Twitter Bootstrap - why is my modal as faded as the background?

Check this issue on the Bootstrap git repository.

Then try putting the modal before the navbar, like this fiddle.

<div id="registration_modal" class="modal hide fade">
    <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal">×</button>
        <h3>Register An Account</h3>
    </div>

    <div class="modal-body">
        Registration form goes here.
    </div>

    <div class="modal-footer">
        <button class="btn btn-secondary" data-dismiss="modal">Cancel</button>
        <button class="btn btn-primary">Register</button>
    </div>

</div>
<div class="navbar navbar-fixed-top"> 
    <a href="#registration_modal" data-toggle="modal">
        Register
    </a>    
</div>

​

Unfortunately the answer here didn't help me.. but fortunately this discussion has the same issue and they have a helpful answer that worked for me. Basically, you have to make sure the modal is not inheriting any weird positioning elements from parent divs:

Bootstrap modal appearing under background