.single_add_to_cart_button,
button.single_add_to_cart_button,
.woocommerce button.button.alt {
    font-size: 18px !important;
    padding: 14px !important;
    width: 100% !important;
    background-color: #28a745 !important;
    color: #ffffff !important;
    border-radius: 8px !important;
    border: none !important;
}