.page-about {
  --about-red: #E63946;
  --about-blue: #1D3557;
  --about-silver: #CAD2C5;
  --about-cream: #F5F0E8;
  --about-warm-gray: #D4C9B8;
  --about-amber: #FFB347;
  --about-deep-gray: #2D2D2D;
  --about-mid-gray: #4A4A4A;
  --about-light-gray: #B0B0B0;
  --about-white: #FFFFFF;
  --about-font-heading: Georgia, "Times New Roman", serif;
  --about-font-body: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --about-radius: 8px;
  --about-shadow: 0 4px 20px rgba(0,0,0,0.06);
  --about-transition: 0.3s ease;

  background-color: var(--about-cream);
  color: var(--about-deep-gray);
  font-family: var(--about-font-body);
  line-height: 1.6;
  padding: 0 0 var(--space-xl) 0;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  max-width: var(--max-width, 1200px);
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md) 0 var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: 0.875rem;
  color: var(--about-light-gray);
}

.page-about .breadcrumb a {
  color: var(--about-blue);
  text-decoration: none;
  transition: color var(--about-transition);
  font-weight: 500;
}

.page-about .breadcrumb a:hover {
  color: var(--about-red);
}

.page-about .breadcrumb__sep {
  color: var(--about-light-gray);
  user-select: none;
}

.page-about .breadcrumb__current {
  color: var(--about-mid-gray);
  font-weight: 500;
}

/* ---------- 品牌声明 ---------- */
.page-about .brand-statement {
  padding: var(--space-xl) 0 var(--space-lg) 0;
}

.page-about .brand-statement__inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  align-items: center;
}

.page-about .brand-statement__text {
  flex: 0 1 56%;
  order: 1;
}

.page-about .brand-statement__heading {
  font-family: var(--about-font-heading);
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--about-blue);
  margin: 0 0 var(--space-md) 0;
  letter-spacing: -0.02em;
  position: relative;
}

.page-about .brand-statement__heading::after {
  content: "";
  display: block;
  width: 60px;
  height: 3px;
  background: var(--about-red);
  margin-top: var(--space-sm);
  border-radius: 2px;
}

.page-about .brand-statement__lead {
  font-size: 1.125rem;
  color: var(--about-deep-gray);
  margin: 0 0 var(--space-sm) 0;
  max-width: 32em;
}

.page-about .brand-statement__detail {
  font-size: 0.9375rem;
  color: var(--about-mid-gray);
  margin: 0 0 var(--space-lg) 0;
  max-width: 34em;
  line-height: 1.7;
}

.page-about .brand-statement__cta {
  display: inline-block;
}

.page-about .brand-statement__visual {
  flex: 0 1 44%;
  order: 2;
  position: relative;
  align-self: stretch;
}

.page-about .brand-statement__figure {
  position: relative;
  width: 100%;
  height: 100%;
  min-height: 280px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-about .brand-statement__img {
  width: 100%;
  height: auto;
  max-width: 600px;
  object-fit: contain;
  border-radius: var(--about-radius);
  box-shadow: var(--about-shadow);
  position: relative;
  z-index: 1;
}

.page-about .brand-statement__decor {
  position: absolute;
  top: -12px;
  right: -12px;
  width: 100%;
  height: 100%;
  border: 2px solid var(--about-red);
  border-radius: var(--about-radius);
  z-index: 0;
  opacity: 0.3;
  pointer-events: none;
}

/* ---------- 筛选栏 ---------- */
.page-about .filter-bar {
  max-width: var(--max-width, 1200px);
  margin: 0 auto var(--space-lg) auto;
  padding: 0 var(--space-md);
  display: flex;
  gap: 0;
  position: relative;
  background: var(--about-white);
  border-radius: var(--about-radius);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  overflow: hidden;
  width: fit-content;
}

.page-about .filter-bar__input {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.page-about .filter-bar__label {
  padding: var(--space-sm) var(--space-lg);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--about-mid-gray);
  cursor: pointer;
  transition: color var(--about-transition), background var(--about-transition);
  user-select: none;
  position: relative;
  z-index: 1;
  text-align: center;
  white-space: nowrap;
}

.page-about .filter-bar__label:hover {
  color: var(--about-blue);
}

.page-about .filter-bar__input:checked + .filter-bar__label {
  color: var(--about-white);
  background: var(--about-blue);
}

.page-about .filter-bar__input:focus-visible + .filter-bar__label {
  outline: 2px solid var(--about-red);
  outline-offset: -2px;
}

