/* ===== 品牌介绍页专属样式 · page-about ===== */
.page-about {
  --page-accent: var(--color-primary-accent, #FF6B35);
  --page-green: var(--color-secondary-accent, #39FF14);
  --page-card-bg: var(--color-card-bg, #132A45);
  --page-border: var(--color-border, #2A4A6A);
  --page-text-muted: var(--color-text-secondary, #B0BEC5);
  --page-bg: var(--color-primary-bg, #0B1E36);

  display: flex;
  flex-direction: column;
  gap: 0;
  background: var(--page-bg);
  color: var(--color-text-primary, #FFFFFF);
  font-family: var(--font-body, 'Noto Sans SC', sans-serif);
  line-height: 1.6;
  padding: 0 0 3rem;
}

/* 容器复用 */
.page-about .container {
  max-width: var(--container-max, 1200px);
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* ===== 面包屑 ===== */
.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--page-text-muted);
  letter-spacing: 0.02em;
  margin-bottom: 1rem;
}
.page-about .breadcrumb a {
  color: var(--page-text-muted);
  text-decoration: none;
  transition: color 0.2s;
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--page-accent);
}
.page-about .breadcrumb-sep {
  color: var(--page-border);
  margin: 0 0.1rem;
}
.page-about .breadcrumb [aria-current="page"] {
  color: var(--page-accent);
  font-weight: 600;
}

/* ===== 框景首屏 ===== */
.page-about .hero-frame {
  position: relative;
  padding: 5rem 0 4rem;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, rgba(11,30,54,0.92) 0%, rgba(19,42,69,0.88) 100%);
  overflow: hidden;
}
.page-about .hero-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    repeating-linear-gradient(90deg, rgba(42,74,106,0.12) 0px, rgba(42,74,106,0.12) 1px, transparent 1px, transparent 24px),
    repeating-linear-gradient(0deg, rgba(42,74,106,0.08) 0px, rgba(42,74,106,0.08) 1px, transparent 1px, transparent 24px);
  pointer-events: none;
}
.page-about .hero-frame-inner {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  align-items: center;
  position: relative;
  z-index: 1;
}
.page-about .hero-visual {
  flex: 0 0 auto;
  width: 100%;
  max-width: 340px;
  position: relative;
}
.page-about .hero-visual-img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 8px;
  object-fit: cover;
  box-shadow: 0 8px 32px rgba(0,0,0,0.45);
}
.page-about .hero-visual-accent {
  position: absolute;
  bottom: -12px;
  right: -12px;
  width: 60%;
  height: 60%;
  border: 2px solid var(--page-green);
  border-radius: 4px;
  opacity: 0.25;
  z-index: -1;
  pointer-events: none;
}
.page-about .hero-content {
  flex: 1;
  text-align: center;
}
.page-about .hero-title {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 900;
  font-size: clamp(2.6rem, 8vw, 4.8rem);
  line-height: 1.05;
  color: #FFFFFF;
  letter-spacing: -0.02em;
  margin: 0 0 0.75rem;
  text-shadow: 0 2px 16px rgba(255,107,53,0.18);
}
.page-about .hero-sub {
  font-size: clamp(1rem, 2.5vw, 1.35rem);
  font-weight: 400;
  color: var(--page-text-muted);
  max-width: 520px;
  margin: 0 auto 1.5rem;
  line-height: 1.7;
}
.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}
.page-about .btn {
  display: inline-block;
  background: var(--page-accent);
  color: #FFFFFF;
  font-family: var(--font-body, sans-serif);
  font-weight: 700;
  font-size: 1rem;
  padding: 0.75rem 2rem;
  border-radius: 40px;
  text-decoration: none;
  transition: transform 0.2s, box-shadow 0.25s;
  box-shadow: 0 4px 14px rgba(255,107,53,0.3);
}
.page-about .btn:hover,
.page-about .btn:focus-visible {
  transform: scale(1.04);
  box-shadow: 0 6px 22px rgba(255,107,53,0.45);
}

/* 框景四角装饰 */
.page-about .frame-corner {
  position: absolute;
  width: 28px;
  height: 28px;
  border-color: var(--page-border);
  border-style: solid;
  pointer-events: none;
  opacity: 0.7;
}
.page-about .frame-corner--tl { top: 12px; left: 12px; border-width: 2px 0 0 2px; }
.page-about .frame-corner--tr { top: 12px; right: 12px; border-width: 2px 2px 0 0; }
.page-about .frame-corner--bl { bottom: 12px; left: 12px; border-width: 0 0 2px 2px; }
.page-about .frame-corner--br { bottom: 12px; right: 12px; border-width: 0 2px 2px 0; }

/* ===== 通用章节样式 ===== */
.page-about .page-section {
  padding: 3.5rem 0;
  border-bottom: 1px solid var(--page-border);
  position: relative;
}
.page-about .page-section:last-of-type {
  border-bottom: none;
}
.page-about .section-label {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}
.page-about .section-label-num {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 900;
  font-size: 1.6rem;
  color: var(--page-accent);
  line-height: 1;
  letter-spacing: -0.04em;
}
.page-about .section-label-text {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--page-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding-left: 0.75rem;
  border-left: 2px solid var(--page-border);
}

