body, div, a {
    padding:0;
    margin:0;
    font-family:"Trebuchet MS", Arial, Helvetica, sans-serif;
}

#calculator {
    background-color: purple;
    width: 315px;
    height: 390px;
    border: 3px black solid;
    margin: 10px auto;
    padding: 5px;
    border-radius: 10px;
}

#total {
    height: 65px;
    width: 285px;
    margin:auto;
    background-color:lightgreen;
    margin-top: 15px;
    margin-bottom: 25px;
    text-align: right;
    font-size: 55px;
    padding: 0 5px;
    border-radius: 20px;
}

#numbers{
    margin: auto;
}

#numbers a {
    display: block;
    width: 38px;
    height: 35px;
    float: left;
    text-decoration: none;
    color: black;
    text-align: center;
    font-size: 28pt;
    padding: 10px;
    margin: 6px 10px;
    border-radius: 10px;
    background-color:lightgray;
}