Jekyll themes let you change your site’s look, layout, and basic UX without rebuilding everything from scratch. They package layouts, includes, and assets into a reusable gem or GitHub repository you can plug into your project with a few lines of config.

Why Themes Are So Useful and Powerful

  • Separation of concerns: Content stays in your Markdown files; presentation lives in the theme. Update or swap the theme without touching your posts and pages.

  • Batteries included: Prebuilt layouts (home, post, page, archives), partials (header, footer, pagination), and styles save hours of boilerplate work.

  • Easy upgrades: Theme authors ship bug fixes and improvements. You update the gem (or remote theme) and your site benefits.

  • Override when needed: Jekyll lets you shadow any layout/include/asset by creating a file with the same path in your site—best of both worlds (speed + control).

  • Good defaults for accessibility & SEO: Most reputable themes ship sensible semantics, meta tags, and mobile-friendly layouts.

The Default Jekyll Theme

When you run jekyll new mysite, Jekyll’s starter site uses the Minima theme by default. You’ll see this in two places:

  1. Gemfile: includes gem “minima”

  2. _config.yml: contains theme: minima

Minima provides standard blog layouts, a basic home page, post styling, and sensible typography—perfect for learning Jekyll before you customize.

Using a Different Theme

You have two primary ways to use themes:

  1. Gem-based theme (installed through RubyGems)

  2. Remote theme (pulled from a GitHub repo at build time)

Choose one approach per project (don’t set both theme: and remote_theme: at the same time).

Using a Gem-Based Theme

  1. Find and install the theme gem: in your project’s Gemfile, add (or replace Minima with) another theme gem, for example:

     gem "jekyll-theme"

  2. Install with bundle install

  3. Point Jekyll at the new theme in _config.yml:

     theme: jekyll-theme

  4. Run the site with bundle exec jekyll serve

Using a Remote Theme

  1. Add the plugin in your Gemfile:

     gem "jekyll-remote-theme"

  2. Enable and configure in _config.yml (remove any theme: line to avoid conflicts):

     plugins:
 - jekyll-remote-theme

 # Replace with the owner/repo of the theme you want:
 remote_theme: owner/theme-repo

  3. Serve locally with bundle exec jekyll serve

Common Customizations

  • Override index.md/html or _layouts/home.html to customize the home page.

  • Site navigation can be customeized on many themes—check your theme’s docs.

  • Social icons & metadata are often configured via _config.yml keys (e.g., twitter_username, github_username).

Troubleshooting Tips

  • “Theme could not be found”

    • For gem themes, ensure it’s in your Gemfile and run bundle install.

    • For remote themes, verify:

        plugins: 
  - jekyll-remote-theme 
        
  # Point to a public owner/repo.
  remote_theme: owner/theme-repo

  • Conflicting settings: use either theme: (gem) or remote_theme: (GitHub repo), not both.

  • Assets not loading: check your baseurl and url in _config.yml, especially when viewing under a subpath (e.g., GitHub Pages project sites).

  • Sass not compiling: make sure your Sass file has front matter (---on the first two lines) so Jekyll processes it.

  • Locked versions on GitHub Pages: if using github-pages, your gem versions are pinned—use remote_theme to use the latest upstream theme.