Change login form on Protected Content

Is it possible to use a custom login form using something like Gravity Forms? I know you can use it to create Registration forms but this changes the signup process

The markup for the forms with the plugins are very inconsistent and i am having trouble using CSS to match the visuals from my client eg.

Login form has

<div class="ms-membership-form-wrapper">...</div>
<div class="ms-login-form">...</div>
<a id="" title="Cancel" class="wpmui-link alignleft" href="/register/?_wpnonce=eca5a966e8&membership_id=71&action=membership_signup&step=payment_table" target="_self">Cancel</a>

but registration has

<div class="ms-membership-form-wrapper">
     <form class="form-membership">...</form>
     <a id="" title="Login" class="wpmui-link alignleft" href="/register/?_wpnonce=eca5a966e8&membership_id=71&action=membership_signup&step=payment_table&do-login=1" target="_self">Already have a user account?</a>

It gets very difficult to modify the CSS as the markup isn't very helpful or consistent