This sample is to set the font size of the axis label. 
ā—¸Layout
<horizontalAxisRenderers>
	Sets the value of the styleName property to "axisLabel" and 
	creates the CSS style in the name of "axisLabel".
	<Axis2DRenderer axis="{hAxis}" styleName="axisLabel"showLine="true"/>
</horizontalAxisRenderers>

<Style>
	.axisLabel{fontSize:15;}
</Style>