body {
    position:relative;
    overflow-x:hidden;
    box-sizing: border-box;
    padding:20px;
    background-color: white;
    color:black;
}
#main_content {
    width:90%;
    margin-left:5%;
    text-align: center;
}
#main_content input {
    margin:10px;
}
#main_content button {
    background-color: blue;
    color:white;
}
footer {
    position:absolute;
    left:0px;
    bottom:0px;
    text-align: center;
    width:100vw;
}
#btn_facebook {
    width:200px;
}