The icon in the bottom left hand corner of every page gives you access to a set of features to enhance the website user experience. Clicking that button takes you to a set of options where you can choose those that are helpful for you. You can for example change the text to help with with dyslexia. You can make the text larger. You can adjust the color scheme and various other settings. Simply check the relevant item. If you want to change the screen back to the way it was, uncheck the relevant items.