Divi user, cannot find how to make a 4 columns layout for your Divi template of custom_post_type. Updating the class with size-1of4 and et_pb_salvattore_content data-columns=4 seems not enough ? Here, the solution you search for 😉 

First, update your PHP template with these 2 class & attributes : et_pb_column_4_4 & data-columns=4 for .et_pb_salvattore_content.

Then, add this code to your custom CSS Divi Theme Options to see the magic happen :

@media screen and (min-width: 981px){
.et_pb_column .et_pb_salvattore_content .column.size-1of4 {
width: 23%!important;
margin-right: 1%;
margin-left: 1%;
}
}
@media screen and (min-width: 981px){
.et_pb_column .et_pb_blog_grid .et_pb_salvattore_content[data-columns]::before {
content: '4 .column.size-1of4'!important;
}
}

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