Fix discussion color contrast and remove gradients

TNL-5163

common/static/common/js/discussion/views/discussion_thread_view.js

@@ -328,7 +328,10 @@
                                 numResponses: responseLimit
                             }, true);
                         }
-                        $loadMoreButton = $('<button>').addClass('load-response-button').text(buttonText);
+                        $loadMoreButton = $('<button>')
+                            .addClass('btn-neutral')
+                            .addClass('load-response-button')
+                            .text(buttonText);
                         $loadMoreButton.click(function() {
                             return self.loadResponses(responseLimit, $loadMoreButton);
                         });

common/static/common/templates/discussion/new-post.underscore

@@ -10,7 +10,7 @@
             </span><select aria-describedby="field_help_visible_to" class="field-input js-group-select" name="group_id" <% if (!is_commentable_cohorted) { print("disabled"); } %>>
                 <option value=""><%- gettext("All Groups") %></option>
                 <% _.each(cohort_options, function(opt) { %>
-                <option value="<%= opt.value %>" <% if (opt.selected) { print("selected"); } %>><%- opt.text %></option>
+                <option value="<%- opt.value %>" <% if (opt.selected) { print("selected"); } %>><%- opt.text %></option>
                 <% }); %>
              </select>
         </label><div class="field-help" id="field_help_visible_to">
@@ -46,7 +46,7 @@
         <% } %>
     </div>
     <div>
-        <input type="submit" class="submit" value="<%- gettext('Add Post') %>">
-        <button type="button" class="cancel"><%- gettext('Cancel') %></button>
+        <button type="submit" class="btn-brand submit"><%- gettext('Add Post') %></button>
+        <button type="button" class="btn cancel"><%- gettext('Cancel') %></button>
     </div>
 </form>

common/static/common/templates/discussion/thread.underscore

@@ -26,7 +26,7 @@
                 <ul class="discussion-errors"></ul>
                 <div class="reply-body" data-id="<%- id %>"></div>
                 <div class="reply-post-control">
-                    <a class="discussion-submit-post control-button" href="#"><%- gettext("Submit") %></a>
+                    <button class="btn-brand discussion-submit-post control-button"><%- gettext("Submit") %></button>
                 </div>
             </form>
             <% } %>