FORTE Template - Change Gallery Navigation Square

I tried by myself, but my css for change color/transparency of that black square didn't work.
Is it possible to change color of arrow and square at the same time with different colors? 
Or even remove it (Set transparency to 100%)

Please link your page so we can help.

On 7/11/2020 at 4:39 PM, rwp said:

Please link your page so we can help.

https://artkartavtsov.com/new-gallery/

On 7/12/2020 at 2:01 AM, tuanphan said:

Add to Home > Design > Custom CSS

.arrow-wrapper {
    background: red !important;
}
.arrow-wrapper * {
    color: blue !important;
}

 

Thanks! It works!