.page-about {
  --about-gold: #FFD700;
  --about-red: #D32F2F;
  --about-dark: #2C2C2C;
  --about-bg-card: #ffffff;
  --about-line: #e0e0e0;
  --about-radius: 0px;
  --about-transition: 300ms ease-out;
  display: block;
  width: 100%;
}

/* ── 面包屑 ── */
.page-about .about-breadcrumb {
  max-width: var(--container-max, 1200px);
  margin: 0 auto;
  padding: 20px 20px 0;
  font-size: 14px;
  color: var(--text-secondary, #666);
  display: flex;
  align-items: center;
  gap: 8px;
  letter-spacing: 0.02em;
}
.page-about .about-breadcrumb a {
  color: var(--primary, #D32F2F);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--about-transition);
}
.page-about .about-breadcrumb a:hover,
.page-about .about-breadcrumb a:focus-visible {
  border-bottom-color: var(--primary, #D32F2F);
}
.page-about .about-breadcrumb__sep {
  color: var(--border, #e0e0e0);
  user-select: none;
}
.page-about .about-breadcrumb [aria-current="page"] {
  color: var(--text-primary, #111);
  font-weight: 500;
}

/* ── 首屏 ── */
.page-about .about-hero {
  background: var(--bg-light, #F5F5F5);
  padding: 40px 0 60px;
  border-bottom: 2px solid var(--border, #e0e0e0);
  position: relative;
}
.page-about .about-hero::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--primary, #D32F2F) 0%, var(--accent, #FFD700) 100%);
  opacity: 0.6;
}
.page-about .about-hero__inner {
  display: flex;
  flex-direction: column;
  gap: 32px;
  align-items: center;
}
.page-about .about-hero__text {
  flex: 1 1 50%;
  text-align: center;
}
.page-about .about-hero__tag {
  display: inline-block;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--primary, #D32F2F);
  border: 1px solid var(--primary, #D32F2F);
  padding: 4px 12px;
  margin-bottom: 16px;
  background: transparent;
}
.page-about .about-hero__text h1 {
  font-family: Inter, sans-serif;
  font-weight: 900;
  font-size: clamp(36px, 8vw, 72px);
  line-height: 1.1;
  color: var(--text-primary, #111);
  margin: 0 0 20px;
  letter-spacing: -0.02em;
}
.page-about .about-hero__text p {
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-secondary, #666);
  max-width: 520px;
  margin: 0 auto 28px;
}
.page-about .about-hero__btn {
  display: inline-block;
}
.page-about .about-hero__visual {
  flex: 1 1 50%;
  display: flex;
  justify-content: center;
  align-items: center;
}
.page-about .about-hero__img {
  width: 100%;
  max-width: 500px;
  height: auto;
  object-fit: contain;
  filter: drop-shadow(0 8px 24px rgba(0,0,0,0.06));
}

/* ── 时间轴区域 ── */
.page-about .about-timeline {
  padding: 60px 20px 80px;
  position: relative;
}
.page-about .timeline__intro {
  text-align: center;
  margin-bottom: 48px;
}
.page-about .timeline__intro .section-title {
  font-size: clamp(28px, 5vw, 48px);
  font-weight: 900;
  color: var(--text-primary, #111);
  margin: 0 0 12px;
  letter-spacing: -0.01em;
}
.page-about .timeline__intro p {
  font-size: 16px;
  color: var(--text-secondary, #666);
  max-width: 560px;
  margin: 0 auto;
}
.page-about .timeline__rail {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
  padding-left: 40px;
}
.page-about .timeline__line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 16px;
  width: 2px;
  background: var(--border, #e0e0e0);
  transform: translateX(-50%);
}
.page-about .timeline__node {
  position: relative;
  margin-bottom: 64px;
  transition: transform var(--about-transition), box-shadow var(--about-transition);
}
.page-about .timeline__node:last-child {
  margin-bottom: 0;
}
.page-about .timeline__node:hover {
  transform: translateX(4px);
}
.page-about .node__marker {
  position: absolute;
  left: -40px;
  top: 0;
  width: 32px;
  height: 32px;
  background: var(--primary, #D32F2F);
  border: 2px solid var(--accent, #FFD700);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2;
  transform: translateX(-50%);
  transition: background var(--about-transition), transform var(--about-transition);
}
.page-about .timeline__node:hover .node__marker {
  background: var(--accent, #FFD700);
  transform: translateX(-50%) scale(1.15);
}
.page-about .node__number {
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 12px;
  font-weight: 700;
  color: #fff;
  line-height: 1;
  transition: color var(--about-transition);
}
.page-about .timeline__node:hover .node__number {
  color: var(--text-primary, #111);
}
.page-about .node__content {
  background: var(--about-bg-card);
  border-left: 3px solid var(--primary, #D32F2F);
  padding: 24px 20px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.04);
  transition: box-shadow var(--about-transition), border-color var(--about-transition);
}
.page-about .timeline__node:hover .node__content {
  box-shadow: 0 8px 32px rgba(211,47,47,0.10);
  border-left-color: var(--accent, #FFD700);
}
.page-about .node__content h2 {
  font-family: Inter, sans-serif;
  font-weight: 800;
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.2;
  color: var(--text-primary, #111);
  margin: 0 0 12px;
}
.page-about .node__content p {
  font-size: 15px;
  line-height: 1.7;
  color: var(--text-secondary, #666);
  margin: 0 0 16px;
}
.page-about .node__content .btn {
  margin-top: 8px;
}
.page-about .node__img-wrap {
  margin: 16px 0;
  max-width: 100%;
}
.page-about .node__img {
  width: 100%;
  max-width: 400px;
  height: auto;
  object-fit: contain;
  border: 1px solid var(--border, #e0e0e0);
  background: var(--bg-light, #F5F5F5);
}

