<div class="alert alert-primary">primary alert</div>
 <div class="alert alert-secondary">secondary alert</div>
 <div class="alert alert-success">success alert</div>
 <div class="alert alert-warning">
 <span class="alert-icon"><i class="fas fa-exclamation-triangle"></i></span>warning alert with an icon
 </div>
 <div class="alert alert-danger">
 <span class="alert-icon"><i class="fas fa-exclamation-circle"></i></span>danger alert with an icon
 </div>