AmCharts.theme

You can set theme for all the charts on your page by setting: AmCharts.theme = AmCharts.themes.light; // or some other theme. If you are creating charts using JavaScript API, not JSON, then this is quite a comfortable way, as you won't need to pass theme to each object you create. Note, you should set theme before write method is called. There is no way to change theme of already created chart, you have to create chart's instance once more if you want to change theme.

AmChart.theme

AmAngularGauge.theme
AmCoordinateChart.theme
AmFunnelChart.theme
AmGanttChart.theme
AmPieChart.theme
AmRadarChart.theme
AmRectangularChart.theme
AmSerialChart.theme
AmSlicedChart.theme
AmXYChart.theme
StockPanel.theme

Theme of a chart. Config files of themes can be found in amcharts/themes/ folder. More info about using themes.