Make sponsor logos smaller

templates/footer.html

@@ -14,7 +14,7 @@
       <p class="title is-5">Unterstützer und Partner*innen</p>
       <div class="columns is-centered is-vcentered is-multiline">
         {% for sponsor in config.extra.footer.sponsor %}
-          <div class="column is-one-third">
+          <div class="column is-one-quarter">
             <figure class="image">
               <a href="{{sponsor.link}}">
                 <img src="/images/sponsoren/{{sponsor.logo}}" alt="{{sponsor.alt}}" />