styles.css

body{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    overflow: hidden;
    background-color: black;
}

a{
    text-decoration: none;
    color: white;
}

ul {
    list-style-type: none;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    color: white;
}

li{

    border: 4px solid goldenrod;
    padding: 20px 80px 20px 80px;
    border-radius: 20px;
    font-family: monospace;
    letter-spacing: 0.4em;
    font-size: larger;
    font-weight: bold;
    z-index: 1;
    position: relative;
    overflow: hidden;
    transition: 0.5s;
}

li:hover{

    cursor: pointer;
}

li span{

    position: absolute;
    background-color: goldenrod;
    height: 100%;
    width:25%;
    border-radius: 100px;
    z-index: -1;
    transform: translateY(150%);
    transition: 0.5s;   
}

/* scale for increasing the size whilw transition */

li:hover span{

    transform: translateY(0) scale(2);
}

ul li span:nth-child(1){

    transition-delay: 0;
    left: 0;
}

ul li span:nth-child(2){

    transition-delay: 0.1s;
    left: 25%;
}

ul li span:nth-child(3){

    transition-delay: 0.2s;
    left: 50%;
}

ul li span:nth-child(4){

    transition-delay: 0.3s;
    left: 75%;
}