Search Bar not using colour theme on rest of device.

I restarted my computer today and this issue has suddenly occured,

It doesnt matter what I change the colour theme too, when searching in the search menu I am presented with this light grey colour with white text which is incredibly hard to read,

Online searches indicated stuff to do with Bing, Cortana and the Search registry keys, but I am not finding these keys anywhere in my registry to edit them.

I have tried a few other solutions such as restarting the search services from task manager, but it is not applying the theme correctly.

Had this computer for several years and never ran into this problem before,

Any advice would be greatly appreciated.