Use below css to Forminator Form custom css

/* FORMINATOR ------------*/
.forminator-button  {
  background-color: #36bfc5!important;
  padding: 12px 20px!important;
  border-radius: 3px!important;
}
.forminator-button:hover  {
  background-color: #2ba9af!important;
  box-shadow: none!important;
}
.forminator-ui.forminator-custom-form:not(.forminator-size--small)[data-grid="open"] .forminator-row:not(:last-child) {
    margin-bottom: 20px!important;
}