[WP] How to change background of slider

You can change background of RoyalSlider via CSS. Styles below should be added in any CSS file that is present on page with slider, for example in style.css of your theme (also, some themes have special textfield for custom CSS, usually in theme options section).

To change background for all sliders:

.royalSlider,
.royalSlider .rsOverflow,
.royalSlider .rsSlide,
.royalSlider .rsVideoFrameHolder,
.royalSlider .rsThumbs {
    background: red !important;
}

To change background of specific slider:

(instead of 123 put ID of your slider)

#new-royalslider-123,
#new-royalslider-123 .rsOverflow,
#new-royalslider-123 .rsSlide,
#new-royalslider-123 .rsVideoFrameHolder,
#new-royalslider-123 .rsThumbs {
    background: red !important;
}

As a third option you may create custom slider skin and apply background in it.

If you wish to remove background, set it to none, but please note that if you use "Fade" transition - slides must have non-transparent background, because opacity of one slide only is animating.