How to Center Floated Divs in a Container

It is possible. Using http://www.pmob.co.uk/pob/centred-float.htm and http://css-discuss.incutio.com/wiki/Centering_Block_Element as a source.

Here is a fiddle demonstrating the concept, using the HTML and CSS from below: https://jsfiddle.net/t9qw8m5x/

<div id="outer">
    <ul id="inner">
        <li><a href="#">Button 1</a></li>
        <li><a href="#">Button 2 with long text</a></li>
        <li><a href="#">Button 3</a></li>
    </ul>
</div>

This is the minimum CSS needed for the effect:

#outer {
    float: right;
    position: relative;
    left: -50%;
}

#inner {
    position: relative;
    left: 50%; 
}

#inner > li {
    float: left;
}

Explanation:

Start off with just the li { float: left; } rule. Then wrap those floats in the left: 50%; relative position, so the left edge of the <ul>'s box is in the horizontal centre of the page, then use the rules in #outer to correctly adjust it so the centre of #inner is aligned with the page.