Animations

/* Base transition variables */
:root {
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  --transition-bounce: 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* Button transitions */
.btn {
  transition: all var(--transition-normal);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* Card transitions */
.card {
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

/* Link transitions */
a {
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary);
}

/* Spinner animation */
.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--color-border);
  border-top: 4px solid var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Skeleton loading */
.skeleton {
  background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
  background-size: 200% 100%;
  animation: skeleton-loading 1.5s infinite;
}

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

/* Fade in animation */
.fade-in {
  opacity: 0;
  animation: fadeIn 0.6s ease forwards;
}

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

/* Reveal on scroll */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s ease;
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children */
.reveal-stagger > * {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s ease;
}

.reveal-stagger.revealed > * {
  opacity: 1;
  transform: translateY(0);
}

.reveal-stagger.revealed > *:nth-child(1) { transition-delay: 0.1s; }
.reveal-stagger.revealed > *:nth-child(2) { transition-delay: 0.2s; }
.reveal-stagger.revealed > *:nth-child(3) { transition-delay: 0.3s; }
.reveal-stagger.revealed > *:nth-child(4) { transition-delay: 0.4s; }

// Intersection Observer for scroll animations
const observerOptions = {
  threshold: 0.1,
  rootMargin: '0px 0px -50px 0px'
};

const observer = new IntersectionObserver((entries) => {
  entries.forEach(entry => {
    if (entry.isIntersecting) {
      entry.target.classList.add('revealed');
    }
  });
}, observerOptions);

// Observe elements with reveal class
document.querySelectorAll('.reveal, .reveal-stagger').forEach(el => {
  observer.observe(el);
});

// Show loading state
function showLoading(element) {
  element.classList.add('loading');
  element.innerHTML = '<div class="spinner"></div>';
}

// Hide loading state
function hideLoading(element, content) {
  element.classList.remove('loading');
  element.innerHTML = content;
}

// Skeleton loading
function showSkeleton(element) {
  element.classList.add('skeleton');
  element.innerHTML = '<div class="skeleton-placeholder"></div>';
}

/* Use transform and opacity for better performance */
.animate {
  transform: translateZ(0); /* Force hardware acceleration */
  will-change: transform, opacity;
}

/* Avoid animating layout properties */
.performance-friendly {
  /* Good: transform, opacity */
  transform: scale(1.1);
  opacity: 0.8;
  
  /* Avoid: width, height, margin, padding */
  /* width: 200px; */
  /* margin: 20px; */
}

/* Respect user's motion preferences */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* Custom reduced motion class */
.reduced-motion {
  animation: none !important;
  transition: none !important;
}

/* Focus indicators */
.focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* High contrast mode */
@media (prefers-contrast: high) {
  .btn:hover {
    outline: 2px solid currentColor;
  }
}

/* Optimize animations */
.optimized-animation {
  /* Use transform instead of position changes */
  transform: translateX(100px);
  
  /* Use opacity for fade effects */
  opacity: 0;
  
  /* Avoid layout-triggering properties */
  /* left: 100px; */
  /* width: 200px; */
}