What are CSS Breakpoints?
CSS breakpoints are the extra code added to the CSS so that the website content will respond to the device screen size. Breakpoints are used to change the layout of the website depending upon the device used by the end-user. These are added in the code, but can be activated using a media query or other methods as well.
Setting CSS breakpoints is a great way to easily ensure that your website is optimized for the various screen sizes your visitors use.
To deep dive into CSS Breakpoints and see how to use them for responsive design, plz go through the following blog: