Question

How can I load a webpage, eg. google.com and then load a local CSS file that overrides certain styles?

The first part I can do, it is the latter that I seem to be unable to do.

Answer 1

As usual, the answer turned out to be quite simple.

WebPreferences *webPrefs = [WebPreferences standardPreferences];
[webPrefs setUserStyleSheetEnabled:YES];
//Point to wherever your local/custom css is
[webPrefs setUserStyleSheetLocation:[[NSBundle mainBundle] URLForResource:@"style" withExtension:@"css"]];

//Set your webview's preferences
[myWebView setPreferences:webPrefs];