.page-about {
  --about-orange: var(--brand-orange);
  --about-navy: var(--deep-navy);
  --about-red: var(--tibetan-red);
  --about-sand: var(--warm-sand);
  --about-paper: var(--paper-white);
  --about-white: var(--white);

  background: var(--about-paper);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.7;
  overflow-x: hidden;
}

.page-about .container {
  max-width: var(--container-w);
  margin: 0 auto;
  padding-left: var(--gutter);
  padding-right: var(--gutter);
}

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

/* ====== 面包屑 ====== */
.page-about .about-breadcrumb {
  padding-top: 20px;
  border-bottom: 1px solid rgba(26, 42, 58, 0.08);
}

.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--slate-gray);
  padding: 0 0 14px;
}

.page-about .breadcrumb-item {
  color: var(--slate-gray);
  text-decoration: none;
  transition: color var(--t-fast);
}

.page-about .breadcrumb-item[aria-current="page"] {
  color: var(--text-primary);
  font-weight: 600;
}

.page-about .breadcrumb-item:hover {
  color: var(--about-orange);
}

.page-about .breadcrumb-sep {
  color: rgba(26, 42, 58, 0.35);
  user-select: none;
}

/* ====== 页眉区域 ====== */
.page-about .about-hero {
  position: relative;
  padding: 48px 0 56px;
  background:
    radial-gradient(circle at 84% 30%, rgba(255, 107, 53, 0.10), transparent 42%),
    radial-gradient(circle at 12% 82%, rgba(192, 57, 43, 0.06), transparent 46%),
    linear-gradient(180deg, var(--about-white), var(--about-paper));
}

.page-about .hero-inner {
  display: grid;
  gap: 28px;
  align-items: center;
}

.page-about .hero-copy {
  position: relative;
  padding-left: 22px;
  border-left: 3px solid var(--about-orange);
}

.page-about .hero-kicker {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--about-red);
  text-transform: uppercase;
  margin-bottom: 12px;
}

.page-about .hero-title {
  font-family: var(--font-display);
  font-size: clamp(34px, 6vw, 68px);
  line-height: 1.08;
  letter-spacing: 0.01em;
  margin: 0 0 16px;
  color: var(--about-navy);
}

.page-about .hero-lead {
  font-size: 17px;
  color: var(--slate-gray);
  max-width: 560px;
  margin: 0 0 24px;
}

.page-about .hero-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--about-navy);
}

.page-about .hero-meta-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--about-orange);
  flex: 0 0 auto;
}

.page-about .hero-art {
  display: flex;
  justify-content: center;
  align-items: center;
}

.page-about .hero-svg {
  width: 100%;
  max-width: 400px;
  height: auto;
  display: block;
}

/* ====== 章节索引 ====== */
.page-about .section-index {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--about-red);
  border-left: 3px solid var(--about-red);
  padding-left: 12px;
  margin: 0 0 12px;
}

.page-about .section-title {
  font-family: var(--font-display);
  font-size: clamp(28px, 4.5vw, 44px);
  line-height: 1.18;
  color: var(--about-navy);
  margin: 0 0 14px;
}

/* ====== 01 起源 ====== */
.page-about .story-origin {
  padding: 64px 0 40px;
  background:
    linear-gradient(120deg, rgba(247, 232, 208, 0.55), transparent 62%),
    var(--about-paper);
}

.page-about .origin-grid {
  display: grid;
  gap: 36px;
}

.page-about .origin-copy {
  order: 1;
}

.page-about .origin-lead {
  font-size: 18px;
  line-height: 1.8;
  color: var(--text-primary);
  margin-bottom: 18px;
}

.page-about .origin-copy p {
  margin-bottom: 14px;
  color: var(--text-secondary);
  font-size: 16px;
}

.page-about .origin-aside {
  order: 2;
}

.page-about .origin-figure {
  margin: 0;
  position: relative;
  background: var(--about-white);
  border: 1px solid rgba(26, 42, 58, 0.08);
  box-shadow: 0 14px 34px rgba(26, 42, 58, 0.10);
}

.page-about .origin-img {
  width: 100%;
  display: block;
  object-fit: cover;
  aspect-ratio: 8 / 5;
}

.page-about .origin-figure figcaption {
  padding: 12px 16px;
  font-size: 14px;
  color: var(--slate-gray);
  background: var(--about-white);
  border-top: 1px solid rgba(26, 42, 58, 0.06);
}

/* ====== 山形分隔 ====== */
.page-about .mountain-divider {
  line-height: 0;
  margin-top: -1px;
}

.page-about .mountain-svg {
  width: 100%;
  height: 56px;
  display: block;
}

/* ====== 02 里程碑 ====== */
.page-about .story-milestones {
  position: relative;
  padding: 48px 0 64px;
  background:
    radial-gradient(closest-side at 12% 8%, rgba(255, 107, 53, 0.10), transparent 70%),
    radial-gradient(closest-side at 92% 68%, rgba(26, 42, 58, 0.08), transparent 72%),
    linear-gradient(180deg, var(--about-white), var(--about-paper));
  overflow: hidden;
}

