Works like it should now. Good job
And I know that this law is pretty weird and confusing. I'm pretty sure a CDN can create cookies under the site's domain but it's not something you have control over. Hopefully such cookies are an exception as they are required to view the site.
BTW, I know that you are not allowed to refuse services when consent to processing personal data was not given but I don't think it's the same for cookies. This means that you can "force" the user to make a choice before they can access the rest of the site. PlanetMinecraft have done it this way.
I've also read somewhere that if a user requests a service that requires the use of cookies, then no consent is needed:
"Under the 2012 ePrivacy Directive, Cookie Consent is always required to set cookies, unless the cookies are strictly necessary to deliver a service requested by the individual".
Might fit your dark theme control but I've seen statements that say that all cookie use requires consent and that there will only be exceptions in the future.