/* ── 版本标签交互 ── */
.page-about .version-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 12px 0 16px;
}
.page-about .version-pair {
  position: relative;
  display: inline-flex;
  flex-direction: column;
}
.page-about .version-tag {
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 13px;
  font-weight: 600;
  color: var(--primary, #D32F2F);
  background: transparent;
  border: 1.5px solid var(--primary, #D32F2F);
  padding: 4px 14px;
  cursor: default;
  transition: background var(--about-transition), color var(--about-transition), border-color var(--about-transition);
  user-select: none;
  outline-offset: 2px;
}
.page-about .version-tag:hover,
.page-about .version-tag:focus-visible {
  background: var(--primary, #D32F2F);
  color: #fff;
  border-color: var(--primary, #D32F2F);
}
.page-about .version-detail {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 200px;
  background: var(--bg-dark, #1A1A1A);
  color: #fff;
  font-size: 13px;
  line-height: 1.5;
  padding: 10px 14px;
  border-left: 3px solid var(--accent, #FFD700);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: opacity var(--about-transition), visibility var(--about-transition), transform var(--about-transition);
  z-index: 10;
  pointer-events: none;
}
.page-about .version-pair:hover .version-detail,
.page-about .version-pair:focus-within .version-detail {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* ── 速度指示器 ── */
.page-about .speed-indicator {
  display: flex;
  align-items: center;
  gap: 20px;
  margin: 12px 0 16px;
  flex-wrap: wrap;
}
.page-about .speed-img {
  width: 100%;
  max-width: 200px;
  height: auto;
  object-fit: contain;
  border-radius: 0;
  border: 1px solid var(--border, #e0e0e0);
}
.page-about .speed-badge {
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 28px;
  font-weight: 700;
  color: var(--accent, #FFD700);
  background: var(--bg-dark, #1A1A1A);
  padding: 8px 20px;
  border: 2px solid var(--accent, #FFD700);
  letter-spacing: 0.04em;
  line-height: 1;
}

/* ── 价值核心 ── */
.page-about .about-values {
  background: var(--bg-dark, #1A1A1A);
  padding: 60px 20px;
  border-top: 3px solid var(--accent, #FFD700);
}
.page-about .about-values .section-title {
  font-size: clamp(24px, 4vw, 36px);
  font-weight: 900;
  text-align: center;
  color: #fff;
  margin: 0 0 40px;
  letter-spacing: -0.01em;
}
.page-about .values__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  max-width: 900px;
  margin: 0 auto;
}
.page-about .value-item {
  text-align: center;
  padding: 28px 20px;
  border: 1px solid rgba(255,255,255,0.10);
  background: rgba(255,255,255,0.03);
  transition: background var(--about-transition), border-color var(--about-transition);
}
.page-about .value-item:hover {
  background: rgba(211,47,47,0.08);
  border-color: var(--primary, #D32F2F);
}
.page-about .value-icon {
  display: block;
  margin-bottom: 16px;
}
.page-about .value-icon svg {
  display: inline-block;
  width: 40px;
  height: 40px;
}
.page-about .value-item h3 {
  font-family: Inter, sans-serif;
  font-weight: 700;
  font-size: 22px;
  color: var(--accent, #FFD700);
  margin: 0 0 8px;
  letter-spacing: 0.02em;
}
.page-about .value-item p {
  font-size: 15px;
  line-height: 1.5;
  color: rgba(255,255,255,0.70);
  margin: 0;
}

