I cannot find a way to have a fixed top navigation bar that isn’t transparent with both dark and light themes.

When toggling to dark (or light), the fixed-top is visibly transparent, content flows visibly underneath.

Before adding the dark theme I had a bg-light and fixed-top which together delivered a perfect result, but bg-light is incompatible with the dark theme, the navbar stays light.

I sense that I have to write a custom JS function to work around this, but before I do, would anyone have a native Bootstrap solution for that ?

Thanks