.page-about {
  background: var(--ink-0);
  color: var(--fg);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(2rem, 6vw, 3.5rem) 0 clamp(2.5rem, 6vw, 4rem);
  background:
    radial-gradient(80% 110% at 100% 0%, rgba(255, 106, 26, .16), transparent 62%),
    linear-gradient(180deg, var(--ink-1) 0%, var(--ink-0) 100%);
  border-bottom: 1px solid var(--line);
}

.page-about .breadcrumbs {
  display: flex;
  align-items: center;
  gap: .55rem;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .crumb {
  color: var(--muted);
  text-decoration: none;
}

.page-about .crumb:hover,
.page-about .crumb:focus-visible {
  color: var(--accent);
}

.page-about .crumb-current {
  color: var(--fg);
}

.page-about .hero-grid {
  align-items: start;
}

.page-about .hero-main {
  padding-bottom: clamp(1.5rem, 4vw, 2rem);
}

.page-about .eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 1rem;
}

.page-about .hero-title {
  margin: 0 0 1.25rem;
  font-size: clamp(1.9rem, 5.6vw, 3.6rem);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -.02em;
}

.page-about .lead {
  margin: 0;
  max-width: 62ch;
  font-size: clamp(1rem, 1.2vw, 1.125rem);
  line-height: 1.8;
  color: var(--fg);
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .hero-aside {
  padding-top: clamp(.5rem, 3vw, 1rem);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.1rem 1rem;
  padding: clamp(1rem, 3vw, 1.4rem);
  background: var(--glass);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
}

.page-about .hero-stats .stat {
  display: flex;
  flex-direction: column;
  gap: .2rem;
}

.page-about .hero-stats .stat-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.4rem, 4vw, 1.9rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--fg);
}

.page-about .hero-stats .stat:first-child .stat-num {
  color: var(--accent);
}

.page-about .hero-stats .stat-label {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
}

.page-about .hero-note {
  margin: 1rem 0 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  position: relative;
  padding: 0 0 clamp(2.5rem, 7vw, 5rem);
}

.page-about .chapter-band {
  display: block;
  width: 100%;
  height: 8px;
  margin-bottom: clamp(1.5rem, 4vw, 2.5rem);
  background: linear-gradient(90deg, var(--accent), rgba(255, 106, 26, .28) 46%, rgba(255, 106, 26, 0));
}

.page-about .chapter-head {
  display: grid;
  gap: 1rem;
  margin-bottom: clamp(1.75rem, 4vw, 2.75rem);
}

.page-about .chapter-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--accent);
  margin-bottom: .6rem;
}

.page-about .chapter-title {
  margin: 0;
  font-size: clamp(1.5rem, 4.4vw, 2.6rem);
  font-weight: 900;
  line-height: 1.16;
  letter-spacing: -.02em;
}

.page-about .chapter-desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .prose {
  margin: 0 0 1.1rem;
  max-width: 66ch;
  font-size: 1rem;
  line-height: 1.8;
}

.page-about .link-more {
  display: inline-block;
  margin-top: .75rem;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 106, 26, .45);
  padding-bottom: .2rem;
}

.page-about .link-more:hover,
.page-about .link-more:focus-visible {
  color: var(--accent-2);
  border-bottom-color: var(--accent-2);
}

/* ---------- 时间线 ---------- */
.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 2rem;
  display: grid;
  gap: clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: linear-gradient(180deg, var(--muted), var(--accent));
}

.page-about .timeline-item {
  position: relative;
}

.page-about .timeline-node {
  position: absolute;
  left: -2rem;
  top: .35rem;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--ink-0);
  border: 2px solid var(--muted);
  box-shadow: 0 0 0 4px rgba(6, 23, 38, .9);
}

.page-about .timeline-item:nth-child(2) .timeline-node {
  border-color: var(--accent-2);
}

.page-about .timeline-item:nth-child(3) .timeline-node {
  border-color: var(--accent);
  background: var(--accent);
}

.page-about .timeline-year {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--muted);
  line-height: 1;
}

.page-about .timeline-item:nth-child(3) .timeline-year {
  color: var(--accent);
}

.page-about .timeline-body {
  margin-top: .65rem;
}

.page-about .timeline-title {
  margin: 0 0 .45rem;
  font-size: 1.0625rem;
  font-weight: 800;
}

.page-about .timeline-body p {
  margin: 0;
  max-width: 60ch;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .timeline-aside {
  padding-top: clamp(1.5rem, 4vw, 2rem);
}

.page-about .aside-quote {
  margin: 0;
  padding-left: 1rem;
  border-left: 2px solid var(--accent);
  font-size: 15px;
  line-height: 1.8;
  color: var(--fg);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: clamp(2rem, 5vw, 3rem) 0 0;
}

