:indeterminate
Applies one or more styles to radio buttons and check boxes whose toggle states cannot be determined—they are neither checked (selected) nor unchecked (cleared).
Syntax
:indeterminate {
sRules
}
Possible values
sRules
Value that specifies one or more Cascading Style Sheets (CSS) attribute/value pairs.
Remarks
The :indeterminate pseudo-class is a UI element states pseudo-class. UI element states pseudo-classes select UI elements (form controls such as radio buttons or check boxes) that are in a certain state—enabled, disabled, or selected (checked).
Standards Information
This pseudo-element is defined in CSS Selectors Level 3 
.
Applies to
a, abbr, acronym, address, b, big, blockquote, body, caption, center, cite, code, col, colgroup, dd, dfn, dir, div, dl, dt, em, form, hn, html, i, img, input, input type=button, input type=checkbox, input type=file, input type=hidden, input type=image, input type=password, input type=radio, input type=reset, input type=submit, input type=text, kbd, label, legend, li, listing, marquee, menu, ol, p, plaintext, pre, s, samp, select, small, span, strike, strong, sub, sup, table, tbody, td, textarea, tfoot, th, thead, tr, tt, u, ul, var, xmp
