/* ===== 品牌概况页面专属样式 ===== */
.page-about {
  --about-hero-gap: var(--spacing-2xl);
  --about-hero-left-max: 640px;
  --about-icon-panel-max: 480px;
  --about-card-min-height: 280px;
  --about-timeline-accent: var(--color-accent);
  --about-border-glow: rgba(255, 215, 0, 0.15);
  --about-compare-transition: var(--transition-base);
}

/* ---- 容器与通用 ---- */
.page-about .container {
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-lg);
  padding-right: var(--spacing-lg);
}

.page-about .visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.page-about .tag {
  display: inline-block;
  padding: 0.2em 0.75em;
  font-family: var(--font-body);
  font-size: var(--size-xs);
  font-weight: var(--weight-bold);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border-radius: var(--radius-sm);
  line-height: 1.6;
}

.page-about .tag--blue {
  background: var(--color-primary);
  color: var(--color-text-primary);
}

.page-about .tag--orange {
  background: var(--color-secondary);
  color: var(--color-bg-dark);
}

.page-about .tag--gold {
  background: var(--color-accent);
  color: var(--color-bg-dark);
}

.page-about .btn--outline {
  background: transparent;
  border: 1.5px solid var(--color-border);
  color: var(--color-text-primary);
  transition: border-color var(--transition-fast), color var(--transition-fast);
}

.page-about .btn--outline:hover,
.page-about .btn--outline:focus-visible {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.page-about .btn--secondary {
  background: var(--color-secondary);
  border: 1.5px solid var(--color-secondary);
  color: var(--color-bg-dark);
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.page-about .btn--secondary:hover,
.page-about .btn--secondary:focus-visible {
  background: var(--color-secondary-hover);
  transform: translateY(-1px);
}

.page-about .btn--sm {
  padding: 0.4em 1.2em;
  font-size: var(--size-sm);
  font-weight: var(--weight-bold);
  border-radius: var(--radius-sm);
  text-decoration: none;
  display: inline-block;
  cursor: default;
}

/* ---- 面包屑 ---- */
.page-about .about__breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35em;
  font-size: var(--size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

.page-about .about__breadcrumb-link {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.page-about .about__breadcrumb-link:hover,
.page-about .about__breadcrumb-link:focus-visible {
  color: var(--color-accent);
}

.page-about .about__breadcrumb-sep {
  color: var(--color-border);
  font-size: 0.8em;
}

.page-about .about__breadcrumb-current {
  color: var(--color-text-primary);
  font-weight: var(--weight-bold);
}

/* ---- 首屏 ---- */
.page-about .about__hero {
  position: relative;
  background: var(--color-bg-dark);
  padding: var(--spacing-2xl) 0 var(--spacing-3xl);
  overflow: hidden;
}

.page-about .about__hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(ellipse at 20% 50%, rgba(0, 61, 122, 0.25) 0%, transparent 70%);
  pointer-events: none;
}

.page-about .about__hero-inner {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
  position: relative;
  z-index: 1;
}

.page-about .about__hero-left {
  flex: 1 1 100%;
  max-width: 100%;
}

.page-about .about__hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.2rem, 8vw, 4rem);
  font-weight: var(--weight-heading);
  letter-spacing: -0.03em;
  line-height: 1.05;
  color: var(--color-text-primary);
  margin: 0 0 0.1em;
}

.page-about .about__hero-subtitle {
  font-family: var(--font-body);
  font-size: clamp(1rem, 3vw, 1.35rem);
  font-weight: var(--weight-bold);
  color: var(--color-accent);
  letter-spacing: 0.06em;
  margin: 0 0 var(--spacing-md);
  text-transform: uppercase;
}

.page-about .about__hero-intro {
  font-family: var(--font-body);
  font-size: var(--size-base);
  line-height: 1.7;
  color: var(--color-text-secondary);
  max-width: 520px;
  margin: 0 0 var(--spacing-lg);
}

.page-about .about__timeline-graphic {
  margin-top: var(--spacing-lg);
  max-width: var(--about-hero-left-max);
}

.page-about .about__timeline-img {
  display: block;
  width: 100%;
  max-width: 600px;
  height: auto;
  border-radius: var(--radius-md);
  object-fit: cover;
}

/* ---- 右侧图标矩阵 ---- */
.page-about .about__hero-right {
  flex: 1 1 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

