Disable injected stylesheets

When testing a webapp (bootstrapped with the ares package) in an old emulator (webOS 6 Simulator 1.3), I am getting some injected stylesheets and was wondering if there’s a way to disable them

One of them is:

  • {
    font-weight: 400 !important;
    //… other stuff

We are not sure exactly what problem you are getting, but you can redefine CSS with higher specificity than the original. Precedence over third-party CSS will be helpful. Thank you.