body {
    display: flex;
    justify-content: center;
    background-color: #23282D;
    color: #fff;
}
#container {
    margin-top: 20vh;    

}
.button {
    height: 60px;
    width: 60px;
}
#red {
    background-color: red;
}
#green {
    background-color: green;
}
#blue {
    background-color: blue;
}
#yellow {
    background-color: yellow;
}
#black {
    background-color: black;
}
#heading {
    font-family:'Segoe UI', Tahoma, Verdana;
    font-size: 25px;
}
#hint {
    font-size: medium;
}
#reset {
    height: 30px;
    width: 90px;
    
}