I'm trying to write a Json for my view.
How can I make the background of groupby column header green if all items in Status column are Completed?

I have the below code so far,
I have this logic:
count the number of times Completed appears for grouped project == @group Count then change the background of the header to green
{
"$schema": "https://developer.microsoft.com/json-schemas/sp/v2/row-formatting.schema.json",
"groupProps": {
"headerFormatter": {
"elmType": "div",
"txtContent": "=@group.fieldData + ' (' + @group.count + ')'",
"style": {
"font-weight": "600"
},
"children": [
{
"elmType": "div",
"forEach": "project in @projectField",
"children": [
{
"elmType": "div",
"attributes": {
"class":"="
}
}
]
}
]
}
}
}
Thanks
