Remove additional accordion arrow on Firefox (#155)

diff --git a/landing-pages/site/assets/scss/_accordion.scss b/landing-pages/site/assets/scss/_accordion.scss
index 8ddae57..a7aa0cb 100644
--- a/landing-pages/site/assets/scss/_accordion.scss
+++ b/landing-pages/site/assets/scss/_accordion.scss
@@ -30,6 +30,7 @@
 
   summary {
     position: relative;
+    display: block;
   }
 
   summary::-webkit-details-marker {