/* ===== 品牌概况页专属样式 ===== */
.page-about {
  --page-about-index-width: 220px;
  --page-about-index-gap: 48px;
  --page-about-timeline-color: #D4A843;
  --page-about-timeline-line-color: rgba(212, 168, 67, 0.25);
  --page-about-accent-glow: rgba(57, 255, 20, 0.08);
  --page-about-card-bg: rgba(11, 26, 46, 0.03);
  --page-about-section-spacing: 3.5rem;

  background-color: var(--color-background-light, #F5F5F0);
  color: var(--color-text-primary-dark, #0B1A2E);
  padding-top: calc(var(--header-height, 80px) + 1.5rem);
  padding-bottom: 4rem;
  font-family: var(--font-body, 'Source Han Serif SC', 'Noto Serif SC', serif);
  line-height: 1.65;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  color: var(--color-text-secondary, #6E7B8B);
  margin-bottom: 2rem;
  letter-spacing: 0.02em;
}
.page-about .breadcrumb a {
  color: var(--color-text-secondary, #6E7B8B);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s, color 0.2s;
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--color-primary-gold, #D4A843);
  border-bottom-color: var(--color-primary-gold, #D4A843);
}
.page-about .breadcrumb .breadcrumb-sep {
  color: var(--color-border-subtle, #2C3E50);
  opacity: 0.4;
}
.page-about .breadcrumb .breadcrumb-current {
  color: var(--color-text-primary-dark, #0B1A2E);
  font-weight: 600;
}

/* ---------- 双栏布局 ---------- */
.page-about .page-about-layout {
  display: flex;
  gap: var(--page-about-index-gap);
  align-items: flex-start;
}

/* ---------- 左侧索引 ---------- */
.page-about .page-about-index {
  flex: 0 0 var(--page-about-index-width);
  position: sticky;
  top: calc(var(--header-height, 80px) + 1rem);
  max-height: calc(100vh - var(--header-height, 80px) - 2rem);
  overflow-y: auto;
  padding-top: 0.25rem;
}
.page-about .page-about-index-inner {
  border-left: 2px solid var(--color-primary-gold, #D4A843);
  padding-left: 1rem;
}
.page-about .page-about-index-label {
  display: block;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--color-text-secondary, #6E7B8B);
  margin-bottom: 0.75rem;
}
.page-about .page-about-index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.page-about .page-about-index-list li {
  counter-increment: idx;
}
.page-about .page-about-index-list li a {
  display: block;
  font-family: var(--font-heading, 'Noto Sans SC', sans-serif);
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--color-text-primary-dark, #0B1A2E);
  text-decoration: none;
  padding: 0.35rem 0.5rem;
  border-radius: 4px;
  transition: background 0.2s, color 0.2s, padding-left 0.2s;
  position: relative;
}
.page-about .page-about-index-list li a::before {
  content: counter(idx, decimal-leading-zero);
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.7rem;
  color: var(--color-primary-gold, #D4A843);
  margin-right: 0.5rem;
  font-weight: 400;
}
.page-about .page-about-index-list li a:hover,
.page-about .page-about-index-list li a:focus-visible {
  background: var(--page-about-accent-glow);
  color: var(--color-primary-gold, #D4A843);
  padding-left: 0.75rem;
}
.page-about .page-about-index-list li a:target {
  background: var(--page-about-accent-glow);
  color: var(--color-primary-gold, #D4A843);
}
.page-about .page-about-index-meta {
  margin-top: 1.25rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--color-border-subtle, #2C3E50);
  opacity: 0.55;
}
.page-about .page-about-index-meta-line {
  display: block;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.68rem;
  color: var(--color-text-secondary, #6E7B8B);
  line-height: 1.6;
}

