CSS Question, bxt-btn top menu actionsContainer

How on earth do I target the bx-btn class in, and ONLY IN,  the top menu actions container.  Everything I've tried that should have worked, hasn't.  What am I missing?

<div class="sys_page_actions">
            <div class="actionsContainer actionsContainerSubmenu">
   
        <button onclick="showPopupAnyHtml('http://physicalfitnessnow.com/m/files/upload');" class="bx-btn bx-btn-img">
    <i class="sys-icon plus"></i>Upload
</button>

   
        <button onclick="window.open ('http://physicalfitnessnow.com/m/files/albums/my/main/','_self');" class="bx-btn bx-btn-img">
    <i class="sys-icon save"></i>My folders
</button>

   
</div>
           
        </div>

Should be something like this at the bottom of general.css

.actionsContainer .bx-btn {
Your css here. like color: #FF0000;
}

That's one I tried Deano ..... didn't work, although I put it in common.css

This is what I finally ended up with in common.css

div.sys_page_actions div.actionsContainer.actionsContainerSubmenu button.bx-btn {

(I was desperate and pulled out all the stops)