Okay, this is seriously a mystery, but I had a few minutes to figure it out.
The overlap “ghost” is your blog title and description. You have replaced the header with a graphic, but you failed to get rid of the text. Now, you can leave the information in there, which I recommend, and just open your style.css and add display:none to the H1 and #description styles. It will go away but still be there for search engines and text readers.
BUT, because you have a lot of styles in the header and styles in the style.css, I recommend that you move the header styles to the style.css style sheet and make sure you don’t have any duplicates. You might find you have more than one H1 and headerimg reference.
Anyway, the H1 and description are set to be white and that is the ghost. If you want to learn about how I figured this out (caught the ghost…I like that!), read https://codex.www.ads-software.com/Finding_Your_CSS_Styles
