What is the font and style used in contribution reports?
The size and font of the Contribution Statements that generate is Arial font, with a size of 11. If you use that size and style of font for your thank you message, it will be consistent.
If you are finding that fonts are not being consistent throughout the statements, you can always export the results to Word. You can do this by clicking the PDF dropdown within the report and selecting the option RTF. Finally you will select the disk icon to save the file.