.page-about {
  --about-accent: var(--cyan);
  --about-gap: clamp(56px, 9vw, 120px);
  --about-line: 1px solid var(--grid);
  position: relative;
  overflow-x: hidden;
  background-color: var(--ink-900);
  background-image: radial-gradient(880px 420px at 92% -8%, rgba(0, 240, 255, 0.10), transparent 62%),
    radial-gradient(680px 380px at -6% 14%, rgba(124, 77, 255, 0.10), transparent 60%);
  background-repeat: no-repeat;
  color: var(--white);
  padding-bottom: clamp(60px, 9vw, 130px);
}

.page-about .about-shell {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: clamp(18px, 4vw, 40px);
}

.page-about .breadcrumbs {
  padding-top: clamp(18px, 3vw, 32px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(30px, 6vw, 72px) 0 clamp(30px, 5vw, 56px);
  border-bottom: var(--about-line);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: min(320px, 62%);
  height: 3px;
  background: linear-gradient(90deg, var(--cyan), var(--violet) 55%, transparent);
}

.page-about .about-hero__title {
  margin: 0.35em 0 0.4em;
  font-family: var(--font-display);
  font-size: clamp(38px, 8.6vw, 92px);
  line-height: 0.98;
  letter-spacing: 0.01em;
  font-weight: 700;
  max-width: 18em;
}

.page-about .about-hero__lede {
  max-width: 46em;
  font-size: clamp(16px, 1.9vw, 19px);
  line-height: 1.75;
  color: rgba(248, 249, 250, 0.82);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(28px, 4vw, 48px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--grid);
  border: var(--about-line);
}

.page-about .about-fact {
  background: var(--ink-800);
  padding: 18px 18px 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .about-fact__num {
  font-family: var(--font-mono);
  font-style: italic;
  font-size: clamp(28px, 5.4vw, 46px);
  line-height: 1;
  color: var(--cyan);
}

.page-about .about-fact--orange .about-fact__num {
  color: var(--orange);
}

.page-about .about-fact__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--grey);
  letter-spacing: 0.02em;
}

.page-about .about-stamp {
  margin: 14px 0 0;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--grey);
}

/* ---------- 章节框架 ---------- */
.page-about .about-chapter {
  padding-top: var(--about-gap);
  scroll-margin-top: 90px;
}

.page-about .about-chapter--origin { --about-accent: var(--cyan); }
.page-about .about-chapter--method { --about-accent: var(--violet); }
.page-about .about-chapter--evolution { --about-accent: var(--orange); }
.page-about .about-chapter--team { --about-accent: var(--cyan); }
.page-about .about-chapter--local { --about-accent: var(--orange); }

.page-about .about-chapter__head {
  position: relative;
  padding-top: 20px;
}

.page-about .about-chapter__head::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, var(--about-accent), rgba(31, 78, 95, 0.6) 46%, transparent 88%);
}

.page-about .about-chapter__idx {
  display: block;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--about-accent);
}

.page-about .about-chapter__title {
  margin: 0.5em 0 0;
  font-family: var(--font-serif);
  font-size: clamp(24px, 4.4vw, 40px);
  line-height: 1.28;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.page-about .about-chapter__body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 48px);
  margin-top: clamp(22px, 3.6vw, 42px);
}

.page-about .about-prose p {
  margin: 0 0 1em;
  font-size: clamp(15px, 1.7vw, 16.5px);
  line-height: 1.85;
  color: rgba(248, 249, 250, 0.84);
}

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

.page-about .about-prose a {
  color: var(--cyan);
}

/* ---------- 旁注 ---------- */
.page-about .about-side {
  border-left: 2px solid var(--about-accent);
  padding: 4px 0 4px 18px;
  align-self: start;
}

.page-about .about-side__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: clamp(17px, 2.4vw, 20px);
  letter-spacing: 0.03em;
  color: var(--white);
}

.page-about .about-side__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--grey);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0;
}

.page-about .about-figure .figure__media {
  overflow: hidden;
  border: var(--about-line);
  background: var(--ink-800);
}

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

.page-about .about-figure .figure__caption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--grey);
}

/* ---------- 筛选与术语 ---------- */
.page-about .about-filters {
  margin-top: clamp(32px, 5vw, 56px);
}

.page-about .about-filters .filter-bar {
  gap: 8px;
  margin-bottom: clamp(18px, 3vw, 26px);
}

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

.page-about .about-term {
  background: var(--ink-800);
}

.page-about .about-term.is-hidden {
  display: none;
}

.page-about .about-term__summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 17px 18px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-display);
  font-size: 17px;
  letter-spacing: 0.04em;
  color: var(--white);
}

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

.page-about .about-term__summary::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 19px;
  color: var(--violet);
}

.page-about .about-term[open] .about-term__summary::after {
  content: "–";
  color: var(--orange);
}

.page-about .about-term__body {
  margin: 0;
  padding: 0 18px 18px;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(248, 249, 250, 0.76);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  margin: 0;
  padding: 0 0 0 24px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  bottom: 10px;
  width: 1px;
  background: var(--grid);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: clamp(24px, 3.6vw, 38px);
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -24px;
  top: 5px;
  width: 11px;
  height: 11px;
  background: var(--ink-900);
  border: 2px solid var(--about-accent);
}

.page-about .about-timeline__stamp {
  display: block;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--about-accent);
}

.page-about .about-timeline__title {
  margin: 0.55em 0 0.45em;
  font-family: var(--font-display);
  font-size: clamp(18px, 2.6vw, 22px);
  letter-spacing: 0.03em;
  color: var(--white);
}

.page-about .about-timeline__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(248, 249, 250, 0.78);
}

.page-about .about-pace {
  margin: clamp(26px, 4vw, 44px) 0 0;
  padding: 16px 18px;
  border-left: 2px solid var(--orange);
  background: rgba(255, 107, 53, 0.06);
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(248, 249, 250, 0.84);
}

/* ---------- 团队 ---------- */
.page-about .about-teams {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--grid);
  border: var(--about-line);
}

.page-about .about-team {
  background: var(--ink-800);
  padding: 20px 18px 22px;
}

.page-about .about-team__idx {
  display: block;
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--cyan);
}

.page-about .about-team__title {
  margin: 0.6em 0 0.5em;
  font-family: var(--font-display);
  font-size: 19px;
  letter-spacing: 0.04em;
  color: var(--white);
}

.page-about .about-team__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(248, 249, 250, 0.76);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  margin-top: var(--about-gap);
  padding-top: 28px;
  border-top: 2px solid var(--cyan);
}

.page-about .about-cta__title {
  margin: 0 0 0.6em;
  font-family: var(--font-serif);
  font-size: clamp(22px, 3.6vw, 32px);
  font-weight: 600;
}

.page-about .about-cta__text {
  margin: 0 0 clamp(20px, 3vw, 30px);
  max-width: 42em;
  font-size: 15.5px;
  line-height: 1.8;
  color: rgba(248, 249, 250, 0.8);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 22px;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .about-chapter__body {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.9fr);
    align-items: start;
  }

  .page-about .about-chapter--origin .about-chapter__body,
  .page-about .about-chapter--local .about-chapter__body {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  }

  .page-about .about-chapter__body .about-figure {
    margin-top: 6px;
  }
}

@media (min-width: 1100px) {
  .page-about .about-hero__title {
    letter-spacing: 0.02em;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition: none !important;
    animation: none !important;
  }
}