[Tex2002ans]

Originally Posted by ebookscovers

maybe the best thing going forward is to avoid using superscripts and just write 21st as is??

Yes, for readability/accessibility—and avoiding all these line-height problems too!—that's exactly what I do.

So instead of:

<p>In the 21<sup>st</sup> century, this happened.</p>

use this:

<p>In the 21st century, this happened.</p>

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Side Note: Word defaulting to "superscript ordinals" (st + nd + rd) is one of the worst settings there is.

It's one of the first things I disable + instantly correct whenever I see it inside documents.

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Side Note #2: Like Hitch said, for footnote numbers, we recommend NOT using superscripted numbers:

<p>In the 21st century.<sup>99</sup></p>

but instead use bracketed numbers:

<p>In the 21st century.[99]</p>

For more info on that, see:

• 2022: "Footnotes: Best Practices?"
• 2022: "bridging endnotes in scanned document"

and even my old post from 2013 which explains why brackets in ebooks are better than superscript notes:

• 2013: "A link to jump back to the original start point?"

(The same logic still applies all these years later.)

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Side Note #3: One of the only few places I can see <sup> needing to be used is languages that have a:

• superior letter
  
  • French 'e'
• ordinal indicator
  
  • Spanish/Portuguese 'ª' + 'º'

For more info on that, see my post here:

• 2021: "superscript code"