Traditional responsive typography uses breakpoints – font sizes jump from one fixed value to another at specific viewport widths. This creates awkward transitions and requires extensive CSS management.
Fluid typography scales smoothly between minimum and maximum values based on viewport width. As the screen gets smaller, fonts gradually reduce in size without jarring jumps or awkward in-between states.
WordPress implements this using CSS clamp() functions with viewport width calculations. You define size ranges and WordPress generates the complex CSS needed to create smooth scaling between your minimum and maximum values.
Fluid typography provides better user experiences across devices while reducing the CSS complexity you need to manage in your block theme development.