Working fine in my Ubuntu 14.10 VM (Firefox 35). It's inheriting font-weight: 300 from <body> and rendering as expected.

The use of <br></br><br></br> instead of <p> does feel distinctly mid-90s though. Especially since <br> isn't even supposed to have an end tag. If you're doing XHTML it's <br />, but for HTML all you need is <br>.