This site uses the font GaramondLatin to display macrons (long marks) over long vowels. If you don't have the font, your screen will display very weird and, unless you're incredibly smart, unintelligible characters for letters that have macrons over them.
The font is available from CL Fonts for both Windows and Mac systems and they don't charge for it. To install the fonts, perform the following steps:
1) go to the CL Fonts site and download either the Windows or Mac CL Font version appropriate for your system (there are other products available at this site, e.g. the Anaxiphorminx font. You won't need them for the Latinpage).
2) install both the fonts [the download will give you documentation on how to do this] and the CL keyboard.
You don't need the keyboard to display pages on this site for now. But eventually you will.
The Latin Page