The CSS font-size-adjust property allows developers to maintain the visual consistency of fonts across different browsers by adjusting the font size based on the x-height of lowercase letters, rather than the height of uppercase letters. This feature is particularly useful when the primary font choice is unavailable and a fallback font with a different aspect ratio is used, helping to preserve text readability. Although the property is supported by Firefox by default, its compatibility is limited in other browsers like Chrome, Opera, Edge, and Safari, with some requiring enabling experimental features. Developers can employ tools like LambdaTest for cross-browser testing to ensure consistent font rendering, as the property was initially introduced in CSS2, removed in CSS2.1, and reintroduced in CSS3. Despite its limitations in browser support, the CSS font-size-adjust property offers a valuable means to enhance text legibility on web pages, and developers are encouraged to start using it while considering fallback strategies for non-supporting browsers.