The default behaviours of HTML and default CSS are accessible to a reasonable degree. PDFs that aren't scans are accessible.
It tends to be when one overrides behaviour that you start to become inaccessible.
JS is awful for breaking a site for a screen reader as the purpose and contents can change after or during it being read.
Scientists and researchers, in my experience, don't tend to futz with the markup, because it's just the delivery tool, not their purpose.
The default behaviours of HTML and default CSS are accessible to a reasonable degree. PDFs that aren't scans are accessible.
It tends to be when one overrides behaviour that you start to become inaccessible.
JS is awful for breaking a site for a screen reader as the purpose and contents can change after or during it being read.
Scientists and researchers, in my experience, don't tend to futz with the markup, because it's just the delivery tool, not their purpose.