Align buttons

Site URL: https://www.gqsafety.com/pss-3000

I would like to do as below. I would like to reduce the size of the green button also.

Add to Home > Design > Custom CSS

@media screen and (max-width:767px) {
div#block-yui_3_17_2_1_1599623891941_113096>div {
    margin-left: auto !important;
    margin-right: auto !important;
    text-align: center !important;
}
}

Thank you @tuanphan

I will test it now.