html {
  margin: 0;
  background-color: #502060;
  color: #00cccc;
  font-family: Monocraft monospace;
}
body {
  margin: auto;
  display: block;
  width: min(700px, 90vw);
  margin-top: min(10em, 30vh);
  margin-bottom: min(10em, 30vh);
}
a {
  color: #00ffff;
}

a.btn {
  background-color: #603060;
  display: inline-block;
  width: 10em;
  max-width: calc(100vw - 30px);
  min-width: fit-content;
  padding: 10px;
  margin: 0;
  text-decoration: none;
  text-align: center;
  transition: 0.2s;
}
a.btn:hover {
  background-color: #605070;
}

form {
  background-color: #425;
  padding: 10px;
  margin: 20px auto 20px auto;
  width: fit-content;
}
label {
  text-align: right;
  display: block;
}
input {
  height: 2em;
  margin-bottom: 0.5em;
  border: 0;
  background-color: #000;
  color: #f0f;
}
button {
  background-color: #a0a;
  color: #000;
  border: 0;
  width: 100%;
  height: 2em;
  cursor: pointer;
  transition: 0.2s;
}
button:hover {
  background-color: #909;
}

div.error {
  background-color: #913;
  color: #fff;
  display: block;
  width: calc(100% - 60px);
  padding: 15px;
  margin: 15px;
}