fix: apply :global() to whole selector + add strict mode

[adrien-k]

Fixing some issues when combining (pseudo)class selectors, ex: .test.test-2 {}, p.test { ... } , .test:over { ... }, etc...

[micantoine]

@adrien-k Thank you for your contribution. I updated the code so that it would work in some other scenarios such as:

• Being used along other global selectors

<style>
 :global(div) .active { color: red; }
</style>
<div><span class="$style.active">Active</span></div>

• Being used in a media query or nested rules (for sass)

<style>
 @media (min-width: 35.7em) {
  .active { color: red; }
 }
</style>
<span class="$style.active">Active</span>

Anything else you'd think of ?

[adrien-k]

@micantoine That looks like a way better approach 👍. Thank you for the fix and for the lib.