.page-about {
  --about-gap: clamp(18px, 3vw, 32px);
  --about-rail: 0px;
  background: var(--ink);
  color: var(--ivory);
  padding-bottom: clamp(32px, 6vw, 80px);
  overflow-x: hidden;
}

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

.page-about .figure {
  margin: 0;
  border: 2px solid var(--line-strong);
  background: var(--ink-2);
}

.page-about .figure-frame {
  overflow: hidden;
  clip-path: polygon(0 0, 100% 0, 100% 92%, 0 100%);
}

.page-about .figure-img {
  width: 100%;
  object-fit: cover;
  filter: saturate(.85) contrast(1.05);
}

.page-about .figure-caption {
  padding: 10px 12px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .03em;
  color: var(--silver);
  border-top: 1px solid var(--line-soft);
}

/* 首屏 */
.page-about .about-hero {
  padding-block: clamp(16px, 3vw, 32px) clamp(24px, 4vw, 48px);
}

.page-about .hero-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .hero-kicker {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  color: var(--red);
}

.page-about .hero-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--mint);
  box-shadow: 0 0 0 4px rgba(57, 245, 200, .14);
  flex: none;
}

.page-about h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.2rem, 9vw, 5.2rem);
  line-height: .94;
  letter-spacing: .01em;
  margin: 14px 0 0;
  text-wrap: balance;
}

.page-about .hero-lede {
  max-width: 48ch;
  margin: 18px 0 0;
  font-size: clamp(15px, 2.3vw, 18px);
  line-height: 1.6;
  color: var(--silver-lt);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 2px solid var(--line-strong);
  align-self: start;
}

.page-about .hero-stat {
  background: var(--ink-2);
  padding: 14px 12px;
}

.page-about .hero-stat b {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(18px, 4vw, 26px);
  letter-spacing: .02em;
  color: var(--mint);
}

.page-about .hero-stat span {
  display: block;
  margin-top: 4px;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--silver);
}

.page-about .about-cut {
  height: 4px;
  background: linear-gradient(96deg, var(--red) 0 34%, var(--red-deep) 34% 46%, var(--line) 46% 100%);
}

/* 通用章节 */
.page-about .about-sec {
  padding-block: clamp(36px, 6vw, 76px);
}

.page-about .sec-head {
  display: grid;
  gap: 8px;
  border-top: 2px solid var(--ivory);
  padding-top: 14px;
  margin-bottom: clamp(16px, 3vw, 26px);
}

.page-about .sec-head .eyebrow {
  margin: 0;
  color: var(--red);
}

.page-about .about-h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.7rem, 5.4vw, 3rem);
  line-height: 1.02;
  letter-spacing: .01em;
  margin: 0;
  text-wrap: balance;
}

.page-about .section-note {
  margin: 0;
  font-size: 14px;
  color: var(--silver);
  line-height: 1.55;
}

.page-about .prose {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.62;
  color: var(--silver-lt);
  max-width: 62ch;
}

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

/* 起点 */
.page-about .start-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .start-figure {
  order: -1;
}

/* 版本轨道 */
.page-about .ver-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: clamp(18px, 3vw, 28px);
}

.page-about .ver-link {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  padding: 7px 14px;
  color: var(--ivory);
  text-decoration: none;
  border: 1px solid var(--line-strong);
  background: var(--ink-2);
  transition: border-color var(--t-fast), color var(--t-fast), transform var(--t-fast);
}

.page-about .ver-link:hover,
.page-about .ver-link:focus-visible {
  border-color: var(--red);
  color: var(--mint);
  transform: translateY(-1px);
}

.page-about .ver-link:focus-visible {
  outline: 2px solid var(--mint);
  outline-offset: 2px;
}

.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
  position: relative;
}

.page-about .tl-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  padding: 18px 16px 20px;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-left: 3px solid var(--red);
  transition: border-color var(--t-fast), box-shadow var(--t-fast), transform var(--t-fast);
}

.page-about .tl-item:hover,
.page-about .tl-item:focus-within {
  border-color: var(--red);
  border-left-color: var(--mint);
  box-shadow: 6px 6px 0 rgba(215, 38, 61, .22);
  transform: translateX(2px);
}

