Web Theme: Refine Selectors (Fixes #132)

[Foldex]

Decent amount of selector changes, partially to avoid theming Big Picture, partially a general cleanup.

Big Picture

Steam provides a useful node ID for avoiding this:

#SteamDesktop

But as it isn't a top level node, tooltips and other hover elements that like to get injected as a direct child of body will bypass this. For these we have to resort to using a :not() selector on the body class itself.

body:not([class*="gamepadui_GamepadUIPopupWindowBody_"])

Cleanup

Did a bit of cleanup to avoid straight up using:

[class*="etc_etc"]

type selectors. Now most selectors include the tag of the element they're targeting:

span[class*="etc_etc"]

Which should at least be a slightly less blatant abuse of wildcard selectors. Moving forward we should avoid tagless selectors when possible.
There are a couple stragglers left where I couldn't easily trigger the corresponding elements to show, like with cloudconflict_.

Dialog selectors that were too general have been constrained to .ModalDialogPopup:

.ModalDialogPopup span[class*="etc_etc"]