fixed a11y for lightbox modal

assets/js/vendors/lightbox.js

 import gLightbox from 'glightbox';
 
-gLightbox({
+let lightboxBtn;
+
+const lightbox = gLightbox({
     openEffect: 'fade',
-    closeEffect: 'fade'
+    closeEffect: 'fade',
+    onOpen: () => {
+        lightboxBtn = document.activeElement;
+    },
+    onClose: () => {
+        if (lightboxBtn) {
+            lightboxBtn.focus();
+        }
+    }
 });
+
+lightbox.on('slide_changed', () => {
+    const currentSlide = document.querySelector('.gslide.current');
+    if (currentSlide) {
+        currentSlide.setAttribute("tabindex", "0");
+        currentSlide.focus();
+    }
+});
\ No newline at end of file