---
title: Limitations
description: What fluidity deliberately doesn't validate or support, and the browser baseline (Baseline Widely Available CSS) every utility requires.
sidebar:
  label: Limitations
  order: 3
---

Fluidity trusts you the same way Tailwind's arbitrary values do — it validates nothing at build time beyond CSS syntax itself.

## No value validation

Fluidity does not check that:

- `min < max` — an inverted ramp (`f6y-p-8/2`) compiles and runs; it just ramps downward.
- Units are compatible between `min` and `max`.
- A curve's `--f6y-base` is greater than 1 — a `base` of 1 or less makes `exp-`/`log-` curves mathematically undefined (`log(x, 1)` is division by zero).

## No third-party plugin integration

Fluidity isn't integrated with tools like Tailwind Merge. A conditional class list that needs to deduplicate `f6y-p-2/8` against another padding utility has to do so itself — fluidity's classes are opaque strings to those tools, same as any other Tailwind utility they don't specifically recognize.

## No negative values

Tailwind's `-m-4` idiom — a leading dash selecting the negative form of a scale value — has no fluidity counterpart. A class like `-f6y-m-4` simply doesn't match any of fluidity's `@utility` patterns. For a negative ramp, use arbitrary values on both bounds instead:

```html
<div class="f6y-m-[-2rem]/[-4rem]"></div>
```

## Browser support

Fluidity targets Baseline Widely Available CSS as of August 2026:

- `calc()`, `clamp()`, `var()`
- The CSS trigonometric functions `atan2()` and `tan()`
- The CSS exponential functions `pow()` and `log()`
- Container query length units (`cqi`, `cqb`, `cqw`, `cqh`, `cqmin`, `cqmax`)

There is **no fallback for older browsers**. Every declaration a fluidity utility emits embeds `tan(atan2(...))` (plus `pow()`/`log()` for `exp-`/`log-` variants). When a browser doesn't support one of these functions, it drops the whole declaration — the property falls back to its initial or inherited value, not a static approximation of the ramp. `f6y-p-2/8` on an unsupported browser produces no padding at all, not `0.5rem` and not `2rem`.

If a static fallback matters for your audience, layer a plain Tailwind utility before the fluid one and let the fluid declaration override it on browsers that support it:

```html
<div class="p-4 f6y-p-2/8"></div>
<!-- p-4 wins on unsupported browsers; f6y-p-2/8 wins everywhere else,
     since it's declared later in the same @layer utilities. -->
```

## Next steps

**[Utility index](/reference/utility-index)**

The complete, generated list of every utility fluidity ships.

**[Quickstart](/quickstart)**

Install fluidity and ship your first fluid utility.