Ng-style how to set a default background image for side menu

Currently I do it like this:
ng-style=“userProfile.coverPhoto_url != ‘’ && {‘background-image’:‘url(’+userProfile.coverPhoto_url+’)’}”

However, if user hasn’t upload a cover photo yet, the sidemenu shows the grey background color which is a bit ugly:flushed:. How can I set a default background image in this case?

thx.

Try:

ion-menu {

  ion-content {
   ...
  }

}

See: https://github.com/Robinyo/big-top/blob/master/src/theme/facebook-messenger-theme.scss