/* ===== 页面专属：.page-about ===== */
.page-about {
  --page-hero-min-height: 85vh;
  --page-card-radius: 12px;
  --page-decorative-opacity: 0.08;
  --page-transition-duration: 0.6s;
  --page-glow-color: rgba(26, 115, 232, 0.25);

  display: block;
  width: 100%;
  max-width: 100%;
  overflow-x: hidden;
  color: var(--color-text-primary);
  background-color: var(--color-bg-dark);
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  position: relative;
  z-index: 10;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 1rem var(--gutter) 0;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}
.page-about .breadcrumb a {
  color: var(--color-secondary);
  text-decoration: none;
  transition: color 0.2s;
}
.page-about .breadcrumb a:hover {
  color: var(--color-primary);
}
.page-about .breadcrumb-sep {
  margin: 0 0.4rem;
  opacity: 0.5;
}
.page-about .breadcrumb [aria-current="page"] {
  color: var(--color-text-primary);
  font-weight: var(--font-weight-bold);
}

/* ---------- 首屏 hero ---------- */
.page-about .hero {
  position: relative;
  min-height: var(--page-hero-min-height);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: 2rem var(--gutter) 3rem;
}
.page-about .hero-bg-img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 30%;
  z-index: 0;
  will-change: transform;
}
.page-about .hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  background: linear-gradient(
    135deg,
    var(--color-bg-dark) 0%,
    rgba(26, 115, 232, 0.55) 60%,
    rgba(30, 30, 47, 0.85) 100%
  );
}
.page-about .hero-decorative {
  position: absolute;
  top: 5%;
  left: 5%;
  z-index: 2;
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: clamp(5rem, 22vw, 18rem);
  line-height: 0.85;
  color: var(--color-text-primary);
  opacity: var(--page-decorative-opacity);
  pointer-events: none;
  user-select: none;
  letter-spacing: -0.04em;
  transform: translateX(-2%) translateY(-2%);
  transition: opacity var(--page-transition-duration) ease;
  will-change: transform;
}
.page-about .hero-inner {
  position: relative;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  width: 100%;
  max-width: var(--content-max-width);
  margin: 0 auto;
}
.page-about .hero-text {
  flex: 1 1 auto;
  text-align: center;
}
.page-about .hero-title {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: clamp(2.4rem, 10vw, 4.8rem);
  line-height: 1.1;
  margin: 0 0 0.5rem;
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
}
.page-about .hero-subtitle {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: clamp(1.1rem, 3.5vw, 1.8rem);
  color: var(--color-secondary);
  margin: 0 0 0.75rem;
  letter-spacing: 0.01em;
}
.page-about .hero-desc {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: clamp(0.95rem, 2vw, 1.15rem);
  color: var(--color-text-secondary);
  max-width: 540px;
  margin: 0 auto 1.5rem;
  line-height: 1.6;
}
.page-about .btn-hero {
  display: inline-block;
  padding: 0.85rem 2.4rem;
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: 1rem;
  color: var(--color-text-primary);
  background: var(--color-primary);
  border: none;
  border-radius: 50px;
  text-decoration: none;
  transition: background 0.25s, box-shadow 0.25s, transform 0.2s;
  box-shadow: 0 4px 20px var(--page-glow-color);
  cursor: pointer;
}
.page-about .btn-hero:hover {
  background: var(--color-secondary);
  box-shadow: 0 6px 28px rgba(255, 109, 1, 0.35);
  transform: translateY(-2px);
}
.page-about .hero-figure {
  flex: 0 0 auto;
  width: 100%;
  max-width: 400px;
}
.page-about .hero-img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--page-card-radius);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.45);
  object-fit: cover;
}

