/* ===== 品牌概况页面专属样式 ===== */
.page-about {
  --about-glow-cyan: 0 0 12px rgba(0, 229, 255, 0.15);
  --about-glow-orange: 0 0 12px rgba(255, 107, 53, 0.12);
  --about-line-color: rgba(0, 229, 255, 0.2);
  --about-node-size: 32px;
  --about-transition: 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  background-color: var(--color-bg-dark);
  color: var(--color-text-primary);
  font-family: var(--font-body);
  line-height: 1.6;
  position: relative;
  overflow-x: hidden;
}

/* ---------- 面包屑 ---------- */
.about-breadcrumb {
  max-width: var(--container-max);
  margin: 1rem auto 0;
  padding: 0 1.5rem 1.5rem;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.about-breadcrumb__link {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--about-transition);
  border-bottom: 1px solid transparent;
}
.about-breadcrumb__link:hover,
.about-breadcrumb__link:focus-visible {
  color: var(--color-accent-cyan);
  border-bottom-color: var(--color-accent-cyan);
}
.about-breadcrumb__sep {
  color: var(--color-border);
  user-select: none;
}
.about-breadcrumb__current {
  color: var(--color-text-primary);
  font-weight: 600;
}

/* ---------- 首屏：品牌使命 ---------- */
.about-hero {
  position: relative;
  padding: 0 1.5rem 3rem;
  max-width: var(--container-max);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
}
.about-hero__grid-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(var(--about-line-color) 1px, transparent 1px),
    linear-gradient(90deg, var(--about-line-color) 1px, transparent 1px);
  background-size: 48px 48px;
  opacity: 0.3;
  z-index: 0;
}
.about-hero__inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}
.about-hero__text {
  flex: 1 1 0%;
  min-width: 0;
}
.about-hero__label {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1rem;
}
.about-hero__rotate {
  display: inline-block;
  writing-mode: vertical-rl;
  font-size: 0.75rem;
  letter-spacing: 0.15em;
  color: var(--color-accent-cyan);
  font-family: var(--font-headings);
  font-weight: 300;
  text-orientation: mixed;
  opacity: 0.8;
  line-height: 1.2;
  padding: 0.25rem 0;
}
.about-hero__index {
  font-family: var(--font-numbers);
  font-size: 0.875rem;
  color: var(--color-accent-orange);
  font-weight: 600;
  letter-spacing: 0.05em;
}
.about-hero__title {
  font-family: var(--font-headings);
  font-size: 2.5rem;
  font-weight: 900;
  line-height: 1.1;
  margin: 0 0 1.25rem;
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
}
.about-hero__desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  max-width: 38em;
  margin-bottom: 1.75rem;
  line-height: 1.7;
}
.about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.875rem;
  align-items: center;
}
.about-hero__visual {
  flex: 0 0 auto;
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
}
.about-hero__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: 8px;
  box-shadow: var(--about-glow-cyan);
  object-fit: cover;
  aspect-ratio: 800 / 500;
}

/* ---------- 数据湖架构 ---------- */
.about-architecture {
  padding: 3rem 0;
  background: var(--color-bg-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  position: relative;
}
.about-architecture::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-accent-cyan), transparent);
  opacity: 0.3;
}
.about-architecture__header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}
.about-architecture__header .section__title {
  margin-bottom: 0;
}
.about-architecture__note {
  font-family: var(--font-numbers);
  font-size: 0.75rem;
  color: var(--color-accent-orange);
  letter-spacing: 0.1em;
  font-weight: 300;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  opacity: 0.7;
  line-height: 1.3;
}
.about-architecture__intro {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  max-width: 40em;
  margin-bottom: 2.5rem;
}
.about-architecture__diagram {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 2.5rem;
  position: relative;
}
.about-step {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.25rem;
  background: var(--color-bg-card);
  border-radius: 8px;
  border: 1px solid var(--color-border);
  position: relative;
  transition: border-color var(--about-transition), box-shadow var(--about-transition);
  cursor: default;
}
.about-step:hover,
.about-step:focus-within {
  border-color: var(--color-accent-cyan);
  box-shadow: var(--about-glow-cyan);
}
.about-step__num {
  font-family: var(--font-numbers);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-accent-cyan);
  line-height: 1;
  flex-shrink: 0;
  min-width: 2.2rem;
  opacity: 0.8;
  transition: opacity var(--about-transition);
}
.about-step:hover .about-step__num {
  opacity: 1;
}
.about-step__content {
  flex: 1;
  min-width: 0;
}
.about-step__title {
  font-family: var(--font-headings);
  font-size: 1.125rem;
  font-weight: 700;
  margin: 0 0 0.25rem;
  color: var(--color-text-primary);
}
.about-step__brief {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin: 0 0 0.5rem;
}
.about-step__detail {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--about-transition), opacity var(--about-transition);
  opacity: 0;
}
.about-step:hover .about-step__detail,
.about-step:focus-within .about-step__detail {
  max-height: 120px;
  opacity: 1;
}
.about-step__glow {
  position: absolute;
  inset: -1px;
  border-radius: 8px;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--about-transition);
  box-shadow: var(--about-glow-cyan);
}
.about-step:hover .about-step__glow,
.about-step:focus-within .about-step__glow {
  opacity: 1;
}
.about-step__connector {
  width: 2px;
  height: 1.5rem;
  margin-left: 2.2rem;
  background: linear-gradient(to bottom, var(--color-accent-cyan), transparent);
  opacity: 0.3;
  flex-shrink: 0;
}
.about-architecture__image-wrap {
  margin-top: 1rem;
  max-width: 100%;
  overflow: hidden;
  border-radius: 8px;
}
.about-architecture__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border-radius: 8px;
  aspect-ratio: 800 / 400;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}

