docs: update styling

[xierenyuan]

增加 sass 使用提示 close #9462

---

View rendered docs/docs/guides/styling.md

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated
umi	✅ Ready (Inspect)	Visit Preview	Sep 29, 2022 at 8:26AM (UTC)

[codecov[bot]]

Codecov Report

Base: 29.34% // Head: 29.34% // No change to project coverage :thumbsup:

Coverage data is based on head (cdfacff) compared to base (a04cfbd). Patch has no changes to coverable lines.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9469   +/-   ##
=======================================
  Coverage   29.34%   29.34%           
=======================================
  Files         416      416           
  Lines       11535    11535           
  Branches     2752     2752           
=======================================
  Hits         3385     3385           
  Misses       7639     7639           
  Partials      511      511           

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

:umbrella: View full report at Codecov.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.