2.1.19 [CSS-Level2-2009] Section 6.2.1, The 'inherit' value
The specification states:
Each property may also have a specified value of 'inherit', which means that, for a given element, the property takes the same computed value as the property for the element's parent. The 'inherit' value can be used to strengthen inherited values, and it can also be used on properties that are not normally inherited.
Quirks Mode and IE7 Mode (All Versions)
inherit value is supported only for the visibility and the direction properties.
All Document Modes (All Versions)
The inherit keyword does not inherit computed values from parent elements.
The inherit keyword does not inherit from a style that has been dynamically changed.