Highlights on search matches practically invisible

[milos-popovic]

I've fixed it for myself by including following CSS items (you might consider adding them to the theme):

/* Search-related styles */ 
--jp-search-toggle-off-opacity: 0.6;
--jp-search-toggle-hover-opacity: 0.8;
--jp-search-toggle-on-opacity: 1;
--jp-search-selected-match-background-color: rgb(255, 225, 0);
--jp-search-selected-match-color: black;
--jp-search-unselected-match-background-color: rgb(255, 123, 0);
--jp-search-unselected-match-color: var(--jp-ui-inverse-font-color0);

[dunovank]

Thanks for the contribution, just published an update with these changes to pypi.