fix: more consistent search input:focus rendering

...across browsers and devices

layouts/partials/search.html

@@ -14,7 +14,7 @@
       <div id="search-box">
         {{ if eq site.Params.search.engine 1 }}
         <input name="q" id="search-query" placeholder="{{i18n "search_placeholder"}}" autocapitalize="off"
-        autocomplete="off" autocorrect="off" spellcheck="false" type="search">
+        autocomplete="off" autocorrect="off" spellcheck="false" type="search" class="form-control">
         {{ else }}
         <!-- Search box will appear here -->
         {{ end }}