I created a survey, with matrix type question (among others of course). The matrix columns have the same width, I want to give a column a width smaller than the others, for example, I want to make these two columns smaller (please click the link below) :

Table to resize 

Here is the qweb code generating my table : 

  <template id="matrix" name="Matrix">

       <table class="table table-hover">

           <thead>

                <tr>
                    <th> </th>
                    <th t-foreach="question.labels_ids" t-as="col_label"><span t-field="col_label.value" /></th>
                </tr>
            </thead>
            <tbody>
                <tr t-foreach="question.labels_ids_2" t-as="row_label">
                    <th><span t-field="row_label.value" /></th>
                    <td t-foreach="question.labels_ids" t-as="col_label">
                       <input type="text" t-if=""/> <!-- the most important line codes-->
                       <input type="number" t-if="">
                    </td>
               </tr>
         </tbody>
    </table>
</template>

I don't know where to start, neither how to write on Sass, I know only the concept. 

Thanks.