Do this, add the following to the very begining of the CSS Inserts
HTML Code:
body { background-color: #00ffff; background-image: none; }
Now move that CSS to the end of the CSS Inserts and go view the page. Is the background light blue? Probably not it you haven't fixed teh syntax errors, so move the code halfway up in the CSS Inserts to see if you can find the error. If it works, you know the error is in the bottom half of your CSS Inserts and keep repeating, if it doesn't then you know the error is in the top half of the CSS inserts. Keep moving it and you can narrow down the issue and find and fix it.