How to hide out of stock variants in Symmetry 7.3

[RhizomeCowboy]

Hi - looking to hide (not delete) out of stock variants so that they do not appear to customers.
There was a solution posted for a previous version of Symmetry, but it referenced an Assets file that no longer exists. 

It said to add this code to the style css file.  Any help on the code snippet to add to the proper file is appreciated!

[Shadab_dev]

Please share your store url, if there is a specific class that Shopify adds to these sold out products that differentiate them from the available ones then we can do this with a little css. If not we will have to add code to hide them.