From Dashboard go down to appearance>Customize>Additional CSS, and within that box put:
Ok, I cheated a little bit. There’s apparently no CSS for automatically creating indentions for the <br> so instead, since there is code for the p tag, what I did was search for code to eliminate the gap between Paragraphs.
I’m realizing now that this solution might not be optimal. Strike that. It’s not. Because when you are using the visual editor within WordPress its discombobulating and seems to screw up finding the + for creating a new paragraph.
But the code for the P is a gem. So for now just do it like so:
This will automatically indent all your new paragraphs, but not line breaks. Still it’s a great start and relief if you are using Twentyeleven and the lack of indention drives you crazy. I’ll keep searching for that other answer though. The above code is totally taken from this post on Lifewire.com. Give them all the credit.
It’s also cool to know that there is a sort of “in-built” on the fly version of child themes with Appearance>>Customize. Or at least I’m assuming it is. I would hate to think that if there was an update to Twentyeleven for example that those customizations would disappear. But at this point nothing would surprise me.