.page-about {
  --about-toc-w: 208px;
  --about-gap: clamp(1.75rem, 4vw, 3.25rem);
  --about-line: 1px solid var(--deep-line);

  background: var(--deep-night);
  color: var(--warm-white);
  font-family: var(--font-body);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(2.25rem, 6vw, 4rem) 0 clamp(1.75rem, 5vw, 3rem);
  background:
    radial-gradient(1100px 520px at 82% -12%, rgba(35, 230, 208, 0.18), transparent 62%),
    radial-gradient(760px 420px at 4% 12%, rgba(255, 106, 77, 0.10), transparent 66%),
    linear-gradient(180deg, var(--deep-night) 0%, var(--deep-step) 100%);
}

.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0 0 clamp(1.25rem, 3vw, 2rem);
  padding: 0;
  list-style: none;
  font-size: var(--fs-sm);
  color: var(--mist);
}

.page-about .breadcrumb a {
  color: var(--neon-soft);
  text-decoration: none;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--coral);
}

.page-about .breadcrumb li + li::before {
  content: "/";
  margin-right: 0.5rem;
  color: var(--deep-line);
}

.page-about .about-hero__frame {
  position: relative;
  padding: clamp(1.75rem, 5vw, 3.25rem) clamp(1.25rem, 4vw, 3rem) clamp(1.5rem, 4vw, 2.5rem);
  border: 1px solid var(--deep-line);
  border-radius: 22px 6px 22px 6px;
  background:
    linear-gradient(135deg, rgba(13, 42, 70, 0.92), rgba(6, 26, 46, 0.92));
}

.page-about .about-hero__frame::before {
  content: "";
  position: absolute;
  inset: 10px;
  border: 1px dashed rgba(27, 74, 115, 0.75);
  border-radius: 16px 4px 16px 4px;
  pointer-events: none;
}

.page-about .about-hero__tag {
  display: inline-block;
  margin-bottom: 1rem;
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--neon-cyan);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.08em;
  color: var(--neon-cyan);
}

.page-about .about-hero h1 {
  margin: 0.35rem 0 1.1rem;
  max-width: 18ch;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.1rem, 6.6vw, 4.1rem);
  line-height: 1.06;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 62ch;
  font-size: var(--fs-md);
  line-height: 1.85;
  color: var(--warm-white);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: clamp(1.5rem, 4vw, 2.5rem) 0 0;
  padding: 0;
  list-style: none;
  border-top: var(--about-line);
}

.page-about .about-hero__facts li {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  padding: 0.85rem 0.25rem;
  border-bottom: var(--about-line);
  font-size: var(--fs-sm);
  color: var(--mist);
}

.page-about .about-hero__facts strong {
  flex: none;
  min-width: 5.4rem;
  font-family: var(--font-mono);
  font-size: var(--fs-lg);
  font-weight: 700;
  color: var(--neon-cyan);
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  padding: clamp(2rem, 5vw, 3.5rem) 0 clamp(3rem, 7vw, 5.5rem);
  background: linear-gradient(180deg, var(--deep-step) 0%, var(--deep-night) 26%, var(--deep-night) 100%);
}

.page-about .about-body__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--about-gap);
  align-items: start;
}

/* ---------- 章节导航 ---------- */
.page-about .about-toc {
  padding: 0.9rem 0;
  border-top: var(--about-line);
  border-bottom: var(--about-line);
}

.page-about .about-toc__title {
  margin: 0 0 0.65rem;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-toc__list {
  display: flex;
  gap: 0.5rem;
  margin: 0;
  padding: 0 0 0.35rem;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-toc__list li {
  flex: none;
}

.page-about .about-toc__list a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 0.75rem;
  border: 1px solid var(--deep-line);
  border-radius: 999px;
  white-space: nowrap;
  font-size: var(--fs-sm);
  color: var(--mist);
  text-decoration: none;
  transition: color var(--t-mid) var(--ease), border-color var(--t-mid) var(--ease);
}

.page-about .about-toc__idx {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--neon-cyan);
}

.page-about .about-toc__list a:hover,
.page-about .about-toc__list a:focus-visible {
  border-color: var(--coral);
  color: var(--warm-white);
}

/* ---------- 章节 ---------- */
.page-about .about-flow {
  display: grid;
  gap: clamp(1.5rem, 4vw, 2.75rem);
}

