That will work on PC. Not sure about Apple computer. But on my Nvidia shield (Android). Color change will not work.You can change this yourself: at the very top of this page, click on Settings; then, on the left-hand sidebar, click General Settings; then under Miscellaneous Options, you'll find the option to change the forum skin to whatever you want.
Be aware that some people's posts have colour tags that may make their content invisible or difficult to read under the new theme - pressing <ctrl>-A to select and highlight the whole page can be useful in such cases.
But this do not work for some pages. I choosed a different skin there with black background, but some pages still show White. For example the search page. Can be a browser issue...You can change this yourself: at the very top of this page, click on Settings; then, on the left-hand sidebar, click General Settings; then under Miscellaneous Options, you'll find the option to change the forum skin to whatever you want.
But this do not work for some pages. I choosed a different skin there with black background, but some pages still show White. For example the search page. Can be a browser issue...