@-ms-viewport is STILL an error

[ctro99]

• VS Code Version: 1.55.1 (Universal)
• OS Version: macOS Big Sur 11.2.3 (20D91)

Steps to Reproduce:

1. Create an HTML file with a CSS style block in the head
2. Add this code within your style
   @-ms-viewport {
   width: device-width;
   }
3. Now VS Code will not display your theme colors properly.

Does this issue occur when all extensions are disabled?: Yes

[alexr00]

We recently moved to a different CSS grammar for providing syntax highlighting. The old one was unmaintained, and the new one has good fixes in it. You can see the full discussion here: #115480

Specifically, see #115480 (comment), which references viewport as a deprecated feature (details https://developer.mozilla.org/en-US/docs/Web/CSS/@viewport). Even though the new grammar is missing ms-viewport, we decided to go with it because the benefits of having a maintained grammar outweighed the negative of missing the deprecated ms-viewport.

If you feel strongly that this is essential for the grammar, I recommend going to https://github.com/atom/language-css/, the repo that we pull our css grammar from, and filing an issue there to ask for ms-viewport to be supported in their textmate grammar.