/* ---------- 核心功能 ---------- */
.page-about .core-features {
  padding: var(--space-lg) 0 var(--space-xl) 0;
  position: relative;
}

.page-about .section__title-wrapper {
  margin-bottom: var(--space-lg);
}

.page-about .section__title {
  font-family: var(--about-font-heading);
  font-size: 1.875rem;
  font-weight: 700;
  color: var(--about-blue);
  margin: 0 0 var(--space-xs) 0;
  position: relative;
}

.page-about .section__title::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  background: var(--about-red);
  margin-top: var(--space-xs);
  border-radius: 2px;
}

.page-about .section__subtitle {
  font-size: 0.9375rem;
  color: var(--about-mid-gray);
  margin: 0;
  max-width: 28em;
}

.page-about .features-bg-wrap {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
  opacity: 0.08;
}

.page-about .features-bg {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 30%;
}

.page-about .features-grid {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.page-about .feature-card {
  background: var(--about-white);
  border-radius: var(--about-radius);
  box-shadow: var(--about-shadow);
  padding: var(--space-lg);
  position: relative;
  transition: transform var(--about-transition), box-shadow var(--about-transition);
  border-left: 4px solid transparent;
}

.page-about .feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.08);
}

.page-about .feature-card:nth-child(1) {
  border-left-color: var(--about-red);
}

.page-about .feature-card:nth-child(2) {
  border-left-color: var(--about-blue);
  margin-left: var(--space-md);
}

.page-about .feature-card:nth-child(3) {
  border-left-color: var(--about-amber);
  margin-left: calc(var(--space-md) * 2);
}

.page-about .card__accent {
  position: absolute;
  top: 0;
  right: 0;
  width: 60px;
  height: 60px;
  background: radial-gradient(circle at top right, var(--about-silver), transparent 70%);
  border-radius: 0 var(--about-radius) 0 60px;
  pointer-events: none;
}

.page-about .card__title {
  font-family: var(--about-font-heading);
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--about-blue);
  margin: 0 0 var(--space-sm) 0;
}

.page-about .card__body {
  font-size: 0.9375rem;
  color: var(--about-mid-gray);
  margin: 0 0 var(--space-md) 0;
  line-height: 1.7;
}

.page-about .feature-card__details {
  margin: var(--space-sm) 0 var(--space-sm) 0;
  font-size: 0.875rem;
  color: var(--about-deep-gray);
  border-top: 1px solid var(--about-warm-gray);
  padding-top: var(--space-sm);
}

.page-about .feature-card__summary {
  cursor: pointer;
  font-weight: 500;
  color: var(--about-red);
  padding: var(--space-xs) 0;
  user-select: none;
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.page-about .feature-card__summary::-webkit-details-marker {
  display: none;
}

.page-about .feature-card__summary::before {
  content: "+";
  display: inline-block;
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1;
  transition: transform var(--about-transition);
  color: var(--about-red);
}

.page-about .feature-card__details[open] .feature-card__summary::before {
  content: "−";
  transform: rotate(0deg);
}

.page-about .feature-card__expanded {
  padding: var(--space-sm) 0 0 0;
  line-height: 1.7;
  color: var(--about-mid-gray);
}

.page-about .feature-card__expanded p {
  margin: 0;
}

.page-about .card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-top: var(--space-sm);
}

.page-about .tag {
  display: inline-block;
  padding: 0.25em 0.75em;
  font-size: 0.75rem;
  font-weight: 500;
  background: var(--about-amber);
  color: var(--about-deep-gray);
  border-radius: 20px;
  line-height: 1.4;
}

.page-about .features-footnote {
  position: relative;
  z-index: 1;
  margin-top: var(--space-lg);
  text-align: center;
}

/* ---------- 数据更新承诺 ---------- */
.page-about .data-commitment {
  padding: var(--space-xl) 0;
  background: var(--about-white);
  position: relative;
}

.page-about .data-commitment::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--about-red), var(--about-blue), var(--about-amber));
  opacity: 0.6;
}

.page-about .commitment__inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  align-items: center;
}

.page-about .commitment__text {
  flex: 0 1 60%;
}

.page-about .commitment__lead {
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--about-deep-gray);
  margin: var(--space-md) 0 var(--space-sm) 0;
  max-width: 30em;
}

.page-about .commitment__body {
  font-size: 0.9375rem;
  color: var(--about-mid-gray);
  margin: 0 0 var(--space-md) 0;
  max-width: 34em;
  line-height: 1.7;
}

