How to change the width of just one column on input matrix table?

How can I change the width of the text column on this table without affecting the width of the other columns? I assume I would use CSS, but what would be the coding? 

Please insert the CSS code below into the form "92818793295171":

#id_48 table.form-matrix-table  td:nth-of-type(4) input{

width: 400px !important;

}

You can change the "px" size according to your requirement.

Related Guide:  How-to-Inject-Custom-CSS-Codes 

Beautiful, thank you! Is it possible to change the width of the label column (far left) using the same code?

To change the width of your left headers, you may use this CSS

.form-matrix-row-headers{
width: 200px;
}

If you need further assistance, let us know.