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Best semantic markup for a Blockquote:
https://coderwall.com/p/tvkd9w/best-semantic-markup-for-a-blockquote
Visually hidden css:
https://mediuma11yproject.com/@jessebeachposts/bewarehow-smushedto-off-screen-accessible-text-5952a4c2cbfe#.2g9wpybl9hide-content/
Great accordion pattern (but maybe put the heading tag in the section tag):
https://www.aditus.io/patterns/accordion
Sortable tables (and some general approaches to making controls accessible):
https://adrianroselli.com/2021/04/sortable-table-columns.html#ScreenReaders