To be able to give you correct custom CSS code, we need to inspect the page content using dev tool, but your site is local, so we can’t do it.
You can try to find correct classes by yourself. Inspect code using inspector tools. Open a web page in Google Chrome. Either:
-Select the Chrome menu at the top-right of your browser window, then select Tools > Developer Tools.
-Right-click on any page element and select Inspect Element.
The DevTools window will open at the bottom of your Chrome browser. https://www.w3schools.com/cssref/pr_pos_z-index.asp
