Suggestion:

As an experiment, consider adding the following to your existing CSS rules below your search box code.  Then test to see if the search box is correctly positioned in all browser types and versions that you wish to support.


  table.gsc-search-box td.gsc-input {
    width: 138px;
    padding-right: 0;
  }

  table.gsc-search-box td.gsc-search-button {
    width: auto;
    text-align: right;
  }

  input.gsc-input {
    width: 124px;
  }

  input.gsc-search-button {
    width: 60px;
    margin: 0;
    padding: 0;
  }


-- omr