It looks like you use the Jetpack plugin, using the custom css part of that add the following code. Change color to your liking.
.entry-content a {
color: #ff0000;
}
Thanks! Should I just add it in the very bottom?
Also, why should I do this in Jetpack and not in the regular template stylesheet?
The regular stylesheet will be over-written if the theme is updated, thereby loosing all customization made the file.
That resulted in a “fatal error” and deactivated the plugin.
Is there another option?
Just to be sure, did you add the CSS to the Jetpack CSS editor under Appearnance > Edit CSS, as seen in this screenshot:

You didn’t edit the Jetpack plugin files themselves, right?
Other options include installing a standalone custom CSS plugin, or creating a child theme.
Hi Kathryn,
batharoy’s instruction was a bit confusing (CSS is also not my forte) so I did edit the Jetpack plugin itself.
But your instruction worked! Thank you 🙂
Great, glad you’re set. 🙂 I’m marking this post as resolved.