This PR replaces all uses of `px` in relation to font size (opposed to borders, spacing, etc.) with the equivalent `rem` value when the body font size is `16px`. The intention is to better scale the website when the user changes the font size for `<body>` (often done for accessibility reasons).
This PR is technically a **breaking change**, though it's a minor one (see subheading below). I'm putting this up so that we can discuss it as a community.
(technically closes#1088 and fixes#1073, but let's see if we end up merging this)
## mechanics
To do this, I systematically went through every `px` value for all `.scss` files. Then, I deleted the `rem` function, the `_functions.scss` file (that was the only function there), and removed the import from `support.scss`. A nice side effect of this is that we no longer perform any SASS division.
The only remaining uses of `px` are for either:
- border-related properties
- shadow-related properties
- sizing for "non-text" elements (ex `hr`, `blockquote` decorative spacing)
- `$root-font-size` (see below)
The only pixel value change in this PR is the `padding-left` for `blockquote`, which I've changed from `15px` to `1rem` (which is `16px` in the "stock" theme).
## deprecating `$root-font-size`
There's a SCSS variable called `$root-font-size`. It is used in two places:
1. the `rem()` function
2. the `.site-title` when printing (i.e. a `@print` style)
The changes I listed above let us ignore the first case. The second case seems like it has the intention of matching the body font size, so I replaced it with `1rem`.
We can choose to leave the variable in (in case others use it in custom code - which I'm sure that some do) and leave a deprecation notice, or just remove it now. I'm leaning towards the former, which is less disruptive.
## how users would upgrade
This is a breaking change of *some* sorts, but the change is very straightforward for users:
1. If they do not change `$root-font-size`, they need to do nothing; this PR is a no-op.
2. if they do change `$root-font-size`
- they should instead set the `font-size` of `body` with the appropriate `px` value
- optionally, they can replace all custom code that uses `$root-font-size` with `1rem` (find-and-replace works here)