How many CSS properties are there?

Here’s what I found.

Count

539.¹

Definitions

CSS: Cascading Style Sheets (CSS) is a simple mechanism for adding style (e.g., fonts, colors, spacing) to Web documents.¹

CSS) property:

(https://developer.mozilla.org/en-US/docs/Learn/CSS/First_steps/What_is_CSS)

[1] https://www.w3.org/Style/CSS/all-properties.en.html#colorkey