body{
    background-color: black;
    color: #fff;
    text-align: center;
}
a{
    display: block;
    background-color: rgb(0, 0, 0);
    color: #fff;
    text-decoration: none;
    padding: 20px 10px ;
    border: #fff 2px solid;
    text-align: center;
    font-size: 20px;
    transition: .5s all;
    margin: 10px;
}
a:hover{
    background-color: #212121;
    border-color: #a8a8a8;
}