[feat]Add md lg view for happening_now column

app/views/conferences/show.html.haml

@@ -49,7 +49,7 @@
     .container
       .row
         -# happening now events are displayed second in md or lg view
-        .col-md-4.col-md-push-8
+        .col-md-6.col-md-push-6.col-lg-4.col-lg-push-8
           #happening-now
             - if @conference.splashpage.include_happening_now
               - if @events_schedules.any?
@@ -61,7 +61,7 @@
                 .row
                   %h3.text-center There are no events happening now.
         - if @conference.description.present?
-          .col-md-8.col-md-pull-4
+          .col-md-6.col-md-pull-6.col-lg-8.col-lg-pull-4
             #about
               .row
                 = markdown(@conference.description, escape_html=false)