div {
    width: 20px;
    height: 20px;
    border-color: black;
    border-style: solid;
}

#st1{
    background-color: green;
}
#st2{
    background-color: yellow;
}
#st3{
    background-color: red;
}
#st4{
    background-color: rebeccapurple;
}
#st5{
    background-color: pink;
}
#st6{
    background-color: royalblue;
}