/* === page-about 专属样式 === */
.page-about {
  --page-font-heading: var(--font-heading);
  --page-font-body: var(--font-body);
  --page-font-mono: var(--font-mono);
  --page-color-primary: #E63946;
  --page-color-accent: #F4A261;
  --page-color-bg: #1A1A1A;
  --page-color-card: #2A2A2A;
  --page-color-data: #2EC4B6;
  --page-color-text: #FFFFFF;
  --page-color-text-secondary: #FFE0A3;
  --page-color-border: #8C1C13;
  --page-shadow-strong: 0 8px 30px rgba(0,0,0,0.6);
  --page-border-thick: 4px;
  --page-header-height: 72px;
  --page-index-width: 200px;
  --page-content-max: 1280px;

  background-color: var(--page-color-bg);
  color: var(--page-color-text);
  font-family: var(--page-font-body);
  line-height: 1.6;
  min-height: calc(100vh - var(--page-header-height));
  padding: 2rem 1rem 4rem;
  box-sizing: border-box;
}

.page-about .container {
  max-width: var(--page-content-max);
  margin: 0 auto;
  padding: 0 1rem;
}

/* 面包屑 */
.page-about .breadcrumb {
  font-size: 0.85rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--page-color-border);
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  align-items: center;
}
.page-about .breadcrumb__link {
  color: var(--page-color-accent);
  text-decoration: none;
  position: relative;
  transition: color var(--transition);
}
.page-about .breadcrumb__link:hover,
.page-about .breadcrumb__link:focus-visible {
  color: var(--page-color-primary);
  outline: 2px solid var(--page-color-data);
  outline-offset: 2px;
}
.page-about .breadcrumb__sep {
  color: var(--page-color-border);
  font-weight: bold;
  margin: 0 0.2rem;
}
.page-about .breadcrumb__current {
  color: var(--page-color-text-secondary);
  font-style: italic;
}

/* 标题 */
.page-about__title {
  font-family: var(--page-font-heading);
  font-size: 2.4rem;
  line-height: 1.1;
  color: var(--page-color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin: 0 0 2rem;
  padding: 0 0 1rem;
  border-bottom: var(--page-border-thick) solid var(--page-color-border);
  background: linear-gradient(135deg, var(--page-color-primary), var(--page-color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
}

/* 布局：桌面双栏 */
@media (min-width: 768px) {
  .page-about__layout {
    display: grid;
    grid-template-columns: var(--page-index-width) 1fr;
    gap: var(--gap);
    align-items: start;
  }
}

/* 索引栏 */
.page-about__index {
  position: sticky;
  top: calc(var(--page-header-height) + 1.5rem);
  border-right: 3px solid var(--page-color-border);
  padding-right: 1rem;
  margin-bottom: 2rem;
}
.page-about__index-list {
  margin: 0;
  padding: 0;
}

.page-about__index-item {
  font-family: var(--page-font-mono);
  font-size: 0.95rem;
  padding: 0.6rem 0.2rem;
  border-bottom: 1px solid rgba(140,28,19,0.35);
  transition: background var(--transition), padding-left var(--transition);
}

.page-about__index-item a {
  color: var(--page-color-text-secondary);
  text-decoration: none;
  display: block;
  position: relative;
}
.page-about__index-item a::before {
  content: "▸";
  color: var(--page-color-data);
  margin-right: 0.4rem;
  opacity: 0.5;
  transition: opacity var(--transition);
}
.page-about__index-item:hover,
.page-about__index-item:focus-within {
  background: rgba(230,57,70,0.12);
  padding-left: 0.4rem;
}
.page-about__index-item:hover a::before,
.page-about__index-item:focus-within a::before {
  opacity: 1;
}
.page-about__index-item a:focus-visible {
  outline: 2px solid var(--page-color-data);
  outline-offset: 2px;
}

/* 内容区域 */
.page-about__content {
  min-width: 0;
}

/* 章节通用 */
.page-about__section {
  margin-bottom: 2.8rem;
  padding: 1.5rem;
  background: var(--page-color-card);
  border: var(--page-border-thick) solid var(--page-color-border);
  box-shadow: var(--page-shadow-strong);
  position: relative;
  transition: box-shadow var(--transition);
}
.page-about__section:hover {
  box-shadow: 0 8px 35px rgba(139,28,19,0.5);
}

