Customizing Form from Nimbit to Mailchimp

I have this code that I need to replace…

<!-- BEGIN NIMBIT FORM -->

<form id="nmbt_form" target="_blank" method="post" action="https://www.nimbitmusic.com/nrp/controllers/artist_subscriber.php">

<input type="hidden" name="artist_id" value="2040088"/>
<input type="hidden" name="confirm"   value="1"/>
<input type="hidden" name="digital_id" value="2263520" />
<input type="hidden" name="hash"     value="14526a8cb16cfe7d72c8f3623618d23c" />

						<input class="text" name="email_address" type="text" value="enter your eMail" onfocus="if(this.value=='enter your email')this.value=''" onblur="if(this.value=='')this.value='enter your email'" /><input class="but" name="join" type="image" value="" src="<?php bloginfo('stylesheet_directory'); ?>/images/ok.gif" />
					</form>

<!-- END NIMBIT FORM -->

With this code…

<!– Begin MailChimp Signup Form –>
<link href=”https://cdn-images.mailchimp.com/embedcode/slim-081711.css&#8221; rel=”stylesheet” type=”text/css”>
<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. */
</style>
<div id=”mc_embed_signup”>
<form action=”https://danielledelaite.us2.list-manage1.com/subscribe/post?u=8f15797010dce0f19ad9a3bca&id=cd4ae69577&#8243; method=”post” id=”mc-embedded-subscribe-form” name=”mc-embedded-subscribe-form” class=”validate” target=”_blank”>
<label for=”mce-EMAIL”>Subscribe to our mailing list</label>
<input type=”email” value=”” name=”EMAIL” class=”email” id=”mce-EMAIL” placeholder=”email address” required>
<div class=”clear”><input type=”submit” value=”Subscribe” name=”subscribe” id=”mc-embedded-subscribe” class=”button”></div>
</form>
</div>

<!–End mc_embed_signup–>

However, when I simply replace it…I lose the styling on the current form + submit button. Anyone know how to get around this?