Step 1:
Write down your text you're going to colorize. I'm using more dummy text in this case.
Step 2:
Right click and do inspect element or use (Ctrl+Shift+I) to open up the html.
Step 3:
Locate the text you want to change. You'll probably have to open up a few tags or use (Ctrl+F) and search for "data-medium-focused" (no spaces, no quotation marks) and it will bring you right above where your story starts. If you have multiple paragraphs as most stories do, you may have to open a few tags up to find the text you want to edit. In my example, I'm going to turn "Aliquam leo mi" red.
Step 4:
Once you find the paragraph your text is in, click on the < p> tag that corresponds to it. Then click on the 3 dots that appear to the left and find the option that says "edit as HTML" and click it.
Step 5:
Surround the text you want to color with "< font color="red">" at the start and "< /font>" at the end. (But without the quotation marks at the ends or the space between the "<" and the next letter. The forums won't let me type them together for some reason.)
Step 6:
Exit out and you should see the text change color.
You can click on the images to make them larger (I think) if the boxes and text are too small.
If you don't want to use red you can change the color by switching the word "red" to "blue" or any common color.
"< font color="green">"
For more specific colors, you can replace "green" with a "#" followed by a hexadecimal color code.
Don't be put off by the walls of HTML, it's easier than it looks. It will probably still take closer to 2 minutes per colorized section than the hour it took for me to create this tutorial though.