# Constants (/xml/ui_elements/consts)



Overview [#overview]

Constants can be defined to replace any value with a selected type or to be used as special values.

The supported types are:

* `color`
* `px`
* `percentage`
* `string`
* `opa`
* `bool`

Usage [#usage]

```xml title="xml" lineNumbers=1
<consts>
    <color name="color1" value="0xff0000" help="Primary color"/>
    <px name="pad_xs" value="8" help="Small padding"/>
</consts>
```

Constants can be used in:

* Style properties
* Widget and Component properties

Constant values can be referenced by `#constant_name`. For example:

```xml title="xml" lineNumbers=1
<styles>
    <style name="style1" bg_color="#color1"/>
</styles>
```