/**
 * Veelearn Lazy Loading CSS
 * Styles for lazy loading images and content
 */

.lazy-image {
    opacity: 0;
    transition: opacity 0.3s ease;
}

.lazy-image.loaded {
    opacity: 1;
}

.lazy-image.error {
    opacity: 0.5;
    filter: grayscale(100%);
}

/* Content lazy loading */
.lazy-content {
    min-height: 200px;
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: 8px;
}

.lazy-content.loaded {
    animation: fadeIn 0.3s ease;
    background: none;
}

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

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

/* Skeleton loaders for different content types */
.skeleton-image {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: 8px;
}

.skeleton-text {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    height: 16px;
    border-radius: 4px;
    margin-bottom: 8px;
}

.skeleton-text.short {
    width: 60%;
}

.skeleton-text.medium {
    width: 80%;
}

.skeleton-text.long {
    width: 100%;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    .lazy-content {
        background: linear-gradient(90deg, #2a2a2a 25%, #3a3a3a 50%, #2a2a2a 75%);
        background-size: 200% 100%;
    }

    .skeleton-image {
        background: linear-gradient(90deg, #2a2a2a 25%, #3a3a3a 50%, #2a2a2a 75%);
        background-size: 200% 100%;
    }

    .skeleton-text {
        background: linear-gradient(90deg, #2a2a2a 25%, #3a3a3a 50%, #2a2a2a 75%);
        background-size: 200% 100%;
    }
}

/* Responsive images */
.responsive-image {
    max-width: 100%;
    height: auto;
    display: block;
}

/* Image placeholder */
.image-placeholder {
    background: #f3f4f6;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #9ca3af;
    font-size: 14px;
    min-height: 200px;
    border-radius: 8px;
}

.image-placeholder::before {
    content: '📷';
    font-size: 48px;
    margin-right: 12px;
}

@media (prefers-color-scheme: dark) {
    .image-placeholder {
        background: #1f2937;
        color: #6b7280;
    }
}

/* Loading spinner for lazy content */
.loading-spinner {
    border: 4px solid rgba(102, 126, 234, 0.2);
    border-top-color: #667eea;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 0.8s linear infinite;
    margin: 20px auto;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}