index.css

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  margin: auto;
  max-width: 38rem;
  padding: 2rem;
  background-color: black;
}

.main {
  margin: auto auto;
  margin-top: 5rem;
  vertical-align: middle;
  text-align: center;
  width: 100%;
  height: 100%;
}

form {
  margin: auto auto;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  text-align: center;
}

.row {
  margin: 1rem auto;
}

h2 {
  color: white;
  font-size: 2rem;
}

input {
  background-color: white;
  border: 2px solid white;
  border-radius: 10px;
}

input {
  width: 50%;
  height: 3rem;
}

input::placeholder {
  text-align: center;
  font-size: 1.5rem;
}

input[type="text"] {
  align-items: center;
  text-align: center;
  font-size: 1.5rem;
  padding-left: 5px;
  padding-top: 5px;
  cursor: text;
  border: 1.5px solid white;
  border-top: 0 none;
  border-left: 0 none;
  border-right: 0 none;
}

input:focus,
select:focus {
  outline: none;
}

.btn2 {
  height: 4rem;
  width: 12rem;
  color: black;
  background-color: grey;
  font-size: 2rem;
  font-weight: bold;
  box-sizing: border-box;
  border-radius: 5px;
  cursor: pointer;
}

#success, #failure, #error {
  display: none;
  font-size: 1.5rem;
}

#success {
  color: green;
}

#failure, #error {
  color: red;
}