@elistro, would you know if this is white or red oak and which stain in particular has been used (brand and color)? I am very surprised that I love those floors so much because I am not a fan of oak. Thank you in advance.

Definitely looks like oak, very hard to differentiate between red & white oak when they are stained. They both stain very similar, have to say white oak looks better with the darker black & brown colors. Check out Dura Seal stains they offer a number of choices plus can be mixed to play with the colors.

Probably red oak from the looks of the grain, red oak tends to have more graining than white. White is a bit tighter on the grain.