From an engineers perspective, whenever specifying colors from now on we should use the form:
```
color: rgb(var(--tone-red-500));
```
Please note:
- Use rgb. This lets us do this like rgb(var(--tone-red-500) / 10%) so we can use a 10% opacity red-500 if we ever need to whilst still making use of our color tokens.
- Use --tone-colorName-000 (so the prefix tone). Previously we could use a mix of --gray-500: $gray-500 (note the left hand CSS prop and right hand SASS var) for the things we need to theme currently. As we no longer use SASS we can't do --gray-500: --gray-500, so we now do --tone-gray-500: --gray-500.
Just for clarity after that, whenever specifying a color anywhere, use rgb and --tone. There is only one reason where you might not use tone, and that is if you never want a color to be affected by a theme (for example a background shadow probably always should use --black)
There are a 2 or 3 left for the code editor, plus our custom-query values
We've always had this idea of being able to markup up information
semantically without thinking about what it should look like, then
applying our %h* placeholder styles to control what the information
should look like.
Back when we originally made our set of %h* placeholders, we tried to
follow Structure as much as possible, which defined the largest header
(which we thought would have been the h1 style) as a super large 3.5rem.
Therefore we made our set of %h* placeholders the same as Structure
beginning at a huge 3.5 size. We then re-overwrote those sizes only in
Consul specific CSS files thinking that this was due to us existing
before Structure did.
Lately we saw an extra clue in Structure - the extra large 3.5 header was
called 'h0'.
This commit moves all our headers to use a zero based scale, and
additionally uses our 3 digit scale as opposed to 1 digit (h1 vs h100),
similar to our color scales (note we don't use a hypen, which we can
alter later if need be), which means we can insert additional h150 etc
if need be.
Additional we stop styling our headers globally (h1 { @extend %h100; }
). This means there is no reason not to use headers for marking up
content depending on what it is rather than what it should look like,
and as a consequence means we can be more purposeful in ordering h*
tags.
Lastly, we use the new scale over the entire codebase and update a
couple of places where we were using using header tags due to what the
styleing for them looked like rather than what the meaning/order was.
John Cowen