/* ===========================================================
   page-about : 平台概览
   纵向时间轴 + 章节主轴，全部选择器限定在 .page-about 内
   =========================================================== */

.page-about {
  --about-rail: 108px;
  --about-spine-gap: 34px;
}

/* ---------- 首屏声明 ---------- */

.page-about .about-hero {
  padding-block: 6px 34px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 10px;
}

.page-about .breadcrumb {
  margin-bottom: 26px;
}

.page-about .kicker {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--lime);
  margin: 0;
}

.page-about .kicker::before {
  content: "";
  flex: none;
  width: 26px;
  height: 1px;
  background: currentColor;
}

.page-about h1 {
  margin: 22px 0 20px;
  font-size: clamp(30px, 6.4vw, 62px);
  font-weight: 200;
  line-height: 1.18;
  letter-spacing: 0.04em;
  color: var(--paper);
  max-width: 20ch;
}

.page-about .about-hero__lede {
  max-width: 64ch;
  color: var(--mist);
}

/* 数据条 */

.page-about .about-figures {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 42px 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-figures > li {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px 18px;
  background: var(--ink-900);
}

.page-about .about-figures__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 4.4vw, 36px);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--amber);
}

.page-about .about-figures__label {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

/* ---------- 章节主轴 ---------- */

.page-about .about-spine {
  position: relative;
}

.page-about .about-step {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  padding-block: 44px;
  border-top: 1px solid var(--line);
}

.page-about .about-step:first-child {
  border-top: 0;
}

.page-about .about-step__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .about-step__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--lime);
}

.page-about .about-step__label {
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.page-about .about-step__body > .h2 {
  margin-top: 0;
}

/* 主从分栏 */

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  margin-top: 26px;
}

/* ---------- 四步流程 ---------- */

.page-about .about-flow {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  border-top: 1px solid var(--line);
}

.page-about .about-flow__step {
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
}

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

.page-about .about-flow__num {
  display: block;
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--amber);
}

.page-about .about-flow__title {
  margin: 0 0 10px;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--paper);
}

.page-about .about-flow__step p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .about-flow__io {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  gap: 7px;
}

.page-about .about-flow__io li {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 10px;
  font-size: 13px;
  line-height: 1.6;
}

.page-about .about-flow__io span:first-child {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--lime);
  padding-top: 2px;
}

.page-about .about-flow__io span:last-child {
  color: var(--paper);
  opacity: 0.86;
}

/* ---------- 图片 ---------- */

.page-about .media {
  margin: 0;
}

.page-about .media__frame {
  overflow: hidden;
  border-radius: var(--radius-m);
  border: 1px solid var(--line);
  background: var(--ink-800);
}

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

.page-about .media__caption {
  margin-top: 12px;
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.page-about .about-step__body > .media {
  margin-top: 34px;
}

/* ---------- 时间轴 ---------- */

.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 34px 0 0;
  padding: 0 0 0 30px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg, var(--lime) 0%, var(--teal-600) 42%, var(--line) 100%);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: 38px;
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 7px;
  width: 11px;
  height: 11px;
  box-sizing: border-box;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--lime);
}

.page-about .about-timeline__item:last-child::before {
  background: var(--amber);
  border-color: var(--amber);
  box-shadow: 0 0 0 5px rgba(255, 179, 71, 0.14);
}

.page-about .about-timeline__mark {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: 0.12em;
}

.page-about .about-timeline__mark span:first-child {
  color: var(--lime);
}

.page-about .about-timeline__mark span:last-child {
  color: var(--mist);
}

.page-about .about-timeline__item .h3 {
  margin: 0 0 10px;
}

.page-about .about-timeline__item p {
  margin: 0;
  max-width: 60ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 维度表格 ---------- */

.page-about .table-scroll {
  margin-top: 32px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-dims-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .about-dims-table__caption {
  caption-side: top;
  text-align: left;
  padding-bottom: 14px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .about-dims-table th,
.page-about .about-dims-table td {
  text-align: left;
  padding: 15px 18px 15px 0;
  border-bottom: 1px solid var(--line);
  vertical-align: baseline;
}

.page-about .about-dims-table thead th {
  padding-top: 0;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--mist);
  border-bottom-color: var(--teal-600);
}

.page-about .about-dims-table tbody th {
  font-weight: 500;
  color: var(--paper);
  letter-spacing: 0.04em;
}

