html, body {
  background-color: #23272a;
  color: white;
  font-family: sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-flow: column nowrap;
  margin: 0;
}
@media (max-width: 500px) {
    html,
    body {
        display: inherit !important;
        padding: 1em;
    }

    main {
        width: 100%;
    }
}

* { box-sizing: border-box; }
.rounded-thing {
  border-radius: 5px;
  background-color: #2c2f33;
  padding: 10px; 
}
input { padding: 5px; }
input[type=submit] { padding: 5px; }
input[type=submit]:hover { background-color: #7298da; padding: 5px; }