Elder Scrolls Online: Changed an option, crashing

As I was being a careless pleb, I fiddled around with options, not realising they are put to effect immidiately. So I changed alpha opacity from 0.95 to 0 under settings tab I think. And now I'm crashing whenever i play 64bit version, which is the one I installed ReShade on.
Where do I find the file to change alpha back to what it was?