body {
    font-family: Arial, Helvetica, sans-serif;
    text-align:center;  
    background-color: ghostwhite;  
}

h3{
    margin-top: 20px;
}

.btn {
    border: 5px solid black;
    border-radius: 20%;
    height: 200px;
    width: 200px;
    height: 200px;
    margin: 1rem;
    align-content: center;
}

.green {
    background-color:#4CAF50;
}

.yellow {
    background-color: #FFEB3B ;
}

.red {
    background-color:#FF4C4C ;
}

.blue {
    background-color: #2196F3;
}

.container {
    display: flex;
    justify-content: center;
    margin-top: 30px;
}

.flash {
    background-color: white;
}