Responsive top navigation menu: hamburger menu on only home page

[rbs]

I've used the html, css, and javascript code from the responsive top navigation page but when I shrink the browser width the hamburger menu is on only the home page and not on any of the other four pages of my web site. I suspect the problem is with styles.css and would like to learn how to have the menu display and work on all five pages.

styles.css

[dsonesuk]

Maybe this https://www.w3schools.com/HOWTO/howto_html_include.asp

and this https://www.w3schools.com/tags/tag_link.asp

With https://www.w3schools.com/tags/att_script_src.asp

Also https://www.w3schools.com/cssref/css3_pr_mediaquery.asp