Moving the left-side logo in layout.css from default 3em to 20em breaks the formatting permanently. Why is this?

I'd love to know why this happens and if there's anything I can do about it in my current project. I tried changing the width back to the default, but that only moves the logo back and does not reinstate any other elements. At this point, it appears that I will not be able to insert my wide, rectangular logo since I would never want to alter the width going forward. Does anyone know a way to fix this? 

Note: This is related to my recent post: "How do I get the filter checkbox back? I did not alter these graphics in the Layout Customization tool."

1. Test project output before change:

• Custom blue TOC books
• Three books with topics
• Books can be opened and closed
• Logo is at default 7em
• Filter checkboxes normal

2. Test project output after change:

• Custom blue TOC books changed color
• Books can be opened but not closed
• Logo is at custom 20em width
• Filter checkboxes abnormal

Thanks and best regards!