/* Lazy Loading Styles */

/* Skeleton loading animation */
@keyframes skeleton-loading {
    0% {
        background-position: -200px 0;
    }
    100% {
        background-position: calc(200px + 100%) 0;
    }
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

@keyframes fade-in {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes pulse-soft {
    0%, 100% {
        opacity: 0.4;
    }
    50% {
        opacity: 0.8;
    }
}

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

.skeleton-dark {
    background: linear-gradient(90deg, #374151 25%, #4b5563 50%, #374151 75%);
    background-size: 200px 100%;
    animation: skeleton-loading 1.5s infinite;
}

/* Shimmer effect */
.shimmer {
    position: relative;
    overflow: hidden;
}

.shimmer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        90deg,
        transparent,
        rgba(255, 255, 255, 0.4),
        transparent
    );
    animation: shimmer 2s infinite;
}

/* Fade in animation for loaded images */
.fade-in {
    animation: fade-in 0.3s ease-out;
}

/* Pulse animation for loading states */
.pulse-soft {
    animation: pulse-soft 2s infinite;
}

/* Blur effect for thumbnails */
.blur-thumbnail {
    filter: blur(4px);
    transition: filter 0.3s ease;
}

.blur-thumbnail.loaded {
    filter: blur(0);
}

/* Progressive image loading */
.progressive-image {
    position: relative;
    overflow: hidden;
}

.progressive-image .thumbnail {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: blur(2px);
    transform: scale(1.05);
    transition: opacity 0.3s ease;
}

.progressive-image .full-image {
    position: relative;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.progressive-image .full-image.loaded {
    opacity: 1;
}

.progressive-image .full-image.loaded + .thumbnail {
    opacity: 0;
}

/* Error state */
.image-error {
    background: linear-gradient(135deg, #f3f4f6 0%, #e5e7eb 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #9ca3af;
}

/* Loading spinner for images */
.image-loading {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 10;
}

.loading-spinner {
    width: 24px;
    height: 24px;
    border: 2px solid #f3f3f3;
    border-top: 2px solid #3b82f6;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Responsive optimizations */
@media (max-width: 640px) {
    .skeleton {
        animation-duration: 1.2s;
    }
    
    .shimmer::before {
        animation-duration: 1.5s;
    }
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
    .skeleton,
    .shimmer::before,
    .pulse-soft,
    .loading-spinner {
        animation: none;
    }
    
    .fade-in {
        animation: none;
        opacity: 1;
        transform: none;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    .skeleton {
        background: linear-gradient(90deg, #000000 25%, #333333 50%, #000000 75%);
    }
    
    .image-error {
        background: #ffffff;
        color: #000000;
        border: 2px solid #000000;
    }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    .skeleton {
        background: linear-gradient(90deg, #374151 25%, #4b5563 50%, #374151 75%);
    }
    
    .image-error {
        background: linear-gradient(135deg, #374151 0%, #4b5563 100%);
        color: #9ca3af;
    }
    
    .shimmer::before {
        background: linear-gradient(
            90deg,
            transparent,
            rgba(255, 255, 255, 0.1),
            transparent
        );
    }
}

/* Performance optimizations */
.lazy-container {
    contain: layout style paint;
    will-change: transform;
}

.lazy-image,
.lazy-video {
    backface-visibility: hidden;
    transform: translateZ(0);
}

/* Intersection observer fallback */
.no-intersection-observer .lazy-container {
    /* Fallback styles for browsers without Intersection Observer */
}

/* Connection-aware loading */
.slow-connection .skeleton {
    animation-duration: 2s;
}

.slow-connection .shimmer::before {
    animation-duration: 3s;
}

/* Accessibility improvements */
.lazy-container:focus-visible {
    outline: 2px solid #3b82f6;
    outline-offset: 2px;
}

/* Screen reader only content */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}