Version: 2022.3
Language : English
Create USS variables
USS built-in variable references

Introduction to USS built-in variables

USS built-in variables specify default values for Editor and runtime UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
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. You can use these variables in your own USS to match your custom interfaces with Unity style.

The name of each built-in variable indicates how and where the variable is used. A variable name consists of one or more parts, separated by hyphens. Each part consists of one or more words separated by underscores.


Each part of the name shows the types of USS rules that use the variable.

  • Group: The kind of data the variable represents.
  • Role/Control: A conceptual grouping for the elements the variable affects.
  • Sub-Element: An element or control the variable affects.
  • Pseudo States: Lists the states Unity uses the variable for.

For example, the following variable name:


Provides the following information about how Unity uses the variable:

Value Meaning
Group colors Represents color data.
Role/Control button Affects buttons.
Sub-Element text Affects text. Its group is colors, so it affects text color.
Pseudo-States hover Applies to elements when the mouse pointer hovers over them.

This USS built-in variable changes the color of button text when a user hovers over the button.


The group specifies what kind of data the variable represents. Each group has several possible sub-elements.

The variable names have the following groups:

Group Used for
colors Color properties, such as background-color and border-color
metrics Properties that control dimensions and shapes. For example, border-radius, border-width, margin, and padding
icons Standard Unity icon images

Role and Control

Roles and controls are two ways of grouping elements conceptually.

  • Role refers to a group of elements that have the same purpose, regardless of what type each element is. For example, the error role includes all elements that display error messages to users.
  • Control refers to a group of elements of the same type, regardless of what they do. For example, buttons includes all buttons in the Editor.

Each variable has either a role or a control.

The variable names have the following roles and controls:


Role Description
default Default style settings such as text color, background, and margin.
alternated_rows Elements that display tabular data with alternating row colors. For example, list items in a list view.
error Elements that communicate error states to users.
highlight Highlighted parts of the UI. For example, text selections, or selected items in tree views.
link Parts of the UI (typically text) that are clickable links. This is the un-clicked state.
play_mode Elements displayed when the Editor is in Play mode.
visited_link Parts of the UI, typically text, that are clickable links that a user has already clicked.
warning Elements that communicate a warning message to users.


Control Description
app_toolbar The main Unity toolbarA row of buttons and basic controls at the top of the Unity Editor that allows you to interact with the Editor in various ways (e.g. scaling, translation). More info
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app_toolbar_button Buttons in the main Unity toolbar
box Boxes used to group elements in the Editor UI
button Buttons in the UI, except for toolbars
dropdown Dropdown lists or menus
helpbox Boxes used to display help information
input_field Fields used to input text or numeric values
label Text labels in the Editor UI
object_field Fields used for object values. For example, property values for a GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
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or Asset.
popup Popup menu and other popup controls
preview Views used to display previews. For example, of Assets such as meshes and textures.
scrollbar_groove The background element of a scrollbar in which users drag the scrollbar thumb
scrollbar_thumb The draggable handle element in a scrollbar
slider_groove The background element of a slider in which users drag the slider thumb
slider_thumb The draggable handle element in a slider
slider_thumb_halo An overlay displayed around the slider thumb when the user drags it
tab Tab items in tab controls
toolbar Any Editor toolbar except for the main Unity toolbar (app_toolbar)
toolbar_button Buttons in an Editor toolbar
window Editor windows


The sub-element is the part of an element that the variable affects. Together with a variable’s group, the sub-element shows what kind of data the variable represents.

For example, when you see a variable name with the colors group and the text sub-element, it means Unity uses the variable in styles that affect text color.

The variable names have the following sub-elements:

Group Sub-element Description
background An element’s background color
border An element’s outer border color
border_accent An element’s inner border color. For example, InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
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windows have a two-tone border
text Text color for elements that display text
margin_{left, top, right, bottom} An element’s margin values
padding_{left, top, right, bottom} An element’s padding values
border_{left, top, right, bottom}_width An element’s border width values
border_{left_top, left_bottom, right_top, right_bottom}_radius An element’s border radius values values
width, height An element’s width and height values


The pseudo-state sequence is a list of UI states that Unity uses a variable for.

For example, when you see a variable name with the hover pseudo state, it means Unity uses the variable in styles that affect elements when a user hovers the pointer over them.

For example: --unity-colors-toolbar_button-text-hover.

A variable name can have more than one pseudo-state. Multiple pseudo states appear in alphabetical order, separated by underscores _.

For example: --unity-colors-toolbar_button-text-focus_selected.

Unity variable names can have any combination of the following pseudo-states:

Pseudo-state Description
(none) Normal state
checked A checkbox-type control is checked
disabled A control is disabled
focus A control has focus
hover A user hovers over a control
inactive A control doesn’t have focus
pressed A control is pressed
selected A control is selected

Additional resources

Create USS variables
USS built-in variable references