I don't have a smartphone, so it wasn't something I noticed, but my previous blog layout with sidebar navigation on the left was not so good for mobile devices with small portrait screens. So I moved the navigation links below the main article/index content, with a link from the page top header. This also has the bonus of making the relevant part of the page load quicker, with about 1.3kB of HTML before the article starts instead of 8.3kB previously. I also added a meta tag that makes it display at a better size by default on mobile devices:
<meta name="viewport" content="width=device-width, initial-scale=1" />
I don't know how/why that tag works, but I saw it recommended all over the place, so maybe it's just how things are broken by default these days and you have to jump through hoops to fix them.
I also added a link back to my website home page from the blog header, and made a few small tweaks to the style sheets (thicker borders around the interesting part of the page).
These changes are spread between two repositories, the public cmcms repository with shell script and XSL style sheets for generating the HTML pages, and a private one with the source code for all the pages and static assets like style sheets and images. I did update the examples in the cmcms repository, but if you're using cmcms with your own site then do note that if/when you upgrade you'll have to fix your CSS to make it look sensible.