#searchsubmit {

  background-color: #eeeeee;
  background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #eeeeee), color-stop(100%, #cccccc));
  background-image: -webkit-linear-gradient(top, #eeeeee, #cccccc);
  background-image: -moz-linear-gradient(top, #eeeeee, #cccccc);
  background-image: -ms-linear-gradient(top, #eeeeee, #cccccc);
  background-image: -o-linear-gradient(top, #eeeeee, #cccccc);
  background-image: linear-gradient(top, #eeeeee, #cccccc);
  border: 1px solid #ccc;
  border-bottom: 1px solid #bbb;
  -webkit-border-radius: 3px;
  -moz-border-radius: 3px;
  border-radius: 3px;
  color: #444;
  font: bold 0.8em "Lucida Grande", "Lucida Sans Unicode", "Lucida Sans", Geneva, Verdana, sans-serif;
  line-height: 1;
  padding: 8px 0;
  text-align: center;
  text-shadow: 0 1px 0 #eee;
  width: 130px; }

#transl1 {
padding: 4px 0px;
margin: 0 0.5em;
}


#masthead_search {
font-size: 1.2em;
padding: 6px;

}

Another demo for the Koha OPAC

Big Koha submit button

search, forms

CSS