When using USS, you can specify values for built-in
VisualElement properties or for custom properties in your UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary code.
In addition of reading their values from USS files, you can assign built-in property values in C#, using the C# properties of
VisualElement. Values assigned in C# override values from a Unity style sheet (USS).
You can extend USS with custom properties. Custom USS Properties require the
This section lists the supported types.
UI Toolkit supports pixelsThe smallest unit in a computer image. Pixel size depends on your screen resolution. Pixel lighting is calculated at every screen pixel. More info
See in Glossary (
px) and percentages (
%) as units of measurement for length. Pixel values are absolute, while percentages are usually relative to the element’s parent.
width:200px;expresses a width of 200 pixels.
width:50%;expresses a width of half of the parent element’s width.
It’s important to specify the unit of measurement. If you do not specify a unit of measurement, UI Toolkit assumes that the property value is expressed in pixels.
0 is a special value that doesn’t require a unit of measurement.
Numeric values are expressed as either floating points or integer literals. For example,
Specific keywords are supported for some built-in properties. Keywords provide a descriptive name instead of a number. For example:
position:absolute. All properties support the
initial global keyword which resets a property to its default value. See supported properties for a list of keywords.
UI Toolkit supports the following literal color values and functions:
#FFFF00(rgba one byte per channel),
rgb(255, 255, 0)
rgba(255, 255, 0, 1.0)
You can reference project assets such as fonts and textures from your USS files. For example, you might reference a texture to use as the background image for an element.
To reference an asset, you can use either the
url() function or the
resource() function. Referenced Assets are resolved when the style sheet is imported.
For example, the style declaration below uses the
resource() function to reference a texture asset named
img.png in the
Images directory, and specify it as the background image.
Unity recommends using
url() function in most cases. However, the
resource() function supports automatically loading different versions of image assets for different screen densities.
When you reference an asset with the
url() function, the path you specify can be relative or absolute:
The path must include the file extension.
For example, let’s say your project has a
USS folder that contains all of your style sheets, and a Resources folder that contains all of your image assets.
Assets └─ Editor └─ Resources └─ USS
To reference an image named
thumb.png, you can use one of the following paths:
|Relative path||Absolute path|
resource() function can reference assets in Unity’s resource folders (
Editor Default Resources). You reference an asset by name.
Editor Default Resources Resourcesfolder, you must include the file extension.
Resourcesfolder, you must not include the file extension.
|Path to file||Reference syntax|
If you need to support screens with different screen densities (DPI), the
resource() function allows you to load the correct versions of texture assets automatically.
You have to:
@2xsuffix in their file names. For example the high DPI version of
When Unity loads the asset, it automatically chooses the correct version for the current screen DPI.
For example, if you use
resource("myimage") in USS, Unity loads either
Use quotes to specify a string value. For example: