Hi Francisco,

First, locate the theme of your application, on the Tab Interface under the folder Themes:

And then paste the following CSS:

.ECT_FeedbackContainer .FeedbackMessage,

.ECT_FeedbackContainer .FeedbackInitial {

    background: red;

    border-radius: 25px;

}

.FeedbackClickMessage b:hover {

    color: white !important;

}    

Replace the colors red and white by the colors of your liking. In my case, red background and white text:

Cheers,
João

Hi Fransisco, 

You can inspect your application in browser using F12 key and then inspect that particular element (feedback button) , you will find css specific to the feedback button and try to make modifications in css to change the background color and color of text of the button. 

At the last paste the same css inside your screen. 

Hope it works, Thanks and happy coding!!