.page-about {
  --about-index-w: 200px;
  --about-gap: clamp(28px, 4.4vw, 64px);
  background: var(--canvas);
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.85;
  padding-bottom: clamp(64px, 9vw, 120px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(96px, 13vw, 150px) clamp(36px, 5vw, 60px);
  border-bottom: 1px solid var(--line);
}

.page-about .breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 clamp(24px, 3.5vw, 40px);
  padding: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ink-2);
}

.page-about .breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--line);
}

.page-about .breadcrumb a {
  color: var(--ink-2);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--ink);
  border-bottom-color: var(--line);
}

.page-about .about-eyebrow {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-2);
  padding-left: 14px;
  border-left: 3px solid var(--spring);
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 5.2vw, 58px);
  line-height: 1.24;
  letter-spacing: -0.01em;
  margin: clamp(16px, 2.4vw, 26px) 0 0;
  max-width: 19em;
  overflow-wrap: break-word;
}

.page-about .about-lede {
  margin: clamp(18px, 2.4vw, 28px) 0 0;
  max-width: 38em;
  font-size: clamp(16px, 1.6vw, 18px);
  color: var(--ink-2);
}

.page-about .about-facts {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 14px clamp(24px, 4vw, 48px);
  margin: clamp(26px, 3.4vw, 40px) 0 0;
  padding: clamp(16px, 2vw, 20px) 0 0;
  border-top: 1px solid var(--line);
}

.page-about .about-facts li {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.page-about .about-fact-key {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ink-2);
}

.page-about .about-fact-val {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(17px, 2vw, 21px);
  color: var(--ink);
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 20px;
  margin-top: clamp(26px, 3.4vw, 38px);
}

.page-about .about-textlink {
  font-family: var(--font-display);
  font-size: 15px;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--mark);
  padding-bottom: 2px;
  transition: color 0.16s var(--ease);
}

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

.page-about .about-seasons-bar {
  display: flex;
  height: 8px;
  margin-top: clamp(36px, 5vw, 58px);
}

.page-about .about-seasons-bar span {
  flex: 1 1 25%;
  display: block;
}

.page-about .about-seasons-bar span:nth-child(1) { background: var(--spring); }
.page-about .about-seasons-bar span:nth-child(2) { background: var(--summer); }
.page-about .about-seasons-bar span:nth-child(3) { background: var(--autumn); }
.page-about .about-seasons-bar span:nth-child(4) { background: var(--winter); }

/* ---------- 主布局 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 48px);
  padding-top: clamp(36px, 5vw, 64px);
}

/* ---------- 左侧索引 ---------- */
.page-about .about-index {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 12px 0 14px;
}

.page-about .about-index-title {
  margin: 0 0 8px;
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-2);
}

.page-about .about-index-list {
  list-style: none;
  display: flex;
  gap: 18px;
  margin: 0;
  padding: 0 0 4px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-index-list li {
  flex: 0 0 auto;
  scroll-snap-align: start;
}

.page-about .about-index-list a {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  font-family: var(--font-display);
  font-size: 14px;
  color: var(--ink-2);
  text-decoration: none;
  white-space: nowrap;
  padding-bottom: 3px;
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.page-about .about-index-list a .mono {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--line);
}

.page-about .about-index-list a:hover,
.page-about .about-index-list a:focus-visible {
  color: var(--ink);
  border-bottom-color: var(--mark);
}

.page-about .about-index-list li:nth-child(1) a:hover { border-bottom-color: var(--spring); }
.page-about .about-index-list li:nth-child(2) a:hover { border-bottom-color: var(--summer); }
.page-about .about-index-list li:nth-child(3) a:hover { border-bottom-color: var(--autumn); }
.page-about .about-index-list li:nth-child(4) a:hover { border-bottom-color: var(--winter); }

.page-about .about-index-list li:nth-child(1) a .mono { color: var(--spring); }
.page-about .about-index-list li:nth-child(2) a .mono { color: var(--summer); }
.page-about .about-index-list li:nth-child(3) a .mono { color: var(--autumn); }
.page-about .about-index-list li:nth-child(4) a .mono { color: var(--winter); }
.page-about .about-index-list li:nth-child(5) a .mono { color: var(--mark); }

