.newsletter-signupForm-mars form #edit-actions {
    display: flex;
    justify-content: center;
}
.newsletter-signupForm-mars form #edit-actions .form-submit{
  text-align: center;
}
.newsletter-signupForm-mars form 
{
  max-width: 600px !important;
  padding: 40px;
}
.newsletter-signupForm-mars form .js-form-item, .newsletter-signupForm-mars form #pn-otp-verify-messages, .newsletter-signupForm-mars form #pn-otp-widget
{
  width: 100% !important; 
  margin-left: 0 !important;
  margin-right: 0 !important;
}
@media (max-width:767px)
{
  .newsletter-signupForm-mars form 
  {
    padding: 20px;
  }        
}