a11y(darkmode): use a button for the theme toggle (#1335)

Andrew

2024-08-24 4c9e8601504f76dcc3c273ea8ad1862df432b7b4

 quartz/components/styles/legacyToc.scss

@@ -12,7 +12,7 @@
      margin: 0;
    }
  }
    

  & ul {
    list-style: none;
    margin: 0.5rem 1.25rem;