The encoding used in the XML and HTML documents is utf-8, and the Greek is standard Unicode, employing the monotonic block (starting at U+0370) and the polytonic block (starting at U+1F00). A modern browser running on a modern computer operating system should have no difficulty displaying the Greek and should require no special settings. In the CSS rules for the paragraphs and spans that are in Greek, the stylesheet gives the following typefaces in preference order: New Athena Unicode, Palatino Linotype, Cardo, Times, Times New Roman, Tahoma.
New Athena Unicode is available for free from the GreekKeys support site: apagreekkeys.org/NAUdownload.html. There is a known problem. During scrolling, the OS X text engines used by Firefox and Safari sometimes display lines incompletely (in the vertical direction) or incorrectly fail to redraw the pixels of descenders as white (creating an extended line). This problem may appear when scrolling is performed with a scroll wheel or touchpad, but it does not occur if scrolling is performed with the page up or page down key or by clicking in the scroll bar. In Firefox, the incomplete display will be redrawn correctly if you use the command to reload the frame containing the scholia (do not use the simple ‘reload page’ command): right-click on the scholia frame, and from the contextual menu select ‘This frame --> Reload frame’. In Safari, there appears to be no command for reloading a frame. A workaround is to use the contextual menu to load the frame in its own window, and in that window the normal reload command can be used. But it is better and quicker to use the page up key and then the page down key to force an accurate redrawing of the frame.
If your Greek display is showing characters from different fonts (typically this occurs for any letter when combined with any diacritic other than the acute accent by itself), it means you have an old Times or Times New Roman or Tahoma font that supports only monotonic Greek. You can avoid this problem if you ensure that the latest version of the font is enabled and older versions disabled. In OS X, installation of MS Word 2008 automatically places numerous old fonts into use, conflicting with the new and fuller fonts already supplied with the OS (Times New Roman, Tahoma, Arial). Use the Font Book application to disable the older versions (instructions). Or obtain one of the fonts that precedes Times in the list of typefaces above (New Athena Unicode and Cardo are free).