.page-about .tl-idx {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.8rem, 6vw, 2.6rem);
  line-height: 1;
  color: var(--red);
  letter-spacing: .02em;
}

.page-about .tl-body {
  min-width: 0;
}

.page-about .tl-title {
  margin: 0 0 6px;
  font-size: clamp(1.05rem, 3vw, 1.25rem);
  font-weight: 700;
  color: var(--ivory);
  line-height: 1.3;
}

.page-about .tl-text {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--silver-lt);
}

.page-about .tl-more {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
  letter-spacing: .02em;
  color: var(--mint);
}

.page-about .tl-fold {
  margin-top: 10px;
  border-top: 1px dashed var(--line);
  padding-top: 8px;
}

.page-about .tl-fold summary {
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--silver);
  list-style: none;
}

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

.page-about .tl-fold summary::before {
  content: "+ ";
  color: var(--red);
}

.page-about .tl-fold[open] summary::before {
  content: "− ";
  color: var(--mint);
}

.page-about .tl-fold summary:focus-visible {
  outline: 2px solid var(--mint);
  outline-offset: 3px;
}

.page-about .tl-fold p {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--silver-lt);
}

/* 团队 */
.page-about .team-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .role-list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .role-card {
  border: 2px solid var(--line-strong);
  border-left: 3px solid var(--red);
  background: var(--ink-2);
  padding: 14px 16px;
  transition: border-color var(--t-fast), background var(--t-fast);
}

.page-about .role-card:hover {
  border-left-color: var(--mint);
  background: var(--smoke);
}

.page-about .role-idx {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--red);
}

.page-about .role-name {
  margin: 4px 0 6px;
  font-size: 1.05rem;
  color: var(--ivory);
}

.page-about .role-card p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--silver-lt);
}

.page-about .team-side {
  display: grid;
  gap: 14px;
  align-content: start;
}

.page-about .update-panel {
  border: 2px solid var(--line-strong);
  background: var(--ink-2);
}

.page-about .panel-title {
  margin: 0;
  font-size: 1rem;
  color: var(--ivory);
}

.page-about .rhythm-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .rhythm-list li {
  font-size: 14.5px;
  line-height: 1.55;
  color: var(--silver-lt);
  border-bottom: 1px solid var(--line-soft);
  padding-bottom: 8px;
}

.page-about .rhythm-list li:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .rhythm-time {
  display: inline-block;
  min-width: 104px;
  color: var(--mint);
  font-size: 12.5px;
  letter-spacing: .03em;
  margin-right: 6px;
}

/* 资料库 */
.page-about .about-sec--light {
  background: var(--ivory);
  color: var(--ink);
}

.page-about .about-sec--light .about-h2,
.page-about .about-sec--light .prose,
.page-about .about-sec--light .sec-head {
  color: var(--ink);
}

.page-about .about-sec--light .prose {
  color: var(--ink-2);
}

.page-about .about-sec--light .sec-head {
  border-top-color: var(--ink);
}

.page-about .about-sec--light .eyebrow {
  color: var(--red-deep);
}

.page-about .library-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .lib-list {
  list-style: none;
  margin: 0 0 16px;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .lib-list li {
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink-2);
  padding-left: 14px;
  position: relative;
}

.page-about .lib-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  background: var(--red);
}

.page-about .lib-list strong {
  display: inline-block;
  margin-right: 6px;
  color: var(--red-deep);
}

.page-about .library-side {
  display: grid;
  gap: 14px;
  align-content: start;
}

.page-about .about-sec--light .figure {
  border-color: var(--ink);
  background: var(--silver-lt);
}

.page-about .about-sec--light .figure-caption {
  background: var(--silver-lt);
  color: var(--ink-2);
  border-top-color: rgba(11, 12, 14, .18);
}

.page-about .lib-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--ink);
  border: 2px solid var(--ink);
}

.page-about .lib-stat {
  background: var(--ink-2);
  padding: 12px 10px;
}

.page-about .lib-stat b {
  display: block;
  font-size: clamp(15px, 3.4vw, 20px);
  color: var(--mint);
  letter-spacing: .02em;
}

.page-about .lib-stat span {
  display: block;
  margin-top: 4px;
  font-size: 11.5px;
  line-height: 1.4;
  color: var(--silver);
}

