Hi Jan,

To be honest every site has different way of styling and element and it is almost impossible for us to provide the general css modification. What I can suggest is that you can inspect the element of button by using your browser console and add the same styling from uk-button to the btn-es-primary css styling inside your custom.css file.

Hi Fazwan and thank you for your fast response

i used my console to inspect the add event button for example (check please the screenshot),
i have a custom.css file inb my css folder under my yootheme but honestly i dont understand what i must put in this file

You can use the sample code below but you need to add in your own colors,

body div#fd.es .btn-es {

    background-color: #000 !important;

}

Please understand that our support does not cover customizations