.page-about {
  --about-rail-w: 226px;
  --about-media-cut: 26px;
  background:
    radial-gradient(115% 75% at 100% 0%, rgba(126, 107, 234, 0.16), transparent 62%),
    radial-gradient(90% 60% at 0% 8%, rgba(53, 224, 193, 0.09), transparent 58%),
    var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  padding-bottom: clamp(48px, 7vw, 96px);
}

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

.page-about h1,
.page-about h2,
.page-about h3 {
  margin: 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(20px, 4vw, 36px) 0 clamp(28px, 5vw, 56px);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: clamp(18px, 3vw, 30px);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: rgba(201, 212, 207, 0.82);
}

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

.page-about .breadcrumb a:hover {
  color: var(--amber);
}

.page-about .breadcrumb-sep {
  color: rgba(201, 212, 207, 0.42);
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 3.5vw, 44px);
  align-items: start;
}

.page-about .about-eyebrow {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cold);
}

.page-about h1 {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 7.4vw, 60px);
  line-height: 1.04;
  letter-spacing: -0.03em;
  color: var(--paper);
}

.page-about .about-lede {
  max-width: 52ch;
  margin: 18px 0 0;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.9;
  color: var(--mist);
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-stat dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: rgba(201, 212, 207, 0.62);
}

.page-about .about-stat dd {
  margin: 6px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(20px, 2.4vw, 28px);
  letter-spacing: -0.02em;
  color: var(--amber);
}

.page-about .about-stat:nth-child(2n) dd {
  color: var(--cold);
}

.page-about .about-hero-media {
  position: relative;
  margin: 0;
}

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

.page-about .about-hero-media img {
  aspect-ratio: 4 / 3;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-media-cut)), calc(100% - var(--about-media-cut)) 100%, 0 100%);
}

.page-about .about-hero-chip {
  position: absolute;
  left: 0;
  bottom: 16px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--paper);
  background: rgba(11, 42, 36, 0.88);
  border: 1px solid var(--line-soft);
  border-left: 2px solid var(--cold);
}

.page-about .chip-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--cold);
  box-shadow: 0 0 0 3px rgba(53, 224, 193, 0.22);
}

/* ---------- 外框与左侧章节轨 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 3.6vw, 48px);
  padding-top: clamp(26px, 4vw, 52px);
}

.page-about .about-rail-title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(201, 212, 207, 0.6);
}

.page-about .about-rail-list {
  position: relative;
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-rail-link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 9px 14px;
  white-space: nowrap;
  font-size: 13px;
  letter-spacing: 0.02em;
  text-decoration: none;
  color: rgba(201, 212, 207, 0.82);
  background: rgba(21, 36, 61, 0.7);
  border: 1px solid var(--line-soft);
  border-bottom: 2px solid transparent;
  transition: color 0.24s var(--ease), border-color 0.24s var(--ease);
}

.page-about .rail-num {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--violet);
}

.page-about .about-rail-link.is-active,
.page-about .about-rail-link[aria-current="true"] {
  color: var(--paper);
  border-bottom-color: var(--cold);
  background: rgba(21, 36, 61, 0.95);
}

/* ---------- 章节画板 ---------- */
.page-about .about-flow {
  display: grid;
  gap: clamp(16px, 2.4vw, 26px);
  min-width: 0;
}

.page-about .about-chapter {
  position: relative;
  padding: clamp(20px, 3vw, 38px);
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-left: 3px solid rgba(53, 224, 193, 0.7);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
}

.page-about [data-reveal] {
  opacity: 1;
  transform: none;
  transition: opacity 0.36s var(--ease), transform 0.36s var(--ease);
}

.page-about .about-chapter--dusk {
  background: rgba(21, 36, 61, 0.82);
  border-left-color: var(--violet);
}

.page-about .about-chapter--team {
  border-left-color: var(--cold);
}

.page-about .about-chapter--milestones {
  border-left-color: var(--amber);
}

.page-about .about-chapter--standards {
  background: rgba(21, 36, 61, 0.7);
  border-left-color: var(--violet);
}

.page-about .about-chapter--partner {
  background: linear-gradient(140deg, rgba(230, 169, 59, 0.13), rgba(21, 36, 61, 0.92) 58%);
  border-left-color: var(--amber);
}

.page-about .chapter-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 18px;
  padding-bottom: 14px;
  border-bottom: 1px dashed rgba(201, 212, 207, 0.2);
}

.page-about .chapter-num {
  flex: none;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3vw, 36px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: rgba(53, 224, 193, 0.3);
  -webkit-text-stroke: 1px rgba(53, 224, 193, 0.85);
}

.page-about .chapter-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(21px, 3vw, 33px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .chapter-body > p {
  max-width: 62ch;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .chapter-body > p + p {
  margin-top: 14px;
}

.page-about .about-quote {
  max-width: 40ch;
  margin: 22px 0 0;
  padding-left: 18px;
  border-left: 2px solid var(--amber);
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(17px, 2.2vw, 23px);
  line-height: 1.68;
  color: var(--paper);
}

/* ---------- 观察三点 ---------- */
.page-about .about-points {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-points li {
  padding: 14px 16px;
  font-size: 14px;
  line-height: 1.85;
  color: var(--mist);
  background: rgba(245, 241, 230, 0.04);
  border-top: 2px solid rgba(53, 224, 193, 0.55);
}

.page-about .point-key {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--cold);
}

/* ---------- 三层内容 ---------- */
.page-about .layer-stack {
  display: grid;
  gap: 14px;
  margin-top: 22px;
}

.page-about .layer {
  position: relative;
  padding: 18px 18px 20px;
  background: rgba(11, 42, 36, 0.58);
  border: 1px solid var(--line);
  border-left: 3px solid var(--line);
}

