Code review comment for lp:~huwshimi/launchpad/hover-row-43231

I have trouble seeing the background colour (#f6f6f6) on LCD displays. The difference
in colour is less that the variation in brightness from the top and bottom angles. I can see the colour change when I hover over a row at the top of my screen, but I cannot see it if the row is at the bottom on my screen. I think the CSS has a lot of disagreement about the hex value for a background colour:

    The app links use #747474
    The involvement links use #eee
    Latests PPA updates alternates odd-even #fff-#eeeeff

And I see that #f6f6f6 is also by a class so I do not think users will see the update
on hover:

    .shaded rows use #f6f6f6

There are some unwanted interactions with this new rule, but I think this maybe case where the rule is write, and we have some pages that need fixing:

Heading rows (tr th) in the body are made /lighter/ on hover:
    https://launchpad.dev/ubuntu/+cdmirrors

Empty rows in poorly constructed table highlight nothing:
    https://launchpad.dev/ubuntu/+source/pmount