/* ---------- 数据覆盖 ---------- */
.about-coverage {
  padding: 3rem 0;
  position: relative;
}
.about-coverage__header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}
.about-coverage__header .section__title {
  margin-bottom: 0;
}
.about-coverage__tagline {
  font-family: var(--font-numbers);
  font-size: 0.9375rem;
  color: var(--color-accent-orange);
  letter-spacing: 0.05em;
  font-weight: 400;
  opacity: 0.8;
}
.about-coverage__intro {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  max-width: 40em;
  margin-bottom: 2.5rem;
}
.about-timeline {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  position: relative;
  padding: 1rem 0 1rem 1.5rem;
  margin-bottom: 2.5rem;
  border-left: 2px solid var(--about-line-color);
}
.about-timeline::before {
  content: '';
  position: absolute;
  top: 0;
  left: -1px;
  width: 2px;
  height: 100%;
  background: linear-gradient(to bottom, var(--color-accent-cyan), var(--color-accent-orange));
  opacity: 0.15;
}
.about-timeline__node {
  position: relative;
  padding: 0.75rem 0 0.75rem 1.5rem;
  cursor: pointer;
  transition: background var(--about-transition);
  border-radius: 4px;
  outline: none;
}
.about-timeline__node::before {
  content: '';
  position: absolute;
  left: -1.5rem;
  top: 50%;
  width: var(--about-node-size);
  height: var(--about-node-size);
  border-radius: 50%;
  background: var(--color-bg-card);
  border: 2px solid var(--color-border);
  transform: translate(-50%, -50%);
  transition: border-color var(--about-transition), box-shadow var(--about-transition), background var(--about-transition);
  z-index: 1;
}
.about-timeline__node:hover::before,
.about-timeline__node:focus-visible::before {
  border-color: var(--color-accent-cyan);
  box-shadow: var(--about-glow-cyan);
  background: var(--color-accent-cyan);
}
.about-timeline__node--current::before {
  border-color: var(--color-accent-orange);
  box-shadow: var(--about-glow-orange);
  background: var(--color-accent-orange);
}
.about-timeline__year {
  font-family: var(--font-headings);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-text-primary);
  display: block;
  margin-bottom: 0.15rem;
}
.about-timeline__tooltip {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  transition: opacity var(--about-transition), max-height var(--about-transition);
}
.about-timeline__node:hover .about-timeline__tooltip,
.about-timeline__node:focus-within .about-timeline__tooltip,
.about-timeline__node:focus-visible .about-timeline__tooltip {
  opacity: 1;
  max-height: 60px;
}
.about-coverage__image-wrap {
  margin-bottom: 1.5rem;
  max-width: 100%;
  overflow: hidden;
  border-radius: 8px;
}
.about-coverage__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border-radius: 8px;
  aspect-ratio: 1000 / 400;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}
.about-coverage__action {
  text-align: center;
}