.page-about .milestones-head {
  max-width: 680px;
  margin-bottom: 48px;
}

.page-about .milestones-desc {
  font-size: 16px;
  color: var(--text-secondary);
  margin-top: 14px;
}

.page-about .timeline {
  position: relative;
  display: grid;
  gap: 18px;
  margin: 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 14px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background-image: linear-gradient(to bottom, var(--about-orange) 0, var(--about-orange) 50%, transparent 50%);
  background-size: 100% 12px;
  background-repeat: repeat-y;
}

.page-about .timeline-item {
  position: relative;
  margin-left: 42px;
  background: var(--about-white);
  border-left: 4px solid var(--about-orange);
  box-shadow: 0 8px 24px rgba(26, 42, 58, 0.08);
  transition: box-shadow var(--t-slow), transform var(--t-slow);
}

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  left: -46px;
  top: 18px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--about-orange);
  border: 3px solid var(--about-white);
  box-shadow: 0 0 0 1px var(--about-orange);
}

.page-about .timeline-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 36px rgba(26, 42, 58, 0.13);
}

.page-about .timeline-trigger {
  display: block;
  width: 100%;
  padding: 18px 20px 14px;
  background: transparent;
  border: 0;
  cursor: pointer;
  list-style: none;
  text-align: left;
  color: var(--text-primary);
}

.page-about .timeline-trigger::-webkit-details-marker {
  display: none;
}

.page-about .timeline-card-head {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .timeline-year {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  color: var(--about-orange);
  letter-spacing: 0.03em;
}

.page-about .timeline-name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 600;
  color: var(--about-navy);
}

.page-about .timeline-summary {
  display: block;
  margin-top: 8px;
  font-size: 15px;
  color: var(--text-secondary);
}

.page-about .timeline-arrow {
  position: absolute;
  right: 18px;
  bottom: 16px;
  font-family: var(--font-mono);
  font-size: 20px;
  color: var(--about-orange);
  transform: rotate(90deg);
  transition: transform var(--t-slow);
}

.page-about .timeline-item[open] .timeline-arrow {
  transform: rotate(45deg);
}

.page-about .timeline-panel {
  padding: 0 20px 20px;
}

.page-about .timeline-panel p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-secondary);
  border-top: 1px dashed rgba(26, 42, 58, 0.12);
  padding-top: 14px;
}

.page-about .milestone-wide {
  margin: 56px 0 0;
  background: var(--about-navy);
  padding: 12px;
  box-shadow: 0 18px 44px rgba(26, 42, 58, 0.22);
}

.page-about .milestone-wide-img {
  width: 100%;
  display: block;
  object-fit: cover;
  aspect-ratio: 1200 / 600;
}

.page-about .milestone-wide figcaption {
  padding: 12px 8px 6px;
  color: var(--mist-blue);
  font-size: 14px;
}

/* ====== 03 数据能力 ====== */
.page-about .story-data {
  position: relative;
  padding: 72px 0 64px;
  background:
    radial-gradient(circle at 82% 18%, rgba(255, 107, 53, 0.18), transparent 40%),
    radial-gradient(circle at 8% 72%, rgba(169, 212, 228, 0.10), transparent 42%),
    linear-gradient(160deg, var(--deep-ocean), var(--deep-navy) 58%, #24394C);
  color: var(--about-white);
  overflow: hidden;
}

.page-about .story-data .section-index {
  color: var(--morning-gold);
  border-left-color: var(--morning-gold);
}

.page-about .story-data .section-title {
  color: var(--about-white);
}

.page-about .data-head {
  max-width: 760px;
  margin-bottom: 44px;
}

.page-about .data-desc {
  font-size: 16px;
  color: rgba(245, 245, 245, 0.85);
  margin-top: 16px;
}

.page-about .stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.10);
  margin-bottom: 40px;
}

.page-about .stat-item {
  background: var(--deep-navy);
  padding: 24px 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: background var(--t-slow);
}

.page-about .stat-item:hover {
  background: rgba(255, 107, 53, 0.12);
}

.page-about .stat-number {
  font-family: var(--font-display);
  font-size: clamp(30px, 5vw, 46px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--about-orange);
}

.page-about .stat-label {
  font-size: 14px;
  color: rgba(245, 245, 245, 0.82);
}

.page-about .data-note {
  display: grid;
  gap: 16px;
  max-width: 900px;
  margin-bottom: 44px;
}

.page-about .data-note p {
  margin: 0;
  font-size: 15px;
  color: rgba(245, 245, 245, 0.88);
  line-height: 1.9;
}

.page-about .data-note-lead {
  font-size: 17px !important;
  color: var(--about-white) !important;
}

.page-about .data-media {
  margin: 0;
  background: var(--deep-ocean);
  border: 1px solid rgba(255, 255, 255, 0.12);
  padding: 10px;
}

.page-about .data-media-img {
  width: 100%;
  display: block;
  object-fit: cover;
  aspect-ratio: 1000 / 600;
}

.page-about .data-media figcaption {
  padding: 12px 6px 4px;
  font-size: 14px;
  color: rgba(245, 245, 245, 0.68);
}

