
The "faded" styles are ones that are not applied to the selected tag. So in your screenshot, you have anh1rule which is normal colored -- that one is applied to whatever element you have selected -- and you have an.SubHeader h1rule that is not being applied to the selected element.
You'll sometimes see this is you dynamically add a CSS rule (the + button in the chrome dev tools) but modify the selector so it doesn't apply to whichever element you have selected.