If anyone's inner CSS eye is twitching at the centered figures and captions but not centered text, open DevTools (F12 most of the time) and fix it with the following CSS (click the + on the right in Chrome/Brave where the CSS is to add new rules)

  div.flexcontainer {
    justify-content: unset;
  }

  figcaption {
    text-align: left;
  }

The figures and captions should be in line with the text now.