Flexbox Magic: Responsive Sign-Up Form

A cool trick by Adam Argyle to create a responsive signup form with flexbox in very few lines of code:

form {
    display: flex;
    flex-wrap: wrap;

    & > input {
      flex: 1 1 10ch;
      margin: .5rem;

      &[type="email"] {
        flex: 3 1 30ch;
      }
    }
  }