Styling New-UDCard

I`m sure this will be a simple one to solve for someone here but it’s really confusing me … can anyone please explain why the backgroundcolor styling is not working in either of these examples (the borders will render fine) ?

New-UDApp -Title 'Grid Example' -Content {

 New-UDGrid -Container -Children {

        New-UDColumn -LargeSize 3 -MediumSize 9 -SmallSize 12 -ExtraSmallSize 12 -Content {
    
            New-UDCard -Title "Card 1" -Id "Card 1" -TitleAlignment center  -Content {
              New-UDTypography -Text "This is card one" -Align 'center' 
        } -Style @{
           border = '2px solid blue'
          backgroundColor = 'red'
        }
    }
        New-UDColumn -LargeSize 3 -MediumSize 9 -SmallSize 12 -ExtraSmallSize 12 -Content {
    
            New-UDCard -Title "Card 2" -Id "Card 2" -TitleAlignment center -Style @{border = '2px solid red';backgroundcolor = 'green'}  -Content {
              New-UDTypography -Text "This is card two" -Align 'center' 
        }
    }
}        
    }

Thanks in advance

Product: PowerShell Universal
Version: 4.0.9

Replying to myself in case anyone else runs into this …

I ended up defining the MaterialDesign theme and the first card then worked without any code changes. The second card needed the word ‘backgroundcolor’ changed to ‘background’

New-UDApp -Title 'Grid Example' -Theme (Get-UDTheme -Name 'MaterialDesign') -Content {

 New-UDGrid -Container -Children {

        New-UDColumn -LargeSize 3 -MediumSize 9 -SmallSize 12 -ExtraSmallSize 12 -Content {
    
            New-UDCard -Title "Card 1" -Id "Card 1" -TitleAlignment center  -Content {
              New-UDTypography -Text "This is card one" -Align 'center' 
        } -Style @{
           border = '2px solid blue'
          backgroundColor = 'red'
        }
    }
        New-UDColumn -LargeSize 3 -MediumSize 9 -SmallSize 12 -ExtraSmallSize 12 -Content {
    
            New-UDCard -Title "Card 2" -Id "Card 2" -TitleAlignment center -Style @{Border = '2px solid red';background = 'green'}  -Content {
              New-UDTypography -Text "This is card two" -Align 'center' 
        }
    }
}   
 }     
    
Cheers