.stilD{
    padding: 15px 25px;
    margin: 20px;
    font-size: 18px;
    letter-spacing: 1px;
    border: 2px solid #ff1744;
    cursor: pointer;
    background: linear-gradient(to right, transparent 50%,#ff1744 50% );
    background-size: 200%;
    background-position: left;
    transition: background-position 0.5s;
    color: black;
    font-weight: bolder;
}
.stilD:hover{
    background-position: right;
    color:#fff;
}