In brief
Captive display does not rewrite the value in the data.
Useful to know
text-transform changes the visual register of text, for example, to uppercase or lowercase. Conversion may depend on language, so the correct lang matters. [1]
Example: .section-label { text-transform: uppercase; }. The original text remains saved in the document ; CSS does not perform server normalization of names or codes . capitalize affects the initial letters of words, but is not a universal editor for correctly spelling titles. For usernames, keep the entered data and do not accept the decorative spelling correction layout.
Sources
For further detail and to check the information: