body {background: #000;color:white !important;}

.register-box {margin: 80px auto 0 auto; background: #2e75b6; width: 300px; padding: 20px 30px 60px 30px; border-radius: 20px; font-size: 0.875em;}
input[type=button].red {background: red; height: 26px; width: 60px; color: white;}
input[type=text]:read-only {background: #ddd;}

@media only screen and (min-width: 400px) {
  .register-box {width: 360px;}
  select {width: 100%;}
  input[type=button].red {min-width: auto;}
}