Change the size of text box in matrix

I have tried using the below CSS provided to others regarding this question, but I can't quite get it right.

.form-matrix-values +

.form-matrix-values +

.form-matrix-values .form-textbox {

width: 200px;

}

On https://form.jotform.com/80815500277151 I would like the "Diagnosis Description" text box under Diagnosis Information for Primary, Secondary and Other to be the same size as "Description" text box under Services Information. 

Thanks. 

Please try add this CSS codes 

#id_67 .form-matrix-row-headers + .form-matrix-values .form-textbox {

width: 200px !important;

}

#id_67 .form-matrix-row-headers + .form-matrix-values + .form-matrix-values .form-textbox {

width: 200px !important;

}