The only way I got the backgroud to alternate is in list view.
The report is in Form View & NOT List or Table View.
Then you could use a conditional formatting expression on your fields.
(you can't apply conditional formatting to the background of your layout)
You could use this formula: (assuming you have a serial number ID field in your table)
If(Mod( Alternate::Id ;2)=0; "1"; "")
And select an orange fill color.
This will give the fields in the even records an orange fill color.
Try this test file if you can't make it work: