body {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100vw;
    height: 100vh;
}
.btn{
    width: 80px;
    height: 40px;
    
    font-size: 20px;
    border: 1px black solid;
    text-align: center;
    font-weight: 700;
}
.btn:active{
    border: none;
}
.btn:hover{
    border: none;
}
#red{
    background: red;
    
}
#blue{
    background: blue;
    
}
#yellow{
    background: yellow;
    
}
#green{
    background: green;
    
}

   background: green;
    
}