/**
 * Production Image Performance Settings
 * Professional image loading with smooth transitions
 */

/* 
 * Base image styles for lazy loading
 */
img[loading="lazy"] {
    background: linear-gradient(110deg, #ececec 8%, #f5f5f5 18%, #ececec 33%);
    background-size: 200% 100%;
    animation: img-shimmer 1.5s linear infinite;
}

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

/* Once loaded, remove shimmer */
img[loading="lazy"]:not([src^="data:"]) {
    animation: none;
    background: none;
}

/* 
 * Smooth fade-in when image loads
 */
img {
    opacity: 1;
    transition: opacity 0.3s ease-in-out;
}

img[src=""],
img:not([src]) {
    opacity: 0;
}

/* 
 * Placeholder styles for JS-enhanced lazy loading
 */
img.lazyload {
    opacity: 0.8;
    transition: opacity 0.4s ease-in-out, filter 0.4s ease-in-out;
    filter: blur(5px);
}

img.lazyload-loading {
    opacity: 0.9;
    filter: blur(3px);
}

img.lazyload-loaded,
img.lazyload[src]:not([src^="data:"]) {
    opacity: 1;
    filter: blur(0);
}

img.lazyload-error {
    opacity: 0.5;
    filter: grayscale(100%);
}

/* 
 * Prevent layout shift with aspect ratio boxes
 */
.teachers-image-column {
    position: relative;
    background-color: #f8f9fa;
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.teachers-image-column img {
    width: 100%;
    height: auto;
    object-fit: cover;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.teachers-image-column:hover img {
    transform: scale(1.05);
}

/* 
 * Image container for aspect ratio preservation
 */
.img-container {
    overflow: hidden;
    background-color: #f5f5f5;
    position: relative;
}

.img-container.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4), transparent);
    animation: shimmer 1.5s infinite;
}

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

/* 
 * Professional skeleton loading for cards
 */
.skeleton-image {
    background: linear-gradient(110deg, #e0e0e0 8%, #f0f0f0 18%, #e0e0e0 33%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s linear infinite;
    border-radius: 4px;
}

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

/* 
 * WebP support with JPEG fallback
 */
picture {
    display: inline-block;
}

/*
 * Responsive image sizing
 */
.img-fluid {
    max-width: 100%;
    height: auto;
}

/* 
 * Error state for broken images 
 */
img[onerror] {
    min-height: 100px;
}

/* Fix for broken image icon on some browsers */
img:-moz-broken {
    opacity: 0;
}

img:not([src]):not([srcset]) {
    visibility: hidden;