Conditional formatting will do the trick nicely; no need for calculations. However, you cannot change the layout background itself ... you need to create a text box (or even button) and set the conditional format on it instead.
So use your text tool and draw a rectangle and type a space into it. Resize the rectangle as large as your layout. Now color it the background which would be the generic (or default color) and then begin applying the conditional format as:
Add > Formula is: TableName::Status = "Pending" ... and below select the color you want
Repeat to add a second color depending upon a different Status.
I have spent this evening trying to implement your suggestion, I am sure it is what I need, I am not surprised that the background colour is not controllable by field input.
I am struggling to implement your formula, because I am not used to this syntax.
Last time I did anything serious with filemaker was when V.3.1 was current... Currently using V.11.3.
I have created a field 'Status' with a defined list of two possible alternate entries: 'Complete', and 'Incomplete'. I created a text box with radio buttons, I would like the text box to be red when default, 'Incomplete' and green when 'Complete' is selected. I need to be able to toggle between the two in case I discover an error in my data which needs further research.
Once I have mastered this I also want to have another similar conditional control, for 'Genus' and 'Species' which will change a large text box forming the background from pale green to pale blue.
"I created a text box with radio buttons, I would like the text box to be red when default, 'Incomplete' and green when 'Complete' is selected."
I'm not sure what you mean. You use the text tool to draw a rectangle and put a single space in it and then resize the rectangle as large as your layout and attach conditional formatting. The radio button has nothing to do with the text box.
What version of FM are you using? Did you find where you apply conditional formatting? Select the text box (and not the radio button) and then either Format > Conditional or right-click on the text box. It is there that you create the formula.
"I am struggling to implement your formula, because I am not used to this syntax."
TableName::Status = "Pending"
In conditional formatting, select ADD and then 'formula' and find your status field in the upper left pop-up and insert it into the calculation and then type what I show in blue.