Built-in Unity variables

Unity’s built-in style sheets define USS variables that specify default values for Editor and runtime UI. You can use these variables in your own style sheets to ensure that your custom interfaces match Unity style.

For information about specific variables, see the List of built-in Unity variables.

Unity variable names

Unity uses a specific naming convention for built-in variables to indicate how and where it uses them. A variable name consists of one or more parts, separated by hyphens. Each part consists of one or more words separated by underscores.

--unity-{group}-{role_and_control}-{sub_element}-{pseudo_state_sequence}

Each part of the name tells you something about 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: the part of an element or control the variable affects.
• Pseudo States: lists the states Unity uses the variable for.

For example, the following variable name:

--unity-colors-button-text-hover

Provides the following information about how Unity uses the variable:

	Value:	Meaning:
Group	colors	The variable represents color data.
Role/Control	button	The variable affects buttons.
Sub-Element	text	The variable affects text. Because its group is colors, you know it affects text color.
Pseudo-States	hover	Unity uses the variable in styles that it applies to elements when the mouse pointer hovers over them.

In other words, Unity uses this variable in styles that change the color of button text when a user hovers over the button.

The rest of this section provides detailed information about each part of the variable name format.

Group

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

Unity variable names can 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 are involved in displaying an error message 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.

Every Unity variable has either a role or a control. It cannot have both.

Unity variable names can have the following roles and controls:

Roles:

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.

Controls:

Control:	Description:
app_toolbar	The main Unity toolbar
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 GameObject 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

Sub-Element

The sub-element is the part of an element that the variable affects. Together with a variable’s group, the sub-element tells you exactly 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.

Unity variable names can have the following sub-elements:

Group:	Sub-element:	Description:
colors
	background	An element’s background color
	border	An element’s outer border color
	border_accent	An element’s inner border color. For example, Inspector windows have a two-tone border
	text	Text color for elements that display text
metrics
	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

Pseudo-States

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 does not have focus
pressed	A control is pressed
selected	A control is selected

List of built-in Unity variables

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