In short: I am trying to understand the meaning of this TypeError: Failed to execute \'getComputedStyle\' on \'Window\': parameter 1 is not of type \'Element\' The error app
The error message is pretty straightforward: getComputedStyle expects an Element as its first argument, and something else was passed to it.
If what you are really asking for is help with debugging your skin, you should make more of an effort to isolate the error.