Hi, Firefox's settings have options where you can set a default zoom level and/or minimum text sizes. To open the settings, go to ''about:preferences'', or follow these steps: # Press the menu button [[Image:Fx89menuButton]] # Click on ''Settings'', which is about three-quarters of the way down the menu I've attached a screenshot of the subsections that the rest of this response will focus on. To set a default zoom level: # In the ''General'' panel, scroll down until you find the ''Language and Appearance'' section. # A bit further down, there will be a subsection for ''Zoom''. Use the drop-down menu for '''Default zoom''' to select a zoom level for all pages. Firefox will still remember individual site zoom levels you set. #* To set a zoom level for text only, select the '''Zoom text only''' checkbox. To set a minimum font size: # In the ''General panel'', in the ''Language and Appearance'' section, go to the subsection for ''Fonts''. # Click '''Advanced...'''. It will open a pop-up, which I've attached a screenshot of. # In the '''Minimum font size''' drop-down, select the minimum size in pixels in which all text must be displayed. # Click ''OK'' to save your changes. For more information about increasing text size: [[Font size and zoom - increase the size of web pages]]

Hello https://support.mozilla.org/en-US/questions/1523792 https://support.mozilla.org/en-US/kb/about-config-editor-firefox Maybe, you can test, the preference, layout.css.devPixelsPerPx