When a body background style is defined in the style option of the init function it's not possible to override.

Given the style:

body {
    background-color: #000000;
}

After changing the background-color in Grapes, the CSS output is:

body {
    background-color:#f80000; /* Colour selected in Grapes */ 
}
body {
    background-color:rgb(0, 0, 0); /* Original colour that should be overwritten */
}

Due to the ordering, the original colour will take precedence when used.

While not necessarily an issue, the repetition of body isn't needed and would probably solve this issue if the body css definition was merged. I believe this happens with other CSS selectors too.

Steps to reproduce

1. https://jsfiddle.net/jk3g2eu2/
2. Click the wrapper in the canvas
3. Change background color.
4. Click the code icon to see generated CSS.