Formatting table colors stops cell calculation

I've setup a table to calculate cells but i'm having trouble with formatting
the colors within the table. When I make certain changes, the table
calculations stop working. I've uploaded some examples:

www.fluxcreative.co.uk/first.html

In this example, the lines numbered 2-6 total at the bottom when checked as
they should do.
but after changing the code for line 1 (so the row changes color when
checked), the line has stopped adding to the totals

Line 1 is almost formatted correctly but you'll notice it is white when the
page loads, turquoise when checked then reverts to light purple. The light
purple is the color it should be before the box is checked but because the line
colors alternate, I don't wanna change the BG color of the whole table. So
i've added some code to set odd numbered rows to dark and even numbers to
light, so line 1 now works how it should do color-wise (see below).

www.fluxcreative.co.uk/second.html

But now, all lines have stopped adding up!!! I've put this together from
snippets on google but I don't really understand CSS well enough to work this
out. Color and functionality are both very important for this site but I can't
get them working together. Can someone please tell me where i'm going wrong?
Thanks guys, Dren