Add styles to UXML

In UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary Toolkit, you can use USS to customize the appearance of visual elementsA node of a visual tree that instantiates or derives from the C# VisualElement class. You can style the look, define the behaviour, and display it on screen as part of the UI. More info
See in Glossary. The suggested workflow for USS is that you visually style an element in UI Builder, extract the style to a USS file, and then reference it in UXML.

If you style an element in UI Builder, the style is added as an inline style to the style attribute of UXML elements:

<ui:UXML ...>
    <ui:VisualElement style="width: 200px; height: 200px; background-color: red;" />
</ui:UXML>

To reference a stylesheet file, add the <Style> element under the root element of a UXML file.

For example, if you have a USS file named styles.uss with the following content:

#root {
    width: 200px;
    height: 200px;
    background-color: red;
}

You can reference it like this:

<ui:UXML ...>
    <Style src="<path-to-file>/styles.uss" />
    <ui:VisualElement name="root" />
</ui:UXML>

You can use a relative or an absolute path:

• Absolute paths start from the project’s Assets folder and begin with a / or project://database/. For example, /Assets/myFolder/myFile.uss or project://database/Assets/myFolder/myFile.uss.
• Relative paths start from the current file and exclude the /. For example, ../myFolder/myFile.uss.

Note: To reference a file from packages, use the absolute path of the package file that starts from the Packages folder. For example, /Packages/com.unity.package.name/file-name.uss or project://database/Packages/com.unity.package.name/file-name.uss. you must use the format of com.unity.package.name rather than package name for the package name.

Additional resources

• Style UI
• Best practices for managing elements