.page-about__section-heading {
  font-family: var(--page-font-heading);
  font-size: 1.8rem;
  color: var(--page-color-primary);
  margin: 0 0 1.2rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  letter-spacing: 0.02em;
}
.page-about__section-num {
  font-family: var(--page-font-mono);
  font-size: 1.2rem;
  background: var(--page-color-primary);
  color: var(--page-color-bg);
  padding: 0.1rem 0.5rem;
  line-height: 1.4;
  border: 1px solid var(--page-color-accent);
}

/* 使命区块 图文网格 */
.page-about__mission-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}
@media (min-width: 640px) {
  .page-about__mission-grid {
    grid-template-columns: 1fr 1fr;
  }
}
.page-about__mission-text p {
  margin: 0 0 1rem;
  font-size: 1rem;
}
.page-about__mission-image {
  background: var(--page-color-bg);
  border: 2px solid var(--page-color-border);
  overflow: hidden;
}

/* 人群区 */
.page-about__audience-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}
@media (min-width: 480px) {
  .page-about__audience-grid {
    grid-template-columns: 1fr 1fr 1fr 1fr;
  }
}
.page-about__audience-item {
  background: var(--page-color-bg);
  border: 2px solid var(--page-color-border);
  padding: 1rem;
  transition: border-color var(--transition), background var(--transition);
}
.page-about__audience-item:hover {
  border-color: var(--page-color-accent);
  background: rgba(244,162,97,0.08);
}
.page-about__audience-item .badge {
  font-family: var(--page-font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  border: 1px solid var(--page-color-data);
  color: var(--page-color-data);
  padding: 0.2rem 0.6rem;
  display: inline-block;
  margin-bottom: 0.4rem;
}
.page-about__audience-item p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--page-color-text-secondary);
}
.page-about__audience-visual {
  margin-top: 1rem;
  background: var(--page-color-bg);
  border: 2px solid var(--page-color-border);
  overflow: hidden;
}

/* 原则区 */
.page-about__principles-list {
  list-style: none;
  margin: 0 0 1.5rem;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}
@media (min-width: 600px) {
  .page-about__principles-list {
    flex-direction: row;
    justify-content: space-between;
  }
  .page-about__principles-list li {
    flex: 1;
    padding: 0.8rem;
    border-left: 3px solid var(--page-color-data);
  }
}
.page-about__principles-list li {
  background: var(--page-color-bg);
  border: 2px solid var(--page-color-border);
  padding: 0.8rem;
  font-size: 0.95rem;
  transition: border-color var(--transition);
}
.page-about__principles-list li:hover {
  border-color: var(--page-color-data);
}
.page-about__principles-list strong {
  color: var(--page-color-accent);
  font-family: var(--page-font-mono);
  display: block;
  margin-bottom: 0.2rem;
}
.page-about__principles-chart {
  margin-top: 1.2rem;
  background: var(--page-color-bg);
  border: 2px solid var(--page-color-border);
  overflow: hidden;
}

/* 时间轴区块 */
.page-about__timeline-section {
  padding-bottom: 2rem;
}
.page-about__timeline {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
  position: relative;
}
.page-about__timeline::before {
  content: "";
  position: absolute;
  left: 1.2rem;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--page-color-border);
}
@media (min-width: 600px) {
  .page-about__timeline {
    flex-direction: row;
    justify-content: space-between;
    gap: 1rem;
  }
  .page-about__timeline::before {
    left: 0;
    right: 0;
    top: auto;
    bottom: auto;
    height: 3px;
    width: 100%;
    top: 2rem;
  }
}
.page-about__timeline-item {
  position: relative;
  padding-left: 3rem;
  background: var(--page-color-bg);
  border: 2px solid var(--page-color-border);
  padding: 1.2rem 1rem 1rem 3rem;
  transition: border-color var(--transition), background var(--transition);
  cursor: default;
}
.page-about__timeline-item:hover {
  border-color: var(--page-color-accent);
  background: rgba(244,162,97,0.06);
}
@media (min-width: 600px) {
  .page-about__timeline-item {
    flex: 1;
    padding: 1rem 0.8rem 0.5rem;
    text-align: center;
    border: 2px solid var(--page-color-border);
    margin-top: 0;
  }
  .page-about__timeline-item::before {
    top: -1.5rem;
    left: 50%;
    transform: translateX(-50%);
    height: 1rem;
    width: 3px;
    background: var(--page-color-border);
  }
}
.page-about__timeline-item::before {
  content: "";
  position: absolute;
  left: 0.5rem;
  top: 1.5rem;
  width: 1rem;
  height: 3px;
  background: var(--page-color-data);
}
.page-about__timeline-item .badge {
  font-family: var(--page-font-mono);
  font-size: 0.75rem;
  background: var(--page-color-primary);
  color: var(--page-color-bg);
  padding: 0.1rem 0.5rem;
  border: 1px solid var(--page-color-accent);
}
.page-about__timeline-item p {
  margin: 0.3rem 0;
  font-size: 0.9rem;
  color: var(--page-color-text);
}
.page-about__timeline-detail {
  margin-top: 0.4rem;
  font-family: var(--page-font-mono);
}
.page-about__timeline-detail .data-label {
  font-size: 0.65rem;
  text-transform: uppercase;
  color: var(--page-color-text-secondary);
  display: block;
}
.page-about__timeline-detail .data-value {
  font-size: 1rem;
  color: var(--page-color-data);
}
.page-about__timeline-detail .data-value--large {
  font-size: 1.3rem;
  font-weight: bold;
}
.page-about__timeline-footnote {
  font-size: 0.8rem;
  color: var(--page-color-text-secondary);
  margin-top: 1.5rem;
  border-top: 1px solid var(--page-color-border);
  padding-top: 0.8rem;
  text-align: right;
  font-style: italic;
}

