/**
 * SEO and Performance Optimizations CSS
 * This file contains styles for loading indicators and performance improvements
 */

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid #f3f3f3;
    border-top: 2px solid #3498db;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

.spinner-inner {
    width: 100%;
    height: 100%;
}

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

/* Image Loading States */
img {
    transition: opacity 0.3s ease-in-out;
}

img[loading="lazy"] {
    opacity: 0;
}

img[loading="lazy"].loaded {
    opacity: 1;
}

/* Font Loading Optimization */
.fonts-loading {
    visibility: hidden;
}

.fonts-loaded {
    visibility: visible;
}

/* Layout Shift Prevention */
.image-container {
    position: relative;
    overflow: hidden;
}

.image-container img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Performance Optimizations */
.performance-optimized {
    will-change: auto;
    contain: layout style paint;
}

/* Loading States */
.loading {
    position: relative;
    min-height: 100px;
}

.loading::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40px;
    height: 40px;
    border: 3px solid #f3f3f3;
    border-top: 3px solid #3498db;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

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

/* Critical CSS Inline */
.critical {
    display: block;
}

/* Non-critical CSS */
.non-critical {
    display: none;
}

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

/* WebP Support Detection */
.webp .webp-image {
    display: block;
}

.no-webp .webp-image {
    display: none;
}

.webp .fallback-image {
    display: none;
}

.no-webp .fallback-image {
    display: block;
}

/* Performance Monitoring */
.performance-marker {
    position: fixed;
    top: 10px;
    right: 10px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 10px;
    border-radius: 5px;
    font-size: 12px;
    z-index: 9999;
}

/* Accessibility Improvements */
.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;
}

/* Focus States */
a:focus,
button:focus,
input:focus,
textarea:focus,
select:focus {
    outline: 2px solid #3498db;
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    .no-print {
        display: none !important;
    }
    
    .print-only {
        display: block !important;
    }
}