I really thought I would love GX as the side bar is customizable, you've integrated Discord, Twitch and Instagram ... but visually it's unusable for me. While many gamers prefer the black background theme, I can't use it at all. For me it's like when you stare at a lamp in your house and turn your head, you see that light kind of burned into your vision for a few minutes. Within 10 minutes or so I'm prone to headaches. There is no way to change that in Opera GX. I've read the forums and instead of giving a straight answer of "that's not a feature, only dark theme is present" or "maybe in the future we will add other themes" it seems the answers are basically a that-seems-to-be-your-problem responses. Regretfully, I will stick with Chrome or standard Opera for the time being.