#main_container{
    width: 50%;
    margin: 0 auto;
    background-color: aliceblue;
}
form div{
    width: 50%;
    min-width: 300px;
    margin: 20px auto;
}
form div input, form div label{
    display: block;
}
form div label{
    color: grey;
    font-size: 16px;
}
form div input{
    width: 100%;
    height: 30px;
    border: 1px solid black;
    border-radius: 8px;
    font-size: 16px;
}