Perhaps you have used the feature of reading layout view in Spreadsheets 2013. It is a useful feature in that you can highlight the active cell by adding background color to the whole row and column where the active cell is. In the latest update of Office 2013, you can apply a custom background color to the active row/column under reading layout view.
Follow these steps to change reading layout color:
Step 1 Open a worksheet file with Spreadsheets 2013.
Step 2 Under 2013 style interface, go to View > Reading Layout. Click on the top part of the reading layout button to enable reading layout view. See screenshot below:
Step 3 Click on the arrow in the lower part of the Reading Layout button. Then in the color pallette, choose a color. You will find the highlight color is changed to bright yellow. To choose from more colors, click on More Colors...