code: public void cssValue(String attribute, String expectedValue) {
          String cssValue = checkCssValue(attribute, expectedValue, 0, 0);
          String reason = NO_ELEMENT_FOUND;
          if (cssValue == null && expectedValue != null && getElement().is().present()) {
              reason = "CSS attribute not found";
          }
          assertFalse(reason, cssValue == null && expectedValue != null);
          assertEquals("CSS Value Mismatch", expectedValue, cssValue);
      }
docs: Asserts that the element has a css attribute with a value equal to the
  value provided. If the element isn't present, or the css doesn't contain
  the desired attribute, this will constitute a failure, same as a
  mismatch. This information will be logged and recorded, with a screenshot
  for traceability and added debugging support.
  
  @param attribute     - the css attribute to be checked
  @param expectedValue the expected css value of the passed attribute of the element