Add size constants and properties for grid areas

[NCrashed]

Hi, I hit missing properties for sizes and grid areas and added them into my project. So, that it is draft for possible additions. I am not sure if experimental CSS API is acceptable in clay. Also, more consistent part of grid areas API should be added to the PR.

Use case:

.grid1 {
  display: grid;
  width: max-content;
}

.grid3 {
  display: grid;
  width: max-content;
}

@media (min-width: 40.0rem) {
  .grid3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    grid-gap: 1rem;
    width: max-content;
  }
}

  ".grid1" ? do
    display grid
    width maxContent
  ".grid3" ? do
    display grid
    width maxContent
  query M.screen [M.minWidth (rem 40)] $ ".grid3" ? do
    display grid
    gridTemplateColumns [fr 1, fr 1, fr 1]
    gridGap $ rem 1
    width maxContent

[turion]

I think it's a good idea to add your usage example to the module docs of your new Clay.Grid module.

[NCrashed]

Thanks for your contribution! I don't understand the CSS aspects well enough to judge this, so ideally you could ping someone who does, for a short review. (If you don't know anyone, no worries.)

Your PR is marked as a draft. What's missing?

Unfortunately, I don't know such experts to call them :). I marked the PR as draft as I feel it doesn't cover all related API for grid areas. So, if it is enough to be merged lets cover the rest of API in subsequent PRs.

[turion]

Unfortunately, I don't know such experts to call them :)

No worries. I think this PR is good, we can merge it. If you want you can open separate issues that explain what should be added to the API to complete it.

[turion]

Thanks!