I appreciate the feedback Brandon. In order to make it more clear, I have updated the story with slightly tweaked button designs which use the 3px minimum border (as recommended here: https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/Contrast_(Minimum)) with a contrast of 3.23:1 (the minimum for AA is 3:1). Originally the codepen had a thin border, which defaulted to 1px on some devices, which is obviously not desired.

Of course, WCAG analysers can be gamed to pass, however there are a number of design elements here that should not only pass WCAG but also help people with poor vision to notice/use the buttons (for example, changing icons and icon colours on press, a more defined border on hover/focus etc.)