I would like to learn gauge theory, starting from the simplest case. I have heard that I should start with electromagnetism, which is just the $U(1)$-gauge theory. All the references I know are written for physics students.

Being familiar with bundle theory, it would be nice if I can start with a short exposition that explains electromagnetism **using the language of bundles, characteristic classes, curvatures, etc..** . Any relevant pointers are appreciated.