.page-about .commitment__trust {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.page-about .tag--trust {
  background: var(--about-silver);
  color: var(--about-blue);
  font-size: 0.8125rem;
  padding: 0.35em 1em;
  border: 1px solid var(--about-blue);
}

.page-about .commitment__brand {
  flex: 0 1 auto;
  text-align: center;
}

.page-about .commitment__logo-figure {
  margin: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
}

.page-about .commitment__logo {
  width: 120px;
  height: auto;
  max-width: 200px;
  border-radius: var(--about-radius);
  box-shadow: var(--about-shadow);
  transition: transform var(--about-transition);
}

.page-about .commitment__logo:hover {
  transform: scale(1.03);
}

.page-about .commitment__logo-caption {
  font-size: 0.8125rem;
  color: var(--about-light-gray);
  letter-spacing: 0.05em;
}

/* ---------- 相关链接 ---------- */
.page-about .related-links {
  padding: var(--space-lg) 0 0 0;
}

.page-about .related-links__inner {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  justify-content: center;
}

.page-about .related-links__item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  background: var(--about-white);
  border-radius: var(--about-radius);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  text-decoration: none;
  color: var(--about-blue);
  font-weight: 500;
  font-size: 0.9375rem;
  transition: transform var(--about-transition), box-shadow var(--about-transition);
}

.page-about .related-links__item:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.08);
  color: var(--about-red);
}

.page-about .related-links__arrow {
  font-size: 1.125rem;
  transition: transform var(--about-transition);
}

.page-about .related-links__item:hover .related-links__arrow {
  transform: translateX(4px);
}

/* ---------- 桌面端 (≥768px) ---------- */
@media (min-width: 768px) {
  .page-about .brand-statement__inner {
    flex-direction: row;
    align-items: center;
  }

  .page-about .brand-statement__heading {
    font-size: 3rem;
  }

  .page-about .brand-statement__visual {
    min-height: 360px;
  }

  .page-about .brand-statement__figure {
    min-height: 360px;
  }

  .page-about .brand-statement__decor {
    top: -16px;
    right: -16px;
  }

  .page-about .features-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: var(--space-lg);
    align-items: start;
  }

  .page-about .feature-card:nth-child(2) {
    margin-left: 0;
    margin-top: var(--space-lg);
  }

  .page-about .feature-card:nth-child(3) {
    margin-left: 0;
    margin-top: calc(var(--space-lg) * 2);
  }

  .page-about .commitment__inner {
    flex-direction: row;
    align-items: flex-start;
    justify-content: space-between;
  }

  .page-about .commitment__brand {
    flex-shrink: 0;
  }

  .page-about .commitment__logo {
    width: 160px;
  }

  .page-about .filter-bar {
    margin-left: var(--space-md);
    margin-right: var(--space-md);
  }

  .page-about .related-links__inner {
    justify-content: flex-start;
  }
}

/* ---------- 大桌面端 (≥1024px) ---------- */
@media (min-width: 1024px) {
  .page-about .brand-statement__heading {
    font-size: 3.5rem;
  }

  .page-about .brand-statement__lead {
    font-size: 1.25rem;
  }

  .page-about .features-grid {
    gap: var(--space-xl);
  }

  .page-about .feature-card:nth-child(2) {
    margin-top: calc(var(--space-lg) * 1.5);
  }

  .page-about .feature-card:nth-child(3) {
    margin-top: calc(var(--space-lg) * 3);
  }

  .page-about .commitment__logo {
    width: 200px;
  }
}

/* ---------- 可访问性 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}

.page-about .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.625rem 1.5rem;
  font-family: var(--about-font-body);
  font-size: 0.9375rem;
  font-weight: 600;
  border: 2px solid transparent;
  border-radius: var(--about-radius);
  cursor: pointer;
  text-decoration: none;
  transition: background var(--about-transition), color var(--about-transition), border-color var(--about-transition), transform var(--about-transition);
  line-height: 1.4;
}

.page-about .btn--primary {
  background: var(--about-red);
  color: var(--about-white);
  border-color: var(--about-red);
}

.page-about .btn--primary:hover {
  background: transparent;
  color: var(--about-red);
}

.page-about .btn--secondary {
  background: var(--about-blue);
  color: var(--about-white);
  border-color: var(--about-blue);
}

.page-about .btn--secondary:hover {
  background: transparent;
  color: var(--about-blue);
}

.page-about .btn:focus-visible {
  outline: 3px solid var(--about-amber);
  outline-offset: 2px;
}