Added box-sizing for a read next story link

assets/css/screen.css

@@ -1441,6 +1441,7 @@ body:not(.post-template) .post-title {
 /* if there are two posts without covers, put a border between them */
 .read-next-story.no-cover + .read-next-story.no-cover {
     border-left: rgba(0,0,100,0.04) 1px solid;
+    box-sizing: border-box;
 }
 
 /* Correctly position site-footer when next to the .read-next container */