CSS Code for "btn" class.
.btn {
display: inline-block;
font-weight: 400;
text-align: center;
white-space: nowrap;
vertical-align: middle;
-webkit-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
border: 1px solid transparent;
padding: .5rem .75rem;
font-size: 1rem;
line-height: 1.25;
border-radius: .25rem;
transition: all .15s ease-in-out
}