The :-moz-system-metric(windows-default-theme) CSS pseudo-class matches an element if the user is currently using one of the following themes in Windows: Luna, Royale, Zune, or Aero (i.e., Vista Basic, Vista Standard, or Aero Glass). This will exclude Windows Classic themes as well as third-party themes.
The :-moz-ui-invalid CSS pseudo-class represents any validated form element whose value isn't valid based on their validation constraints, in certain circumstances. This pseudo-class is applied according to the following rules:
The :out-of-range CSS pseudo-class matches when an element has its value attribute outside the specified range limitations for this element. It allows the page to give a feedback that the value currently defined using the element is outside the range limits. A value can be outside of a range if it is either smaller or larger than maximum and minimum set values.
CSS Background and Borders is a module of CSS that defines how background and borders of elements are described. Borders can be lines or images, boxes can have one or multiple backgrounds, have rounded corners, and shadows.