h1 { font-family: Arial, Helvetica, sans-serif; }

The

font-family

property should hold several font names as a "fallback" system, to ensure maximum compatibility between browsers/operating systems. If the browser does not support the first font, it tries the next font. Start with the font you want, and end with a generic family, to let the browser pick a similar font in the generic family, if no other fonts are available