/* ===== 品牌使命页专属样式 .page-about ===== */
.page-about {
  --about-number-size: 4.5rem;
  --about-number-bg-w: 5.5rem;
  --about-vertical-w: 2.75rem;
  --about-frame-pad: 2rem;
  --about-chapter-gap: 2.5rem;
  --about-accent-line: 2px solid var(--color-brand-accent);
  --about-transition: var(--transition-fast, .15s ease);

  display: flex;
  flex-direction: column;
  gap: 0;
  background-color: var(--color-primary-bg);
  color: var(--color-primary-fg);
  font-family: var(--font-body);
  line-height: 1.6;
  padding-top: calc(var(--header-total, 5.75rem) + var(--space-lg));
  padding-left: var(--space-md);
  padding-right: var(--space-md);
  padding-bottom: var(--space-2xl);
  position: relative;
  min-height: 100vh;
}

/* 容器最大宽度 */
.page-about .chapter,
.page-about .hero-frame,
.page-about .trust-banner {
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  width: 100%;
}

/* ===== 垂直品牌口号（固定左侧） ===== */
.page-about .vertical-brand {
  position: fixed;
  left: 0;
  top: calc(var(--header-total, 5.75rem) + var(--space-lg));
  bottom: var(--space-lg);
  width: var(--about-vertical-w);
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-heading);
  font-size: var(--size-h4);
  font-weight: 700;
  letter-spacing: 0.3em;
  color: var(--color-brand-accent);
  background: linear-gradient(180deg, transparent 0%, var(--color-surface-dark) 20%, var(--color-surface-dark) 80%, transparent 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  user-select: none;
  z-index: 50;
  transition: color var(--about-transition), background var(--about-transition);
  border-right: var(--about-accent-line);
  padding: var(--space-sm) 0;
}
.page-about .vertical-brand:hover,
.page-about .vertical-brand:focus-visible {
  color: var(--color-accent-secondary);
  background: linear-gradient(180deg, transparent 0%, var(--color-surface-light) 20%, var(--color-surface-light) 80%, transparent 100%);
}
.page-about .vertical-brand::after {
  content: "点击复制";
  position: absolute;
  bottom: var(--space-xs);
  left: 50%;
  transform: translateX(-50%) rotate(0deg);
  writing-mode: horizontal-tb;
  font-size: var(--size-small);
  font-family: var(--font-mono);
  color: var(--color-neutral-gray);
  opacity: 0;
  transition: opacity var(--about-transition);
  white-space: nowrap;
}
.page-about .vertical-brand:hover::after,
.page-about .vertical-brand:focus-visible::after {
  opacity: 1;
}
.page-about .vertical-brand:focus-visible {
  outline: 2px solid var(--color-accent-secondary);
  outline-offset: -2px;
}

/* ===== 首屏框景 ===== */
.page-about .hero-frame {
  position: relative;
  margin-bottom: var(--space-2xl);
  padding-left: var(--about-vertical-w);
}
.page-about .frame-outer {
  position: relative;
  border: var(--about-accent-line);
  padding: var(--about-frame-pad);
  background-color: var(--color-surface-dark);
  box-shadow: 0 0 0 1px var(--color-border-subtle), inset 0 0 0 1px var(--color-border-subtle);
}
/* 刻度尺边框装饰 */
.page-about .frame-border-top,
.page-about .frame-border-bottom {
  position: absolute;
  left: 0;
  right: 0;
  height: 6px;
  background-repeat: repeat-x;
  background-size: 12px 6px;
  z-index: 2;
  pointer-events: none;
}
.page-about .frame-border-top {
  top: -4px;
  background-image: repeating-linear-gradient(90deg, var(--color-brand-accent) 0px, var(--color-brand-accent) 1px, transparent 1px, transparent 11px, var(--color-brand-accent) 11px, var(--color-brand-accent) 12px);
}
.page-about .frame-border-bottom {
  bottom: -4px;
  background-image: repeating-linear-gradient(90deg, var(--color-brand-accent) 0px, var(--color-brand-accent) 1px, transparent 1px, transparent 11px, var(--color-brand-accent) 11px, var(--color-brand-accent) 12px);
}
/* 左侧刻度竖线 */
.page-about .frame-outer::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 0;
  bottom: 0;
  width: 6px;
  background-image: repeating-linear-gradient(180deg, var(--color-brand-accent) 0px, var(--color-brand-accent) 1px, transparent 1px, transparent 11px, var(--color-brand-accent) 11px, var(--color-brand-accent) 12px);
  z-index: 2;
  pointer-events: none;
}
.page-about .frame-inner {
  position: relative;
  z-index: 1;
}
.page-about .page-context-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--size-small);
  color: var(--color-accent-secondary);
  background-color: var(--color-surface-light);
  padding: var(--space-xs) var(--space-sm);
  border: 1px solid var(--color-border-subtle);
  margin-bottom: var(--space-lg);
  letter-spacing: 0.1em;
}
.page-about .hero-layout {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: var(--space-xl);
}
.page-about .hero-text {
  flex: 1 1 60%;
}
.page-about .hero-brand {
  font-family: var(--font-heading);
  font-size: var(--size-h1);
  font-weight: 900;
  color: var(--color-primary-fg);
  margin: 0 0 var(--space-sm) 0;
  line-height: 1.05;
  letter-spacing: -0.02em;
  text-transform: uppercase;
  position: relative;
  display: inline-block;
}
.page-about .hero-brand::after {
  content: "";
  display: block;
  width: 60%;
  height: 4px;
  background-color: var(--color-brand-accent);
  margin-top: var(--space-xs);
}
.page-about .hero-tagline {
  font-family: var(--font-mono);
  font-size: var(--size-h4);
  color: var(--color-brand-accent);
  margin: var(--space-sm) 0;
  font-weight: 600;
}
.page-about .hero-desc {
  font-size: var(--size-body);
  color: var(--color-neutral-gray);
  max-width: 48ch;
  line-height: 1.7;
  margin: var(--space-sm) 0 0 0;
}
.page-about .hero-poster {
  flex: 0 0 auto;
  max-width: 280px;
}
.page-about .hero-img {
  display: block;
  width: 100%;
  height: auto;
  border: 2px solid var(--color-border-subtle);
  object-fit: cover;
  aspect-ratio: 2 / 3;
}