/* ===== 品牌原则 ===== */
.page-about .principle-card {
  background: var(--page-card-bg);
  border-radius: 12px;
  padding: 1.8rem 1.5rem 1.2rem;
  border: 1px solid var(--page-border);
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
  position: relative;
}
.page-about .principle-card-body {
  position: relative;
  z-index: 1;
}
.page-about .principle-card-title {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 900;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  color: #FFFFFF;
  letter-spacing: -0.02em;
  margin: 0 0 0.8rem;
}
.page-about .principle-card-desc {
  color: var(--page-text-muted);
  font-size: 1rem;
  max-width: 620px;
  margin-bottom: 1.2rem;
}
.page-about .principle-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.page-about .principle-list-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  font-size: 0.95rem;
  color: #E0E6EA;
}
.page-about .principle-list-icon {
  flex: 0 0 auto;
  font-size: 1.3rem;
  line-height: 1.4;
}
.page-about .principle-list-item strong {
  color: #FFFFFF;
  font-weight: 600;
}

/* 刻度尺 */
.page-about .principle-card-ruler {
  position: relative;
  height: 28px;
  margin-top: 1.8rem;
  border-top: 2px solid var(--page-border);
  padding-top: 4px;
}
.page-about .ruler-tick {
  position: absolute;
  top: -6px;
  width: 2px;
  height: 14px;
  background: var(--page-accent);
  transform: translateX(-50%);
  opacity: 0.7;
}
.page-about .ruler-label {
  position: absolute;
  top: 14px;
  transform: translateX(-50%);
  font-size: 0.65rem;
  font-weight: 300;
  color: var(--page-text-muted);
  letter-spacing: 0.04em;
}

/* ===== 边界与范围 ===== */
.page-about .boundaries-layout {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}
.page-about .boundaries-heading {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 900;
  font-size: clamp(1.5rem, 3.6vw, 2.2rem);
  color: #FFFFFF;
  margin: 0 0 0.6rem;
  letter-spacing: -0.02em;
}
.page-about .boundaries-desc {
  color: var(--page-text-muted);
  font-size: 1rem;
  margin-bottom: 1.2rem;
}
.page-about .boundaries-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.page-about .boundaries-list-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  font-size: 0.95rem;
  color: #E0E6EA;
  padding: 0.75rem 1rem;
  background: rgba(19,42,69,0.4);
  border-radius: 8px;
  border-left: 3px solid var(--page-accent);
}
.page-about .boundaries-list-marker {
  flex: 0 0 auto;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--page-green);
  margin-top: 0.5rem;
}
.page-about .boundaries-list-item strong {
  color: #FFFFFF;
  font-weight: 600;
}
.page-about .boundaries-visual {
  flex: 0 0 auto;
  max-width: 500px;
}
.page-about .boundaries-img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 8px;
  border: 1px solid var(--page-border);
  background: var(--page-card-bg);
  object-fit: cover;
}
.page-about .boundaries-img-caption {
  font-size: 0.8rem;
  color: var(--page-text-muted);
  margin-top: 0.4rem;
  font-style: italic;
}

/* ===== 应用场景 ===== */
.page-about .usecases-heading {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 900;
  font-size: clamp(1.5rem, 3.6vw, 2.2rem);
  color: #FFFFFF;
  margin: 0 0 0.3rem;
  letter-spacing: -0.02em;
}
.page-about .usecases-desc {
  color: var(--page-text-muted);
  font-size: 1rem;
  margin-bottom: 1.8rem;
}
.page-about .cases-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin-bottom: 2.5rem;
}
.page-about .case-card {
  background: var(--page-card-bg);
  border-radius: 12px;
  padding: 1.6rem 1.4rem;
  border: 1px solid var(--page-border);
  transition: border-color 0.3s, box-shadow 0.35s, transform 0.25s;
  cursor: default;
  position: relative;
  overflow: hidden;
}
.page-about .case-card::after {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: 12px;
  border: 2px solid transparent;
  pointer-events: none;
  transition: border-color 0.35s;
}
.page-about .case-card:hover,
.page-about .case-card:focus-within {
  border-color: var(--page-accent);
  box-shadow: 0 0 0 2px rgba(255,107,53,0.2), 0 8px 28px rgba(0,0,0,0.35);
  transform: translateY(-3px);
}
.page-about .case-card:hover::after,
.page-about .case-card:focus-within::after {
  border-color: var(--page-accent);
}
.page-about .case-card-icon {
  margin-bottom: 0.8rem;
  display: flex;
  align-items: center;
}
.page-about .case-card-icon svg {
  display: block;
  width: 44px;
  height: 44px;
}
.page-about .case-card-title {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 800;
  font-size: 1.15rem;
  color: #FFFFFF;
  margin: 0 0 0.4rem;
}
.page-about .case-card-text {
  font-size: 0.92rem;
  color: var(--page-text-muted);
  line-height: 1.6;
  margin: 0;
}
.page-about .usecases-device {
  display: flex;
  justify-content: center;
  margin-top: 0.5rem;
}
.page-about .usecases-device-img {
  display: block;
  width: 100%;
  max-width: 320px;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--page-border);
  background: var(--page-card-bg);
  object-fit: cover;
  box-shadow: 0 6px 24px rgba(0,0,0,0.3);
}

