Fix Remaining ships color schema in Fullscreen mode

[np25071984]

it is hard to read the "Opponent's remaining ships" section when it is Fullscreen mode. I don't know why the background color becomes black but we have to consider it.

[CzhCN0]

@np25071984 Hi mate. The change in background color to black is due to the default styles added by Chrome when handling fullscreen mode. The following CSS takes effect when a non-root element is in fullscreen mode. You only need to add a background color to the "game-boards" element, or alternatively, use a vibrant seascape background.

:not(:root):fullscreen::backdrop {
position: fixed;
inset: 0px;
background: black;
}

[np25071984]

@CzhCN0 thank you for the response!

the default styles added by Chrome when handling fullscreen mode

I think those default styles make sense so that it is better to update the text color and follow default fullscreen logic