css: twin 50% liquid columns respecting min width

i'm perplexing plans twin 50% buttress extent instead. nonetheless seems right columns reaches the 'min-width', goes underneath left column. there any proceed 'shim' technique set min-width coupling both columns stop resizing. thus, expelling problem right buttress awaiting itself underneath left column.

my page follows.

<style type="text/css">

#left {
    float: left;
    width: 50%;
}

.minwidth {
    width: 500px;
    height: 0;
    line-height: 0;
}

</style>

<div id="wrapper">
    <div id="left">
        left
    </div>
    <div id="right">
        right
    </div>
    <div class="minwidth">&nbsp;</div>
</div>

the emanate left buttress stop resizing, nonetheless right buttress next left buttress keep resizing. basically, outcome i wish once wrappers extent goes bellow, both left, right columns also stop resizing. putting shim both left right columns work either.

is there presumably another proceed going abouts removing twin 50% extent columns controlling shim morally set min width?

thank you.

edit: whitespace minwidth category indeed &nbsp nonetheless got converted. ;)