Hide checkboxes and icons when no CSS in head is loaded

This seems to help in Firefox's reader mode.
Also adjust images to not be huge without CSS.

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

layouts/partials/icon.html

@@ -1,4 +1,4 @@
-<svg class="feather">
+<svg class="feather" style="display: none;">
     <use xlink:href="/feather-sprite.svg#{{ . }}"/>
 </svg>
 {{- /* This comment is to remove trailing whitespace */ -}}