.page-about .about__icon-panel {
  width: 100%;
  max-width: var(--about-icon-panel-max);
  background: rgba(26, 35, 50, 0.72);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  transition: border-color var(--transition-fast);
}

.page-about .about__icon-panel:hover {
  border-color: rgba(255, 215, 0, 0.25);
}

.page-about .about__icon-grid-img {
  display: block;
  width: 100%;
  max-width: 400px;
  height: auto;
  margin: 0 auto var(--spacing-md);
  border-radius: var(--radius-sm);
  object-fit: cover;
}

.page-about .about__icon-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-sm);
}

.page-about .about__icon-item {
  display: flex;
  align-items: center;
  gap: 0.5em;
  padding: 0.6em 0.8em;
  background: rgba(44, 58, 74, 0.5);
  border-radius: var(--radius-sm);
  cursor: default;
  transition: background var(--transition-fast), transform var(--transition-fast);
  position: relative;
}

.page-about .about__icon-item:hover {
  background: rgba(44, 58, 74, 0.85);
  transform: translateY(-1px);
}

.page-about .about__icon-item:hover .about__icon-desc {
  opacity: 1;
  visibility: visible;
}

.page-about .about__icon-symbol {
  font-size: 1.3rem;
  line-height: 1;
  flex-shrink: 0;
}

.page-about .about__icon-label {
  font-family: var(--font-body);
  font-size: var(--size-sm);
  font-weight: var(--weight-bold);
  color: var(--color-text-primary);
  white-space: nowrap;
}

.page-about .about__icon-desc {
  position: absolute;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-bg-medium);
  color: var(--color-text-primary);
  padding: 0.4em 0.8em;
  border-radius: var(--radius-sm);
  font-size: var(--size-xs);
  line-height: 1.4;
  white-space: nowrap;
  max-width: 220px;
  border: 1px solid var(--color-border);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast), visibility var(--transition-fast);
  z-index: 10;
  pointer-events: none;
}

.page-about .about__icon-desc::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: var(--color-bg-medium);
}

/* ---- 章节标题 ---- */
.page-about .about__section-title {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  letter-spacing: -0.015em;
  line-height: 1.15;
  margin: 0 0 var(--spacing-md);
}

.page-about .about__section-title--primary {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  color: var(--color-primary);
}

.page-about .about__section-title--accent {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  color: var(--color-accent);
}

.page-about .about__section-title--light {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  color: var(--color-text-primary);
}

.page-about .about__section-title--small {
  font-size: clamp(1.2rem, 3vw, 1.6rem);
  color: var(--color-text-primary);
}

/* ---- 品牌定位 ---- */
.page-about .about__positioning {
  background: var(--color-bg-medium);
  padding: var(--spacing-3xl) 0;
  position: relative;
}

.page-about .about__positioning::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-secondary), var(--color-primary));
  opacity: 0.6;
}

.page-about .about__positioning-frame {
  position: relative;
  padding: var(--spacing-xl) 0;
}

.page-about .about__positioning-quote {
  position: absolute;
  top: -0.15em;
  left: -0.05em;
  font-family: var(--font-heading);
  font-size: 5rem;
  line-height: 1;
  color: var(--color-accent);
  opacity: 0.15;
  pointer-events: none;
  user-select: none;
}

.page-about .about__positioning-content {
  position: relative;
  z-index: 1;
}

.page-about .about__positioning-text {
  font-family: var(--font-body);
  font-size: var(--size-base);
  line-height: 1.75;
  color: var(--color-text-secondary);
  max-width: 720px;
  margin: 0 0 var(--spacing-md);
}

.page-about .about__positioning-text:last-of-type {
  margin-bottom: 0;
}

.page-about .about__highlight {
  color: var(--color-accent);
  font-weight: var(--weight-bold);
}

.page-about .about__positioning-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
}

/* ---- 核心业务 ---- */
.page-about .about__core-business {
  background: var(--color-bg-dark);
  padding: var(--spacing-3xl) 0;
}

.page-about .about__business-desc {
  font-family: var(--font-body);
  font-size: var(--size-base);
  color: var(--color-text-secondary);
  max-width: 580px;
  margin: 0 0 var(--spacing-xl);
  line-height: 1.6;
}

