Mostly change some properties from things like "transparent" to "unset". A lot of things that are just overriding the default Naturalcrit "colored button". Moved some properties to the top level `.toolbar` class and let it cascade down.
more closely match the properties editor behavior. removed some unnecessary (unused) properties. Outline only appears when element is focused (rather than on hover as well).
replace column-/row-gap with a single gap at 5px. Padding on each child element will provide the space. Set a height on toolbar, so child elements can be set to 100% height to improve bg color change on hover.
Doesn't need to be Sticky positioning, relative is fine (it is still fixed above the iframe). Allows us to remove a bunch of extra properties.
Add a smidgen of padding.
Avoid over-styling of browser-defined slider, but still apply a HB appropriate color scheme. Prevents us from having to create our own tick marks, so we can just define the `option`s in the datalist and get tick marks in the right spot.
