.page-about {
  --about-line: rgba(27, 72, 119, .55);
  --about-line-soft: rgba(27, 72, 119, .3);
  --about-card: rgba(14, 42, 71, .62);
  --about-orange-ink: #c24e0a;
  background: var(--night);
  color: var(--ice);
  overflow-x: hidden;
}

/* ---------- 首屏封面 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(26px, 5vw, 52px) 0 clamp(30px, 5vw, 56px);
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-hero .crumbs {
  margin-bottom: clamp(22px, 4vw, 40px);
}

.page-about .about-hero-head {
  max-width: 62rem;
}

.page-about .about-kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  line-height: 1.6;
  color: var(--cyan);
}

.page-about h1 {
  margin: 0 0 20px;
  font-size: clamp(30px, 6.2vw, 52px);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.18;
  color: var(--ice);
  max-width: 20em;
}

.page-about .about-lede {
  margin: 0;
  max-width: 36em;
  font-size: clamp(16px, 2.1vw, 18px);
  line-height: 1.8;
  color: var(--ice);
}

.page-about .about-lede--second {
  margin-top: 14px;
  font-size: clamp(15px, 1.9vw, 17px);
  color: var(--mist);
}

.page-about .about-cover {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
  background: var(--about-line-soft);
  border-top: 1px solid var(--about-line-soft);
  border-bottom: 1px solid var(--about-line-soft);
}

.page-about .about-cover li {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 18px;
  background: var(--night);
}

.page-about .about-cover-num {
  font-family: var(--font-mono);
  font-size: clamp(22px, 3.6vw, 30px);
  font-weight: 700;
  letter-spacing: -.02em;
  line-height: 1.05;
  color: var(--orange);
}

.page-about .about-cover-label {
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 正文骨架：左索引 + 右正文 ---------- */
.page-about .about-body {
  padding: clamp(32px, 5vw, 68px) 0 clamp(40px, 6vw, 88px);
}

.page-about .about-body-grid {
  display: grid;
  gap: 30px;
}

.page-about .about-toc {
  border: 1px solid var(--about-line);
  background: var(--about-card);
  padding: 16px 18px;
  border-radius: var(--r-md);
}

.page-about .about-toc-title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--mist);
}

.page-about .about-toc ol {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-toc a {
  display: block;
  padding: 8px 10px;
  border-left: 2px solid transparent;
  font-size: 14px;
  line-height: 1.5;
  color: var(--mist);
  text-decoration: none;
  transition: color .2s var(--ease), border-color .2s var(--ease), background-color .2s var(--ease);
}

.page-about .about-toc a:hover,
.page-about .about-toc a:focus-visible {
  color: var(--ice);
  background: rgba(27, 72, 119, .28);
}

.page-about .about-toc a[aria-current="true"] {
  color: var(--orange);
  border-left-color: var(--orange);
  background: rgba(255, 122, 24, .09);
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  margin-bottom: clamp(46px, 7vw, 84px);
  scroll-margin-top: 130px;
}

.page-about .about-sec:last-of-type {
  margin-bottom: 0;
}

.page-about .about-sec-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 14px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-sec-num {
  flex: none;
  font-size: 13px;
  letter-spacing: .1em;
}

.page-about .about-sec-title {
  margin: 0;
  font-size: clamp(21px, 3.2vw, 29px);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.32;
  color: var(--ice);
}

.page-about .about-prose p {
  margin: 0 0 1em;
  font-size: 17px;
  line-height: 1.8;
  color: var(--ice);
}

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

.page-about a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(47, 227, 200, .35);
  transition: border-color .2s var(--ease), color .2s var(--ease);
}

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

/* ---------- 01 内容线 ---------- */
.page-about .about-lines {
  display: grid;
  gap: 1px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  background: var(--about-line-soft);
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-lines li {
  display: grid;
  gap: 6px;
  padding: 20px 0;
  background: var(--night);
}

.page-about .about-line-tag {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  line-height: 1.6;
  color: var(--cyan);
}

.page-about .about-lines p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ice);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
  border: 1px solid var(--about-line);
  background: var(--blueprint);
  border-radius: var(--r-md);
  overflow: hidden;
}

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

.page-about .about-figure--tall img {
  aspect-ratio: 5 / 7;
}

.page-about .about-banner img {
  aspect-ratio: 14 / 9;
}

.page-about .about-figure figcaption {
  padding: 12px 16px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
  border-top: 1px solid var(--about-line-soft);
}

/* ---------- 02 五步流程 ---------- */
.page-about .about-flow {
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-flow li {
  position: relative;
  padding: 0 0 26px 44px;
}

.page-about .about-flow li::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 26px;
  bottom: 2px;
  width: 1px;
  background: var(--about-line);
}

