You can use Safari Reader to view a webpage article in one page, formatted for easy reading, and presented without ads, navigation, or other distracting items. You can adjust font, font size, and background color for Reader.
In the Safari app on your Mac, do any of the following:
View an article using Reader: Click the Reader button at the left end of the Smart Search field. The button appears only if the webpage has an article that Reader can show.
Change how your webpages look in Reader: In Reader, click the letter button that appears at the right end of the Smart Search field, then do any of the following to adjust the settings:
Choose a font size.
Choose a white, sepia, gray, or black background.
Choose a font.
Reader always shows you the last font, size, and background you chose.
Stop using Reader: Click the Reader button again or press Esc.
You can also permanently enable Reader mode in Safari preferences. Select the Reader tab (or Websites > Reader), find the "When visiting other websites" drop-down list, and select "On".