To colour the text & background so they're the same, you could use:
Code:
Private Sub Document_ContentControlOnExit(ByVal ContentControl As ContentControl, Cancel As Boolean)
Const StrPwd As String = "abc"
With ContentControl
Select Case .Title
Case "Lst1", "Lst2"
If ActiveDocument.ProtectionType <> wdNoProtection Then ActiveDocument.Unprotect Password:=StrPwd
With .Range
Select Case .Text
Case "High"
.Cells(1).Shading.BackgroundPatternColorIndex = wdRed
.Font.ColorIndex = wdRed
Case "Medium"
.Cells(1).Shading.BackgroundPatternColorIndex = wdYellow
.Font.ColorIndex = wdYellow
Case "Low"
.Cells(1).Shading.BackgroundPatternColorIndex = wdBrightGreen
.Font.ColorIndex = wdBrightGreen
Case Else
.Cells(1).Shading.BackgroundPatternColorIndex = wdNoHighlight
.Font.ColorIndex = wdAuto
End Select
End With
ActiveDocument.Protect wdAllowOnlyFormFields, True, StrPwd
End Select
End With
End Sub
Regarding your file type, do be aware that docx files cannot contain macros. You will need to use either: a docx file attached to a template containing the macro; or a docm file.