/* ===== page-about 专属样式 (移动端优先) ===== */
.page-about {
  --pa-accent-gold: #D4AF37;
  --pa-accent-blue: #00D4FF;
  --pa-deep-purple: #4A0E4E;
  --pa-bg-cream: #FFF8E7;
  --pa-text-dark: #2C1A0E;
  --pa-text-body: #3A2A1A;
  --pa-glass-bg: rgba(74, 14, 78, 0.12);
  --pa-card-shadow: 0 4px 20px rgba(74, 14, 78, 0.15);
  --pa-gap: 1.5rem;
  --pa-max-width: 1200px;
  --pa-header-h: 60px;
  display: flex;
  flex-direction: column;
  gap: 2rem;
  min-height: 60vh;
}

/* 面包屑 */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.875rem;
  color: var(--pa-text-body);
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}

.breadcrumb__link {
  color: var(--pa-accent-gold);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
}

.breadcrumb__link:hover,
.breadcrumb__link:focus-visible {
  border-bottom-color: var(--pa-accent-gold);
}

.breadcrumb__sep {
  color: var(--pa-text-body);
  user-select: none;
}

.breadcrumb__current {
  font-weight: 600;
  color: var(--pa-deep-purple);
}

/* 首屏对角线分割 */
.hero-split {
  display: flex;
  flex-direction: column;
  gap: var(--pa-gap);
  padding: calc(var(--pa-header-h) + 1rem) 1rem 2rem;
  background: linear-gradient(135deg, var(--pa-bg-cream) 0%, var(--pa-bg-cream) 50%, var(--pa-deep-purple) 50%, var(--pa-deep-purple) 100%);
  position: relative;
  min-height: 70vh;
}

.hero-split__media {
  order: 2;
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
}

.hero-split__img {
  max-width: 100%;
  height: auto;
  object-fit: contain;
  border-radius: var(--border-radius, 8px);
  box-shadow: var(--pa-card-shadow);
}

.hero-split__content {
  order: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 1rem 0;
}

.hero-split__title {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: clamp(2.5rem, 10vw, 5rem);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
  margin: 0 0 0.5rem;
}

.hero-split__subtitle {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: clamp(1rem, 3vw, 1.375rem);
  line-height: 1.6;
  color: var(--pa-text-body);
  max-width: 32ch;
  margin: 0 0 1.5rem;
}

.hero-split__preview-links {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.hero-split__preview-links .btn-gold,
.hero-split__preview-links .btn-outline {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.9375rem;
  padding: 0.625rem 1.5rem;
  border-radius: var(--border-radius, 8px);
  text-decoration: none;
  display: inline-block;
  transition: transform 0.2s, box-shadow 0.2s;
  cursor: pointer;
}

.hero-split__preview-links .btn-gold {
  background: linear-gradient(135deg, var(--pa-accent-gold), #b8941e);
  color: var(--pa-deep-purple);
  font-weight: 700;
  border: none;
}

.hero-split__preview-links .btn-outline {
  background: transparent;
  color: var(--pa-deep-purple);
  border: 2px solid var(--pa-accent-gold);
  font-weight: 600;
}

.hero-split__preview-links .btn-gold:hover,
.hero-split__preview-links .btn-gold:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(212, 175, 55, 0.4);
}

.hero-split__preview-links .btn-outline:hover,
.hero-split__preview-links .btn-outline:focus-visible {
  background: var(--pa-accent-gold);
  color: var(--pa-deep-purple);
}

/* 内容容器通用 */
.content-container {
  width: 100%;
  max-width: var(--pa-max-width);
  margin: 0 auto;
  padding: 0 1rem;
}

/* 服务演进时间轴 */
.evolution-section {
  padding: 2rem 0;
}

.evolution-section .section-title {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: clamp(1.75rem, 6vw, 2.5rem);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0 0 2rem;
}

.time-axis {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  position: relative;
  padding-left: 2rem;
}

.time-axis::before {
  content: '';
  position: absolute;
  left: 0.75rem;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--pa-accent-gold), var(--pa-deep-purple), var(--pa-accent-blue));
  border-radius: 2px;
}

