🐛 Fixed images on infinite scroll index pages being stretched in Safari (#636)

closes #634, closes #635

- use `document.importNode` to create a clone of post card elements when pulling them in from infinite scroll pages
- cloning the element means the element's owner document matches the viewed document and ensures images in the inserted post card elements are sized according to the viewed document

assets/js/infinite-scroll.js

@@ -45,7 +45,10 @@
         // append contents
         var postElements = this.response.querySelectorAll('.post-card');
         postElements.forEach(function (item) {
-            feedElement.appendChild(item);
+            // document.importNode is important, without it the item's owner
+            // document will be different which can break resizing of
+            // `object-fit: cover` images in Safari
+            feedElement.appendChild(document.importNode(item, true));
         });
 
         // set next link