When designing website forms, you will come across a nasty default border being generated when a button is clicked. This is because, by default, an outline or border is present when a button receives a focus state. This can be removed by simply adding the following CSS code.
/** Remove focused button styles when an element received focus via mouse click or touch. */ *:focus:not(:focus-visible) { outline: 0 !important; box-shadow: none !important; }