/* ===== 章节通用布局 ===== */
.page-about .chapter {
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  gap: var(--about-chapter-gap);
  margin-bottom: var(--space-2xl);
  padding-left: var(--about-vertical-w);
  scroll-margin-top: calc(var(--header-total, 5.75rem) + var(--space-md));
}
.page-about .chapter-number-wrap {
  flex: 0 0 var(--about-number-bg-w);
  position: relative;
  padding-top: var(--space-xs);
}
.page-about .chapter-number {
  width: var(--about-number-bg-w);
  height: var(--about-number-bg-w);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: var(--about-number-size);
  font-weight: 900;
  color: #fff;
  background-color: var(--color-brand-accent);
  clip-path: polygon(0 0, 100% 0, 88% 100%, 0 100%);
  line-height: 1;
  transition: transform var(--about-transition), opacity var(--about-transition);
  /* 滚动驱动动画：进入视口时放大 */
  animation: about-number-grow linear;
  animation-timeline: view();
  animation-range: entry 0% entry 100%;
}
@keyframes about-number-grow {
  from { transform: scale(0.85); opacity: 0.7; }
  to { transform: scale(1.15); opacity: 1; }
}
.page-about .chapter-number:hover {
  transform: scale(1.1);
  opacity: 0.95;
}
.page-about .chapter-body {
  flex: 1 1 0;
  min-width: 0;
}
.page-about .chapter-title {
  font-family: var(--font-heading);
  font-size: var(--size-h2);
  font-weight: 700;
  color: var(--color-primary-fg);
  margin: 0 0 var(--space-md) 0;
  line-height: 1.15;
  position: relative;
  display: inline-block;
}
.page-about .chapter-title::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 100%;
  height: 3px;
  background-color: var(--color-brand-accent);
  transform: scaleX(0.3);
  transform-origin: left;
  transition: transform var(--about-transition);
}
.page-about .chapter:hover .chapter-title::after {
  transform: scaleX(0.8);
}
.page-about .chapter-text {
  font-size: var(--size-body);
  color: var(--color-neutral-gray);
  line-height: 1.75;
  margin-bottom: var(--space-md);
}
.page-about .chapter-text p {
  margin: 0 0 var(--space-sm) 0;
}
.page-about .chapter-text strong {
  color: var(--color-primary-fg);
  font-weight: 600;
}

/* ===== 按钮 ===== */
.page-about .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--size-small);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: var(--space-sm) var(--space-lg);
  background-color: var(--color-brand-accent);
  color: #fff;
  border: 2px solid transparent;
  cursor: pointer;
  transition: background var(--about-transition), border-color var(--about-transition), color var(--about-transition);
  text-decoration: none;
  line-height: 1.2;
}
.page-about .btn:hover,
.page-about .btn:focus-visible {
  background-color: transparent;
  border-color: var(--color-accent-secondary);
  color: var(--color-accent-secondary);
}
.page-about .btn--outline {
  background-color: transparent;
  border-color: var(--color-border-subtle);
  color: var(--color-primary-fg);
}
.page-about .btn--outline:hover,
.page-about .btn--outline:focus-visible {
  border-color: var(--color-brand-accent);
  color: var(--color-brand-accent);
  background-color: transparent;
}
.page-about .btn:focus-visible {
  outline: 2px solid var(--color-accent-secondary);
  outline-offset: 2px;
}

