add LibraryOptions styling

src/pages/_partials/MainHeader.vue

@@ -39,7 +39,7 @@
 
       <b-button
         v-if="['library', 'kit'].includes($route.name)"
-        class="d-tb-none"
+        class=""
         :class="optionsVisible ? null : 'collapsed'"
         :aria-expanded="optionsVisible ? 'true' : 'false'"
         aria-controls="collapse-options"
@@ -206,7 +206,7 @@ export default {
   .btn {
     font-size: inherit;
 
-    @include media-breakpoint-up(tb) {
+    @include media-breakpoint-up(md) {
       font-size: 1rem;
     }
   }