a[button].button-block button.button-block

a[button].button-block icon button.button-block icon

a[button].button-block.button-outline-secondary button.button-block.button-outline-secondary

a[button].button-block.button-clear-dark button.button-block.button-clear-dark

a[button].button-block.button-round button.button-block.button-round

a[button].button-block.button-round.button-outline button.button-block.button-round.button-outline