Go with the same margin width and general feel on your resume and cover letter. (uptowork.com)
The recommended margin width is usually between one - half and one inch. (careerdigital.com)
You can customize its look in a variety of ways: You choose among three different themes (black text on white, white text on black, or dark brown text on a sepia - toned background); a variety of fonts and font sizes; and three different margin widths. (macworld.com)