Hi @interprojets,
I hope you are well today and thank you for your question.
In the admin area the sidebars are responsive by default so i think you want to make the sidebars responsive displayed in the front end of your site.
Most of the time if the theme that you are using is responsive then the sidebars in the front end are also responsive but if it is not then you can make it responsive by developing the CSS code using media query.
You will find more information about CSS media query on the following pages.
https://www.w3schools.com/cssref/css3_pr_mediaquery.asp
https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Media_queries
https://css-tricks.com/css-media-queries/
https://developers.google.com/web/fundamentals/layouts/rwd-fundamentals/use-media-queries?hl=en
Best Regards,
Vinod Dalvi
