.woocommerce form .woocommerce-billing-fields input#billing_phone{border:2px solid red!important;background-color:#fff3f3}.woocommerce form .woocommerce-billing-fields label[for=billing_phone]::after{content:" *";color:red}.add-to-cart-button{display:block;background:#0073aa;color:white;padding:10px;text-decoration:none;border-radius:4px;margin-top:10px}