.page-about .about-dims-table tbody td {
  color: var(--mist);
}

.page-about .about-dims-table td.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--amber);
  letter-spacing: 0;
}

.page-about .about-dims-table tbody tr {
  transition: background-color 220ms var(--ease);
}

.page-about .about-dims-table tbody tr:hover {
  background: var(--glass);
}

/* 年龄段标签 */

.page-about .about-ages {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
}

.page-about .about-ages li {
  padding: 7px 18px;
  border-radius: 999px;
  border: 1px solid var(--teal-600);
  background: var(--glass);
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 14px;
  letter-spacing: 0.08em;
  color: var(--paper);
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 30px 0 0;
  padding: 0;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-team__item {
  padding: 24px 20px;
  background: var(--ink-900);
}

.page-about .about-team__num {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  line-height: 1;
  color: var(--lime);
}

.page-about .about-team__role {
  display: block;
  margin-bottom: 10px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.page-about .about-team__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

/* 协作方 */

.page-about .about-partners {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  margin-top: 40px;
}

.page-about .about-partners__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.page-about .about-partners__figure {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 40px;
  line-height: 1;
  color: var(--amber);
}

.page-about .about-partners__row .h3 {
  margin: 0 0 10px;
}

.page-about .about-partners__row p {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 口径与纠错 ---------- */

.page-about .about-tabs {
  margin-top: 30px;
}

.page-about .tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  border-bottom: 1px solid var(--line);
}

.page-about .tab {
  appearance: none;
  margin-bottom: -1px;
  padding: 12px 18px;
  border: 0;
  border-bottom: 2px solid transparent;
  background: none;
  font-family: var(--font-sans);
  font-size: 14px;
  letter-spacing: 0.08em;
  color: var(--mist);
  cursor: pointer;
  transition: color 220ms var(--ease), border-color 220ms var(--ease);
}

.page-about .tab:hover {
  color: var(--paper);
}

.page-about .tab[aria-selected="true"] {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

.page-about .tab:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 2px;
}

.page-about .panel {
  padding-top: 26px;
}

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

.page-about .about-fix {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 16px;
  padding: 20px 0 4px;
  border-top: 1px solid var(--line);
}

.page-about .about-fix__label {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--mist);
}

.page-about .about-fix__mail {
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--amber);
  word-break: break-all;
}

.page-about .copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: var(--radius-s);
  border: 1px solid var(--teal-600);
  background: var(--glass);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--paper);
  cursor: pointer;
  transition: border-color 220ms var(--ease), color 220ms var(--ease);
}

.page-about .copy-btn:hover {
  border-color: var(--lime);
  color: var(--lime);
}

.page-about .copy-btn:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 2px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 700px) {
  .page-about .about-figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-partners__row {
    grid-template-columns: 96px minmax(0, 1fr);
    align-items: start;
    gap: 26px;
  }
}

@media (min-width: 820px) {
  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-team__item {
    padding: 28px 24px;
  }

  .page-about .about-partners {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 36px;
  }

  .page-about .about-partners__row {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
  }
}

@media (min-width: 900px) {
  .page-about .about-spine {
    padding-left: var(--about-spine-gap);
  }

  .page-about .about-spine::before {
    content: "";
    position: absolute;
    left: 0;
    top: 12px;
    bottom: 12px;
    width: 1px;
    background: linear-gradient(180deg, transparent 0%, var(--line) 5%, var(--line) 95%, transparent 100%);
  }

  .page-about .about-step {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 42px;
    padding-block: 60px;
  }

  .page-about .about-step::before {
    content: "";
    position: absolute;
    left: calc(-1 * var(--about-spine-gap) - 5px);
    top: 68px;
    width: 11px;
    height: 11px;
    box-sizing: border-box;
    border-radius: 50%;
    background: var(--ink-900);
    border: 1px solid var(--teal-600);
  }

  .page-about .about-step__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding-top: 6px;
  }

  .page-about .about-flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    border-bottom: 1px solid var(--line);
  }

  .page-about .about-flow__step {
    padding: 28px 22px;
    border-bottom: 0;
    border-left: 1px solid var(--line);
  }

  .page-about .about-flow__step:first-child {
    padding-left: 0;
    border-left: 0;
  }

  .page-about .about-flow__step:last-child {
    padding-right: 0;
    padding-bottom: 28px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .about-split--coverage {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    margin-top: 44px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}