html - Css for fieldset is not working on responsive view -

i trying set width of field set on responsive view not able set width. below link having captca. need test width that

you need align textboxes adjusted

try --> https://jsfiddle.net/prasanth_jaya/65c6cg7c/

<div style="width:100%;display:flex">      <h4 style="width:35%">first name</h4>      <input type="text" style="width:65%" /> </div>