how to change button color with bootstrap code example

Example 1: bootstarp btn colors

<button type="button" class="btn btn-primary">Blue</button>
<button type="button" class="btn btn-secondary">Grey</button>
<button type="button" class="btn btn-success">Green</button>
<button type="button" class="btn btn-danger">Red</button>
<button type="button" class="btn btn-warning">Yellow</button>
<button type="button" class="btn btn-info">Ligth blue</button>
<button type="button" class="btn btn-light">White</button>
<button type="button" class="btn btn-dark">Black</button>

<button type="button" class="btn btn-link">White with blue text</button>

Example 2: how to change the color of a bootstrap button

.btn-default
 
{
 
background-color: #68889E;
 
color:#FFF;
 
border-color: #2F3E48;
 
}
 
.btn-default:hover, .btn-default:focus, .btn-default:active, .btn-default.active, .open .dropdown-toggle.btn-default {
 
 
 
background-color: #2F3E48;
 
color:#FFF;
 
border-color: #31347B;
 
}