/* 页尾链接 */
.page-about__footer-links {
  margin-top: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

/* 按钮复写 */
.page-about .btn {
  font-family: var(--page-font-heading);
  background: var(--page-color-primary);
  color: var(--page-color-bg);
  border: var(--page-border-thick) solid var(--page-color-border);
  padding: 0.5rem 1.4rem;
  text-decoration: none;
  transition: background var(--transition), border-color var(--transition), color var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  letter-spacing: 0.04em;
}
.page-about .btn:hover,
.page-about .btn:focus-visible {
  background: var(--page-color-accent);
  border-color: var(--page-color-accent);
  color: var(--page-color-bg);
  outline: 2px solid var(--page-color-data);
  outline-offset: 2px;
}
.page-about .btn--outline {
  background: transparent;
  color: var(--page-color-primary);
  border-color: var(--page-color-primary);
}
.page-about .btn--outline:hover,
.page-about .btn--outline:focus-visible {
  background: var(--page-color-primary);
  color: var(--page-color-bg);
  border-color: var(--page-color-accent);
}

/* 分割线 */
.page-about .divider {
  height: 4px;
  background: repeating-linear-gradient(45deg, var(--page-color-border) 0, var(--page-color-border) 8px, transparent 8px, transparent 16px);
  margin: 2rem 0;
  border: none;
}

/* 通用徽章重设 */
.page-about .badge {
  font-family: var(--page-font-mono);
  font-size: 0.75rem;
  display: inline-block;
  border: 1px solid var(--page-color-border);
  padding: 0.1rem 0.6rem;
  color: var(--page-color-accent);
  background: transparent;
}

/* 移动端适配 */
@media (max-width: 767px) {
  .page-about {
    padding: 1rem 0.8rem 3rem;
  }
  .page-about__title {
    font-size: 1.8rem;
  }
  .page-about__section {
    padding: 1rem;
    margin-bottom: 1.8rem;
  }
  .page-about__index {
    position: static;
    border-right: none;
    border-bottom: 3px solid var(--page-color-border);
    padding: 0 0 1rem;
    margin-bottom: 2rem;
  }
  .page-about__index-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
  }
  .page-about__index-item {
    border-bottom: none;
    padding: 0.3rem 0.5rem;
    font-size: 0.85rem;
    flex: 1 0 auto;
  }
  .page-about__timeline-item {
    padding-left: 2.5rem;
  }
}

/* 打印优化 */
@media print {
  .page-about {
    background: #fff !important;
    color: #111 !important;
    padding: 0;
  }
  .page-about__index,
  .page-about .breadcrumb,
  .page-about__footer-links {
    display: none !important;
  }
  .page-about__section {
    border: 1px solid #ccc !important;
    box-shadow: none !important;
    page-break-inside: avoid;
  }
  .page-about__title {
    -webkit-text-fill-color: #111 !important;
    background: none !important;
    border-bottom: 2px solid #111 !important;
  }
}
</style>