/**
 * Image Optimization CSS
 * Provides loading states, aspect ratios, and smooth transitions for images
 */

/* Base image container with aspect ratio */
.book-cover {
  position: relative;
  overflow: hidden;
  background: var(--bg-elevated, #1a1a2e);
  /* Maintain aspect ratio to prevent layout shifts */
  aspect-ratio: 3 / 4;
}

.book-cover-large {
  position: relative;
  overflow: hidden;
  background: var(--bg-elevated, #1a1a2e);
  aspect-ratio: 3 / 4;
}

/* Image loading skeleton animation */
.book-cover::before,
.book-cover-large::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    90deg,
    var(--bg-elevated, #1a1a2e) 0%,
    var(--bg-surface, #252540) 50%,
    var(--bg-elevated, #1a1a2e) 100%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  z-index: 1;
  opacity: 1;
  transition: opacity 0.3s ease;
}

/* Hide skeleton when image is loaded */
.book-cover.loaded::before,
.book-cover-large.loaded::before {
  opacity: 0;
  pointer-events: none;
}

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

/* Image styles with smooth fade-in */
.book-cover img,
.book-cover-large img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity 0.3s ease, transform 0.3s ease;
  z-index: 2;
}

/* Show image when loaded */
.book-cover img.loaded,
.book-cover-large img.loaded,
.book-cover.loaded img,
.book-cover-large.loaded img {
  opacity: 1;
}

/* Hover effect for book covers */
.book-card:hover .book-cover img.loaded {
  transform: scale(1.05);
}

/* Placeholder styling */
.book-cover-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--bg-elevated, #1a1a2e) 0%, var(--bg-surface, #252540) 100%);
  color: var(--text-muted, #6b7280);
  z-index: 2;
}

.book-cover-placeholder i {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  opacity: 0.6;
}

.book-cover-placeholder span {
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  opacity: 0.6;
}

/* Large placeholder for detail pages */
.book-cover-large-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--bg-elevated, #1a1a2e) 0%, var(--bg-surface, #252540) 100%);
  color: var(--text-muted, #6b7280);
  z-index: 2;
}

.book-cover-large-placeholder i {
  font-size: 3.5rem;
  margin-bottom: 1rem;
  opacity: 0.6;
}

.book-cover-large-placeholder .placeholder-text {
  font-size: 0.875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  opacity: 0.6;
}

/* Error state for failed images */
.book-cover.error::before,
.book-cover-large.error::before {
  opacity: 0;
}

.book-cover.error img,
.book-cover-large.error img {
  display: none;
}

/* Blur-up effect for progressive loading */
.book-cover img.blur-up {
  filter: blur(10px);
  transform: scale(1.1);
}

.book-cover img.blur-up.loaded {
  filter: blur(0);
  transform: scale(1);
}

/* Native lazy loading support indicator */
.book-cover img[loading="lazy"] {
  /* Browser handles lazy loading */
}

/* Intersection observer fallback styles */
.book-cover img.lazy-load {
  opacity: 0;
}

.book-cover img.lazy-load.visible {
  opacity: 1;
}

/* Responsive image sizes */
@media (max-width: 768px) {
  .book-cover {
    aspect-ratio: 3 / 4;
  }
  
  .book-cover-placeholder i {
    font-size: 2rem;
  }
}

@media (max-width: 480px) {
  .book-cover-placeholder i {
    font-size: 1.5rem;
  }
  
  .book-cover-placeholder span {
    font-size: 0.625rem;
  }
}

/* Prefers reduced motion */
@media (prefers-reduced-motion: reduce) {
  .book-cover::before,
  .book-cover-large::before {
    animation: none;
    background: var(--bg-elevated, #1a1a2e);
  }
  
  .book-cover img,
  .book-cover-large img {
    transition: none;
  }
  
  .book-card:hover .book-cover img.loaded {
    transform: none;
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .book-cover-placeholder,
  .book-cover-large-placeholder {
    border: 2px solid currentColor;
  }
}