/* ---------- 移动端索引（窄屏） ---------- */
.page-about .page-about-mobile-index {
  display: none;
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border-subtle, #2C3E50);
}
.page-about .page-about-mobile-index-label {
  display: block;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-text-secondary, #6E7B8B);
  margin-bottom: 0.5rem;
}
.page-about .page-about-mobile-index-list {
  display: flex;
  gap: 0.4rem;
  overflow-x: auto;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
  padding-bottom: 0.3rem;
}
.page-about .page-about-mobile-index-list a {
  flex: 0 0 auto;
  font-family: var(--font-heading, 'Noto Sans SC', sans-serif);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--color-text-primary-dark, #0B1A2E);
  text-decoration: none;
  padding: 0.3rem 0.8rem;
  border: 1px solid var(--color-border-subtle, #2C3E50);
  border-radius: 20px;
  white-space: nowrap;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}
.page-about .page-about-mobile-index-list a:hover,
.page-about .page-about-mobile-index-list a:focus-visible {
  background: var(--color-primary-dark-blue, #0B1A2E);
  color: var(--color-primary-gold, #D4A843);
  border-color: var(--color-primary-gold, #D4A843);
}

/* ---------- 右侧内容区 ---------- */
.page-about .page-about-content {
  flex: 1;
  min-width: 0;
}

/* ---------- 页面主标题（h1） ---------- */
.page-about .page-about-main-title {
  font-family: var(--font-heading, 'Noto Sans SC', sans-serif);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary-dark-blue, #0B1A2E);
  margin: 0 0 1.5rem;
  letter-spacing: -0.01em;
  line-height: 1.2;
}

/* ---------- 品牌概念图 ---------- */
.page-about .page-about-hero-figure {
  margin: 0 0 2.5rem;
  border-radius: 8px;
  overflow: hidden;
  position: relative;
  background: var(--color-background-dark-section, #111820);
  box-shadow: 0 4px 20px rgba(0,0,0,0.08);
}
.page-about .page-about-hero-img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  aspect-ratio: 800 / 500;
}
.page-about .page-about-hero-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 0.75rem 1.25rem;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.78rem;
  color: var(--color-text-primary-light, #FFFFFF);
  background: linear-gradient(transparent, rgba(11, 26, 46, 0.85));
  letter-spacing: 0.04em;
  pointer-events: none;
}

/* ---------- 章节通用 ---------- */
.page-about .page-about-section {
  margin-bottom: var(--page-about-section-spacing);
  scroll-margin-top: calc(var(--header-height, 80px) + 1.5rem);
}
.page-about .page-about-section:last-child {
  margin-bottom: 0;
}
.page-about .page-about-section-title {
  font-family: var(--font-heading, 'Noto Sans SC', sans-serif);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-primary-dark-blue, #0B1A2E);
  margin: 0 0 0.5rem;
  letter-spacing: -0.01em;
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
}
.page-about .page-about-section-title::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--color-primary-gold, #D4A843) 0%, transparent 100%);
  opacity: 0.35;
}
.page-about .page-about-section-body {
  padding-left: 0.25rem;
}
.page-about .page-about-section-lede {
  font-size: 1.02rem;
  color: var(--color-text-secondary, #6E7B8B);
  margin-bottom: 1.25rem;
  max-width: 60ch;
}
.page-about .page-about-section p {
  margin: 0 0 1rem;
  max-width: 72ch;
}
.page-about .page-about-section-actions {
  margin-top: 1.5rem;
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

