common: fix modal animation on mobile & tweak some transition & animation css

js/src/common/components/ModalManager.tsx

@@ -58,7 +58,11 @@ export default class ModalManager extends Component {
 
         MicroModal.show('Modal', {
             awaitCloseAnimation: true,
+            awaitOpenAnimation: true,
+            onShow: () => $('body').addClass('modal-open'),
             onClose: () => {
+                $('body').removeClass('modal-open');
+
                 const backdrop = $('.modal-backdrop');
 
                 backdrop.fadeOut(200, () => {