I would like for customers to select their array of multi-choice select

I would like for customers to select their array of multi-choice selections that reflect their design requirements and then, I would like those selections to determine which design options that are available for them...

i.e. when their floor area is large and they want really nice feature lighting, the cheaper design options become unavailable...

How would I do this? Would I do this with CSS Coding?

No, CSS code does not work for this, the code will only style the form, but your requirement involves other features. 

I think you may add the check box fields with the desired options and then show/hide them according to the selections the users made, the following guide will help you with the show/hide conditions: https://www.jotform.com/help/316-How-to-Show-or-Hide-Fields-Base-on-User-s-Answer 

If you need further assistance, please share us the form you're working on. 

Thanks.