.page-about .about__business-grid {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.page-about .about__business-card {
  background: var(--color-bg-medium);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  border: 1px solid var(--color-border);
  transition: border-color var(--transition-fast), transform var(--transition-fast);
  position: relative;
  overflow: hidden;
}

.page-about .about__business-card:hover {
  border-color: rgba(255, 215, 0, 0.2);
  transform: translateY(-2px);
}

.page-about .about__business-card--featured {
  border-left: 4px solid var(--color-accent);
}

.page-about .about__business-card--highlight {
  border-left: 4px solid var(--color-secondary);
}

.page-about .about__business-icon {
  margin-bottom: var(--spacing-sm);
}

.page-about .about__business-title {
  font-family: var(--font-heading);
  font-size: var(--size-xl);
  font-weight: var(--weight-heading);
  color: var(--color-text-primary);
  margin: 0 0 var(--spacing-sm);
  letter-spacing: -0.01em;
}

.page-about .about__business-text {
  font-family: var(--font-body);
  font-size: var(--size-base);
  line-height: 1.65;
  color: var(--color-text-secondary);
  margin: 0 0 var(--spacing-md);
}

.page-about .about__business-link {
  font-family: var(--font-body);
  font-size: var(--size-sm);
  font-weight: var(--weight-bold);
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.3em;
}

.page-about .about__business-link:hover,
.page-about .about__business-link:focus-visible {
  color: var(--color-accent-hover);
}

/* ---- 版本对照 ---- */
.page-about .about__version-compare {
  background: var(--color-bg-medium);
  padding: var(--spacing-3xl) 0;
  position: relative;
}

.page-about .about__version-compare::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent), var(--color-secondary));
  opacity: 0.3;
}

.page-about .about__compare-header {
  margin-bottom: var(--spacing-xl);
}

.page-about .about__compare-desc {
  font-family: var(--font-body);
  font-size: var(--size-base);
  color: var(--color-text-secondary);
  max-width: 600px;
  line-height: 1.6;
  margin: var(--spacing-sm) 0 0;
}

.page-about .about__compare-visual {
  margin-bottom: var(--spacing-xl);
}

.page-about .about__compare-panels {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.page-about .about__compare-panel {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-bg-dark);
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition-fast);
}

.page-about .about__compare-panel--old {
  border-color: var(--color-primary);
}

.page-about .about__compare-panel--new {
  border-color: var(--color-secondary);
}

.page-about .about__compare-label {
  position: absolute;
  top: var(--spacing-sm);
  left: var(--spacing-sm);
  z-index: 2;
}

.page-about .about__compare-img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about__compare-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  pointer-events: none;
}

.page-about .about__compare-dot {
  position: absolute;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-accent);
  border: 2px solid var(--color-bg-dark);
  opacity: 0.6;
  transition: opacity var(--transition-fast);
}

.page-about .about__compare-dot--active {
  opacity: 1;
  background: var(--color-secondary);
  box-shadow: 0 0 8px rgba(255, 107, 53, 0.5);
}

/* ---- 版本切换控件 ---- */
.page-about .about__compare-controls {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  position: relative;
  background: var(--color-bg-dark);
  border-radius: var(--radius-sm);
  padding: 0.35em;
  width: fit-content;
}

.page-about .about__compare-radio {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.page-about .about__compare-btn {
  font-family: var(--font-body);
  font-size: var(--size-sm);
  font-weight: var(--weight-bold);
  color: var(--color-text-secondary);
  padding: 0.45em 1.2em;
  border-radius: var(--radius-sm);
  cursor: default;
  transition: color var(--transition-fast), background var(--transition-fast);
  position: relative;
  z-index: 2;
  user-select: none;
}

.page-about .about__compare-radio:checked + .about__compare-btn {
  color: var(--color-bg-dark);
  background: var(--color-accent);
}

.page-about .about__compare-track {
  display: none;
}

/* ---- 版本对照特色列表 ---- */
.page-about .about__compare-features {
  margin-top: var(--spacing-lg);
}

.page-about .about__compare-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.page-about .about__compare-item {
  display: flex;
  align-items: flex-start;
  gap: 0.6em;
  font-family: var(--font-body);
  font-size: var(--size-base);
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.page-about .about__compare-check {
  flex-shrink: 0;
  color: var(--color-accent);
  font-weight: var(--weight-bold);
  font-size: 1.1em;
  margin-top: 0.1em;
}

