As designers, it makes sense to think about what space is available in the browser, and adjust your typography accordingly. It's also important to remember that different users will have different font-size needs -- and the more a font size is responsive to the viewport, the less responsive it will be to user inputs.

OddBird

Fluid typography requires balancing viewport-based sizing with user font preferences. Using CSS comparison functions like clamp() with em/rem and viewport units allows responsive text scaling without forcing a choice between fixed and relative units. The key challenge is ensuring font sizes remain responsive to both available space and user accessibility settings, as viewport-responsive sizing can conflict with user-defined font preferences.

Responsive and Fluid Typography with Baseline CSS Features