The portable and most effective way to change color and font definitions is to first change the definitions in the color and font tables, then use the PUT–KEY–VALUE statement to write the new definitions from the modified tables. You can affect the color and font tables in the current environment using the COLOR–TABLE and FONT–TABLE handles (see Accessing the current color and font tables), and you can allow the user to affect the current color and font tables using the SYSTEM–DIALOG COLOR and SYSTEM–DIALOG FONT statements (see Allowing the user to change colors and fonts).