Hi, I'm Shamim Hossain
Answer some questions and I will help you to figure out the right CSS unit for your project.
Assuming you are only using these units for web development, not for print media.
rem
Most of the time, you will probably use rem when declaring font sizes. It's easy to use, predictable, and very importantly, respects the users choice if they have made changes to their default font size at the OS or browser level.