Set class to editor modal

Hi, i am having an issue when trying to style to Editor modal. I am using bootstrap 5 and this picks up the modal-content from the scss file. I am working with a css file and i want to specify my own styling for the modal and then set this to be picked up. However i am unsure where to set the Class name for the modal.
I have tried a few different ways including setting the node as described here; https://datatables.net/forums/discussion/comment/159312/#Comment_159312
Which seems to be editing the container behind the modal rather than the modal itself.

Any suggestions would be much appreciated and i apologise if this isnt very clear as i am new to using these components.

CSS
.modal-progress {
    background-color: red!important
}

 editor = new $.fn.dataTable.Editor({
                table: "#dtPurchaseEnquiryLines",
                idSrc: 'LineNo',
                formOptions: {
                    main: {
                        focus: 4
                      
                    }
                }, 
               ** // Set class name here?**
                className: 'modal-progress',
                template: '#customForm',
                fields: [{
                    label: "Item No",
                    name: "ItemNo",
                    type: "readonly"
                }, {
                    label: "Part No",
                    name: "PartNo",
                    type: "readonly"
                }, {
                    label: "Qty",
                    name: "Quantity",
                    type: "readonly",
                    attr: {
                        type: "number"
                    }
                }, {
                    label: "UOP",
                    name: "UOP",
                    type: "readonly"
                }, {
                    label: "Lead Time (days)",
                        name: "LeadTime",                 
                    attr: {
                        type: "number"
                    }
                }, {
                    label: "Unit Price",
                    name: "UnitPriceFC",
                    attr: {
                        type: "number",                    
                        },                      
                }, {
                    label: "Additional",
                    name: "AdditionalFC",
                    attr: {
                        type: "number"
                    }
                }, {
                    label: "Freight",
                    name: "FreightFC",
                    attr: {
                        type: "number"
                    }
                }, {
                    label: "Discount",
                    name: "Discount",
                    attr: {
                        type: "number"
                    }
                }, {
                    label: "Net Price",
                    name: "NetFC",
                    type: "readonly"
                },
                {
                    label: "Decline",
                    name: "Declined",
                    type: "radio",
                    options: [
                        //{ label: "Open", value: 0 },
                        { label: "", value: 1 }
                    ]
                    }, {                     
                    name: "FeedbackNote",
                    type: "textarea"
                    }
                ]
            });

           ** // Set class name here ?**
            var node = $.fn.DataTable.Editor.display.bootstrap.node('editor');
            $(node).addClass("modal-progress");
                
 ** // Set class name here ?**
            editor.on('open', function () {
                editor.title('Update Feedback')
                editor.className('modal-progress')
            })