.page-about .media-frame {
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--ink-1);
}

.page-about .fig-band {
  aspect-ratio: 16 / 9;
}

.page-about .fig-square {
  aspect-ratio: 1 / 1;
}

.page-about .fig-band img,
.page-about .fig-square img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  max-width: 100%;
}

.page-about .media-caption {
  margin-top: .65rem;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--muted);
}

/* ---------- 层级图 ---------- */
.page-about .layer-map {
  display: block;
  width: 100%;
  max-width: 520px;
  height: auto;
  margin-top: clamp(1rem, 3vw, 1.75rem);
}

.page-about .layer-map .layer-rect {
  transition: opacity .3s var(--ease);
}

.page-about .layer-map:hover .layer-rect {
  opacity: .3;
}

.page-about .layer-map .layer-rect:hover {
  opacity: 1;
}

.page-about .layer-rect--1 {
  fill: rgba(110, 130, 150, .08);
  stroke: rgba(110, 130, 150, .5);
}

.page-about .layer-rect--2 {
  fill: rgba(22, 57, 92, .38);
  stroke: rgba(110, 130, 150, .55);
}

.page-about .layer-rect--3 {
  fill: rgba(22, 57, 92, .6);
  stroke: rgba(110, 130, 150, .65);
}

.page-about .layer-rect--4 {
  fill: rgba(255, 106, 26, .18);
  stroke: var(--accent);
}

.page-about .layer-label {
  fill: var(--fg);
  font-family: var(--font-head);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: .06em;
}

.page-about .layer-sub {
  fill: var(--muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .04em;
}

/* ---------- 折叠面板 ---------- */
.page-about .accordion {
  margin-top: clamp(1.75rem, 4vw, 2.5rem);
  border-top: 1px solid var(--line-strong);
}

.page-about .accordion-item {
  border-bottom: 1px solid var(--line);
}

.page-about .acc-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: 100%;
  padding: 1.1rem 0;
  background: none;
  border: 0;
  color: var(--fg);
  font-family: inherit;
  font-size: 1rem;
  font-weight: 700;
  text-align: left;
  cursor: pointer;
}

.page-about .acc-trigger:hover,
.page-about .acc-trigger:focus-visible {
  color: var(--accent);
}

.page-about .acc-trigger[aria-expanded="true"] {
  color: var(--accent);
}

.page-about .acc-panel-inner {
  padding: 0 0 1.25rem;
  max-width: 68ch;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .acc-panel-inner p {
  margin: 0;
}

/* ---------- 校验列表 ---------- */
.page-about .check-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .9rem;
}

.page-about .check-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: .85rem 1rem;
  padding: clamp(1rem, 2.5vw, 1.35rem);
  background: var(--ink-1);
  border: 1px solid var(--line);
  border-left: 2px solid var(--ink-2);
  border-radius: var(--radius);
}

.page-about .check-index {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--accent);
  padding-top: .2rem;
}

.page-about .check-title {
  margin: 0 0 .35rem;
  font-size: 1rem;
  font-weight: 800;
}

.page-about .check-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .revision-note {
  margin-top: 1.35rem;
  padding: 1.1rem 1.25rem;
  background: linear-gradient(120deg, rgba(22, 57, 92, .55), rgba(11, 33, 54, .9));
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.page-about .revision-note p {
  margin: 0;
  max-width: 64ch;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--fg);
}

.page-about .version-box {
  padding: clamp(1.15rem, 3vw, 1.5rem);
  background: var(--ink-1);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
}

.page-about .version-box .eyebrow {
  display: block;
  margin: 0 0 .5rem;
}

.page-about .version-code {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1rem, 3vw, 1.2rem);
  letter-spacing: .06em;
  color: var(--accent-2);
  word-break: break-all;
}

.page-about .version-text {
  margin: .9rem 0 1.1rem;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .copy-btn {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  padding: .55rem .9rem;
  background: transparent;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  color: var(--fg);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  cursor: pointer;
  transition: border-color .25s var(--ease), color .25s var(--ease);
}

.page-about .copy-btn:hover,
.page-about .copy-btn:focus-visible {
  border-color: var(--accent);
  color: var(--accent);
}

.page-about .copy-btn.is-copied {
  border-color: var(--signal);
  color: var(--signal);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: .9rem;
}

.page-about .team-cell {
  padding: clamp(1.25rem, 3vw, 1.85rem);
  background: var(--ink-1);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.page-about .team-cell--lead {
  background: linear-gradient(155deg, var(--ink-2), var(--ink-1));
  border-color: rgba(255, 106, 26, .35);
}