/* ---------- 使命 mission ---------- */
.page-about .mission {
  position: relative;
  padding: 4rem var(--gutter);
  background: var(--color-bg-dark);
}
.page-about .mission-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  text-align: center;
}
.page-about .section-label {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: clamp(1.8rem, 5vw, 2.8rem);
  letter-spacing: -0.01em;
  margin: 0 0 1.2rem;
  color: var(--color-text-primary);
  position: relative;
  display: inline-block;
}
.page-about .section-label::after {
  content: "";
  display: block;
  width: 60%;
  height: 4px;
  margin: 0.5rem auto 0;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  border-radius: 2px;
}
.page-about .mission-text {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: clamp(0.95rem, 2vw, 1.1rem);
  line-height: 1.8;
  color: var(--color-text-secondary);
  max-width: 780px;
  margin: 0 auto 1.5rem;
}
.page-about .mission-text strong {
  color: var(--color-secondary);
  font-weight: var(--font-weight-bold);
}
.page-about .mission-highlight {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.6rem 1.4rem;
  background: rgba(255, 109, 1, 0.12);
  border-left: 3px solid var(--color-secondary);
  border-radius: 0 8px 8px 0;
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: 1rem;
  color: var(--color-text-primary);
}
.page-about .highlight-icon {
  font-size: 1.3rem;
}

/* ---------- 核心功能 features ---------- */
.page-about .features {
  position: relative;
  padding: 4rem var(--gutter);
  background: var(--color-card-bg);
}
.page-about .features-header {
  max-width: var(--content-max-width);
  margin: 0 auto 2.5rem;
  text-align: center;
}
.page-about .features-intro {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: 1rem;
  color: var(--color-text-secondary);
  margin: 0.5rem 0 1.5rem;
}
.page-about .features-chart {
  display: block;
  width: 100%;
  max-width: 320px;
  height: auto;
  margin: 0 auto;
  border-radius: var(--page-card-radius);
  object-fit: cover;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}
.page-about .card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  max-width: var(--content-max-width);
  margin: 0 auto;
}
.page-about .feature-card {
  position: relative;
  background: var(--color-bg-dark);
  border-radius: var(--page-card-radius);
  padding: 2rem 1.8rem;
  border-left: 4px solid var(--color-secondary);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  will-change: transform;
}
.page-about .feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 36px rgba(0, 0, 0, 0.4);
}
.page-about .card-number {
  font-family: var(--font-mono);
  font-weight: var(--font-weight-bold);
  font-size: 2.2rem;
  color: rgba(255, 109, 1, 0.18);
  position: absolute;
  top: 1rem;
  right: 1.2rem;
  line-height: 1;
  user-select: none;
  pointer-events: none;
}
.page-about .card-title {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: 1.3rem;
  margin: 0 0 0.6rem;
  color: var(--color-text-primary);
}
.page-about .card-desc {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--color-text-secondary);
  margin: 0 0 0.8rem;
}
.page-about .card-details {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  background: rgba(255, 255, 255, 0.04);
  border-radius: 6px;
  padding: 0.4rem 1rem;
  cursor: pointer;
  transition: background 0.2s;
}
.page-about .card-details summary {
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  padding: 0.3rem 0;
  outline: none;
}
.page-about .card-details summary::-webkit-details-marker {
  color: var(--color-secondary);
}
.page-about .card-details[open] {
  background: rgba(26, 115, 232, 0.08);
}
.page-about .card-details p {
  margin: 0.6rem 0 0.2rem;
  padding-top: 0.4rem;
  border-top: 1px solid var(--color-border);
}

