/* Motion & Interaction Animations */

/* Keyframes */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes shimmer {
  0% {
    background-position: -200% 0;
  }
  100% {
    background-position: 200% 0;
  }
}

/* Page Entrance Animations */
.animate-fade-up {
  animation: fadeUp var(--duration-slow) var(--ease-out) both;
}

.animate-fade-up:nth-child(2) { animation-delay: 80ms; }
.animate-fade-up:nth-child(3) { animation-delay: 160ms; }
.animate-fade-up:nth-child(4) { animation-delay: 240ms; }

/* Content Loading States */
.img-placeholder {
  background: linear-gradient(
    90deg,
    var(--color-fill-secondary) 25%,
    var(--color-fill-tertiary) 50%,
    var(--color-fill-secondary) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s var(--ease-standard) infinite;
}

/* Navigation Interactions */
.nav-links a {
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1.5px;
  background: var(--color-label-primary);
  transition: width var(--duration-base) var(--ease-out);
}

.nav-links a:hover::after,
.nav-links a[aria-current="page"]::after {
  width: 100%;
}

/* Reduced Motion Overrides */
@media (prefers-reduced-motion: reduce) {
  .animate-fade-up {
    animation: none;
    opacity: 1;
    transform: none;
  }
  
  .img-placeholder {
    animation: none;
  }
  
  .nav-links a::after {
    transition: none;
  }
}