A zoomable value which specifies the bottom padding between the shield and the text. The shield will automatically resize to include this padding.
You can specify the padding in either absolute terms (in pixels) or as a percentage of the overall shield height.
Examples:
shield-padding-bottom : 5
defines the bottom padding of the shield to be 5 pixels.
shield-padding-bottom : 5:5;10:20
defines the bottom padding of the shield to be 5 pixels on the zoom level 5 and 20 pixels on the zoom level 10.
shield-padding-bottom : 30%
defines the bottom padding of the shield to be 30% of the overall shield height.
