Center tags in dash

Why do they do not center?

html.Div(
    html.A(
        html.Button('Google', className='three columns', style={'text-align': 'center'}),
        href='www.google.com', style={'text-align': 'center'}
    ), style={'text-align': 'center'}
),

Individually they do not center either.

Any advice? Thanks!

ah never mind, I was imposing a css class with style that’s not centered. The className=‘threeColumns’. My bad. Thanks!