Pamasich, 4 months ago

Edit: actually, this isn't behaving as expected, it's coloring comments too... will edit this comment in a moment when I find out why.

Go to your settings (via the dropdown that opens when you hover over your avatar and name in the top right) and you should see the "Appearance" section right at the top, containing a textbox labeled "Custom CSS".

Just paste the code in there.
Here it is again for reference:

div#content {
    > article {
        /* thread styling */
    }
    > blockquote {
        /* microblog post styling */
       background-color: red;
    }
}

If you want to have a bigger textbox, you can drag it longer by clicking and dragging below the scrollbar.

After pasting the code into the textbox, scroll to the bottom of the settings page and press the "Save" button between the Notifications and Account Deletion sections.

You should now see microblog posts in your main feed highlighted in red.

---

Now you can go back and change the color to something you actually want to see.

You can replace the red with another color name, or you can look up your desired color using this color picker and then copy the HSLA color it outputs below the color picker.

I recommend HSLA over the other options because it's easy to change later. It's just a base color + saturation + lightness + transparency. Rather than having to mix red green and blue in your head like you'd have to for adjusting rgb.

If you just want microblog posts to be a bit lighter or darker (depending on your theme) than threads, you can use hsla(0,0%,100%,0.15) (this makes them lighter, change the 100% to 0% for darker). Tweak the transparency (the last value) to change the intensity of the color change.

Besides the background color, you can also change other CSS properties. Just add additional lines in the pattern property: value;.
For example, you can set a border using border: 1px red solid;, which creates a red solid border of 1 pixel width.
I like to use this site as a reference myself for what properties exist and how they're used.