.time-axis__item {
  position: relative;
  cursor: pointer;
  transition: transform 0.2s;
}

.time-axis__item:hover,
.time-axis__item:focus-within {
  transform: translateX(4px);
}

.time-axis__dot {
  position: absolute;
  left: -1.375rem;
  top: 1rem;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--pa-accent-gold);
  border: 3px solid var(--pa-bg-cream);
  box-shadow: 0 0 0 2px var(--pa-deep-purple);
  z-index: 1;
}

.time-axis__content {
  padding: 1rem 1.25rem;
  background: var(--pa-glass-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: var(--border-radius, 8px);
  box-shadow: var(--pa-card-shadow);
  border: 1px solid rgba(212, 175, 55, 0.25);
  transition: border-color 0.3s, box-shadow 0.3s;
}

.time-axis__item:hover .time-axis__content,
.time-axis__item:focus-within .time-axis__content {
  border-color: var(--pa-accent-gold);
  box-shadow: 0 8px 24px rgba(212, 175, 55, 0.2);
}

.time-axis__heading {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: 1.125rem;
  letter-spacing: -0.01em;
  color: var(--pa-deep-purple);
  margin: 0 0 0.375rem;
}

.time-axis__text {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--pa-text-body);
  margin: 0;
}

/* 核心功能网格 */
.functions-section {
  padding: 2rem 0;
  background: var(--pa-bg-cream);
}

.functions-section .section-title {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: clamp(1.75rem, 6vw, 2.5rem);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0 0 2rem;
}

.functions-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--pa-gap);
}

.function-card {
  background: #ffffff;
  border-radius: var(--border-radius, 8px);
  box-shadow: var(--pa-card-shadow);
  overflow: hidden;
  transition: transform 0.3s, box-shadow 0.3s;
  cursor: default;
  display: flex;
  flex-direction: column;
}

.function-card:hover,
.function-card:focus-within {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(74, 14, 78, 0.2);
}

.function-card__img-wrapper {
  overflow: hidden;
  aspect-ratio: 3 / 2;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
}

.function-card__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.4s;
}

.function-card:hover .function-card__img,
.function-card:focus-within .function-card__img {
  transform: scale(1.05);
}

.function-card__title {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: 1.125rem;
  letter-spacing: -0.01em;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  padding: 0.75rem 1rem 0.25rem;
  margin: 0;
}

.function-card__desc {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--pa-text-body);
  padding: 0 1rem 1rem;
  margin: 0;
  flex: 1;
}

/* 数据原则 */
.principles-section {
  padding: 2rem 0;
}

.principles-section .section-title {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: clamp(1.75rem, 6vw, 2.5rem);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0 0 2rem;
}

.principles-list {
  padding: 1.5rem;
  background: var(--pa-glass-bg);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border-radius: var(--border-radius, 8px);
  box-shadow: var(--pa-card-shadow);
  border: 1px solid rgba(212, 175, 55, 0.2);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.principles-list__item {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--pa-text-body);
  margin: 0;
}

.principles-list__mark {
  color: var(--pa-deep-purple);
  font-weight: 700;
}

.principles-list__link {
  color: var(--pa-accent-gold);
  text-decoration: underline;
  transition: color 0.2s;
}

.principles-list__link:hover,
.principles-list__link:focus-visible {
  color: var(--pa-deep-purple);
}

/* 地域元素 */
.region-section {
  padding: 2rem 0;
  background: var(--pa-bg-cream);
}

.region-layout {
  display: flex;
  flex-direction: column;
  gap: var(--pa-gap);
  align-items: center;
}

.region-layout__img-wrapper {
  width: 100%;
  max-width: 500px;
  border-radius: var(--border-radius, 8px);
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(74, 14, 78, 0.1);
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
}

.region-layout__img {
  width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

.region-layout__content {
  text-align: center;
}

.region-layout__content .section-title {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: clamp(1.5rem, 5vw, 2.125rem);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0 0 0.75rem;
}

.region-layout__text {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--pa-text-body);
  max-width: 48ch;
  margin: 0 auto;
}

