Adding a Theme

You can personalize your Jekyll site by adding and customizing a theme.

People with write permissions for a repository can add a theme to a GitHub Pages site using Jekyll.

Changes to your site are published automatically when the changes are merged into your site’s publishing source. If you want to preview your changes first, you can make the changes locally instead of on GitHub. Then, test your site locally.

Choosing Themes/Creating Themes

The theme chooser adds a Jekyll theme to your repository!

How the theme chooser works depends on whether your repository is public or private.

• If GitHub Pages is already enabled for your repository, the theme chooser will add your theme to the current publishing source.
• If your repository is public and GitHub Pages is disabled for your repository, using the theme chooser will enable GitHub Pages and configure the default branch as your publishing source.
• If your repository is private and GitHub Pages is disabled for your repository, you must enable GitHub Pages by configuring a publishing source before you can use the theme chooser.

If you manually added a Jekyll theme to your repository in the past, those files may be applied even after you use the theme chooser. To avoid conflicts, remove all manually added theme folders and files before using the theme chooser.

To add a custom theme you will need to create your own theme using the jeykll theme edditor You can find more info, Here

Enter the config.yml file and create a new line and make it theme: and then enter the name of the theme you want/created. Ex: theme: minimal

Find more documentations here