/* ============ 页面作用域变量 ============ */
.page-about {
  --about-rule: rgba(201, 162, 39, 0.3);
  --about-hair: rgba(168, 180, 190, 0.16);
  --about-celadon-line: rgba(111, 168, 147, 0.45);
  --about-year-size: clamp(1.9rem, 6vw, 2.9rem);
  --about-node-off: rgba(168, 180, 190, 0.4);
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  padding: 1.75rem 0 2.75rem;
  border-bottom: 1px solid var(--about-hair);
  background:
    radial-gradient(92% 74% at 88% -12%, rgba(201, 162, 39, 0.1), transparent 62%),
    linear-gradient(180deg, rgba(14, 31, 48, 0.6), transparent 80%);
}

.page-about .about-hero__grid {
  display: grid;
  gap: 1.75rem;
  margin-top: 1.5rem;
}

.page-about .about-hero__copy .display {
  margin: 0.75rem 0 1.25rem;
}

.page-about .about-hero__copy .lead {
  margin: 0;
  max-width: 46ch;
}

.page-about .about-hero__figure {
  margin: 0;
  border: 1px solid var(--about-rule);
  background: var(--ink-slate);
  overflow: hidden;
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 12 / 7;
  object-fit: cover;
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 2rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
}

.page-about .about-hero__facts > li {
  background: var(--ink-abyss);
  padding: 1rem 0.8rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.page-about .about-hero__fact-num {
  font-size: clamp(1.3rem, 4.4vw, 1.85rem);
  line-height: 1;
  color: var(--gold-light);
  letter-spacing: 0.01em;
}

.page-about .about-hero__fact-label {
  font-size: 0.8125rem;
  line-height: 1.5;
  color: var(--mist);
}

/* ============ 主体骨架：左索引 + 主区 ============ */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2rem;
  padding: 2.75rem 0 3.5rem;
}

.page-about .about-main > .section {
  padding: 2.25rem 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-main > .section:first-child {
  padding-top: 0;
  border-top: 0;
}

/* ============ 左侧索引 ============ */
.page-about .about-rail .rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0.35rem;
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-rail .rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail .rail__link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 0.8rem;
  border: 1px solid var(--about-hair);
  background: var(--glass);
  color: var(--rice);
  font-size: 0.875rem;
  line-height: 1.4;
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 160ms var(--ease), color 160ms var(--ease);
}

.page-about .about-rail .rail__link:hover,
.page-about .about-rail .rail__link:focus-visible {
  border-color: var(--gold);
  color: var(--gold-light);
}

.page-about .rail__num {
  font-size: 0.72rem;
  color: var(--gold);
  letter-spacing: 0.08em;
}

.page-about .about-rail .rail__meta {
  margin: 1rem 0 0;
  font-size: 0.8125rem;
  line-height: 1.75;
  color: var(--mist);
}

/* ============ 我们在做什么 ============ */
.page-about .about-brief__text {
  margin: 1.25rem 0 0;
  padding-left: 1.15rem;
  border-left: 2px solid var(--gold);
  font-family: var(--font-serif);
  font-size: 1.0625rem;
  line-height: 1.95;
  color: var(--rice);
}

.page-about .about-brief__note {
  margin: 1.25rem 0 0;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--mist);
}

/* ============ 年份快捷跳转 ============ */
.page-about .year-jump {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0 0 0.25rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.page-about .year-jump .chip {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  text-decoration: none;
}

/* ============ 时间轴 ============ */
.page-about .timeline {
  position: relative;
  margin-top: 1.75rem;
  padding-left: 2.5rem;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 0.55rem;
  bottom: 0.55rem;
  width: 1px;
  background: linear-gradient(
    180deg,
    rgba(201, 162, 39, 0.92) 0%,
    rgba(201, 162, 39, 0.45) 36%,
    rgba(111, 168, 147, 0.42) 70%,
    rgba(168, 180, 190, 0.18) 100%
  );
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: 2.25rem;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -2.5rem;
  top: 0.62rem;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--gold);
  border: 1px solid var(--gold);
  transition: background-color 320ms var(--ease), border-color 320ms var(--ease), box-shadow 320ms var(--ease);
}

.js .page-about .timeline__item::before {
  background: var(--ink-abyss);
  border-color: var(--about-node-off);
}

.js .page-about .timeline__item.is-visible::before {
  background: var(--gold);
  border-color: var(--gold-light);
  box-shadow: 0 0 0 5px rgba(201, 162, 39, 0.13);
}

.page-about .timeline__year {
  margin: 0 0 0.35rem;
  font-size: var(--about-year-size);
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--gold-light);
}

.page-about .timeline__title {
  margin: 0 0 0.55rem;
  font-size: 1.125rem;
  line-height: 1.5;
  color: var(--rice);
}

.page-about .timeline__text {
  margin: 0;
  max-width: 46ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .timeline__figure {
  position: relative;
  margin: 0 0 2.25rem;
  border: 1px solid var(--about-hair);
  background: var(--ink-slate);
  overflow: hidden;
}

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

.page-about .timeline__figure .media__caption {
  padding: 0.7rem 0.9rem;
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--mist);
  border-top: 1px solid var(--about-hair);
}

/* ============ 团队分工 ============ */
.page-about .crew {
  display: grid;
  gap: 1px;
  margin-top: 1.5rem;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
}

.page-about .crew__item {
  background: var(--ink-slate);
  padding: 1.5rem 1.2rem 1.65rem;
}

