#switchtheme-switch-form div {
  width: 100%;
}
#switchtheme-switch-form div.form-item {
  float: left;
  width: auto;
  margin: 0;
  padding: 0;
}
#switchtheme-switch-form #edit-submit {
  float: left;
  width: auto;
  margin-left: 3px;
}