how to add css class to textblock?, 'cause i need to apply styles depends upon my project theme.
$(go.TextBlock,
{
row: 0, alignment: go.Spot.Center,
textAlign: 'center',
margin: new go.Margin(0, 15, 0, 8), // leave room for Button
isMultiline: false,
stroke: "#FCFCFC",
editable: true,
minSize: new go.Size(150, NaN),
textValidation: entityNameValidation,
textEdited: updateEntityName
},
new go.Binding("text", "key"))```