EPub File has 114 errors that look similar

I am publishing an academic book on transportation and I have created and edited the basic ePub so it looks better. When I went to validate it with the publisher I got 114 errors (same with my ePub software) Examples:

ERROR: CSS: Property: Invalid value for "CSS Level 2.1" property: 1.8rem [148:3: font-size]    [OEBPS/Styles/base.css]
ERROR: CSS: Property: Invalid value for "CSS Level 2.1/CSS3 Paged Media Module" property: auto [1:1: orphans]    [OEBPS/Text/c012.xhtml]
ERROR: CSS: Property: Invalid value for "CSS Level 2.1/CSS3 Paged Media Module" property: auto [1:32: widows]    [OEBPS/Text/c012.xhtml]
ERROR: CSS: Property: Invalid value for "CSS Level 2.1" property: start [1:18: text-align]    [OEBPS/Text/c019.xhtml]
WARNING: The file OEBPS/Images/image000.png is not referenced    [OEBPS/Images/image000.png]
WARNING: The linked resource 'Text/c020.xhtml' does not exist    [OEBPS/toc.ncx]

I need help as I have no idea how to fix these.

I need a firm estimate to move forward. I will send ePub under separate cover for review prior to hiring