Hello @elmirasln
Thank you very much for using our plugin.
A control has multiple components: its container, label, input tag, user instructions, etc. (the components can vary based on the control type). When you assign a class name to a field via its “Add CSS Layout Keywords” attribute, it is applied to the tag that contains the control elements. If you want to modify the appearance of the button tag in the button control, the correct would be:
#fbuilder .select-deselect-all input {text-decoration: underline !important; background: #fff !important; color: #000 !important}Note the selector is #fbuilder .select-deselect-all input
Best regards.