Out of Stock Strike Variant Selection strike through or Color change on Prestige Theme

Where can I change the color for out of stock sizes in ‘edit code’ on the prestige theme? I want it to look like this below for the Medium size just having it lightly grayed out or make a strike through for out of stock sizes. I am in product-form.liquid but cannot find the section to actually change the color hex code.

This is where I am looking