The radio buttons (the blue and yellow circles in the middle of the TwoColConflict interface) are colored via CSS. It appears like this extra coloring destroyed the focus styling for these elements (a thin white circle is shown on top of the blue radio button). Using the tab key to focus elements on the page gets confusing because the radio buttons don't show a visual indicator for the focus. The original OOUI element is able to do this, see https://doc.wikimedia.org/oojs-ui/master/demos/?page=widgets&theme=wikimediaui&direction=ltr&platform=desktop.