stylesheet_1.css

#blue {
        width: 100px;
        height: 100px;
        border: 2px solid;
        line-height: 90px;
        background-color: #61A1D6;
        box-shadow: 5px 5px 15px blue;
        border-radius: 10px;
        text-align: center;
        margin-left: 10px;
        display: inline-block;
        margin-left: 10px;

}

#green {
        width: 100px;
        height: 100px;
        border: 2px solid;
        background-color: #99ff45;
        box-shadow: 5px 5px 15px green;
        border-radius: 10px;
        text-align: center;
        line-height: 90px;
        margin-left: 10px;
        display: inline-block;
}

#red {
        width: 100px;
        height: 100px;
        border: 2px solid;
        background-color: #ff5534;
        box-shadow: 5px 5px 15px red;
        border-radius: 10px;
        line-height: 90px;
        text-align: center;
        margin-left: 10px;
        display: inline-block;
}

div#blue:hover {
        background-color: blue;
}
div#green:hover{
        background-color:green;
}
div#red:hover{
}