/* ---------- 更新频率与精度 ---------- */
.about-precision {
  padding: 3rem 0;
  background: var(--color-bg-surface);
  border-top: 1px solid var(--color-border);
  position: relative;
}
.about-precision::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-accent-orange), transparent);
  opacity: 0.2;
}
.about-precision__header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}
.about-precision__header .section__title {
  margin-bottom: 0;
}
.about-precision__badge {
  font-family: var(--font-numbers);
  font-size: 0.75rem;
  color: var(--color-accent-cyan);
  border: 1px solid var(--color-accent-cyan);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  letter-spacing: 0.08em;
  font-weight: 500;
  opacity: 0.85;
}
.about-precision__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin-bottom: 2rem;
}
.about-precision__card {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 2rem 1.5rem;
  transition: transform var(--about-transition), box-shadow var(--about-transition);
}
.about-precision__card:hover {
  transform: translateY(-4px);
  box-shadow: var(--about-glow-cyan), 0 8px 32px rgba(0, 0, 0, 0.3);
}
.about-precision__card-label {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.about-precision__number {
  font-family: var(--font-numbers);
  font-size: 3rem;
  font-weight: 700;
  line-height: 1;
  margin-bottom: 0.75rem;
  color: var(--color-accent-cyan);
  display: block;
}
.about-precision__card:nth-child(2) .about-precision__number {
  color: var(--color-accent-orange);
}
.about-precision__card:nth-child(3) .about-precision__number {
  color: var(--color-success);
}
.about-precision__desc {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  max-width: 22em;
  margin: 0 auto;
}
.about-precision__footnote {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
  text-align: center;
  border-top: 1px solid var(--color-border);
  padding-top: 2rem;
  margin-top: 1rem;
}
.about-precision__footnote p {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  max-width: 36em;
  line-height: 1.7;
}

/* ---------- 响应式：桌面端 (>=768px) ---------- */
@media (min-width: 768px) {
  .about-hero {
    padding: 2rem 1.5rem 4rem;
  }
  .about-hero__inner {
    flex-direction: row;
    align-items: center;
    gap: 3rem;
  }
  .about-hero__text {
    flex: 1 1 55%;
  }
  .about-hero__visual {
    flex: 0 0 40%;
    max-width: 480px;
  }
  .about-hero__title {
    font-size: 3.75rem;
  }
  .about-hero__desc {
    font-size: 1.0625rem;
  }
  .about-hero__rotate {
    font-size: 0.8125rem;
  }

  .about-architecture__diagram {
    flex-direction: row;
    gap: 0;
    align-items: stretch;
  }
  .about-step {
    flex: 1 1 0%;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 1.5rem 1rem;
    border-radius: 8px;
    min-height: 200px;
  }
  .about-step__num {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
  }
  .about-step__content {
    display: flex;
    flex-direction: column;
    align-items: center;
  }
  .about-step__title {
    font-size: 1rem;
  }
  .about-step__brief {
    font-size: 0.8125rem;
  }
  .about-step__detail {
    font-size: 0.75rem;
    text-align: center;
  }
  .about-step__connector {
    width: 2rem;
    height: 2px;
    margin: 0;
    flex-shrink: 0;
    align-self: center;
    background: linear-gradient(to right, var(--color-accent-cyan), transparent);
  }
  .about-step:hover .about-step__detail,
  .about-step:focus-within .about-step__detail {
    max-height: 80px;
  }

  .about-timeline {
    flex-direction: row;
    padding: 1.5rem 0 0;
    border-left: none;
    border-top: 2px solid var(--about-line-color);
    justify-content: space-between;
  }
  .about-timeline::before {
    top: -1px;
    left: 0;
    width: 100%;
    height: 2px;
    background: linear-gradient(to right, var(--color-accent-cyan), var(--color-accent-orange));
  }
  .about-timeline__node {
    padding: 1rem 0 0;
    text-align: center;
    flex: 1;
  }
  .about-timeline__node::before {
    left: 50%;
    top: -1px;
    transform: translate(-50%, -50%);
  }
  .about-timeline__year {
    font-size: 0.9375rem;
  }
  .about-timeline__tooltip {
    text-align: center;
    padding: 0 0.5rem;
  }

  .about-precision__grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
  }
  .about-precision__number {
    font-size: 3.5rem;
  }
  .about-precision__footnote {
    flex-direction: row;
    justify-content: center;
    gap: 2rem;
  }

  .about-coverage__intro {
    font-size: 1rem;
  }
  .about-architecture__intro {
    font-size: 1rem;
  }
}

/* ---------- 桌面大屏优化 (>=1024px) ---------- */
@media (min-width: 1024px) {
  .about-hero__title {
    font-size: 4.5rem;
  }
  .about-hero__visual {
    max-width: 560px;
  }
  .about-step__title {
    font-size: 1.125rem;
  }
  .about-step__brief {
    font-size: 0.875rem;
  }
  .about-step__detail {
    font-size: 0.8125rem;
  }
  .about-precision__number {
    font-size: 4rem;
  }
}

/* ---------- 减少 motion 偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
  .about-step__detail {
    max-height: none !important;
    opacity: 1 !important;
  }
  .about-timeline__tooltip {
    max-height: none !important;
    opacity: 1 !important;
  }
}