.page-about .about__compare-item strong {
  color: var(--color-text-primary);
  font-weight: var(--weight-bold);
}

/* ---- 品牌信任区 ---- */
.page-about .about__trust {
  background: var(--color-bg-dark);
  padding: var(--spacing-2xl) 0 var(--spacing-3xl);
}

.page-about .about__trust-inner {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
}

.page-about .about__trust-content {
  max-width: 680px;
}

.page-about .about__trust-text {
  font-family: var(--font-body);
  font-size: var(--size-base);
  line-height: 1.7;
  color: var(--color-text-secondary);
  margin: 0 0 var(--spacing-lg);
}

.page-about .about__trust-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.page-about .about__trust-note {
  background: rgba(255, 107, 53, 0.06);
  border-left: 3px solid var(--color-secondary);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.page-about .about__trust-note-text {
  font-family: var(--font-body);
  font-size: var(--size-sm);
  color: var(--color-text-secondary);
  margin: 0;
  line-height: 1.6;
}

/* ---- 返回顶部 ---- */
.page-about .about__back-top {
  text-align: center;
  padding: var(--spacing-lg) 0 var(--spacing-xl);
  background: var(--color-bg-dark);
}

.page-about .about__back-link {
  font-family: var(--font-body);
  font-size: var(--size-sm);
  font-weight: var(--weight-bold);
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.page-about .about__back-link:hover,
.page-about .about__back-link:focus-visible {
  color: var(--color-accent);
}

/* ===== 响应式：平板与桌面 ===== */
@media (min-width: 720px) {
  .page-about .container {
    padding-left: var(--spacing-xl);
    padding-right: var(--spacing-xl);
  }

  /* 首屏左右分屏 */
  .page-about .about__hero-inner {
    flex-direction: row;
    align-items: flex-start;
    gap: var(--spacing-2xl);
  }

  .page-about .about__hero-left {
    flex: 1 1 55%;
    max-width: var(--about-hero-left-max);
  }

  .page-about .about__hero-right {
    flex: 1 1 40%;
    justify-content: flex-end;
  }

  .page-about .about__icon-panel {
    padding: var(--spacing-xl);
  }

  .page-about .about__icon-list {
    gap: var(--spacing-md);
  }

  /* 核心业务三列网格 */
  .page-about .about__business-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: var(--spacing-lg);
  }

  .page-about .about__business-card {
    min-height: var(--about-card-min-height);
  }

  .page-about .about__business-card--featured {
    grid-column: 1 / 2;
  }

  .page-about .about__business-card--highlight {
    grid-column: 3 / 4;
  }

  /* 版本对照并排面板 */
  .page-about .about__compare-panels {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
  }

  .page-about .about__compare-list {
    flex-direction: row;
    flex-wrap: wrap;
    gap: var(--spacing-lg) var(--spacing-2xl);
  }

  .page-about .about__compare-item {
    flex: 1 1 200px;
  }

  /* 信任区左右并排 */
  .page-about .about__trust-inner {
    flex-direction: row;
    align-items: flex-start;
    gap: var(--spacing-2xl);
  }

  .page-about .about__trust-content {
    flex: 2;
  }

  .page-about .about__trust-note {
    flex: 1;
  }
}

/* ===== 桌面大屏 ===== */
@media (min-width: 1024px) {
  .page-about .about__hero {
    padding: var(--spacing-3xl) 0 var(--spacing-4xl);
  }

  .page-about .about__hero-left {
    flex: 1 1 50%;
  }

  .page-about .about__hero-right {
    flex: 1 1 45%;
  }

  .page-about .about__icon-panel {
    max-width: 500px;
  }

  .page-about .about__positioning-frame {
    padding: var(--spacing-xl) var(--spacing-2xl);
  }

  .page-about .about__positioning-quote {
    font-size: 7rem;
  }

  .page-about .about__business-grid {
    gap: var(--spacing-xl);
  }

  .page-about .about__compare-panels {
    gap: var(--spacing-xl);
  }

  .page-about .about__trust-inner {
    gap: var(--spacing-3xl);
  }
}

/* ===== 移动端小屏微调 ===== */
@media (max-width: 380px) {
  .page-about .about__icon-list {
    grid-template-columns: 1fr;
  }

  .page-about .about__compare-controls {
    flex-wrap: wrap;
  }
}

.page-about {
  --spacing-4xl: 1rem;
}