how can i divide 2 columns on a page of mobile version?

i tried to divide 2 column on the following page when visitors use mobile device to view, but it can’t work,
it can showed with left half column , but its following next grid couldn’t go after first grid alongside right column,anyone can give a help?

i use virtue theme’s custom CSS box to tweak your page builder:

https://i.moxiecorp.com/%E7%94%A2%E5%93%81/

@media only screen and (max-width: 800px) {
#pg-196-2 .panel-grid-cell {
padding: 10px!important;
wdith:48%;
display:inline-block;
float:left;
}
}