I'm struggling with my font sizes for my headings.

When the browser window is resized the same h2 heading is suddenly as big as my h1 heading this seems to have the knock on effect of a nested div within my Jumbotron being squished.

How can I fix this issue (so my h1 remains the biggest font and the greenpromobox div isn't squished on browser resize?)

Live example: http://185.123.96.102/~kidsdrum/moneynest.co.uk/

Useful HTML:

HTML Code:
<div class="special">
<div class="jumbotron">
  <div class="container text-center">
    <div class="h1extrapadding hidden-xs hidden-sm"></div>  <h1 class="boldme">Aged 20-30 & frustrated with money?</h1> 
    <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>


            <!-- Begin MailChimp Signup Form -->
<div id="mc_embed_signup">
<form action="//moneynest.us11.list-manage.com/subscribe/post?u=9ccf2d2219536b32eaae3c3d1&amp;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-->

</div>
</div>

 </div>
</div>
  </div>
Many thanks,

Sam