Thanks @Decimus for asking this question, and @scrambler for providing the CSS 🙂
I wanted to do something similar on my site, and had achieved it by creating a custom menu and then adding the posts as children of the blog page. However, I could see that as more blog posts were added this was quickly going to become unwieldy – and I had to remember to add the post to the menu every time I created a new post! The CSS solution is much neater 🙂