anchor targets are below the sticky header

Can you please assist me with a problem caused by the Sticky Header? I couldn’t find a thread that exactly matches my problem, so I’m opening this one.

I’m using anchor links on longer text pages. In Safari, Opera and Firefox under MacOSX everything is fine. But in Chrome an under Windows 10 the targets are under the Sticky Header. I looked around and found a short CSS trick to solve the problem:

:target:before {
content:””;
display:block;
height:90px; /* fixed header height*/
margin:-90px 0 0; /* negative fixed header height */
}

But with the Enfold-Theme these CSS-lines causing no effect.