People in the past have used the style attribute in JavaScript, but that only works for inline style or for computed style, there are cross-browser issues.
I looked and I cannot see any request for this functionality??
The Selenium API exposes functionality to check CSS style in a cross-browser way from a WebElement, but it is not exposed directly in Selenium2Library.
To work around, you can use Execute Javascript to return the WebElement you are interested in and go from there...
Try:
${elem}= Execute Javascript return document.getElementById('table-row');
${bg color}= Call Method ${elem} value_of_css_property background-color
${bg color} should end up as a unicode string with a value like "rgba(238, 238, 238, 1)"
Kevin