Try apply this following custom css from your site backend > Easysocial > theme > custom css and see how it goes.
body #es .es-container .es-sidebar {
width: 300px;
-webkit-flex: 0 0 300px;
-ms-flex: 0 0 300px;
flex: 0 0 300px;
}
body #es.is-mobile .es-container .es-sidebar {
width: 220px;
-webkit-flex: 0 0 220px;
-ms-flex: 0 0 220px;
flex: 0 0 220px;
}
Make sure you have clear your backend and browser cache before you test.