Change the hover of the bootstrap btn class

Hello.

I have a menu with bootstrap, however a certain item is with the btn-success class. The problem is when I hover over this item, the background turns white. How would I make the background to remain green?

<div class="navbar navbar-default navbar-static-top">
            <div class="container">
                <div class="navbar-collapse collapse ">
                    <ul class="nav navbar-nav">
                       ....
                       <li class="btn-success btn-xs">Acessar</li>
                       ....
                    </ul>
                </div> 
            </div>
</div>