The most complete CSS and PostCSS-cssnext support for Sublime Text.
(Required) Disable the default CSS package
Make sure you don't have any open files set to the default CSS syntax (bottom-right) or you may get an error message.
(Strongly Recommended) Enable completions inside completions
By default, Sublime will not offer completions inside completions. In other words, the completions menu is suppressed when you're tabbing through a snippet. This prevents a lot of CSS3 completions from appearing. Add these keys to your User Settings to fix this:
"auto_complete_commit_on_tab": true, "auto_complete_with_fields": true,
(Recommended) Hide CSS completions from Emmet
If you have Emmet installed, its completions will drown out the carefully researched, standards-based completions offered by this package. You can hide Emmet completions for CSS only by adding this line to your Emmet package settings.
(Recommended) Set CSS3 as the default language for
url(). Unquoted URLs are intentionally not highlighted.
If you think something's missing, make sure you're not asking for something on this list of bad CSS properties. If it's not on that list, open an issue and I'll investigate. Definitely check out the CONTRIBUTING guidelines before submitting your PR. It could save you a lot of time. I'll be monitoring the specs as they're updated on this W3C feed, but I still need your help. Let's keep bad code out of the Web!