*{
    margin:0;
    padding: 0;
    box-sizing: border-box;
    font-family: cursive;
}
body{
    background-color:beige;
    display: flex;
    justify-content: center;
    height: 100vh;
    align-items: center;
  

}
.btn{
    background-color: aquamarine;
    border: 2px solid black;
    border-radius: 10px;
    padding: 20px 40px;
    box-shadow: 0 0 20px 5px rgba(5, 99, 33, 0.6);
    color: black;
    font-size: 20px;
    font-weight: 1000;
    text-decoration: none; 
    position: relative;
    overflow: hidden;
}
.btn::before{
    content:"";
    background-color: deeppink;
    border-radius: 50%;
    height:0;
    width:0;
    position:absolute;
    top:var(--posY);
    left:var(--posX);
    transform: translate(-50%,-50%); 
    transition: 1s;
}
.btn:hover::before{
    width: 200px;
    height:200px;
}
.btn span{
    position:relative;
    z-index: 1;
}