What is causing this accordion nav to lose browser default focus?
<div class="panel panel-default">
<div class="panel-heading">
<button aria-controls="collapseTwo" aria-selected="false" data-target="#collapseTwo" data-toggle="collapse">Display</button>
</div>
<div class="panel-collapse collapse" id="collapseTwo">
<div class="panel-body">
<ul>
<li class="iso-btn" data-filter=".desktop">
<a href="#">Desktop</a>
</li>
<li class="iso-btn" data-filter=".mobile">
<a href="#">Mobile</a>
</li>
</ul>
</div>
</div>
</div>
In Chrome, if I tab through the buttons with all CSS removed, focus is shown clearly on each button. I've gone through process of elimination with my CSS but I must be missing something - there needs to be default browser focus on the button when tabbed.
Any ideas what I'm doing wrong? HTML structure? Bootstrap? CSS?