Fixed theme links

_mixins.pug

@@ -6,7 +6,7 @@ mixin responsive_image(thumb, fallback, urls, sizes, aspect_ratio)
       img(data-src=fallback, sizes=sizes, data-srcset=urls)
 
 mixin theme_card(id, name)
-  a.card(href="/assets/images/#{id}.png")
+  a.card(href=`/assets/images/${id}.png`)
     .image
       +responsive_image(`/assets/images/${id}@thumb.jpg`, `/assets/images/${id}@266.png`, `/assets/images/${id}@220.png 220w, /assets/images/${id}@266.png 266w, /assets/images/${id}@335.png 335w, /assets/images/${id}@352.png 352w, /assets/images/${id}@532.png 532w`, "(max-width: 767px) calc(50vw - 2em + 1px), (max-width: 991px) 336px, (max-width: 1199px) 221px, 267px", "177.7777777777778%")
     .content