/* 覆盖与协作 */
.page-about .cov-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 2px solid var(--line-strong);
}

.page-about .cov-figure {
  background: var(--ink-2);
  padding: 16px 14px 18px;
}

.page-about .cov-num {
  margin: 0;
  font-size: clamp(20px, 5vw, 30px);
  letter-spacing: .02em;
  color: var(--ivory);
}

.page-about .cov-label {
  margin: 6px 0 12px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--silver);
}

.page-about .cov-bar {
  height: 6px;
  background: var(--smoke);
  overflow: hidden;
}

.page-about .cov-fill {
  display: block;
  height: 100%;
  background: var(--red);
}

.page-about .cov-fill--users { width: 92%; }
.page-about .cov-fill--dau { width: 64%; background: var(--red-deep); }
.page-about .cov-fill--peak { width: 37%; background: var(--mint); }
.page-about .cov-fill--area { width: 100%; }

.page-about .partner-block {
  margin-top: clamp(18px, 3vw, 28px);
  border-left: 3px solid var(--red);
  padding-left: 16px;
}

.page-about .partner-title {
  margin: 0 0 10px;
  font-size: 1.05rem;
  color: var(--ivory);
}

.page-about .partner-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .partner-list li {
  font-size: 15px;
  line-height: 1.6;
  color: var(--silver-lt);
}

.page-about .partner-list .mono {
  color: var(--red);
  font-size: 16px;
  margin-right: 6px;
}

/* 认可 */
.page-about .honor-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .honor-seals {
  display: grid;
  gap: 16px;
  align-content: start;
}

.page-about .seal {
  color: var(--red);
  justify-self: start;
  border: 2px solid var(--line-strong);
  padding: 12px;
  background: var(--ink-2);
}

.page-about .seal-num {
  font-family: var(--font-mono);
  font-size: 17px;
  fill: var(--ivory);
  letter-spacing: .02em;
}

.page-about .seal-txt {
  font-size: 10px;
  fill: var(--silver);
  letter-spacing: .12em;
}

.page-about .honor-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .honor-list li {
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--silver-lt);
  border-bottom: 1px solid var(--line-soft);
  padding-bottom: 10px;
}

.page-about .honor-list li:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .honor-year {
  display: inline-block;
  min-width: 46px;
  color: var(--mint);
  font-size: 12.5px;
  letter-spacing: .05em;
  margin-right: 8px;
}

/* 下一步 */
.page-about .about-next {
  border-top: 2px solid var(--line-strong);
}

.page-about .next-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .next-links {
  display: grid;
  gap: 10px;
  align-content: start;
}

.page-about .next-links .btn {
  text-align: left;
}

/* 平板及以上 */
@media (min-width: 720px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

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

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

/* 桌面 */
@media (min-width: 960px) {
  .page-about {
    --about-rail: 108px;
  }

  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    align-items: end;
  }

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

  .page-about .start-grid {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    align-items: start;
  }

  .page-about .start-figure {
    order: 0;
    position: sticky;
    top: 24px;
  }

  .page-about .tl {
    gap: 16px;
  }

  .page-about .tl-item {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 20px;
    padding: 22px 24px 24px;
  }

  .page-about .tl-idx {
    font-size: 3rem;
  }

  .page-about .team-grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.85fr);
    align-items: start;
  }

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

  .page-about .library-grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    align-items: start;
  }

  .page-about .honor-grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    align-items: start;
  }

  .page-about .next-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: center;
  }

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

/* 悬停展开能力摘要只在支持悬停的设备上生效 */
@media (hover: hover) and (min-width: 960px) {
  .page-about .tl-more {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height var(--t-fast), opacity var(--t-fast), margin var(--t-fast);
    margin-top: 0;
  }

  .page-about .tl-item:hover .tl-more,
  .page-about .tl-item:focus-within .tl-more {
    max-height: 120px;
    opacity: 1;
    margin-top: 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ver-link,
  .page-about .tl-item,
  .page-about .role-card,
  .page-about .tl-more {
    transition: none;
  }

  .page-about .ver-link:hover,
  .page-about .tl-item:hover {
    transform: none;
  }
}
<<<END>>>