Improve top buttons

app/views/layouts/authenticated.html.slim

@@ -8,13 +8,13 @@ html
         .float-end style="margin-top: -8px;"
           nav.navbar.bg-body-primary
             - if @current_user.admin
-              a.navbar-brand href=users_path
+              a.navbar-brand href=users_path class="btn btn-light" style="margin-right: 0"
                 = t("nav.users")
-            a.navbar-brand href=contests_path
+            a.navbar-brand href=contests_path class="btn btn-light" style="margin-right: 0"
                 = t("nav.home")
-            a.navbar-brand href=user_path(@current_user)
+            a.navbar-brand href=user_path(@current_user) class="btn btn-light"
                 = t("nav.settings")
-            = button_to t("nav.log_out"), session_path, method: :delete
+            = button_to t("nav.log_out"), session_path, method: :delete, class: "btn btn-danger"
 
       css:
         .toast {