.page-about {
  --about-pad: 20px;
  --about-rule: 1px solid var(--c-line);
  background:
    radial-gradient(1100px 520px at 18% -8%, rgba(31, 122, 77, 0.24), transparent 62%),
    radial-gradient(900px 460px at 92% 6%, rgba(242, 107, 29, 0.09), transparent 60%),
    var(--c-deep);
  color: var(--c-white);
  font-family: var(--font-body);
  min-height: 100vh;
  overflow-x: hidden;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about .shell {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--about-pad);
}

/* ---------- 面包屑 ---------- */

.page-about .crumb {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-block: 18px;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--c-mist);
}

.page-about .crumb__link {
  color: var(--c-mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .crumb__link:hover,
.page-about .crumb__link:focus-visible {
  color: var(--c-orange);
  border-bottom-color: var(--c-orange);
}

.page-about .crumb__sep {
  color: var(--c-line);
}

.page-about .crumb__current {
  color: var(--c-warm);
}

/* ---------- 首屏 ---------- */

.page-about .intro {
  border-top: var(--about-rule);
  border-bottom: var(--about-rule);
  background:
    linear-gradient(180deg, rgba(18, 58, 50, 0.55), rgba(11, 43, 38, 0.1));
}

.page-about .intro__inner {
  padding-block: 44px 40px;
}

.page-about .intro__eyebrow {
  margin: 0 0 18px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--c-pitch);
}

.page-about .intro__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(30px, 7vw, 58px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--c-white);
  max-width: 16ch;
}

.page-about .intro__lede {
  margin: 24px 0 0;
  max-width: 60ch;
  font-size: 16px;
  line-height: 1.9;
  color: var(--c-warm);
}

.page-about .intro__meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 36px 0 0;
  background: var(--c-line);
  border: var(--about-rule);
}

.page-about .intro__meta-item {
  background: var(--c-night);
  padding: 14px 16px;
}

.page-about .intro__meta-item dt {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-mist);
}

.page-about .intro__meta-item dd {
  margin: 6px 0 0;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--c-yellow);
}

/* ---------- 章节骨架 ---------- */

.page-about .chapter {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  padding-block: 42px;
  border-bottom: var(--about-rule);
}

.page-about .chapter__aside {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about .chapter__num {
  display: block;
  font-size: 40px;
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--c-pitch);
}

.page-about .chapter__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 21px;
  line-height: 1.45;
  color: var(--c-white);
}

.page-about .chapter__key {
  margin: 0;
  padding-top: 10px;
  border-top: var(--about-rule);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--c-yellow);
}

.page-about .chapter__body p {
  margin: 0 0 18px;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.88;
  color: var(--c-warm);
}

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

.page-about .chapter__body h3 {
  margin: 34px 0 14px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 19px;
  line-height: 1.5;
  color: var(--c-white);
}

/* ---------- 行列表（用户 / 团队分工） ---------- */

.page-about .rows {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .rows__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 18px 0;
  border-top: var(--about-rule);
}

.page-about .rows__item:last-child {
  border-bottom: var(--about-rule);
}

.page-about .rows__label {
  margin: 0;
  font-size: 15px;
  font-weight: 600;
  color: var(--c-orange);
  letter-spacing: 0.01em;
}

.page-about .rows__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-warm);
}

/* ---------- 图片 ---------- */

.page-about .fig {
  margin: 30px 0;
  border: var(--about-rule);
  background: var(--c-night);
}

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

.page-about .fig__cap {
  padding: 12px 16px;
  border-top: var(--about-rule);
  font-size: 13px;
  line-height: 1.7;
  color: var(--c-mist);
}

/* ---------- 数据脚注 ---------- */

.page-about .facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  margin: 28px 0;
  background: var(--c-line);
  border: var(--about-rule);
}

.page-about .facts__cell {
  background: var(--c-night);
  padding: 18px 16px;
}

.page-about .facts__label {
  display: block;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--c-mist);
}

.page-about .facts__num {
  display: block;
  margin: 8px 0 0;
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-yellow);
}

/* ---------- 城市点阵 ---------- */

.page-about .dotmap {
  margin: 28px 0;
  padding: 20px 18px;
  border: var(--about-rule);
  background:
    repeating-linear-gradient(0deg, rgba(46, 87, 75, 0.28) 0 1px, transparent 1px 24px),
    repeating-linear-gradient(90deg, rgba(46, 87, 75, 0.28) 0 1px, transparent 1px 24px),
    var(--c-night);
}