/* ====== 04 适配清单 ====== */
.page-about .story-compat {
  padding: 64px 0;
  background: var(--about-paper);
}

.page-about .compat-head {
  max-width: 720px;
  margin-bottom: 36px;
}

.page-about .compat-desc {
  font-size: 16px;
  color: var(--text-secondary);
  margin-top: 14px;
}

.page-about .compat-list {
  display: grid;
  gap: 12px;
  margin-bottom: 32px;
}

.page-about .compat-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 18px;
  background: var(--about-white);
  border-left: 4px solid rgba(26, 42, 58, 0.15);
  border-top: 1px solid rgba(26, 42, 58, 0.07);
  border-bottom: 1px solid rgba(26, 42, 58, 0.07);
  transition: background var(--t-slow), border-color var(--t-slow), transform var(--t-slow);
}

.page-about .compat-item:hover {
  background: var(--about-sand);
  border-left-color: var(--about-orange);
  transform: translateX(4px);
}

.page-about .compat-browser {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 600;
  color: var(--about-navy);
  min-width: 76px;
}

.page-about .compat-version {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
  color: var(--about-orange);
  background: rgba(255, 107, 53, 0.10);
  padding: 2px 10px;
  line-height: 1.4;
}

.page-about .compat-note {
  font-size: 14px;
  color: var(--text-secondary);
  flex: 1;
}

.page-about .compat-footnote {
  font-size: 14px;
  color: var(--slate-gray);
  max-width: 860px;
  padding-top: 20px;
  border-top: 1px dashed rgba(26, 42, 58, 0.15);
}

.page-about .compat-footnote a,
.page-about .cta-sub a {
  color: var(--about-red);
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid rgba(192, 57, 43, 0.35);
  transition: color var(--t-fast), border-color var(--t-fast);
}

.page-about .compat-footnote a:hover,
.page-about .cta-sub a:hover {
  color: var(--about-orange);
  border-bottom-color: var(--about-orange);
}

/* ====== 收尾CTA ====== */
.page-about .story-cta {
  padding: 56px 0 72px;
  background:
    linear-gradient(135deg, var(--deep-ocean) 0%, var(--deep-navy) 52%, #23384C 100%);
  border-top: 4px solid var(--about-orange);
}

.page-about .cta-inner {
  text-align: center;
  max-width: 680px;
  margin: 0 auto;
}

.page-about .cta-kicker {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--morning-gold);
  margin-bottom: 12px;
}

.page-about .cta-text {
  font-family: var(--font-display);
  font-size: clamp(24px, 4vw, 38px);
  font-weight: 600;
  color: var(--about-white);
  margin: 0 0 28px;
  line-height: 1.3;
}

.page-about .btn-primary {
  display: inline-block;
  background: var(--about-orange);
  color: var(--about-white);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 600;
  padding: 14px 32px;
  border-radius: var(--radius);
  text-decoration: none;
  transition: background var(--t-fast), transform var(--t-fast), box-shadow var(--t-fast);
  box-shadow: 0 4px 14px rgba(255, 107, 53, 0.30);
}

.page-about .btn-primary:hover {
  background: var(--about-navy);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(26, 42, 58, 0.32);
}

.page-about .cta-sub {
  margin-top: 20px;
  font-size: 14px;
  color: rgba(245, 245, 245, 0.70);
}

/* ====== 桌面端适配 ====== */
@media (min-width: 768px) {
  .page-about .stats-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about .compat-list {
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
  }

  .page-about .compat-item {
    padding: 18px 20px;
  }

  .page-about .timeline::before {
    left: 24px;
  }

  .page-about .timeline-item {
    margin-left: 68px;
  }

  .page-about .timeline-item::before {
    left: -68px;
    width: 18px;
    height: 18px;
  }

  .page-about .mountain-svg {
    height: 80px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    padding: 64px 0 72px;
  }

  .page-about .hero-inner {
    grid-template-columns: 1.1fr 0.9fr;
    gap: 40px;
  }

  .page-about .origin-grid {
    grid-template-columns: 1.15fr 0.85fr;
    gap: 60px;
    align-items: center;
  }

  .page-about .hero-lead {
    font-size: 19px;
  }

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

  .page-about .story-data {
    padding: 84px 0;
  }

  .page-about .data-note {
    grid-template-columns: 1.2fr 0.8fr;
    gap: 40px;
  }

  .page-about .timeline {
    padding-right: 36px;
  }

  .page-about .timeline-trigger {
    padding: 20px 24px 16px;
  }

  .page-about .timeline-panel {
    padding: 0 24px 24px;
  }

  .page-about .timeline-panel p {
    padding-top: 16px;
  }

  .page-about .milestone-wide {
    padding: 16px;
  }

  .page-about .milestone-wide figcaption {
    padding: 16px 12px 8px;
  }

  .page-about .stats-grid {
    margin-bottom: 48px;
  }

  .page-about .stat-item {
    padding: 32px 26px;
  }

  .page-about .compat-head {
    margin-bottom: 44px;
  }

  .page-about .story-cta {
    padding: 72px 0 88px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }
}