.page-about .crew__badge {
  margin: 0 0 0.8rem;
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--gold);
}

.page-about .crew__title {
  margin: 0 0 0.65rem;
  font-size: 1.25rem;
  color: var(--rice);
}

.page-about .crew__text {
  margin: 0 0 1.1rem;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .crew__text a {
  color: var(--gold-light);
  text-decoration: none;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .crew__text a:hover,
.page-about .crew__text a:focus-visible {
  border-bottom-color: var(--gold-light);
}

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

.page-about .datalist__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--about-hair);
  font-size: 0.8125rem;
}

.page-about .datalist__key {
  color: var(--mist);
}

.page-about .datalist__val {
  color: var(--celadon);
  text-align: right;
}

/* ============ 服务范围与规模 ============ */
.page-about .scale-stats {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--about-celadon-line);
  border: 1px solid var(--about-celadon-line);
}

.page-about .scale-stats > li {
  background:
    linear-gradient(180deg, rgba(111, 168, 147, 0.14), rgba(111, 168, 147, 0) 82%),
    var(--ink-abyss);
  padding: 1.15rem 1rem 1.25rem;
}

.page-about .scale-stat__num {
  display: block;
  font-size: clamp(1.55rem, 5vw, 2.1rem);
  line-height: 1.12;
  color: var(--celadon);
  letter-spacing: 0.01em;
}

.page-about .scale-stat__label {
  display: block;
  margin-top: 0.45rem;
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .plates {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
  margin-top: 1.75rem;
}

.page-about .plates__item {
  padding: 1.25rem 1.15rem 1.4rem;
  background: var(--ink-slate);
  border: 1px solid var(--about-hair);
  transition: border-color 160ms var(--ease);
}

.page-about .plates__item:hover {
  border-color: var(--about-rule);
}

.page-about .plates__item h3 {
  margin: 0.7rem 0 0.55rem;
  font-size: 1.0625rem;
  color: var(--rice);
}

.page-about .plates__item p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--mist);
}

/* ============ 服务标准 ============ */
.page-about .standards-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.75rem;
  margin-top: 1.5rem;
}

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

.page-about .standards__item {
  position: relative;
  padding: 0 0 1.1rem 2.4rem;
  margin-bottom: 1.1rem;
  border-bottom: 1px solid var(--about-hair);
  font-size: 1rem;
  line-height: 1.85;
  color: var(--rice);
}

.page-about .standards__item:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: 0;
}

.page-about .standards__item::before {
  counter-increment: std;
  content: counter(std, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 0.28rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--gold);
}

.page-about .standards__figure {
  margin: 0;
  border: 1px solid var(--about-hair);
  background: var(--ink-slate);
  overflow: hidden;
}

.page-about .standards__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .standards__figure .media__caption {
  padding: 0.7rem 0.9rem;
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--mist);
  border-top: 1px solid var(--about-hair);
}

/* ============ 收尾 ============ */
.page-about .about-next__panel {
  padding: 1.75rem 1.4rem 2rem;
  border: 1px solid var(--about-rule);
  background:
    linear-gradient(135deg, rgba(201, 162, 39, 0.13), rgba(7, 19, 31, 0) 62%),
    var(--ink-slate);
}

.page-about .about-next__title {
  margin: 0 0 0.75rem;
  font-size: 1.5rem;
  color: var(--rice);
}

.page-about .about-next__text {
  margin: 0 0 1.35rem;
  max-width: 54ch;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

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

@media (min-width: 700px) {
  .page-about .plates {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .plates > *:nth-child(1),
  .page-about .plates > *:nth-child(2) {
    grid-column: span 3;
  }

  .page-about .plates > *:nth-child(3),
  .page-about .plates > *:nth-child(4),
  .page-about .plates > *:nth-child(5) {
    grid-column: span 2;
  }

  .page-about .plates > .plates__item--wide {
    grid-column: span 6;
  }
}

@media (min-width: 760px) {
  .page-about .crew {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 860px) {
  .page-about .timeline {
    padding-left: 3rem;
  }

  .page-about .timeline__item {
    display: grid;
    grid-template-columns: 9rem minmax(0, 1fr);
    column-gap: 1.75rem;
    padding-bottom: 2.75rem;
  }

  .page-about .timeline__item::before {
    left: -3rem;
  }

  .page-about .timeline__year {
    grid-column: 1;
    grid-row: 1 / span 3;
    margin: 0;
    padding-top: 0.18rem;
    text-align: right;
  }

  .page-about .timeline__title,
  .page-about .timeline__text {
    grid-column: 2;
  }

  .page-about .timeline__text {
    max-width: 54ch;
  }

  .page-about .timeline__figure {
    margin-bottom: 2.75rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 2.5rem 0 3.5rem;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 3rem;
    align-items: start;
  }

  .page-about .standards-wrap {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 2.5rem;
    align-items: start;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: 15rem minmax(0, 1fr);
    gap: 3rem;
    padding: 3.5rem 0 4.5rem;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 1.5rem);
    align-self: start;
  }

  .page-about .about-rail .rail__list {
    flex-direction: column;
    gap: 0.35rem;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail .rail__link {
    width: 100%;
    justify-content: flex-start;
    padding: 0.6rem 0.75rem;
    white-space: normal;
  }

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

  .page-about .about-main > .section {
    padding: 3rem 0;
  }
}