### retina-query()

Create the query part of a media query for retina/hdpi screens, which you can store in a variable, to use when you make a media block.  

> **Warning:** since version `0.9`, the retina-query() mixin has changed: it's now a *block* mixin.

#### Signature

`+retina-query( media [, density ] )`

* `media`: the media of the query
* `density`: pixel density for the query. *Optional*. Default to `1`

#### Example

##### Usage

```stylus
+retina-query( all, 1.3 )
    div
        color: red

+retina-query( only screen, 2 )
    div
        color: red

+retina-query( screen )
    div
        color: red
```

##### Result

```css
@media all and (-webkit-min-device-pixel-ratio: 1.3), all and (min--moz-device-pixel-ratio: 1.3), all and (-o-min-device-pixel-ratio: 1.3/1), all and (min-device-pixel-ratio: 1.3), all and (min-resolution: 125dpi), all and (min-resolution: 1.3dppx) {
  div {
    color: #f00;
  }
}
@media only screen and (-webkit-min-device-pixel-ratio: 2), only screen and (min--moz-device-pixel-ratio: 2), only screen and (-o-min-device-pixel-ratio: 2/1), only screen and (min-device-pixel-ratio: 2), only screen and (min-resolution: 192dpi), only screen and (min-resolution: 2dppx) {
  div {
    color: #f00;
  }
}
@media screen and (-webkit-min-device-pixel-ratio: 1), screen and (min--moz-device-pixel-ratio: 1), screen and (-o-min-device-pixel-ratio: 1/1), screen and (min-device-pixel-ratio: 1), screen and (min-resolution: 96dpi), screen and (min-resolution: 1dppx) {
  div {
    color: #f00;
  }
}
```

#### Alias

`hidpi-query()`