/* ---------- 章节通用 ---------- */
.page-about .about-body {
  min-width: 0;
}

.page-about .about-section {
  --sec: var(--line);
  padding-bottom: clamp(48px, 7vw, 88px);
  margin-bottom: clamp(40px, 6vw, 72px);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-section:last-child {
  margin-bottom: 0;
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-section--origin { --sec: var(--spring); }
.page-about .about-section--system { --sec: var(--summer); }
.page-about .about-section--timeline { --sec: var(--autumn); }
.page-about .about-section--team { --sec: var(--winter); }
.page-about .about-section--reach { --sec: var(--mark); }

.page-about .about-section-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-top: 14px;
  border-top: 2px solid var(--sec);
  margin-bottom: clamp(20px, 2.8vw, 32px);
}

.page-about .about-num {
  font-family: var(--font-mono);
  font-size: clamp(13px, 1.5vw, 15px);
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--sec);
}

.page-about .about-section-head h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(23px, 3.2vw, 36px);
  line-height: 1.3;
  margin: 0;
  letter-spacing: -0.005em;
}

.page-about .about-section-lede {
  margin: 0 0 clamp(22px, 3vw, 34px);
  max-width: 36em;
  color: var(--ink-2);
  font-size: clamp(15px, 1.5vw, 17px);
}

.page-about .about-section-foot {
  margin: clamp(20px, 2.6vw, 30px) 0 0;
  font-size: 14px;
  color: var(--ink-2);
  padding-left: 14px;
  border-left: 2px solid var(--line);
}

.page-about .about-section-foot a,
.page-about .about-prose a,
.page-about .about-cta-text a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--mark);
  text-underline-offset: 4px;
  transition: color 0.16s var(--ease);
}

.page-about .about-section-foot a:hover,
.page-about .about-prose a:hover,
.page-about .about-cta-text a:hover {
  color: var(--mark);
}

.page-about .about-prose p {
  margin: 0 0 1.1em;
  font-size: clamp(15px, 1.5vw, 17px);
  color: var(--ink-2);
  max-width: 40em;
}

.page-about .about-prose p:first-child {
  color: var(--ink);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 8px;
}

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

.page-about .about-figure--team img { aspect-ratio: 10 / 7; }
.page-about .about-figure--reach img { aspect-ratio: 12 / 7; }

.page-about .about-figure figcaption {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  line-height: 1.7;
  color: var(--ink-2);
  padding: 10px 4px 2px;
  border-top: 1px solid var(--line-soft);
  margin-top: 8px;
}

/* ---------- 01 缘起 ---------- */
.page-about .about-grid-origin {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3vw, 36px);
}

/* ---------- 02 栏目体系 ---------- */
.page-about .about-seasons-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-season-cell {
  --cell: var(--line);
  position: relative;
  background: var(--paper);
  padding: 22px 18px 24px;
}

.page-about .about-season-cell--spring { --cell: var(--spring); }
.page-about .about-season-cell--summer { --cell: var(--summer); }
.page-about .about-season-cell--autumn { --cell: var(--autumn); }
.page-about .about-season-cell--winter { --cell: var(--winter); }

.page-about .about-season-cell::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--cell);
}

.page-about .about-cell-tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cell);
}

.page-about .about-season-cell h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(18px, 2vw, 21px);
  margin: 8px 0 4px;
  line-height: 1.4;
}

.page-about .about-cell-meta {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--ink-2);
}

.page-about .about-season-cell ul {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-season-cell li {
  padding: 7px 0 7px 14px;
  position: relative;
  font-size: 14px;
  color: var(--ink-2);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-season-cell li:last-child { border-bottom: 0; }

.page-about .about-season-cell li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.05em;
  width: 6px;
  height: 6px;
  background: var(--cell);
  border-radius: 50%;
}

.page-about .about-service-strip {
  margin-top: clamp(20px, 2.6vw, 28px);
  border: 1px solid var(--line);
  background: var(--paper);
  padding: 16px 18px;
  display: grid;
  gap: 12px;
}

.page-about .about-service-title {
  margin: 0;
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-2);
}

.page-about .about-service-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
}

.page-about .about-service-list a {
  font-family: var(--font-display);
  font-size: 14px;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
  transition: border-color 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .about-service-list a:hover,
.page-about .about-service-list a:focus-visible {
  color: var(--summer-ink);
  border-bottom-color: var(--summer);
}

/* ---------- 03 时间轴 ---------- */
.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 28px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 10px;
  width: 1px;
  background: var(--line);
}

.page-about .about-timeline > li {
  position: relative;
  padding-bottom: clamp(22px, 3vw, 32px);
}

