I need help fixing alignment problem with my search box

I have a small coding issue with my search box, which you can see on the header of my site here: https://www.snugbabyshop.co.uk. The word 'search' is misaligned with the actual box. Can someone code-savy advise please which file I need to amend and how to amend it please? It would be greatly appreciated.

In the green box top right, it looks perfectly middle aligned to me.

Thanks dw. Are you viewing with Firefox? It shows ok with FF but is mis-aligned with Safari and Chrome. Please see the attachment.

Yes FF17. Did not check the others.

FWIW I have this in my includes\templates\MyTemplate\sideboxes\tpl_search_header.php

  if (strtolower(IMAGE_USE_CSS_BUTTONS) == 'yes') {
    $content .= zen_draw_input_field('keyword', '', 'size="28" maxlength="28" style="width: 100px" value="' . HEADER_SEARCH_DEFAULT_TEXT . '" onfocus="if (this.value == \'' . HEADER_SEARCH_DEFAULT_TEXT . '\') this.value = \'\';" onblur="if (this.value == \'\') this.value = \'' . HEADER_SEARCH_DEFAULT_TEXT . '\';"') . ' ' . zen_image_submit (BUTTON_IMAGE_SEARCH,HEADER_SEARCH_BUTTON);
  } else {
    $content .= zen_draw_input_field('keyword', '', 'size="28" maxlength="28" style="width:14.5em; margin-top:0.25em; padding:0.15em 0em;" value="' . HEADER_SEARCH_DEFAULT_TEXT . '" onfocus="if (this.value == \'' . HEADER_SEARCH_DEFAULT_TEXT . '\') this.value = \'\';" onblur="if (this.value == \'\') this.value = \'' . HEADER_SEARCH_DEFAULT_TEXT . '\';"') . zen_image_submit(BUTTON_IMAGE_SEARCH2, HEADER_SEARCH_BUTTON,'style="float:right; margin-top:0.3em; padding:0em 0.25em; border:0;"');

Hope this helps.

Thanks DW. I don't have that filename, just tpl_search.php and the coding looks a lot different (see below). I'm no coding expert so it means very little to me. Thanks anyway for trying :)

The original tpl_search_header.php should be in includes\templates\template_default\sideboxes.

Copy it to includes\templates\YourTemplate\sideboxes\ to edit.