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

.page-about .about-flow li:last-child::before {
  display: none;
}

.page-about .about-flow .idx {
  position: absolute;
  left: 0;
  top: 2px;
  font-size: 13px;
  letter-spacing: .08em;
}

.page-about .about-flow h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.01em;
  line-height: 1.5;
  color: var(--ice);
}

.page-about .about-flow p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ice);
  opacity: .86;
}

/* ---------- 03 团队 ---------- */
.page-about .about-team {
  margin-top: 26px;
  padding: clamp(22px, 3.4vw, 34px);
  border-radius: var(--r-md);
  border-left: 3px solid var(--orange);
}

.page-about .about-team-grid {
  display: grid;
  gap: 26px;
}

.page-about .about-team-item h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.5;
  color: var(--ink);
}

.page-about .about-team-num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--about-orange-ink);
}

.page-about .about-team-item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: #3d4f61;
}

.page-about .about-team-item a {
  color: #0d6f60;
  border-bottom-color: rgba(13, 111, 96, .35);
}

.page-about .about-team-item a:hover,
.page-about .about-team-item a:focus-visible {
  color: #0a5348;
  border-bottom-color: #0a5348;
}

/* ---------- 04 赛季节奏 ---------- */
.page-about .about-rhythm {
  display: grid;
  gap: 26px;
  margin-top: 26px;
}

.page-about .about-rhythm .about-figure {
  margin: 0;
}

.page-about .about-phase {
  margin-bottom: 12px;
  border: 1px solid var(--about-line);
  background: var(--about-card);
  border-radius: var(--r-md);
  overflow: hidden;
}

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

.page-about .about-phase summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 15px 18px;
  cursor: pointer;
  list-style: none;
  transition: background-color .2s var(--ease);
}

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

.page-about .about-phase summary:hover {
  background: rgba(27, 72, 119, .3);
}

.page-about .about-phase summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--orange);
}

.page-about .about-phase[open] summary::after {
  content: "–";
}

.page-about .about-phase-name {
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--ice);
}

.page-about .about-phase-count {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--mist);
}

.page-about .about-phase-body {
  padding: 0 18px 18px;
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-phase-body p {
  margin: 14px 0 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ice);
  opacity: .88;
}

/* ---------- 05 合作 ---------- */
.page-about .about-partners {
  display: grid;
  gap: 1px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  background: var(--about-line-soft);
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-partners li {
  display: grid;
  gap: 8px;
  padding: 20px 0;
  background: var(--night);
}

.page-about .about-partners li > .idx {
  font-size: 12px;
  letter-spacing: .1em;
}

.page-about .about-partners h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.01em;
  line-height: 1.5;
  color: var(--ice);
}

.page-about .about-partners p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ice);
  opacity: .88;
}

.page-about .about-contact-hint {
  margin: 22px 0 0;
  padding: 16px 18px;
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--cyan);
  border-radius: var(--r-md);
  background: rgba(47, 227, 200, .05);
  font-size: 15px;
  line-height: 1.78;
  color: var(--ice);
}

/* ---------- 06 赛季历程 ---------- */
.page-about .about-versions {
  display: grid;
  gap: 1px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  background: var(--about-line-soft);
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-versions li {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  background: var(--night);
}

.page-about .about-ver-tag {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  line-height: 1.6;
  color: var(--orange);
}

.page-about .about-versions p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ice);
  opacity: .88;
}

.page-about .about-next {
  margin: 26px 0 0;
  padding: 18px 20px;
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--orange);
  border-radius: var(--r-md);
  background: var(--about-card);
  font-size: 15px;
  line-height: 1.8;
  color: var(--ice);
}

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

  .page-about .about-lines li {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 22px;
    align-items: start;
  }

  .page-about .about-line-tag {
    padding-top: 3px;
  }

  .page-about .about-team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px 34px;
  }

  .page-about .about-partners li {
    grid-template-columns: 46px minmax(0, 1fr);
    gap: 20px;
    align-items: start;
  }

  .page-about .about-partners li > .idx {
    padding-top: 4px;
  }

  .page-about .about-versions li {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 22px;
    align-items: baseline;
  }
}

@media (min-width: 900px) {
  .page-about .about-rhythm {
    grid-template-columns: minmax(0, 300px) minmax(0, 1fr);
    gap: 38px;
    align-items: start;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body-grid {
    grid-template-columns: 230px minmax(0, 1fr);
    gap: 58px;
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 132px;
    max-height: calc(100vh - 160px);
    overflow-y: auto;
  }

  .page-about .about-flow li {
    padding-left: 58px;
  }

  .page-about .about-flow li::before {
    left: 17px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}