Changing/Making Bigger the Register button on register.php page?

[XRumerGeek]

Hello all,

 

I am trying to change the register button located here; /http://xrumergeek.com/clients/register.php. The button is too small and out of place, ideally I am looking to replace it with something a little bigger and a little brighter.

 

I've contacted WHMCS Support and they've guided me in the right direction but will not assist any further. Can anyone make sense of what's below (this is what they've told me to edit) and explain exactly how I can change the button to something bigger and brighter, and perhaps align it more central on the page? Thank you!!

 

<p align="center"><input class="btn btn-large btn-primary" type="submit" value="{$LANG.clientregistertitle}" /></p>

 

.input-btn-large, input.btn-large {
width: auto; /* Fix for Massive Width on Buttons from Bootstrap */

 

I'd really appreciate any further guidance.