body.section-prikentik .layout-center form.webform-submission-form input.form-submit {
  display: block;
  margin: 20px auto 30px; 
}

body.section-prikentik form.webform-submission-form .fieldset-wrapper div[id^="edit-welk"] {
  display: inline-block;
  margin-left: auto;
  margin-right: auto;
  max-width: none;
}