*{
    margin: 0;
    padding: 0;
}
#mybtn{
    position: fixed;
    height: 40px;
    width: 100px;
    background: red;
    border: none;
    border-radius: 5px;
    right: 20px;
    bottom: 20px;
    cursor: pointer;
    display: none;}
#mybtn:hover{
    background-color: #888888;
+color: #FFFFFF;}