To ensure people with vision impairments have equal access to your website, you might need to add some Custom CSS.  Not all WordPress sites come with compliant color schemes. Luckily there is a Plugin to help with this. 

Basically, we need to make sure that the text color is easy to read on its background color. It seems a little subjective, so the WCAG 2.0 AA has a specific contrast ratio to determine what exactly is compliant and what is not.  Small text, like the body text, needs to meet a 4.5:1 ratio.  Big text, like headings, needs to be 3:1.

How to add custom CSS with the  Simple Custom CSS Plugin:

Go to the admin part of your site.

Step 1. Click the Plugins link

Step 2. Search for "simple custom css"

Step 3. Click the "Activate" link.

Screenshot of the three steps sited above

Step 4. Then the “Add CSS” link will appear.  We want to click on that.

Screenshot of Add CSS link

Step 5. Paste in your custom CSS and click the "Update Custom CSS" button.

Screenshot of the Simple Custom CSS text field and update custom css button

Step 6. Take a look at your site.  Vask in your accomplishment.