Reduce padding of div - html

Question

I've created a div (greenpromobox) which an email form sits in.
There is a chunk of padding to the right, bottom and left of the div and I can't workout how to reduce it to slim down the div?
I believe it maybe in one of the pre-built Bootstrap styles.
Live example: http://185.123.96.102/~kidsdrum/moneynest.co.uk/
HTML
<div class="greenpromobox">
<div class="h2extrapadding hidden-xs hidden-sm"></div> <h2 class="boldme">Take our free <b class="jumpstarttext">Jumpstart Your Finances</b> class to<br /> quickly gain control over your finances</h2>
<p class="text-center">
<br>
<!-- Begin MailChimp Signup Form -->
<div id="mc_embed_signup">
<form action="//moneynest.us11.list-manage.com/subscribe/post?u=9ccf2d2219536b32eaae3c3d1&id=299de51b4e" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
<div id="mc_embed_signup_scroll">
<img src="http://185.123.96.102/~kidsdrum/moneynest.co.uk/img/hand-drawn-arrow.png" id="handarrow" class="hidden-xs hidden-sm" alt="arrow"><input type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="Enter your email address" required autofocus>
<!-- 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;" aria-hidden="true"><input type="text" name="b_9ccf2d2219536b32eaae3c3d1_299de51b4e" tabindex="-1" value=""></div>
<div class="clear"><input type="submit" value="Start Class Now" name="subscribe" id="mc-embedded-subscribe" class="text-uppercase btn btn-primary btn-lg"></div>
</div>
</form>
</div>
<!--End mc_embed_signup-->

Answer 1

Just before the div with id #mc_embed_signup you have this code
<p class="text-center">
<br>
<!-- Begin MailChimp Signup Form -->
</p>
Which basically does nothing, but adds empty space. As I see you reduced this space by doing things like
#mc_embed_signup input.email {
position: relative;
top: -35px;
}
and
.btn-lg {
position: relative;
top: -37px;
}
And this is why you have "padding" at the bottom. It's not padding, it's the space where buttons located. So:
Remove html code we don't need (or display: none it, whatever)
Remove css I've placed here
Put normal bottom padding you want

Answer 2

The problem came from your CSS.
First, remove the width:70%; into your CSS File
After you can add this :
width:auto;
padding:0 15px 15px 15px;
display:table;
The result must be like this :
CSS
.greenpromobox {
display: table;
padding: 15px;
background-color: green;
padding-top: 1px;
margin-top: 25px;
width: auto;
border-radius: 5px;
text-align: center;
margin-left: auto;
margin-right: auto;
}
Hope this answer will help you :)
Richie