Add the following CSS in the Divi theme options area and customize however you like.
.woocommerce-error,
.woocommerce .woocommerce-error,
.woocommerce-info,
.woocommerce .woocommerce-info,
.woocommerce-message,
.woocommerce .woocommerce-message {
padding: 1em 2em 1em 3.5em !important;
margin: 0 0 2em !important;
position: relative !important;
background-color: #f7f6f7 !important;
background: #f7f6f7 !important;
color: #515151 !important;
border-top: 3px solid #79bde9 !important;
border-top-color: rgb(121, 189, 233) !important;
list-style: none outside !important;
width: auto !important;
word-wrap: break-word !important;
}
.woocommerce-info::before {
color: #79bde9 !important;
}
.woocommerce-error::before,
.woocommerce-info::before,
.woocommerce-message::before {
font-family: WooCommerce;
content: '\e028' !important;
display: inline-block !important;
position: absolute !important;
top: 1em !important;
left: 1.5em !important;
color: #79bde9!important;
}
.woocommerce-info a {color: #79bde9 !important;}