If you’ve been creating charts in Excel 2007 or a newer version for very long you know how easy it is to format a chart using one of the predefined formats. For a worksheet, just select the Page Layout tab then at the far left on the Ribbon click the Themes drop-down and mouse over a theme until your worksheet appears with a theme you want. Your charts in this worksheet will have an appearance to match the worksheet theme.
If you want to change the appearance of a chart to one of the other chart styles in that theme, select the chart, then in Chart Tools, on the Design tab, click the drop-down in Chart Styles group to see the predefined chart styles.
If you like most of a Page Layout Theme, but want a different font or color, then change the Colors, Fonts, and Effects using the drop-downs adjacent to the Themes drop-down. When you get a theme, font, color, and effect combination you like, you can save and reuse it with a name you define.