.page-about .chapter {
  padding-top: clamp(1.5rem, 4vw, 2.25rem);
  border-top: var(--about-line);
}

.page-about .chapter__head {
  display: flex;
  align-items: flex-start;
  gap: clamp(0.75rem, 2.5vw, 1.5rem);
  margin-bottom: 1.25rem;
}

.page-about .chapter__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 700;
  line-height: 0.9;
  color: var(--deep-line);
  letter-spacing: -0.04em;
}

@supports (-webkit-text-stroke: 1px black) {
  .page-about .chapter__num {
    color: transparent;
    -webkit-text-stroke: 1px var(--deep-line);
  }
}

.page-about .chapter__headtext {
  padding-top: 0.2rem;
}

.page-about .chapter h2 {
  margin: 0.35rem 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.6rem, 4.4vw, 2.6rem);
  line-height: 1.15;
  color: var(--white);
}

.page-about .chapter h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-md);
  letter-spacing: 0.01em;
  color: var(--white);
}

.page-about .chapter__body {
  max-width: 68ch;
}

.page-about .chapter__body p {
  margin: 0 0 1rem;
  font-size: var(--fs-md);
  line-height: 1.85;
  color: var(--warm-white);
}

.page-about .chapter__aside {
  margin-top: 0.5rem;
  padding-left: 1rem;
  border-left: 3px solid var(--neon-cyan);
}

.page-about .about-quote {
  margin: 0;
  max-width: 46ch;
  font-family: var(--font-display);
  font-size: var(--fs-lg);
  line-height: 1.45;
  color: var(--neon-soft);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: 16px 4px 16px 4px;
  border: 1px solid var(--deep-line);
}

.page-about .about-figure .media-caption {
  margin-top: 0.65rem;
  font-size: var(--fs-sm);
  color: var(--mist);
}

/* ---------- 团队卡片 ---------- */
.page-about .about-team {
  margin-top: 0.5rem;
}

.page-about .about-team__card {
  padding: 1.25rem 1.25rem 1.35rem;
  border: 1px solid var(--deep-line);
  border-left: 3px solid var(--pitch);
  border-radius: 14px 3px 14px 3px;
  background: linear-gradient(160deg, rgba(13, 42, 70, 0.95), rgba(6, 26, 46, 0.9));
  transition: border-color var(--t-mid) var(--ease), transform var(--t-mid) var(--ease);
}

.page-about .about-team__card:hover,
.page-about .about-team__card:focus-within {
  border-color: var(--neon-cyan);
  border-left-color: var(--coral);
  transform: translateY(-3px);
}

.page-about .about-team__card p {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-team__card--support {
  border-left-color: var(--amber);
}

/* ---------- 流程条 ---------- */
.page-about .flow {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--deep-line);
  border: 1px solid var(--deep-line);
  border-radius: 16px 4px 16px 4px;
  overflow: hidden;
}

.page-about .flow__step {
  position: relative;
  padding: 1.1rem 1.1rem 1.25rem;
  background: var(--deep-night);
  transition: background var(--t-mid) var(--ease);
}

.page-about .flow__step:hover,
.page-about .flow__step:focus-within {
  background: var(--deep-step);
}

.page-about .flow__step::after {
  content: "";
  position: absolute;
  left: 1.1rem;
  right: 1.1rem;
  bottom: 0;
  height: 3px;
  background: var(--neon-cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--t-in) var(--ease);
}

.page-about .flow__step:hover::after,
.page-about .flow__step:focus-within::after {
  transform: scaleX(1);
}

.page-about .flow__idx {
  display: block;
  margin-bottom: 0.5rem;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.16em;
  color: var(--neon-cyan);
}

.page-about .flow__step h3 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: var(--fs-lg);
  font-weight: 700;
  color: var(--white);
}

.page-about .flow__out {
  margin: 0 0 0.55rem;
  font-size: var(--fs-sm);
  font-weight: 600;
  color: var(--neon-soft);
}

.page-about .flow__note {
  margin: 0;
  font-size: var(--fs-xs);
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  position: relative;
  margin: 0;
  padding: 0 0 0 2.25rem;
  list-style: none;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 0.5rem;
  bottom: 0.5rem;
  width: 2px;
  background: linear-gradient(180deg, var(--neon-cyan), rgba(27, 74, 115, 0.6));
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: clamp(1.4rem, 4vw, 2rem);
}

