How to change feature icon color and feature icon hover color

Here you go :

.feature-item .icon-background-default { color : #your-color ;}
.feature-item:hover .icon-background-default { color : #your-color ;}

Hope it helps!

Unfortunately it does not work properly. My hover color is 05A0BF but I see #333333 color.

Did you replace by your color yet ?

Like this :
.feature-item:hover .icon-background-default { color : #05A0BF;}

Also what is your site url?

Yes,but it does not work. https://www.studiofazzari.it