First, take a close look at the following code snippet:
function lmscoder_purplified_focus_mode() { $script = " const style = document.createElement( 'style' ); const css = ` * { color: purple !important; background-color: purple !important; border-color: purple !important; outline-color: purple !important; } `; style.appendChild( document.createTextNode( css ) ); document.getElementsByTagName( 'head' )[0].appendChild( style ); "; echo '<script>' . $script . '</script>'; } add_action( 'learndash-focus-template-end', 'lmscoder_purplified_focus_mode' );