CSS header broken

I use the CSS code to turn the header white while I’m downloading:

# site-header {background-color: transparent; }
# mysticky-nav.wrapfixed # site-header.transparent-header {
transition: 0.7s;
background-color: #ffffff;
}

However with the new update, this CSS stopped working, I don’t know what kind of CSS changes have been made in 2.3.3, but if this can be removed again or addressed differently, it would be great.

Since there are several users who are having these problems with CSS,

Thank you so much

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