Google's new Sheets allows you to change the tab colors, but the color is just a narrow stripe—not enough of a visual cue to immediately identify tabs by their color. This stylesheet causes your selected colors to fill the whole tab, similar to the way Excel does it. It also includes optional increased rounding of the bottom corners of each tab to further help distinguish one tab from the next. The rounding styles can be deleted. 3/23/15 update makes the active tab title bold, making it easier to confirm which tab is active. These styles can be deleted.