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

.page-about .about-timeline > li::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 8px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--paper);
  border: 1px solid var(--autumn);
  box-shadow: 0 0 0 4px var(--canvas);
}

.page-about .about-timeline > li:nth-child(2)::before { border-color: var(--summer); }
.page-about .about-timeline > li:nth-child(4)::before { border-color: var(--winter); }
.page-about .about-timeline > li:nth-child(5)::before { border-color: var(--mark); background: var(--mark); }

.page-about .about-tl-era {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--autumn-ink);
}

.page-about .about-tl-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(17px, 2vw, 20px);
  line-height: 1.5;
  margin: 4px 0 6px;
}

.page-about .about-tl-text {
  margin: 0;
  font-size: 15px;
  color: var(--ink-2);
  max-width: 38em;
}

/* ---------- 04 团队 ---------- */
.page-about .about-grid-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3vw, 34px);
}

.page-about .about-bars {
  list-style: none;
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-bar-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
}

.page-about .about-bar-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  color: var(--ink);
}

.page-about .about-bar-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--ink-2);
}

.page-about .about-bar-track {
  display: block;
  height: 6px;
  margin: 6px 0 6px;
  background: var(--line-soft);
  border: 1px solid var(--line);
}

.page-about .about-bar-fill {
  display: block;
  height: 100%;
  background: var(--winter);
  transition: width 0.5s var(--ease);
}

.page-about .about-bar-fill--edit { width: 42%; background: var(--spring); }
.page-about .about-bar-fill--design { width: 21%; background: var(--summer); }
.page-about .about-bar-fill--tech { width: 19%; background: var(--autumn); }
.page-about .about-bar-fill--service { width: 19%; background: var(--winter); }

.page-about .about-bar-desc {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--ink-2);
}

.page-about .about-process {
  margin-top: clamp(24px, 3vw, 34px);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-details {
  border-bottom: 1px solid var(--line-soft);
  padding: 4px 0;
}

.page-about .about-details summary {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  padding: 12px 0;
  color: var(--ink);
}

.page-about .about-details .disclosure-body {
  padding-bottom: 14px;
}

.page-about .about-details .disclosure-body p {
  margin: 0;
  font-size: 14px;
  color: var(--ink-2);
  max-width: 40em;
}

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

.page-about .about-steps li {
  font-size: 14px;
  color: var(--ink-2);
  padding-left: 14px;
  border-left: 2px solid var(--line-soft);
}

.page-about .about-steps .mono {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--winter-ink);
  margin-right: 8px;
}

/* ---------- 05 覆盖 ---------- */
.page-about .about-grid-reach {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 2.8vw, 30px);
}

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

.page-about .about-stat {
  background: var(--paper);
  padding: 18px 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.page-about .about-stat-num {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.1;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.page-about .about-stat-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--ink-2);
}

.page-about .about-cta {
  margin-top: clamp(26px, 3.6vw, 40px);
  padding: clamp(20px, 3vw, 28px);
  background: var(--paper);
  border: 1px solid var(--line);
  border-left: 4px solid var(--mark);
  display: grid;
  gap: 18px;
}

.page-about .about-cta-text {
  margin: 0;
  font-size: 15px;
  color: var(--ink-2);
  max-width: 40em;
}

.page-about .about-cta .btn {
  justify-self: start;
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 700px) {
  .page-about .about-seasons-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .about-service-strip {
    grid-template-columns: auto 1fr;
    align-items: center;
    gap: 18px;
  }
}

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

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    border-top: 0;
    border-bottom: 0;
    border-left: 1px solid var(--line);
    padding: 4px 0 4px 18px;
  }

  .page-about .about-index-title {
    margin-bottom: 12px;
  }

  .page-about .about-index-list {
    display: block;
    overflow: visible;
    padding: 0;
  }

  .page-about .about-index-list li {
    padding: 9px 0;
  }

  .page-about .about-index-list a {
    white-space: normal;
  }

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

  .page-about .about-grid-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.72fr);
    align-items: start;
  }

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

  .page-about .about-cta {
    grid-template-columns: 1fr auto;
    align-items: center;
  }
}

@media (min-width: 1100px) {
  .page-about .about-seasons-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-bar-fill,
  .page-about .about-textlink,
  .page-about .about-service-list a,
  .page-about .about-index-list a,
  .page-about .breadcrumb a {
    transition: none;
  }
}