.page-about .layer--announce {
  border-left-color: var(--amber);
}

.page-about .layer--data {
  border-left-color: var(--cold);
}

.page-about .layer--read {
  border-left-color: var(--violet);
}

.page-about .layer-tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: rgba(201, 212, 207, 0.68);
}

.page-about .layer h3 {
  margin: 8px 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(18px, 2.2vw, 22px);
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .layer p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 团队 ---------- */
.page-about .about-inline-media {
  margin: 22px 0 0;
}

.page-about .about-inline-media img {
  aspect-ratio: 4 / 3;
  clip-path: polygon(0 0, 100% 0, 100% 100%, calc(100% - 24px) 100%, 0 calc(100% - 24px));
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 20px;
}

.page-about .team-card {
  padding: 16px 18px;
  background: rgba(245, 241, 230, 0.05);
  border: 1px solid var(--line-soft);
  border-left: 2px solid rgba(53, 224, 193, 0.5);
}

.page-about .team-role {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--cold);
}

.page-about .team-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .team-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 版本历程 ---------- */
.page-about .milestone-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  margin-top: 22px;
}

.page-about .milestone-list {
  position: relative;
  display: grid;
  gap: 18px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .milestone-list::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--cold), var(--violet) 55%, var(--amber));
  transform: skewX(-7deg);
  transform-origin: top center;
  opacity: 0.62;
}

.page-about .milestone {
  position: relative;
  padding-left: 32px;
}

.page-about .milestone::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 9px;
  width: 11px;
  height: 11px;
  transform: rotate(45deg);
  background: var(--dusk);
  border: 1px solid var(--cold);
}

.page-about .milestone-year {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .milestone h3 {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .milestone p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-inline-media--portrait img {
  aspect-ratio: 3 / 4;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 30px), calc(100% - 30px) 100%, 0 100%);
}

/* ---------- 日常更新 ---------- */
.page-about .mech-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 22px;
}

.page-about .mech {
  padding: 16px 16px 18px;
  background: rgba(21, 36, 61, 0.6);
  border: 1px solid var(--line);
  border-top: 2px solid rgba(126, 107, 234, 0.6);
}

.page-about .mech-num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 22px;
  letter-spacing: -0.02em;
  color: var(--amber);
}

.page-about .mech h3 {
  margin: 8px 0 6px;
  font-size: 15px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .mech p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 合作联系 ---------- */
.page-about .about-partner-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 20px;
}

.page-about .about-contact-list {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-contact-item {
  padding: 12px 14px;
  background: rgba(11, 42, 36, 0.62);
  border: 1px solid var(--line-soft);
  border-left: 2px solid var(--cold);
}

.page-about .about-contact-key {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: rgba(201, 212, 207, 0.66);
}

.page-about .about-contact-val {
  display: block;
  margin-top: 5px;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.7;
  color: var(--paper);
  word-break: break-word;
}

.page-about .about-partner-note p {
  margin: 0 0 12px;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.page-about .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  font-size: 14px;
  letter-spacing: 0.02em;
  text-decoration: none;
}

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

  .page-about .about-points {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }

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

  .page-about .about-inline-media img {
    aspect-ratio: 16 / 10;
  }

  .page-about .about-inline-media--portrait img {
    aspect-ratio: 3 / 4;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 960px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
  }

  .page-about .about-hero-media img {
    aspect-ratio: 14 / 10;
  }

  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    align-self: start;
  }

  .page-about .about-rail-list {
    flex-direction: column;
    gap: 0;
    padding: 0 0 0 24px;
    overflow: visible;
  }

  .page-about .about-rail-list::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 10px;
    bottom: 10px;
    width: 2px;
    background: linear-gradient(180deg, var(--cold), var(--violet) 55%, var(--amber));
    transform: skewX(-7deg);
    transform-origin: top center;
    opacity: 0.5;
  }

  .page-about .about-rail-link {
    position: relative;
    padding: 11px 0;
    white-space: normal;
    font-size: 14px;
    background: none;
    border: 0;
    border-bottom: 1px solid rgba(201, 212, 207, 0.1);
  }

  .page-about .about-rail-link::before {
    content: "";
    position: absolute;
    left: -24px;
    top: 50%;
    width: 9px;
    height: 9px;
    margin-top: -4px;
    transform: rotate(45deg);
    background: var(--ink);
    border: 1px solid rgba(201, 212, 207, 0.6);
    transition: background 0.24s var(--ease), border-color 0.24s var(--ease), box-shadow 0.24s var(--ease);
  }

  .page-about .about-rail-link:hover {
    color: var(--paper);
  }

  .page-about .about-rail-link.is-active,
  .page-about .about-rail-link[aria-current="true"] {
    background: none;
    color: var(--paper);
  }

  .page-about .about-rail-link.is-active::before,
  .page-about .about-rail-link[aria-current="true"]::before {
    background: var(--cold);
    border-color: var(--cold);
    box-shadow: 0 0 0 4px rgba(53, 224, 193, 0.16);
  }

  .page-about .layer-stack {
    gap: 16px;
  }

  .page-about .layer:nth-child(1) {
    margin-right: 14%;
  }

  .page-about .layer:nth-child(2) {
    margin-left: 9%;
  }

  .page-about .layer:nth-child(3) {
    margin-left: 4%;
    margin-right: 5%;
  }

  .page-about .milestone-layout {
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: 30px;
    align-items: start;
  }

  .page-about .about-partner-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.95fr);
    gap: 28px;
  }
}

@media (min-width: 1180px) {
  .page-about .mech-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-chapter {
    padding: clamp(26px, 3vw, 44px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal],
  .page-about .about-rail-link,
  .page-about .about-rail-link::before {
    transition: none;
  }
}