/* ===== 常见疑问 (折叠面板) ===== */
.page-about .faq-heading {
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 900;
  font-size: clamp(1.5rem, 3.6vw, 2.2rem);
  color: #FFFFFF;
  margin: 0 0 1.5rem;
  letter-spacing: -0.02em;
}
.page-about .faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.page-about .faq-item {
  background: var(--page-card-bg);
  border-radius: 10px;
  border: 1px solid var(--page-border);
  overflow: hidden;
  transition: border-color 0.25s;
}
.page-about .faq-item[open] {
  border-color: var(--page-accent);
}
.page-about .faq-question {
  display: block;
  padding: 1rem 1.25rem;
  font-family: var(--font-heading, 'Montserrat', sans-serif);
  font-weight: 700;
  font-size: 1rem;
  color: #FFFFFF;
  cursor: pointer;
  list-style: none;
  position: relative;
  transition: background 0.2s;
  user-select: none;
}
.page-about .faq-question::-webkit-details-marker {
  display: none;
}
.page-about .faq-question::marker {
  display: none;
}
.page-about .faq-question::after {
  content: "+";
  position: absolute;
  right: 1.25rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.4rem;
  font-weight: 300;
  color: var(--page-accent);
  transition: transform 0.25s;
  line-height: 1;
}
.page-about .faq-item[open] .faq-question::after {
  transform: translateY(-50%) rotate(45deg);
}
.page-about .faq-question:hover,
.page-about .faq-question:focus-visible {
  background: rgba(255,107,53,0.08);
}
.page-about .faq-answer {
  padding: 0 1.25rem 1.1rem;
  color: #E0E6EA;
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px solid var(--page-border);
  padding-top: 0.9rem;
  margin-top: 0;
}
.page-about .faq-answer a {
  color: var(--page-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}
.page-about .faq-answer a:hover {
  color: var(--page-green);
}

/* ===== 页底上下文提示 ===== */
.page-about .page-context-hint {
  max-width: var(--container-max, 1200px);
  margin: 2rem auto 0;
  padding: 0 1.25rem;
  text-align: center;
}
.page-about .page-context-hint p {
  font-size: 0.75rem;
  color: var(--page-text-muted);
  letter-spacing: 0.04em;
  opacity: 0.6;
}

/* ===== 响应式：平板及以上 ===== */
@media (min-width: 640px) {
  .page-about .hero-frame {
    padding: 5.5rem 0 4.5rem;
  }
  .page-about .hero-frame-inner {
    flex-direction: row;
    text-align: left;
    gap: 2.5rem;
  }
  .page-about .hero-visual {
    max-width: 300px;
    flex-shrink: 0;
  }
  .page-about .hero-content {
    text-align: left;
  }
  .page-about .hero-sub {
    margin-left: 0;
    margin-right: 0;
  }
  .page-about .hero-actions {
    justify-content: flex-start;
  }
  .page-about .principle-card {
    padding: 2.2rem 2rem 1.5rem;
  }
  .page-about .principle-list {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 1.2rem;
  }
  .page-about .principle-list-item {
    flex: 1 1 180px;
    max-width: 280px;
  }
  .page-about .boundaries-layout {
    flex-direction: row;
    align-items: flex-start;
    gap: 2.5rem;
  }
  .page-about .boundaries-text {
    flex: 1;
  }
  .page-about .boundaries-visual {
    flex: 0 0 320px;
  }
  .page-about .cases-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-about .case-card {
    padding: 1.8rem 1.2rem;
  }
  .page-about .usecases-device-img {
    max-width: 280px;
  }
  .page-about .faq-question {
    font-size: 1.05rem;
    padding: 1.1rem 1.5rem;
  }
  .page-about .faq-answer {
    padding-left: 1.5rem;
    padding-right: 1.5rem;
  }
}

/* ===== 响应式：桌面 ===== */
@media (min-width: 1024px) {
  .page-about .hero-frame {
    padding: 6rem 0 5rem;
  }
  .page-about .hero-visual {
    max-width: 360px;
  }
  .page-about .frame-corner {
    width: 36px;
    height: 36px;
  }
  .page-about .frame-corner--tl { top: 18px; left: 18px; }
  .page-about .frame-corner--tr { top: 18px; right: 18px; }
  .page-about .frame-corner--bl { bottom: 18px; left: 18px; }
  .page-about .frame-corner--br { bottom: 18px; right: 18px; }
  .page-about .page-section {
    padding: 4.5rem 0;
  }
  .page-about .principle-list-item {
    flex: 1 1 200px;
  }
  .page-about .boundaries-visual {
    flex-basis: 380px;
  }
  .page-about .cases-grid {
    gap: 1.5rem;
  }
  .page-about .case-card {
    padding: 2rem 1.5rem;
  }
  .page-about .faq-list {
    max-width: 780px;
  }
}
</main>