/* ---------- 时间线 ---------- */
.page-about .page-about-timeline {
  position: relative;
  padding-left: 2.2rem;
  margin-bottom: 2rem;
}
.page-about .page-about-timeline::before {
  content: '';
  position: absolute;
  left: 0.6rem;
  top: 0.4rem;
  bottom: 0.4rem;
  width: 2px;
  background: var(--page-about-timeline-line-color);
  border-radius: 1px;
}
.page-about .page-about-timeline-item {
  display: block;
  margin-bottom: 1rem;
  border: none;
  border-radius: 6px;
  background: var(--page-about-card-bg);
  transition: background 0.2s;
}
.page-about .page-about-timeline-item[open] {
  background: rgba(11, 26, 46, 0.06);
}
.page-about .page-about-timeline-item:last-child {
  margin-bottom: 0;
}
.page-about .page-about-timeline-summary {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1rem 0.75rem 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-heading, 'Noto Sans SC', sans-serif);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text-primary-dark, #0B1A2E);
  user-select: none;
  transition: color 0.2s;
  position: relative;
}
.page-about .page-about-timeline-summary::-webkit-details-marker {
  display: none;
}
.page-about .page-about-timeline-summary::marker {
  display: none;
  content: '';
}
.page-about .page-about-timeline-summary:hover,
.page-about .page-about-timeline-item[open] .page-about-timeline-summary {
  color: var(--color-primary-gold, #D4A843);
}
.page-about .page-about-timeline-marker {
  flex: 0 0 12px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--color-primary-gold, #D4A843);
  border: 2px solid var(--color-background-light, #F5F5F0);
  box-shadow: 0 0 0 2px var(--color-primary-gold, #D4A843);
  position: relative;
  z-index: 1;
  transition: transform 0.2s, background 0.2s;
}
.page-about .page-about-timeline-item[open] .page-about-timeline-marker {
  background: var(--color-accent-fluorescent-green, #39FF14);
  box-shadow: 0 0 0 2px var(--color-accent-fluorescent-green, #39FF14);
  transform: scale(1.15);
}
.page-about .page-about-timeline-heading {
  flex: 1;
}
.page-about .page-about-timeline-badge {
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.65rem;
  font-weight: 400;
  color: var(--color-text-primary-light, #FFFFFF);
  background: var(--color-primary-dark-blue, #0B1A2E);
  padding: 0.15rem 0.5rem;
  border-radius: 10px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  opacity: 0.8;
}
.page-about .page-about-timeline-detail {
  padding: 0 1rem 1rem 1.75rem;
  font-size: 0.92rem;
  color: var(--color-text-primary-dark, #0B1A2E);
  line-height: 1.6;
}
.page-about .page-about-timeline-detail p {
  margin: 0;
}
.page-about .page-about-timeline-detail p + p {
  margin-top: 0.5rem;
}

/* ---------- 内联图片 ---------- */
.page-about .page-about-inline-figure {
  margin: 1.5rem 0;
  border-radius: 6px;
  overflow: hidden;
  background: var(--color-background-dark-section, #111820);
  max-width: 600px;
}
.page-about .page-about-inline-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  aspect-ratio: attr(width) / attr(height);
}
.page-about .page-about-inline-figure figcaption {
  padding: 0.5rem 0.85rem;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.72rem;
  color: var(--color-text-secondary, #6E7B8B);
  background: var(--color-background-dark-section, #111820);
  letter-spacing: 0.03em;
}
.page-about .page-about-inline-figure--wide {
  max-width: 100%;
}

/* ---------- 技术承诺卡片网格 ---------- */
.page-about .page-about-tech-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}
.page-about .page-about-tech-card {
  background: var(--color-background-light, #F5F5F0);
  border: 1px solid var(--color-border-subtle, #2C3E50);
  border-radius: 8px;
  padding: 1.25rem 1rem;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.page-about .page-about-tech-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  border-color: var(--color-primary-gold, #D4A843);
}
.page-about .page-about-tech-icon {
  display: inline-flex;
  margin-bottom: 0.75rem;
}
.page-about .page-about-tech-icon svg {
  display: block;
}
.page-about .page-about-tech-title {
  font-family: var(--font-heading, 'Noto Sans SC', sans-serif);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-primary-dark-blue, #0B1A2E);
  margin: 0 0 0.5rem;
}
.page-about .page-about-tech-card p {
  font-size: 0.88rem;
  color: var(--color-text-secondary, #6E7B8B);
  line-height: 1.55;
  margin: 0;
  max-width: none;
}