/* ---------- 用户承诺 commitment ---------- */
.page-about .commitment {
  position: relative;
  padding: 4rem var(--gutter) 3rem;
  background: var(--color-bg-dark);
  overflow: hidden;
}
.page-about .commitment-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(ellipse at 70% 20%, rgba(26, 115, 232, 0.08), transparent 70%);
  pointer-events: none;
}
.page-about .commitment-inner {
  position: relative;
  z-index: 2;
  max-width: var(--content-max-width);
  margin: 0 auto;
  text-align: center;
}
.page-about .commitment-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin: 2rem 0 2.5rem;
}
.page-about .commitment-item {
  background: var(--color-card-bg);
  border-radius: var(--page-card-radius);
  padding: 2rem 1.5rem;
  border: 1px solid var(--color-border);
  transition: transform 0.3s ease, border-color 0.3s ease;
  will-change: transform;
}
.page-about .commitment-item:hover {
  transform: translateY(-3px);
  border-color: var(--color-primary);
}
.page-about .commitment-icon {
  font-size: 2.2rem;
  margin-bottom: 0.6rem;
}
.page-about .commitment-title {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: 1.15rem;
  margin: 0 0 0.4rem;
  color: var(--color-text-primary);
}
.page-about .commitment-text {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: 0.92rem;
  line-height: 1.6;
  color: var(--color-text-secondary);
  margin: 0;
}
.page-about .trust-statement {
  font-family: var(--font-sans);
  font-weight: var(--font-weight-regular);
  font-size: 0.82rem;
  color: var(--color-text-secondary);
  opacity: 0.7;
  max-width: 600px;
  margin: 1.2rem auto 1.5rem;
  line-height: 1.5;
}
.page-about .btn-commitment {
  display: inline-block;
  padding: 0.8rem 2.2rem;
  font-family: var(--font-sans);
  font-weight: var(--font-weight-bold);
  font-size: 0.95rem;
  color: var(--color-text-primary);
  background: transparent;
  border: 2px solid var(--color-secondary);
  border-radius: 50px;
  text-decoration: none;
  transition: background 0.25s, color 0.25s, transform 0.2s;
  cursor: pointer;
}
.page-about .btn-commitment:hover {
  background: var(--color-secondary);
  color: var(--color-text-primary);
  transform: translateY(-2px);
}

/* ---------- 滚动显现动画 ---------- */
.page-about [data-observe] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
}
.page-about [data-observe].fade-in {
  opacity: 1;
  transform: translateY(0);
}
.page-about .hero[data-observe] {
  opacity: 1;
  transform: none;
}
.page-about .hero-decorative {
  transition: opacity 1.2s ease, transform 1.2s ease;
}
.page-about .hero-decorative.fade-in {
  opacity: calc(var(--page-decorative-opacity) + 0.04);
  transform: translateX(-2%) translateY(-2%) scale(1.02);
}

/* ---------- 桌面端（≥768px） ---------- */
@media (min-width: 768px) {
  .page-about .hero {
    padding: 2rem var(--gutter) 4rem;
  }
  .page-about .hero-inner {
    flex-direction: row;
    align-items: center;
    gap: 3rem;
  }
  .page-about .hero-text {
    text-align: left;
    flex: 1 1 55%;
  }
  .page-about .hero-desc {
    margin-left: 0;
    margin-right: 0;
  }
  .page-about .hero-figure {
    flex: 0 0 40%;
    max-width: 440px;
  }
  .page-about .hero-decorative {
    top: 2%;
    left: 4%;
    font-size: clamp(6rem, 18vw, 16rem);
  }
  .page-about .mission {
    padding: 5rem var(--gutter);
  }
  .page-about .features {
    padding: 5rem var(--gutter);
  }
  .page-about .card-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.8rem;
  }
  .page-about .features-chart {
    max-width: 280px;
  }
  .page-about .commitment {
    padding: 5rem var(--gutter) 4rem;
  }
  .page-about .commitment-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
  }
  .page-about .commitment-item {
    padding: 2.5rem 1.8rem;
  }
}

/* ---------- 大桌面端（≥1024px） ---------- */
@media (min-width: 1024px) {
  .page-about .hero-decorative {
    font-size: clamp(8rem, 16vw, 18rem);
    top: 0;
    left: 3%;
  }
  .page-about .hero-figure {
    max-width: 500px;
  }
  .page-about .card-grid {
    gap: 2rem;
  }
}

/* ---------- 减少动效  ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about [data-observe] {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .page-about .hero-decorative {
    transition: none;
  }
  .page-about .hero-bg-img {
    will-change: auto;
  }
  .page-about .feature-card,
  .page-about .commitment-item {
    transition: none;
  }
}