html, body{
   width: 100%;
   min-height: 100vh;
}
body{
   display: flex;
   flex-direction: column
}
#main_section{
   flex: auto;
   /* background-color: red; */
   display: flex;
   flex-direction: row;
   justify-content: center;
}

#form_container{
   max-width: 640px;
   width: 100%;
   /* background-color: blue; */
   margin: 1em;
   display: flex;
   flex-direction: column;
   justify-content: center;
   align-content: stretch;
}

#form_container form{
   border: 1px solid #666;
   border-radius: 1em;
   padding: 1em;
}