Hello José,

FullCalendar component has an input parameter with the name "AdvancedOptions" where you can configure your calendar options, including the theme. 

In the case of theme, I believe you need also to include extra CSS files as you can see here

https://fullcalendar.io/docs/bootstrap-theme

For the bootstrap theme to work, you need to define the theme as (themeSystem: 'bootstrap') and include the bootstrap CSS theme file.

Hello Nelson

Thanks for your reply. I'll give it a go. But I wanted to use some other theme other than bootstrap. Some of the themes in fullcalendar.io (demos) look much nicer than the standard.