I am creating several org-mode documents to track code example and would like to be able to view the results of tangling or executing these code blocks in a browser. In the example below, I've created a source code block that starts a browsersync session; this which should reflect my changes in the web browser when I tangle a CSS or HTML file. How can I run this process in the background so it doesn't freeze Emacs? Currently, executing this code makes Emacs unusable in the same way that starting it in a shell would make the shell unusable.
#+BEGIN_SRC bash :tangle no :exports none browser-sync start --server --browser "Google Chrome" --files "*.css, css3_by_example.html" & #+END_SRC