* {
  box-sizing: border-box;
}

form {
  min-width: 250px;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
  display: flex;
  flex-direction: column;
}

form input[type="email"] {
  padding: 0.5rem;
  border-top: 0;
  border-right: 0;
  border-bottom: 1px solid #ccc;
  border-left: 0;
}

form button[type="submit"] {
  background: black;
  color: white;
  margin: 1rem 0 0 0;
  padding: 0.5rem;
  border: 0;
  border-radius: 4px;
}