Plus floating button - purely html and css

gistfile1.txt

<div class="fab"> + </div>

.fab {
   width: 70px;
   height: 70px;
   background-color: red;
   border-radius: 50%;
   box-shadow: 0 6px 10px 0 #666;
   transition: all 0.1s ease-in-out;
 
   font-size: 50px;
   color: white;
   text-align: center;
   line-height: 70px;
 
   position: fixed;
   right: 50px;
   bottom: 50px;
}
 
.fab:hover {
   box-shadow: 0 6px 14px 0 #666;
   transform: scale(1.05);
}