It is possible to customize the color of the tabs in your booking page.
In your Bookeo account:
1. Go to Settings>Colors and Styles
2. in the Custom CSS section at the bottom, paste this code:
.bookeocss .smallbLeft, .bookeocss .smallbRight {background-image: none !important; background: #09172A; color: #FFFFFF;}
You can also add other attributes, such as upper case for words in the Tabs:
.bookeocss .smallbLeft, .bookeocss .smallbRight {background-image: none !important; background: #09172A; color: #FFFFFF;
text-transform: uppercase;}
The text color value is an HTML color code, which you can select here: http://html-color-codes.info/