On The Athletic app for Android, tap the “Aa” in the top bar when viewing an article. You can adjust text size or choose to match your system text size. Use the brightness slider to control display brightness.
On The Athletic app for iOS and Android, tap the "Account" button in the bottom right of the app. Then select "App Settings" to be provided with the option to select Light, Dark, or System. The System setting follows your device's current setting of dark mode or light mode. You can also change your theme while reading an article or headline by tapping "Aa" in the top right.
On the website font size is dependent on your browser. Check with your browser’s help manual, but normally “Zoom In” is “Cmd+” on Mac and “Ctl+” on Windows, while “Zoom Out” is “Cmd-” and “Ctl-” on Windows. The website currently does not support brightness or theme settings.