/* ---------- 基础信息 ---------- */
.page-about .page-about-info-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-bottom: 1.25rem;
  max-width: 600px;
}
.page-about .page-about-info-card {
  background: var(--color-background-light, #F5F5F0);
  border-left: 3px solid var(--color-primary-gold, #D4A843);
  padding: 0.75rem 1rem;
  border-radius: 0 6px 6px 0;
}
.page-about .page-about-info-label {
  display: block;
  font-family: var(--font-mono, 'JetBrains Mono', monospace);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-secondary, #6E7B8B);
  margin-bottom: 0.2rem;
}
.page-about .page-about-info-value {
  display: block;
  font-family: var(--font-heading, 'Noto Sans SC', sans-serif);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-primary-dark, #0B1A2E);
  word-break: break-word;
}
.page-about .page-about-info-value a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-color: var(--color-primary-gold, #D4A843);
  transition: color 0.2s;
}
.page-about .page-about-info-value a:hover,
.page-about .page-about-info-value a:focus-visible {
  color: var(--color-primary-gold, #D4A843);
}
.page-about .page-about-info-note {
  font-size: 0.82rem;
  color: var(--color-text-secondary, #6E7B8B);
  font-style: italic;
  max-width: 65ch;
}

/* ===== 响应式 ===== */
/* 窄屏：≤ 767px */
@media (max-width: 767px) {
  .page-about {
    padding-top: calc(var(--header-height, 80px) + 0.75rem);
    padding-bottom: 2.5rem;
  }
  .page-about .breadcrumb {
    font-size: 0.75rem;
    margin-bottom: 1.25rem;
  }
  .page-about .page-about-layout {
    flex-direction: column;
    gap: 1rem;
  }
  .page-about .page-about-index {
    display: none;
  }
  .page-about .page-about-mobile-index {
    display: block;
  }
  .page-about .page-about-main-title {
    font-size: 1.6rem;
    margin-bottom: 1rem;
  }
  .page-about .page-about-section-title {
    font-size: 1.3rem;
  }
  .page-about .page-about-section-body {
    padding-left: 0;
  }
  .page-about .page-about-timeline {
    padding-left: 1.5rem;
  }
  .page-about .page-about-timeline::before {
    left: 0.3rem;
  }
  .page-about .page-about-timeline-summary {
    font-size: 0.92rem;
    padding: 0.6rem 0.6rem 0.6rem 0;
  }
  .page-about .page-about-timeline-marker {
    flex: 0 0 10px;
    width: 10px;
    height: 10px;
  }
  .page-about .page-about-timeline-detail {
    padding: 0 0.6rem 0.8rem 1.2rem;
    font-size: 0.85rem;
  }
  .page-about .page-about-tech-grid {
    grid-template-columns: 1fr;
    gap: 0.85rem;
  }
  .page-about .page-about-tech-card {
    padding: 1rem 0.85rem;
  }
  .page-about .page-about-info-grid {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
  .page-about .page-about-hero-caption {
    font-size: 0.7rem;
    padding: 0.5rem 0.85rem;
  }
  .page-about .page-about-section-actions .btn {
    width: 100%;
    text-align: center;
  }
}

/* 中屏及以上：≥ 768px */
@media (min-width: 768px) {
  .page-about .page-about-mobile-index {
    display: none !important;
  }
  .page-about .page-about-index {
    display: block;
  }
}

/* 大屏微调：≥ 1024px */
@media (min-width: 1024px) {
  .page-about {
    --page-about-index-width: 240px;
    --page-about-index-gap: 56px;
  }
  .page-about .page-about-main-title {
    font-size: 2.2rem;
  }
  .page-about .page-about-section-title {
    font-size: 1.85rem;
  }
  .page-about .page-about-tech-grid {
    gap: 1.5rem;
  }
  .page-about .page-about-hero-figure {
    border-radius: 12px;
  }
}