Subscribe Form Field and Button on Same Line - wordpress

Question

I am trying to style a mailchimp subscribe form with just an email field and submit button. I want to have them both on the same line, but nothing I seem to try is working. It is for use inside a fancybox popup on a Wordpress platform (if that information turns out to be relevant). I've tried floating the field left and the button right, with no luck. What am I doing wrong?
Code Below:
<!-- Begin MailChimp Signup Form -->
<style type="text/css">
#mc_embed_signup{background:#fff; clear:left; font:14px Helvetica,Arial,sans-serif; }
/* Add your own MailChimp form style overrides in your site stylesheet or in this style block.
We recommend moving this block and the preceding CSS link to the HEAD of your HTML file. */
#mc_embed_signup input.email {display: block;
padding: 8px 0;
margin: none !important;
text-indent: 5px;
width: 58%;
min-width: 130px;}
#mc_embed_signup input.button {
float: right;
position: relative;
top: -25px;
}
</style>
<div id="mc_embed_signup">
<form action="http://entertainment.us3.list-manage.com/subscribe/post?9" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
<input style="float:left;" type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="email address" required>
<input style="float:right; margin-right:75px;" type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button">
<!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
<div style="position: absolute; left: -5000px;"><input type="text" name="b_7b66660df" tabindex="-1" value=""></div>
</form>
</div>
<!--End mc_embed_signup-->