However most of the styles are inherited from other ancestor elements like "div.k-widget.k-spreadsheet" and "div.k-spreadsheet-view".
You can use the browser's developer tools console to get the cells via jQuery (e.g. $('.k-spreadsheet-cell');) and inspect the cells with the elements inspector to see the full list of styles, and where they are coming from.
Thanks for the very detailed reply! I am changing the background colour of a cell if a certain condition is met, but the user can change things, which mean I need to revert the background colour of the cell.