Under Construction WP3.3

I’ve searched these forums and many top returned posts are from several years ago.

Is there a preferred way to edit a site live while having an under construction (any static text) on the home page in WP 3.3. index.html vs index.php? A Dashboard setting I’ve overlooked?

I’m not advanced enough yet to do the work in a subdirectory and export to the main directory (getting there). I’m building some sites locally now (MAMP) and when ready to publish will work on learning the site transfer, but for now would like to work a site that is hosted online and take the main site down for a few days while it gets converted to WP.