/* ============ 德天下 - 德智兼备/可靠 深色主题 ============ */
:root {
  --brand-from: #2563eb;
  --brand-to: #0d9488;
  --dark: #0b1220;
}

html { scroll-behavior: smooth; }
body { font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif; color: #0f172a; }

/* 渐变文字 */
.gradient-text {
  background: linear-gradient(120deg, #38bdf8, #2dd4bf);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* 网格背景（深色） */
.bg-grid {
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 46px 46px;
}

/* 顶部导航透明 -> 深色毛玻璃 */
#navbar { transition: background .35s ease, box-shadow .35s ease, backdrop-filter .35s ease; }
#navbar.nav-blur {
  background: rgba(11, 18, 32, 0.85);
  backdrop-filter: saturate(160%) blur(16px);
  -webkit-backdrop-filter: saturate(160%) blur(16px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
}

/* 卡片 hover */
.card-hover {
  transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease;
}
.card-hover:hover {
  transform: translateY(-6px);
  box-shadow: 0 22px 44px -18px rgba(13, 148, 136, 0.45);
  border-color: rgba(45, 212, 191, 0.4);
}

/* 发光按钮 */
.btn-glow {
  box-shadow: 0 10px 28px -8px rgba(13, 148, 136, 0.6);
  transition: transform .25s ease, box-shadow .25s ease, filter .25s ease;
}
.btn-glow:hover { transform: translateY(-2px); box-shadow: 0 16px 36px -8px rgba(13, 148, 136, 0.75); filter: brightness(1.05); }

/* 淡入动画 */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(22px); }
  to { opacity: 1; transform: translateY(0); }
}
.fade-in { animation: fadeInUp .7s ease both; }
.delay-1 { animation-delay: .12s; }
.delay-2 { animation-delay: .24s; }
.delay-3 { animation-delay: .36s; }

/* 半透明 Stats 数字 */
.stat-num { color: rgba(255, 255, 255, 0.95); }

/* FAQ 手风琴 */
.faq-item {
  border: 1px solid #e2e8f0;
  border-radius: 14px;
  overflow: hidden;
  background: #fff;
  transition: box-shadow .3s ease, border-color .3s ease;
}
.faq-item:hover { border-color: rgba(13, 148, 136, 0.35); }
.faq-question {
  cursor: pointer;
  padding: 18px 22px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  user-select: none;
}
.faq-icon {
  flex: none;
  width: 28px; height: 28px;
  display: grid; place-items: center;
  border-radius: 50%;
  color: #0d9488;
  background: rgba(13, 148, 136, 0.1);
  transition: transform .3s ease, background .3s ease, color .3s ease;
}
.faq-item.open .faq-icon { transform: rotate(135deg); background: #0d9488; color: #fff; }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height .35s ease, padding .35s ease;
  color: #64748b;
  line-height: 1.8;
}
.faq-item.open .faq-answer { max-height: 360px; padding: 0 22px 20px; }

/* 轮播 */
.slide { display: none; animation: fadeInUp .5s ease; }
.slide.active { display: block; }
.dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: #cbd5e1;
  cursor: pointer;
  transition: background .25s ease, transform .25s ease;
}
.dot.active { background: #0d9488; transform: scale(1.3); }

/* 页脚链接 */
.footer-link { transition: color .2s ease; }
.footer-link:hover { color: #fff; }