It’s pretty easy if you know how to use inspector tool of your browser (Right click->Inspect Element). If you want to learn CSS this would be a very important tool.

Add new line to your CSS:

.table-condensed>thead>tr>th, .table-condensed>tbody>tr>th, .table-condensed>tfoot>tr>th, .table-condensed>thead>tr>td, .table-condensed>tbody>tr>td, .table-condensed>tfoot>tr>td{
    padding: 5px;
}

you can get even more narrow padding, with change padding value to 1px.

Padding 1px example: