Background color not showing in print preview

The Chrome CSS property -webkit-print-color-adjust: exact; works appropriately.

However, making sure you have the correct CSS for printing can often be tricky. Several things can be done to avoid the difficulties you are having. First, separate all your print CSS from your screen CSS. This is done via the @media print and @media screen.

Often times just setting up some extra @media print CSS is not enough because you still have all your other CSS included when printing as well. In these cases you just need to be aware of CSS specificity as the print rules don’t automatically win against non-print CSS rules.

In your case, the -webkit-print-color-adjust: exact is working. However, your background-color and color definitions are being beaten out by other CSS with higher specificity.

While I do not endorse using !important in nearly any circumstance, the following definitions work properly and expose the problem:

@media print {
    tr.vendorListHeading {
        background-color: #1a4567 !important;
        -webkit-print-color-adjust: exact; 
    }
}

@media print {
    .vendorListHeading th {
        color: white !important;
    }
}

Here is the fiddle (and embedded for ease of print previewing).