Progress update

Things are still a bit of a mess, but it currently works in this state.

* All of the hide notice/ad options are now handled exclusively by the CSS.
* Like the input references, there's now an element reference for easy access to necessary elements in the menu.
* Style rules now use concatenation for readability and editing.
* Multiple element.style declarations are now handled by CSS class/ID rules.
* The menu layout is now wider to allow for less scrolling and increased option possibilities. The current width assumes 1024 will be the minimum user resolution width.
* The menu no longer vertically centers. It will instead stay a constant distance from the top of the viewport. Its height will be allowed to shrink and grow to fit the current option set and viewport height.
* The menu now features tabs.

The tabs and wider format also tie in with an upgrade to the border options that I'm planning. Some other potential tabs are "import/export settings", "help", and "about".