Alertsv5.x

---- Light background --------
<div class="alert alert-light" role="alert">
A simple light alert—check with <a class='alert-link' href="#">sample link!</a>
</div>
---- Secondary background --------
<div class="alert alert-secondary" role="alert">
A simple secondary alert—check with <a class='alert-link' href="#">sample link!</a>
</div>
---- Dark background --------
<div class="alert alert-dark" role="alert">
A simple dark alert—check with <a class='alert-link' href="#">sample link!</a>
</div>
---- Primary background --------
<div class="alert alert-primary" role="alert">
A simple primary alert—check with <a class='alert-link' href="#">sample link!</a>
</div>
---- Info background --------
<div class="alert alert-info" role="alert">
A simple info alert—check with <a class='alert-link' href="#">sample link!</a>
</div>
---- Success background --------
<div class="alert alert-success" role="alert">
A simple success alert—check with <a class='alert-link' href="#">sample link!</a>
</div>
---- Warning background --------
<div class="alert alert-warning" role="alert">
A simple warning alert—check with <a class='alert-link' href="#">sample link!</a>
</div>
---- Danger background --------
<div class="alert alert-danger" role="alert">
A simple danger alert—check with <a class='alert-link' href="#">sample link!</a>
</div>