<footer> are new HTML5 elements, but as it seems in the screen shot below both the elements are marked as red which probably means Geany is telling :
Warining : Unknown elements
How can I make this normal? What files do I need to edit?
I found that when I revert back to default (white background, as shown in Morlunk's answer) theme then no error occurs. Any way to make this happen in my theme? Because I don't want to leave dark theme