.page-about .team-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(2.4rem, 7vw, 3.5rem);
  font-weight: 700;
  line-height: 1;
  color: var(--fg);
}

.page-about .team-cell--lead .team-num {
  color: var(--accent);
}

.page-about .team-cell h3 {
  margin: 1rem 0 .5rem;
  font-size: 1.0625rem;
  font-weight: 800;
}

.page-about .team-cell p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .team-foot {
  margin-top: clamp(1.5rem, 4vw, 2rem);
  padding-left: 1rem;
  border-left: 1px solid var(--line-strong);
}

.page-about .team-foot p {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 合作 ---------- */
.page-about .partner-grid {
  display: grid;
  gap: .9rem;
}

.page-about .partner-card {
  padding: clamp(1.25rem, 3vw, 1.75rem);
  background: var(--ink-1);
  border: 1px solid var(--line);
  border-top: 2px solid var(--accent);
  border-radius: var(--radius);
}

.page-about .partner-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.75rem, 5vw, 2.25rem);
  font-weight: 700;
  line-height: 1;
  color: var(--accent-2);
}

.page-about .partner-label {
  margin: .7rem 0 .55rem;
  font-size: 1rem;
  font-weight: 800;
}

.page-about .partner-card p:last-child {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 能力清单 ---------- */
.page-about .cap-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .cap-item {
  display: grid;
  gap: .35rem;
  padding: 1.05rem 0;
  border-bottom: 1px solid var(--line);
}

.page-about .cap-key {
  font-size: 15px;
  font-weight: 800;
}

.page-about .cap-val {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 14px;
  letter-spacing: .04em;
  color: var(--accent-2);
}

.page-about .cap-note {
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 收束 ---------- */
.page-about .cta-band {
  padding: 0 0 clamp(3rem, 8vw, 5.5rem);
}

.page-about .about-cta {
  padding: clamp(1.75rem, 5vw, 3rem);
  background: linear-gradient(120deg, var(--ink-2), var(--ink-1) 70%);
  border: 1px solid rgba(255, 106, 26, .3);
  border-radius: var(--radius);
}

.page-about .cta-copy h2 {
  margin: 0 0 .75rem;
  font-size: clamp(1.4rem, 3.6vw, 2rem);
  font-weight: 900;
  letter-spacing: -.02em;
}

.page-about .cta-copy p {
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .cta-links {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: 1.5rem;
}

/* ---------- 章节刻度尺 ---------- */
.page-about .in-page-ruler {
  display: none;
}

@media (min-width: 1180px) {
  .page-about .in-page-ruler {
    position: fixed;
    right: clamp(.75rem, 2vw, 1.6rem);
    top: 50%;
    transform: translateY(-50%);
    z-index: 20;
    display: flex;
    flex-direction: column;
    gap: .55rem;
  }

  .page-about .ruler-item {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: .5rem;
    text-decoration: none;
    color: var(--muted);
  }

  .page-about .ruler-num {
    font-family: var(--font-mono);
    font-size: 10px;
    letter-spacing: .12em;
  }

  .page-about .ruler-bar {
    display: block;
    width: 16px;
    height: 2px;
    background: currentColor;
    opacity: .55;
    transition: width .25s var(--ease), background-color .25s var(--ease), opacity .25s var(--ease);
  }

  .page-about .ruler-item.is-current {
    color: var(--accent);
  }

  .page-about .ruler-item.is-current .ruler-bar {
    width: 34px;
    opacity: 1;
  }

  .page-about .ruler-top .ruler-bar {
    background: var(--line-strong);
  }
}

/* ---------- 桌面网格 ---------- */
@media (min-width: 900px) {
  .page-about .chapter-head {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(2rem, 5vw, 4rem);
    align-items: end;
  }

  .page-about .chapter-desc {
    border-left: 1px solid var(--line-strong);
    padding-left: clamp(1rem, 2vw, 1.5rem);
  }

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

  .page-about .team-grid {
    grid-template-columns: 1.7fr 1fr 1fr;
  }

  .page-about .cap-item {
    grid-template-columns: minmax(0, 3fr) minmax(0, 2fr) minmax(0, 6fr);
    gap: 1.5rem;
    align-items: baseline;
  }

  .page-about .timeline-aside {
    padding-top: .35rem;
  }
}

@media (min-width: 700px) {
  .page-about .partner-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .layer-map .layer-rect,
  .page-about .copy-btn,
  .page-about .ruler-bar {
    transition: none;
  }

  .page-about .layer-map:hover .layer-rect {
    opacity: 1;
  }
}