# number-zero-length-no-unit

Disallow units for lengths of zero.

```css
    a { top: 0px; }
/**          ↑ ↑
 * This zero and this type of length unit */
```

For zero lengths the unit identifier is optional.

The following patterns are considered warnings:

```css
a { top: 0px }
```

```css
a { top: 0.000px }
```

The following patterns are *not* considered warnings:

```css
a { top: 0 }
```

```css
a { top: 1px }
```

```css
a { top: 1.001px }
```

# number-zero-length-no-unit

Disallow units for zero lengths.

```css
    a { top: 0px; }
/**          ↑ ↑
 * This zero and this type of length unit */
```

*Lengths* refer to distance measurements. A length is a *dimension*, which is a *number* immediately followed by a *unit identifier*. However, for zero lengths the unit identifier is optional. The length units are: `em`, `ex`, `ch`, `vw`, `vh`, `cm`, `mm`, `in`, `pt`, `pc`, `px`, `rem`, `vmin`, and `vmax`.

The following patterns are considered warnings:

```css
a { top: 0px }
```

```css
a { top: 0.000em }
```

The following patterns are *not* considered warnings:

```css
a { top: 0 } /* no unit */
```

```css
a { transition-delay: 0s; } /* dimension */
```

```css
a { top: 2in; }
```

```css
a { top: 1.001vh }
```

Expand description of zero-length rule
Expand description of zero-length rule
