How to change keep color logo when I change logo default in page login nextcloud?

Nextcloud 15.02

Steps to reproduce

  1. I changed logo at:
    core/img/logo/logo.svg and core/img/logo/logo.png

Expected behavior

  1. Keep color origin logo at the login page.

  2. Image:

Actual behavior

  1. My logo in the login page was filled white color.

  2. Image:


  1. I investigated this issue cause because
#theming-preview-logo,#header .logo{

in file generate.

How to fix when auto-generate scss doesn’t color=fff

Pls, Thank you.