Custom CSS when using e.g. Avada

Hi there,

I recently purchased GD and tried a lot using the Supreme theme.
For example I wanted to get rid of the right sidebar und expand the actual content to 100% site width.
Using this forum everything worked fine by making changes in the styles css und functions php files.

Now I am using Avada. While the changes in the functions php file work, I cannot make any changes to the Details page via css.
In particular, I wanted to remove the borders of the ul Container on the details page (the one with the Profile, map, Reviews..)

ul.geodir-tabs-content {
margin: 0 0 10px 0;
padding: 0;
min-height: 350px;
border: 1px #e1e1e1 solid;
border-top: none;
}

So when I Change the border to 10px it won’t work, while I put this into the custom css section in Avada.
In the supreme theme style css file, these kind of things worked without any problem.

Isn’t it possible at all when using other themes or am I missing something?

Regards