*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 12px);
}

body {
  font-family: var(--font-sans);
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body.menu-open,
body.modal-open { overflow: hidden; }

a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }

.container {
  width: min(var(--container-max), 100% - 2.5rem);
  margin-inline: auto;
}

.section {
  padding: var(--section-pad) 0;
  position: relative;
}

.section-white,
.section-alt,
.section-dark {
  background: transparent;
  color: var(--text-primary);
}

.section + .section {
  border-top: 1px solid rgba(255, 255, 255, 0.04);
}

.section-head {
  text-align: center;
  margin-bottom: 2.5rem;
}

.section-head h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.25rem);
  font-weight: 700;
  color: var(--text-light);
  margin-bottom: 0.75rem;
}

.section-head p {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin-inline: auto;
}

.section-head .head-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--color-cyan);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: 0.85rem;
  padding: 0.3rem 0.9rem;
  border: 1px solid rgba(125, 211, 252, 0.28);
  border-radius: 999px;
  background: rgba(125, 211, 252, 0.07);
}

#particleCanvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

/* 全站背景（参考 Banner hero-bg） */
.bg-aurora {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  pointer-events: none;
}

.page-bg-mesh {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 55% at 15% 40%, rgba(0, 82, 217, 0.45) 0%, transparent 55%),
    radial-gradient(ellipse 55% 50% at 85% 25%, rgba(0, 164, 255, 0.28) 0%, transparent 50%),
    radial-gradient(ellipse 45% 40% at 60% 85%, rgba(99, 102, 241, 0.2) 0%, transparent 50%),
    var(--bg-page);
}

.page-bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 95% 85% at 50% 35%, #000 25%, transparent 82%);
}

.page-bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  animation: pageOrbFloat 12s ease-in-out infinite;
}

.page-bg-orb-1 {
  width: 320px;
  height: 320px;
  background: rgba(0, 82, 217, 0.35);
  top: -8%;
  right: 10%;
}

.page-bg-orb-2 {
  width: 240px;
  height: 240px;
  background: rgba(0, 164, 255, 0.2);
  bottom: 5%;
  left: 5%;
  animation-delay: -4s;
}

.page-bg-orb-3 {
  width: 180px;
  height: 180px;
  background: rgba(99, 102, 241, 0.18);
  top: 40%;
  left: 45%;
  animation-delay: -8s;
}

@keyframes pageOrbFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(20px, -16px) scale(1.06); }
}

@media (prefers-reduced-motion: reduce) {
  .page-bg-orb { animation: none; }
}

.page-wrap { position: relative; z-index: 1; }

.glass {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
}