fix(comp:anchor): style update and css variable support

[danranVm]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines
• Tests for the changes have been added/updated or not needed
• Docs and demo have been added/updated or not needed

What is the current behavior?

What is the new behavior?

Other information

[idux-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #1379 (7412d9c) into main (edb23d4) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1379   +/-   ##
=======================================
  Coverage   92.86%   92.86%           
=======================================
  Files         324      324           
  Lines       29845    29845           
  Branches     2474     2474           
=======================================
  Hits        27717    27717           
  Misses       2128     2128           

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