body {
    font-family: 'Open Sans', sans-serif;
    background-color: black;
}
.container {
    background-image: url('images/bg.jpg');
    height: 700px;
    margin-top: 30px;
}
#calculator {
    background-color: #eee;
    margin: 40px 35px;
    border-radius: 5px;
    box-shadow: 1px 1px 8px 1px #000000;
    padding-top: 0px;
    padding-left: 5px;
}
#result {
    height: 50px;
    padding: 35px;
}
#error {
    height: 20px;
    text-align: center;
    color: red;
}
#output {
    height: 80px;
    padding: 2px 35px;
    text-align: right;
    /* float: right; */
    font-size: 30px;
}
#buttons {
    height: 450px;
    padding-top: 15px;
}
.operator, .number, .space {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    margin: 15px;
    border: 0;
    font-weight: bold;
    font-size: 15px;
}
.space {
    visibility: hidden;
}
.blue{
    background-color: #20b2aa;
    font-size: 20px;
}
.orange {
    background-color: #ffa500;
    font-size: 20px;
}
.pink {
    background-color: #f08080;
    font-size: 20px;
}
.lightblue {
    background-color: #7d93e0;
    font-size: 20px;
}
.purple {
    background-color: #9477af;
    font-size: 20px;
}
.gray {
    background-color:rgb(216, 211, 211);
}
.operator:focus, .number:focus, .space:focus {
    outline: 0;
}
.number:hover {
    font-size: 20px;
}
.operator:hover {
    opacity: 0.5;
}