A few comments about using color in spreadsheets.
The general rule of thumb - minimize the use of color. Too much color in a spreadsheet actually makes it harder to read. It gets worse if you are not consistent with the colors you use.
If you search "using color for formatting spreadsheets" you will get a lot of results that tell you the standard color scheme for financial statements:
Blue for inputs or any hardcoded data.
Black for calculations and references to the same sheet.
Green for calculations and references to other sheets.
Red for references to separate files or external links.
Keep in mind that, simple as this is, it still may confuse some users of your spreadsheet, especially if they are not used to looking at spreadsheet financial statements. Of course, the users of the financial statements may not really care where the information is coming from - only the results of the spreadsheet.
If you want to emphasize a font, consider using other techniques, like bold, italic, or indenting the text.
Instead of color, consider using light colors or shades of gray to highlight cells that you want to emphasize.
Finally, remember that not everyone sees color the same way. For people that are color blind or have a visual impairment, for example, red and green are not clearly distinguishable from each other. For such users, the financial statement color suggestions above would not help in their understanding of the spreadsheet.