Got it.
Some good directions at https://docs.zen-cart.com/user/accessibility/tools/siteimprove/
Product by browser available at https://www.siteimprove.com/integrations/browser-extensions/
Sites with A failures are ripe fruit for the new internet favorite of lawsuits for accessibility.
AA rankings are next and AAA are things that any e-commerce site should try to accomplish simply to make it easier for their customers.
Using the Siteimprove addon, we find one A failure on your site. And, as often happens, the problem is with the inclusion of the letsencrypt info in your footer. Today's browser will warn or even block a site without a current SSL certificate, so the link is really not needed. Also, you site does not qualify for the CSS badge (22 errors). Personally, I don't recommend that or the HTML badge as they can easily be unvalidated with one stray character.
AA failures on your site are for element size and contrast. Both are critical to staying off the lawsuit list.
I'm not sure what slider you are using but the dots at the bottom of the slider are not given enough space for someone to select them. Especially on a mobile. To meet AA standards, the 8 x 8 setting should be at least 24 x 24. For best practices, the size should be 44 x 44. Those settings are minimums.
Your AA contrast problems are in your footer where you have a background of #C0C0C0 and a foreground of #364FB5. That's a contrast of 3.92:1. In order to meet AA compliance the ratio should be 4.5:1 and AAA should be 7:1. It's often difficult to figure out the right value when you want to keep a particular color. I created a site that can help with this (click on a little help with colors in my sig). Keeping the #C0C0C0 background, the foreground is displayed for all ratios.
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Likewise, all of your product numbers in the Category sidebox are set for a #FFFFFF background with a #666666 text color. Using the same generator, you would need to be at least #6E28DC to meet AAA standards. It may look fine on a desktop but, when you get to mobile, the numbers are small. If you want to stay with the gray, the Color Contrast Generator is not much help. The Colour Contrast Analyzer is your helper in this case. Synchronizing the colour values starting with #666666, you can click on the red value's round slider and use the arrow keys to reach a valid setting while maintaining a gray look.
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You'll find both tools very helpful in making your site more accessibie to your users.
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