* {
    border: 0px;
    padding: 0px;
    margin: 0px;
}


body {
    background: grey;
    text-align: center;
}

h1 {
    font-family: sans-serif;
}

#container {
    display: inline-block;
    text-align: center;
    background: blue;
}

.col {
    display: inline-block;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: white;
    margin: 5px;
}
.col.empty {
    cursor: pointer;
}

.col.red {
    background: red;
}

.col.pred {
    background: darkred;
}

.col.yellow {
    background: yellow;
}

.col.pyellow {
    background: rgb(112, 112, 8);
}

#restart {
    margin: 10px;
    border: 1px solid white;
    visibility: hidden;
    padding: 8px 14px;
    border-radius: 15px;
}   

#restart:hover {
    border: 1px solid black;
    background-color: lightgrey;
}