/* 联系反馈 */
.feedback-section {
  padding: 2rem 0 4rem;
}

.feedback-section .section-title {
  font-family: var(--heading-font, 'Compacta Bold', Impact, sans-serif);
  font-size: clamp(1.75rem, 6vw, 2.5rem);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--pa-deep-purple), var(--pa-accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0 0 2rem;
}

.feedback-card {
  padding: 1.5rem;
  background: var(--pa-glass-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: var(--border-radius, 8px);
  box-shadow: var(--pa-card-shadow);
  border: 1px solid rgba(212, 175, 55, 0.2);
}

.feedback-card__text {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--pa-text-body);
  margin: 0 0 1.25rem;
}

.feedback-card__list {
  list-style: none;
  padding: 0;
  margin: 0 0 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.feedback-card__list li {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--pa-text-dark);
}

.feedback-card__list strong {
  color: var(--pa-deep-purple);
}

.feedback-card__note {
  font-family: var(--body-font, 'IBM Plex Sans', sans-serif);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--pa-text-body);
  margin: 0;
}

.feedback-card__link {
  color: var(--pa-accent-gold);
  text-decoration: underline;
  transition: color 0.2s;
}

.feedback-card__link:hover,
.feedback-card__link:focus-visible {
  color: var(--pa-deep-purple);
}

/* 滚动显现动画 (渐进增强) */
[data-scroll-reveal] {
  opacity: 1;
  transform: none;
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

@media (prefers-reduced-motion: no-preference) {
  [data-scroll-reveal] {
    opacity: 0;
    transform: translateY(24px);
  }

  [data-scroll-reveal].revealed {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 桌面端响应式 */
@media (min-width: 768px) {
  .page-about {
    gap: 3rem;
  }

  .hero-split {
    flex-direction: row;
    padding: calc(var(--pa-header-h) + 2rem) 2rem 3rem;
    min-height: 80vh;
    align-items: stretch;
  }

  .hero-split__media {
    order: 1;
    flex: 0 0 45%;
    max-width: 45%;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .hero-split__img {
    width: 100%;
    height: auto;
    max-height: 80%;
  }

  .hero-split__content {
    order: 2;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 0 0 0 3rem;
  }

  .hero-split__title {
    font-size: clamp(4rem, 7vw, 6rem);
  }

  .hero-split__subtitle {
    font-size: 1.25rem;
  }

  .content-container {
    padding: 0 2rem;
  }

  .functions-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .function-card__img-wrapper {
    aspect-ratio: 3 / 2;
  }

  .time-axis {
    padding-left: 3rem;
  }

  .time-axis::before {
    left: 1rem;
  }

  .time-axis__dot {
    left: -2rem;
    width: 18px;
    height: 18px;
  }

  .time-axis__content {
    padding: 1.25rem 1.5rem;
  }

  .time-axis__heading {
    font-size: 1.25rem;
  }

  .region-layout {
    flex-direction: row;
    text-align: left;
    gap: 2rem;
  }

  .region-layout__img-wrapper {
    flex: 0 0 45%;
    max-width: 45%;
  }

  .region-layout__content {
    flex: 1;
    text-align: left;
  }

  .region-layout__text {
    margin: 0;
  }

  .feedback-card {
    padding: 2rem;
  }

  .feedback-card__list {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 1rem 2rem;
  }
}

@media (min-width: 1024px) {
  .functions-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .hero-split {
    padding: calc(var(--pa-header-h) + 3rem) 3rem 4rem;
  }

  .hero-split__content {
    padding-left: 4rem;
  }
}

/* reduced-motion handling */
@media (prefers-reduced-motion: reduce) {
  .function-card,
  .time-axis__item,
  .hero-split__preview-links .btn-gold,
  .hero-split__preview-links .btn-outline,
  .function-card__img,
  .time-axis__content,
  .breadcrumb__link {
    transition: none !important;
    transform: none !important;
  }

  .function-card__img-wrapper,
  .function-card__img {
    transition: none !important;
  }

  [data-scroll-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }
}