0 8px;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.14rem, 2.6vw, 1.5rem);
  letter-spacing: 0.02em;
  color: var(--cream);
}

.page-about .timeline__summary {
  margin: 0;
  font-size: 0.96rem;
  line-height: 1.78;
  color: var(--fg);
}

.page-about .timeline__detail {
  margin-top: 10px;
  padding-left: 14px;
  border-left: 1px solid var(--about-rule);
  color: var(--fg-dim);
  font-size: 0.9rem;
  line-height: 1.8;
  transition: border-color var(--speed) ease, color var(--speed) ease;
}

.page-about .timeline__item:hover .timeline__detail,
.page-about .timeline__item:focus-within .timeline__detail {
  border-left-color: var(--line-strong);
  color: var(--fg-muted);
}

.page-about .timeline__detail p {
  margin: 0;
}

/* ---------- 03 技术底座 ---------- */
.page-about .about-infra__grid {
  display: grid;
  gap: clamp(26px, 4.5vw, 52px);
  align-items: center;
}

.page-about .about-infra .section-head {
  margin-bottom: 20px;
}

.page-about .about-metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 14px;
  margin-top: 26px;
}

.page-about .about-metric {
  padding: 18px 16px;
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: var(--about-surface);
}

.page-about .about-metric__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.5rem;
  letter-spacing: -0.01em;
  color: var(--gold);
}

.page-about .about-metric__label {
  display: block;
  margin-top: 8px;
  font-size: 0.84rem;
  line-height: 1.62;
  color: var(--fg-muted);
}

/* ---------- 04 覆盖规模 ---------- */
.page-about .about-reach__head {
  margin-bottom: clamp(24px, 4vw, 40px);
}

.page-about .about-reach__head .lede {
  max-width: 66ch;
  color: var(--fg-muted);
  line-height: 1.86;
}

.page-about .about-reach__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--about-rule);
  background: var(--about-rule);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-reach__cell {
  padding: clamp(20px, 3.2vw, 30px) clamp(16px, 2.6vw, 26px);
  background: linear-gradient(180deg, rgba(14, 36, 64, 0.92) 0%, rgba(6, 16, 32, 0.92) 100%);
}

.page-about .about-reach__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 4vw, 2rem);
  letter-spacing: -0.02em;
  color: var(--jade-soft);
}

.page-about .about-reach__label {
  display: block;
  margin-top: 8px;
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--fg-muted);
}

.page-about .about-reach__note {
  margin: clamp(22px, 3.4vw, 32px) 0 0;
  padding-left: 16px;
  border-left: 2px solid var(--amber-deep);
  color: var(--fg-muted);
  font-size: 0.92rem;
  line-height: 1.82;
}

/* ---------- 05 未来规划 ---------- */
.page-about .about-ahead .section-head {
  margin-bottom: clamp(18px, 3vw, 28px);
}

.page-about .ahead-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .ahead-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: clamp(14px, 3vw, 34px);
  padding: clamp(20px, 3.4vw, 32px) 0;
  border-bottom: 1px solid var(--about-rule);
  align-items: start;
}

.page-about .ahead-item__num {
  padding-top: 6px;
  font-size: 0.82rem;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .ahead-item__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.1rem, 2.4vw, 1.4rem);
  letter-spacing: 0.02em;
  color: var(--cream);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta {
  position: relative;
  margin-top: clamp(40px, 7vw, 82px);
  padding: clamp(36px, 6vw, 66px) 0;
  border-top: 1px solid var(--line-strong);
  background: linear-gradient(115deg, rgba(255, 140, 66, 0.15) 0%, rgba(58, 175, 169, 0.12) 56%, rgba(6, 16, 32, 0) 100%);
}

.page-about .about-cta__inner {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
  align-items: center;
}

.page-about .about-cta__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.5rem, 4vw, 2.3rem);
  letter-spacing: 0.02em;
  color: var(--cream);
}

.page-about .about-cta__text-body {
  margin: 0;
  max-width: 60ch;
  color: var(--fg-muted);
  font-size: 0.96rem;
  line-height: 1.84;
}

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

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

  .page-about .ahead-item {
    grid-template-columns: 64px minmax(0, 1fr);
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 0.82fr);
    gap: clamp(40px, 6vw, 86px);
  }

  .page-about .about-origin__grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: clamp(36px, 5vw, 64px);
    align-items: center;
  }

  .page-about .about-infra__grid {
    grid-template-columns: minmax(0, 0.88fr) minmax(0, 1.12fr);
    gap: clamp(34px, 5vw, 60px);
  }

  .page-about .about-reach__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1.3fr) auto;
    gap: clamp(28px, 5vw, 64px);
  }
}

@media (min-width: 960px) {
  .page-about .about-versions__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.68fr);
    gap: clamp(36px, 5vw, 64px);
  }

  .page-about .about-versions__figure {
    position: sticky;
    top: calc(var(--header-h) + 30px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .timeline__item::before,
  .page-about .timeline__detail,
  .page-about .about-index__list a {
    transition: none;
  }
}