Disallow Box Closing?

Okay wow I’m an idiot – just saw the code –
add_filter( ‘stb_box_options’, function( $opts ) {
$opts[‘unclosable’] = true;
return $opts;
});

That takes care of the closing by clicking outside of the box – now I’m trying to delete the “X” close button in the upper right.

I’ve tried using .stb-close in CSS but nothing is working – display:none and visibility:hidden aren’t doing anything. Does anyone have any suggestions? Thanks!

Solved! Use customizer or edit your theme’s css to include the code

.stb-stbBoxID .stb-close {
font-size: 0px;
}

where stbBoxID is the ID of the box you want to edit ??