:root {
  --brand-1: #2563eb;
  --brand-2: #f59e0b;
  --ink: #e2e8f0;
  --muted: #94a3b8;
  --card: #0f172a;
  --line: rgba(148, 163, 184, 0.16);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  background: #020617;
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
}

/* 渐变文字 */
.gradient-text {
  background: linear-gradient(120deg, #3b82f6 0%, #f59e0b 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* 网格背景 */
.bg-grid {
  background-image:
    linear-gradient(rgba(148, 163, 184, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.07) 1px, transparent 1px);
  background-size: 48px 48px;
}

/* 毛玻璃导航 */
.nav-blur {
  background: rgba(2, 6, 23, 0.82) !important;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
  border-bottom: 1px solid rgba(245, 158, 11, 0.16);
}

/* 卡片 hover */
.card-hover { transition: transform .32s ease, box-shadow .32s ease, border-color .32s ease; }
.card-hover:hover {
  transform: translateY(-8px);
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.55);
  border-color: rgba(245, 158, 11, 0.5);
}

/* 按钮光晕 */
.btn-glow {
  box-shadow: 0 10px 34px rgba(245, 158, 11, 0.4);
  transition: transform .25s ease, box-shadow .25s ease;
}
.btn-glow:hover {
  transform: translateY(-3px);
  box-shadow: 0 18px 48px rgba(245, 158, 11, 0.55);
}

/* 入场动画 */
.fade-in { animation: fadeIn 1s ease both; }
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(26px); }
  to { opacity: 1; transform: translateY(0); }
}

/* FAQ 手风琴 */
.faq-item {
  border: 1px solid var(--line);
  border-radius: 14px;
  margin-bottom: 14px;
  overflow: hidden;
  background: var(--card);
}
.faq-question {
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 22px;
  font-weight: 600;
  color: #f1f5f9;
}
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height .35s ease, padding .35s ease;
  padding: 0 22px;
  color: var(--muted);
  line-height: 1.85;
}
.faq-item.open .faq-answer { max-height: 320px; padding: 0 22px 20px; }
.faq-icon { transition: transform .3s ease; color: #f59e0b; }
.faq-item.open .faq-icon { transform: rotate(180deg); }

/* 徽章悬浮 */
.badge-float { animation: floatY 4.5s ease-in-out infinite; }
@keyframes floatY {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

/* 圆点轮播指示 */
.dot { transition: all .3s ease; }
.dot.active { width: 26px; background: #f59e0b; }

/* 三端版本切换标签 */
[data-tab].active-tab {
  background-image: linear-gradient(120deg, #2563eb, #f59e0b) !important;
  color: #fff !important;
  border-color: transparent !important;
}
[data-tab]:not(.active-tab) {
  background-image: none !important;
  background-color: transparent !important;
  color: #cbd5e1 !important;
  border: 1px solid #334155 !important;
}