Which CSS property changes the opacity of text?

The property that changes the opacity of text is opacity. The opacity property in CSS is used to specify the transparency level of an element. It accepts a value between 0.0 (completely transparent) and 1.0 (completely opaque). When applied to text, it affects the text's visibility in a way that it can have a blurred or faded appearance, allowing for some background elements to be seen through the text. This property is particularly useful for creating layered effects and enhancing the visual appeal of a webpage.

Other properties, like visibility, adjust whether an element is visible or not, but do not provide the gradual effect that opacity offers. The color property changes the actual color of the text but does not affect its transparency. The display property controls how an element is displayed on the page (e.g., block, inline, none) but does not influence the opacity of the text itself. Thus, the opacity property is distinctly focused on transparency, making it the correct choice for altering the opacity of text.