[Bug]: New Zen Mode in overlay is always transparent mixing with what is behind

Pre-Submission Checklist

• I have checked the existing/closed issues to ensure this issue has not already been reported.
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Bug Summary

With the new Zen Mode, that uses overlay, it is ignoring theming and making the tabs bar and unselected tab transparent making things very confusing some times. Worth saying that I'm on Niri not sure if it would influence on that. I'm wondering if there is a way to identify the Floorp overlay and set a window-rule for it.

Reproduction Steps

1. Install Florpp 12.17;
2. Start using it on Niri, Hyprland or MangoWM;
3. Enable Zen Mode;
4. Navigate pages and try to access the tabs bar;
5. Gets works if you hover over the side bar and it is at the right side;

Expected Behavior

To have a fully opaque tab bar and not have the side bar eating into it.

Actual Behavior

It makes the tab bar and non active tabs transparent and hovering the side bar, at least when its on the right side, "merges" with it making things worse.

Screenshots

Browser Version

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Operating System

CachyOS (Linux)

Additional Context

No response