Add styles to UXML

In UI Toolkit, you can use USS to customize the appearance of visual elements. 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 in the same folder of the UXML file with the following content:

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

You can reference it like this:

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

その他の参考資料

• Style UI
• Best practices for managing elements