/* ── 响应式：平板及以上 ── */
@media (min-width: 640px) {
  .page-about .about-hero {
    padding: 60px 0 80px;
  }
  .page-about .about-hero__inner {
    flex-direction: row;
    text-align: left;
    gap: 48px;
  }
  .page-about .about-hero__text {
    text-align: left;
  }
  .page-about .about-hero__text p {
    margin: 0 0 28px;
  }
  .page-about .about-hero__visual {
    justify-content: flex-end;
  }
  .page-about .values__grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
  }
  .page-about .value-item {
    padding: 32px 16px;
  }
}

@media (min-width: 768px) {
  .page-about .timeline__rail {
    padding-left: 0;
  }
  .page-about .timeline__line {
    left: 50%;
    transform: translateX(-50%);
  }
  .page-about .timeline__node {
    width: 50%;
    margin-bottom: 80px;
  }
  .page-about .timeline__node:nth-child(odd) {
    margin-left: 0;
    margin-right: auto;
    padding-right: 48px;
  }
  .page-about .timeline__node:nth-child(even) {
    margin-left: auto;
    margin-right: 0;
    padding-left: 48px;
  }
  .page-about .timeline__node:nth-child(odd) .node__marker {
    left: auto;
    right: -16px;
    transform: translateX(50%);
  }
  .page-about .timeline__node:nth-child(even) .node__marker {
    left: -16px;
    transform: translateX(-50%);
  }
  .page-about .timeline__node:nth-child(odd):hover .node__marker {
    transform: translateX(50%) scale(1.15);
  }
  .page-about .timeline__node:nth-child(even):hover .node__marker {
    transform: translateX(-50%) scale(1.15);
  }
  .page-about .node__content {
    padding: 28px 28px;
  }
  .page-about .node__content h2 {
    font-size: clamp(24px, 2.5vw, 30px);
  }
  .page-about .node__content p {
    font-size: 16px;
  }
  .page-about .timeline__node:hover {
    transform: translateY(-4px);
  }
  .page-about .timeline__node:nth-child(odd):hover {
    transform: translateX(4px) translateY(-4px);
  }
  .page-about .timeline__node:nth-child(even):hover {
    transform: translateX(-4px) translateY(-4px);
  }
  .page-about .version-detail {
    min-width: 220px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    padding: 80px 0 100px;
  }
  .page-about .about-hero__text h1 {
    font-size: 72px;
  }
  .page-about .about-hero__text p {
    font-size: 18px;
  }
  .page-about .about-timeline {
    padding: 80px 20px 100px;
  }
  .page-about .about-values {
    padding: 80px 20px;
  }
  .page-about .values__grid {
    gap: 32px;
  }
}

/* ── 容器重置 ── */
.page-about .container {
  max-width: var(--container-max, 1200px);
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
}

/* ── 按钮 ── */
.page-about .btn {
  display: inline-block;
  font-family: Inter, sans-serif;
  font-weight: 600;
  font-size: 14px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-decoration: none;
  color: #fff;
  background: var(--primary, #D32F2F);
  border: 1.5px solid var(--primary, #D32F2F);
  padding: 10px 24px;
  transition: background var(--about-transition), color var(--about-transition), border-color var(--about-transition);
  cursor: default;
}
.page-about .btn:hover,
.page-about .btn:focus-visible {
  background: transparent;
  color: var(--primary, #D32F2F);
  border-color: var(--accent, #FFD700);
}

/* ── 等宽辅助 ── */
.page-about .mono {
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
}

/* ── section-title 局部覆盖 ── */
.page-about .section-title {
  font-family: Inter, sans-serif;
  font-weight: 900;
  line-height: 1.2;
}

/* ── 图片通用响应 ── */
.page-about img {
  max-width: 100%;
  height: auto;
}

/* ── 打印优化 ── */
@media print {
  .page-about .about-hero {
    background: #fff;
    border-bottom: 1px solid #ccc;
    padding: 20px 0;
  }
  .page-about .about-hero::after {
    display: none;
  }
  .page-about .timeline__line {
    display: none;
  }
  .page-about .node__marker {
    border: 2px solid #333;
    background: #333;
  }
  .page-about .node__number {
    color: #fff;
  }
  .page-about .node__content {
    box-shadow: none;
    border-left-color: #333;
  }
  .page-about .about-values {
    background: #f5f5f5;
    border-top: 2px solid #333;
  }
  .page-about .about-values .section-title {
    color: #111;
  }
  .page-about .value-item h3 {
    color: #111;
  }
  .page-about .value-item p {
    color: #555;
  }
  .page-about .version-detail {
    display: none !important;
  }
  .page-about .btn {
    border: 1px solid #333;
    color: #333;
    background: transparent;
  }
}