Change:
.drop_area_fileselect {
position: absolute;
margin-left: -8em;
to:
.drop_area_fileselect {
position: absolute;
margin-left: -9em;
and:
#chrome .drop_area_fileselect, #safari .drop_area_fileselect {
padding-left: 160px;
to:
#chrome .drop_area_fileselect, #safari .drop_area_fileselect {
padding-left: 180px;
That should tweak better the click and avoid that single letter out of the input area.