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

.page-about .timeline__dot {
  position: absolute;
  left: -2.25rem;
  top: 0.42rem;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  border: 2px solid var(--neon-cyan);
  background: var(--deep-night);
  transition: background var(--t-mid) var(--ease), transform var(--t-mid) var(--ease);
}

.page-about .timeline__item:hover .timeline__dot {
  background: var(--coral);
  border-color: var(--coral);
  transform: scale(1.18);
}

.page-about .timeline__season {
  margin: 0 0 0.3rem;
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  letter-spacing: 0.08em;
  color: var(--neon-cyan);
}

.page-about .timeline__item h3 {
  margin: 0 0 0.4rem;
  font-family: var(--font-display);
  font-size: var(--fs-md);
  font-weight: 700;
  color: var(--white);
}

.page-about .timeline__item p:last-child {
  margin: 0;
  max-width: 60ch;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 三条标准 ---------- */
.page-about .rules {
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  border: 1px solid var(--deep-line);
  border-radius: 16px 4px 16px 4px;
  overflow: hidden;
  background: var(--deep-line);
}

.page-about .rules__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 1rem;
  padding: 1.15rem 1.15rem 1.3rem;
  background: var(--deep-step);
}

.page-about .rules__mark {
  display: grid;
  place-items: center;
  width: 2.2rem;
  height: 2.2rem;
  border-radius: 50%;
  border: 1px solid var(--neon-cyan);
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  font-weight: 700;
  color: var(--neon-cyan);
}

.page-about .rules__item h3 {
  margin: 0 0 0.45rem;
  font-family: var(--font-display);
  font-size: var(--fs-md);
  font-weight: 700;
  color: var(--white);
}

.page-about .rules__item p {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 合作 ---------- */
.page-about .about-partners {
  margin-bottom: clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .about-partners__card {
  padding: 1.3rem 1.25rem 1.4rem;
  border: 1px solid var(--deep-line);
  border-top: 3px solid var(--neon-cyan);
  border-radius: 4px 4px 16px 16px;
  background: linear-gradient(180deg, rgba(13, 42, 70, 0.95), rgba(6, 26, 46, 0.92));
  transition: border-color var(--t-mid) var(--ease), transform var(--t-mid) var(--ease);
}

.page-about .about-partners__card:hover,
.page-about .about-partners__card:focus-within {
  border-top-color: var(--coral);
  transform: translateY(-3px);
}

.page-about .about-partners__card--topic {
  border-top-color: var(--pitch);
}

.page-about .about-partners__card--data {
  border-top-color: var(--amber);
}

.page-about .about-partners__card h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: var(--fs-md);
  font-weight: 700;
  color: var(--white);
}

.page-about .about-partners__card p {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-outro {
  padding-top: 1.25rem;
  border-top: var(--about-line);
}

.page-about .about-outro a {
  color: var(--neon-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(35, 230, 208, 0.4);
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .about-outro a:hover,
.page-about .about-outro a:focus-visible {
  color: var(--coral);
  border-bottom-color: var(--coral);
}

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

@media (min-width: 780px) {
  .page-about .flow {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .page-about .about-body__grid {
    grid-template-columns: var(--about-toc-w) minmax(0, 1fr);
    gap: clamp(2rem, 4.5vw, 4rem);
  }

  .page-about .about-toc {
    position: sticky;
    top: 104px;
    padding-bottom: 1.1rem;
  }

  .page-about .about-toc__list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-toc__list li + li {
    margin-top: 0.4rem;
  }

  .page-about .about-toc__list a {
    display: flex;
    padding: 0.4rem 0.15rem;
    border: 0;
    border-radius: 0;
    border-left: 2px solid transparent;
    white-space: normal;
  }

  .page-about .about-toc__list a:hover,
  .page-about .about-toc__list a:focus-visible {
    border-left-color: var(--coral);
    color: var(--warm-white);
  }

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

  .page-about .about-hero__facts li {
    display: block;
    padding: 0.9rem 1rem 0.9rem 0;
    border-bottom: 0;
    border-right: var(--about-line);
  }

  .page-about .about-hero__facts li:last-child {
    border-right: 0;
  }

  .page-about .about-hero__facts strong {
    display: block;
    margin-bottom: 0.25rem;
  }
}

@media (min-width: 1160px) {
  .page-about .chapter__head {
    gap: 2rem;
  }
}