background and fonts

Yes the documentation describes how to use a custom stylesheet to change how the tabs are displayed.

The optional tabby responsive tabs customiser add-on plugin enables the tab background color to be easily changed along with a lot of other parameters, however this does not have an option to change the font, which is inherited from the theme’s styles.

The font can be changed by adding a simple CSS rule, eg:

.responsive-tabs .responsive-tabs__list__item {
font-family: georgia;
}