/* Background - clean, no pattern */

/* Hero grid background */
.hero-grid {
  background-image:
    radial-gradient(ellipse 600px 400px at 50% 50%, rgba(56, 189, 248, 0.06), transparent),
    linear-gradient(rgba(56, 189, 248, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(56, 189, 248, 0.04) 1px, transparent 1px);
  background-size: 100% 100%, 60px 60px, 60px 60px;
}

/* Hero fade-in animation */
.hero-fade {
  opacity: 0;
  transform: translateY(24px);
  animation: heroFadeIn 0.8s ease-out forwards;
}
.hero-fade-delay-1 { animation-delay: 0.2s; }
.hero-fade-delay-2 { animation-delay: 0.4s; }
.hero-fade-delay-3 { animation-delay: 0.6s; }

@keyframes heroFadeIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Scroll fade-in */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* OSI Stack */
.osi-stack {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.osi-layer {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 20px;
  border-radius: 8px;
  background: #1e293b;
  border: 1px solid #334155;
  font-size: 14px;
  color: #94a3b8;
  transition: opacity 0.4s ease-out, transform 0.4s ease-out;
}
.osi-layer-8 {
  background: linear-gradient(135deg, rgba(14, 165, 233, 0.15), rgba(139, 92, 246, 0.15));
  border-color: rgba(56, 189, 248, 0.3);
  color: #38bdf8;
  font-weight: 700;
  box-shadow: 0 0 24px rgba(56, 189, 248, 0.1);
}
.osi-number {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  width: 24px;
  text-align: center;
  opacity: 0.6;
}
.osi-layer-8 .osi-number { opacity: 1; }
.osi-name { flex: 1; }
.osi-star {
  color: #38bdf8;
  font-size: 16px;
}

/* OSI stagger animation */
.osi-stack .osi-layer {
  opacity: 0;
  transform: translateY(10px);
}
.osi-stack.visible .osi-layer {
  opacity: 1;
  transform: translateY(0);
}
.osi-stack.visible .osi-layer:nth-child(8) { transition-delay: 0.0s; }
.osi-stack.visible .osi-layer:nth-child(7) { transition-delay: 0.06s; }
.osi-stack.visible .osi-layer:nth-child(6) { transition-delay: 0.12s; }
.osi-stack.visible .osi-layer:nth-child(5) { transition-delay: 0.18s; }
.osi-stack.visible .osi-layer:nth-child(4) { transition-delay: 0.24s; }
.osi-stack.visible .osi-layer:nth-child(3) { transition-delay: 0.30s; }
.osi-stack.visible .osi-layer:nth-child(2) { transition-delay: 0.36s; }
.osi-stack.visible .osi-layer:nth-child(1) { transition-delay: 0.42s; }

/* Nav scroll state */
.nav-scrolled {
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(51, 65, 85, 0.5);
}

/* Smooth scroll */
html { scroll-behavior: smooth; }