Upgrading/Updating using Pacman

[Corconegre]

Aside from the tray menu where you have a display control to adjust brightness, you can also do that from the system settings (open the app from the kde menu).
System settings in section energy saver allows you to change brightness.
Font size can be adjusted in System settings/appearance/fonts

You can easily find setting in the system settings tool using the search bar on the top left (just type fonts and it will show you the relevant entries).