How do I change the font for article content?

Is there a quick pointer to what I can change in the css box under Preferences to change the font article content is displayed in? The font looks great on my retina MacBook Pro, but it’s really hard on the eyes on my regular Dell 1920x1200 LCD. I’d like to change the font to something like what Ars Technica uses for their articles but I don’t know how to do that.

I’m not an idiot, though! So if someone can give me a pointer, I can work with it.

“Yeah, put this in the box {div:article.content font=whatever px=whatyoulike} and reload” – this kind of thing is fine. Thanks!

I enjoy this:

div.postContent {
    font-size   : 21px           ! important;
    line-height : 1.5em          ! important;
    color       : #000000        ! important;
    font-family : georgia, serif ! important;
    max-width   : 850px          ! important;
}

I just checked with developer tools, they use Open Sans. You could host the font files yourself with a bit of work on your own installation (recommended) — or report to Google whenever you are visiting a particular site:

@import url('https://fonts.googleapis.com/css?family=Open+Sans');

div.postContent {
    font-family: 'Open sans', sans-serif;
    font-size: 15px;
    line-height: 22px;
}

I don’t think the !important overrides are necessary, at least I don’t need them in mine.