/* ===== 数据可视化 ===== */
.page-about .data-visual {
  position: relative;
  margin: var(--space-lg) 0;
  overflow: hidden;
  border: 1px solid var(--color-border-subtle);
  max-width: 800px;
}
.page-about .viz-img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  transition: filter var(--about-transition);
}
.page-about .viz-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  background-color: rgba(10, 10, 10, 0.82);
  color: #fff;
  font-family: var(--font-mono);
  font-size: var(--size-small);
  opacity: 0;
  transition: opacity var(--about-transition);
  pointer-events: none;
  padding: var(--space-md);
}
.page-about .data-visual:hover .viz-overlay,
.page-about .data-visual:focus-within .viz-overlay {
  opacity: 1;
}
.page-about .data-visual:hover .viz-img,
.page-about .data-visual:focus-within .viz-img {
  filter: blur(2px);
}
.page-about .metric {
  display: block;
  padding: var(--space-xs) var(--space-sm);
  border-left: 3px solid var(--color-accent-secondary);
  background-color: rgba(255, 193, 7, 0.08);
  width: 100%;
  max-width: 24ch;
  text-align: center;
  color: var(--color-accent-secondary);
  font-weight: 500;
}

/* ===== 宁夏根基配图 ===== */
.page-about .landscape-fig {
  margin: var(--space-lg) 0 0 0;
  border: 1px solid var(--color-border-subtle);
  overflow: hidden;
}
.page-about .landscape-img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  transition: transform var(--about-transition);
}
.page-about .landscape-fig:hover .landscape-img {
  transform: scale(1.01);
}

/* ===== 品牌承诺链接组 ===== */
.page-about .promise-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

/* ===== 信任横幅 ===== */
.page-about .trust-banner {
  margin-top: var(--space-lg);
  padding-left: var(--about-vertical-w);
  border-top: 1px solid var(--color-border-subtle);
  padding-top: var(--space-lg);
  text-align: center;
}
.page-about .trust-banner p {
  font-size: var(--size-small);
  color: var(--color-neutral-gray);
  max-width: 64ch;
  margin: 0 auto;
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
}

/* ===== 响应式：窄屏 ===== */
@media (max-width: 768px) {
  .page-about {
    padding-left: var(--space-sm);
    padding-right: var(--space-sm);
    padding-top: calc(var(--header-total, 5.75rem) + var(--space-md));
  }
  .page-about .vertical-brand {
    display: none;
  }
  .page-about .hero-frame,
  .page-about .chapter,
  .page-about .trust-banner {
    padding-left: 0;
  }
  .page-about .hero-layout {
    flex-direction: column;
    align-items: stretch;
  }
  .page-about .hero-text {
    flex: 1 1 auto;
  }
  .page-about .hero-poster {
    max-width: 200px;
    margin: var(--space-md) auto 0;
  }
  .page-about .hero-brand {
    font-size: var(--size-h2);
  }
  .page-about .hero-tagline {
    font-size: var(--size-h4);
  }
  .page-about .chapter {
    flex-direction: column;
    gap: var(--space-md);
  }
  .page-about .chapter-number-wrap {
    flex: 0 0 auto;
    padding-top: 0;
  }
  .page-about .chapter-number {
    width: 3.5rem;
    height: 3.5rem;
    font-size: 2.25rem;
    clip-path: polygon(0 0, 100% 0, 88% 100%, 0 100%);
  }
  .page-about .chapter-title {
    font-size: var(--size-h3);
  }
  .page-about .frame-outer {
    padding: var(--space-md);
  }
  .page-about .page-context-label {
    margin-bottom: var(--space-md);
  }
  .page-about .trust-banner {
    text-align: left;
  }
  .page-about .promise-links {
    flex-direction: column;
  }
  .page-about .promise-links .btn {
    width: 100%;
  }
}

/* ===== 中屏微调 ===== */
@media (min-width: 769px) and (max-width: 1024px) {
  .page-about {
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
  }
  .page-about .vertical-brand {
    width: 2.25rem;
    font-size: var(--size-h4);
  }
  .page-about .hero-frame,
  .page-about .chapter,
  .page-about .trust-banner {
    padding-left: 2.5rem;
  }
  .page-about .hero-poster {
    max-width: 220px;
  }
  .page-about .chapter-number {
    width: 4rem;
    height: 4rem;
    font-size: 3rem;
  }
  .page-about .chapter-number-wrap {
    flex: 0 0 4rem;
  }
}

/* ===== 高屏占比适配 ===== */
@media (min-height: 900px) {
  .page-about .hero-frame {
    min-height: 60vh;
    display: flex;
    align-items: center;
  }
  .page-about .frame-outer {
    width: 100%;
  }
}