.page-about .dotmap__svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .dotmap__svg circle {
  fill: var(--c-pitch);
  transition: fill 0.2s var(--ease), r 0.2s var(--ease);
}

.page-about .dotmap__svg circle.is-lead {
  fill: var(--c-orange);
}

.page-about .dotmap:hover .dotmap__svg circle {
  fill: var(--c-pitch-dark);
}

.page-about .dotmap .dotmap__svg circle:hover {
  fill: var(--c-yellow);
}

.page-about .dotmap__note {
  margin: 16px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--c-mist);
}

/* ---------- 字段折叠面板 ---------- */

.page-about .fields {
  margin: 26px 0 0;
  border: var(--about-rule);
  background: var(--c-night);
}

.page-about .fields__summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 500;
  color: var(--c-white);
  transition: background 0.2s var(--ease);
}

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

.page-about .fields__summary:hover {
  background: rgba(31, 122, 77, 0.16);
}

.page-about .fields__summary::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--c-orange);
}

.page-about .fields[open] .fields__summary::after {
  content: "\2013";
}

.page-about .fields__body {
  padding: 14px 18px 20px;
  border-top: var(--about-rule);
}

.page-about .field-list {
  margin: 0;
}

.page-about .field-list__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid rgba(46, 87, 75, 0.6);
}

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

.page-about .field-list__row dt {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--c-pitch);
}

.page-about .field-list__row dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-warm);
}

/* ---------- 赛季时间线 ---------- */

.page-about .seasons {
  list-style: none;
  margin: 30px 0 0;
  padding: 0 0 0 26px;
  border-left: var(--about-rule);
}

.page-about .seasons__item {
  position: relative;
  padding-bottom: 32px;
}

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

.page-about .seasons__item::before {
  content: "";
  position: absolute;
  left: -32px;
  top: 6px;
  width: 10px;
  height: 10px;
  background: var(--c-deep);
  border: 2px solid var(--c-pitch);
  border-radius: 50%;
}

.page-about .seasons__item:first-child::before {
  border-color: var(--c-orange);
  background: var(--c-orange);
}

.page-about .seasons__tag {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-yellow);
}

.page-about .seasons__title {
  margin: 8px 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 18px;
  line-height: 1.5;
  color: var(--c-white);
}

.page-about .seasons__text {
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-warm);
}

/* ---------- 收束区 ---------- */

.page-about .outro {
  border-bottom: var(--about-rule);
  background:
    radial-gradient(760px 380px at 78% 100%, rgba(242, 107, 29, 0.14), transparent 66%),
    linear-gradient(180deg, rgba(18, 58, 50, 0.2), rgba(11, 43, 38, 0.7));
}

.page-about .outro__inner {
  padding-block: 44px 52px;
}

.page-about .outro__fig {
  margin: 0 0 26px;
  border: var(--about-rule);
  overflow: hidden;
}

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

.page-about .outro__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(24px, 5.4vw, 38px);
  line-height: 1.25;
  color: var(--c-white);
}

.page-about .outro__text {
  margin: 18px 0 0;
  max-width: 56ch;
  font-size: 16px;
  line-height: 1.88;
  color: var(--c-warm);
}

.page-about .outro__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 28px 0 0;
}

.page-about .outro__actions .btn {
  flex: 0 1 auto;
}

/* ---------- 桌面端 ---------- */

@media (min-width: 720px) {
  .page-about {
    --about-pad: 32px;
  }

  .page-about .intro__inner {
    padding-block: 64px 56px;
  }

  .page-about .intro__meta {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    margin-top: 44px;
  }

  .page-about .rows__item {
    grid-template-columns: 170px minmax(0, 1fr);
    gap: 28px;
    align-items: start;
    padding: 20px 0;
  }

  .page-about .field-list__row {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }

  .page-about .fig--narrow {
    max-width: 620px;
  }
}

@media (min-width: 960px) {
  .page-about {
    --about-pad: 40px;
  }

  .page-about .chapter {
    grid-template-columns: 232px minmax(0, 1fr);
    gap: 56px;
    padding-block: 72px;
  }

  .page-about .chapter__aside {
    position: sticky;
    top: 96px;
    align-self: start;
  }

  .page-about .chapter__num {
    font-size: 56px;
  }

  .page-about .chapter__title {
    font-size: 22px;
  }

  .page-about .chapter__body p {
    font-size: 17px;
  }

  .page-about .rows__item {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: 40px;
  }

  .page-about .outro__inner {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 56px;
    align-items: center;
    padding-block: 72px 80px;
  }

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