How to control the width of bars while browser width reducing

Hi All,
I am trying to control the bars width while reducing browser width
actually the problem is on 100% browser width bars width is fine but when I am reducing the zoom/width of browser
bar width increasing automatically on browser resize do we have any property or any option to control width of bars while doing browser resize

  • Normal 100% zoom of browser

  • After resize browser to 50% zoom

Thanks in advance