body {
    margin: 0;
    padding: 0;
    background: #000;

}
a {
    position: absolute;
    top: 50% ;
    left: 50%;
    transform: translate(-50%,-50%);
    width: 200px;
    height: 60px;
    /* width: 400px;
    height: 120px; */
    text-align: center ;
    line-height: 60px ;
    color: #fff;
    font-size: 20px;
    text-transform: uppercase;
    text-decoration: none;
    font-family: sans-serif;
    box-sizing: border-box;
    background: linear-gradient(90deg, #03a9f4, #f441a5 , #ffeb3b, #03a9f4);
    background-size: 400%;
    border-radius: 30px;
    z-index: -1;

}
a:hover
{
    animation: animate 8s linear infinite;
}
@keyframes animate
{
    0%
    {
        background-position: 0% ;
    }
    100%
    {
        background-position: 400% ;
    }
}
a:before
{
    content: '';
    position: absolute;
    top: -10px;
    left: -10px;
    right: -10px;
    bottom: -10px;
    z-index: -1;
    background: linear-gradient(90deg, #03a9f4, #f441a5 , #ffeb3b, #03a9f4);
    background-size: 400%;
    border-radius: 40px;
    filter: blur(20px);
    opacity: 0;
    transition: 0.5s;
}
a:hover:before
{
    filter: blur(20px);
    opacity: 1; 
     animation: animate 8s linear infinite; 

}