Chrome browser instant chat messanger shows ananoumsly on Veronica theme
 see
messages and notifications column

You mean column titles?

Yes

@nijamutheen
Add following code to file:
oc-content/plugins/instant_messenger/css/user.css


@media screen and (max-width: 767px) {
  .im-table-head > div.im-col-2 {display:none;}
}

Not working
DeskTop view: http://prntscr.com/g693eq
Mobile View(chrome browser):   http://prntscr.com/g69e67

@nijamutheen
Then you know you have not placed code to that file.

So where to place ? And which code do I want to place ?

@nijamutheen
Add following code to file:
oc-content/plugins/instant_messenger/css/user.css

Code: [Select]

@media screen and (max-width: 767px) {
  .im-table-head > div.im-col-2 {display:none;}
}

you can place it at start at for sure to add !important  after ;

see totally 3 columns are Hidden on mobile devices http://prntscr.com/g6edgu

And thaat is correct