The best way to achieve precise control over the appearance of your fonts and other attributes is by using a templating engine like Jekyll.

You’ll need to set up GitHub Pages and install a Jekyll template to work as a remote domain, such as your profile page, at https://github.com/username. At first, this process may seem daunting, especially if you only want to make a simple change, like adjusting the body font size from 18px to 16px. However, using Jekyll is a more effective solution compared to making kludgy, overwrought markdown hacks. Plus, it’s completely free and open-source.

As someone new to templating, I understand the anxiety over unfamiliar technologies, but the level of control it provides will ultimately improve your experience. Although many resources are available, my workflow isn’t polished enough to recommend specific options. Google is your friend if you choose this path.