*{
    margin: 0;
    padding: 0;
}
.container{
    height: 100vh;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f2f2fe;
}
.icon a{
    display: inline-flex;
    width: 100px;
    height: 100px;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 40px;
    background: #fff;
    margin: 10px;
    box-shadow: 0 10px 10px rgba(0,0,0,0.1);
    background-image: linear-gradient(#ddd 50%, red 50%);
background-size: 100% 200%;
background-position: 0% 5% ;
transition: background-position 0.5s,  color 0.5s;
}
.icon a:nth-child(1){
    color: #1976d3;
    background-image: linear-gradient(#ddd 50%,#1976d3 50%);
}
.icon a:nth-child(2){
color:#f44236;
background-image: linear-gradient(#ddd 50%,#f44236 50%);
}
.icon a:nth-child(3){

color: #03a9f5;
background-image: linear-gradient(#ddd 50%,#03a9f5 50%);

}
.icon a:hover{
    background-position: 0% 100%;
    color: #fff;
}