fix: Firefox 69 disclosure triangle masked

src/styles/base/header.scss

@@ -65,7 +65,7 @@
     summary {
   
       &::-moz-list-bullet {
-        list-style-type: none;
+        list-style-type: none; /* To remove the disclosure triangle on Firefox v.<69 */
       }
   
       &::-webkit-details-marker {
@@ -114,6 +114,8 @@
     summary {
       padding: 18px;
       cursor: pointer;
+      display: block; /* To remove the disclosure triangle on Firefox v.>=69 */
+
       &:focus {
         background-color: $color-233-18-29;
         color: $color-0-0-100;