The style is json data, its json schema is as follows:
{
     "$schema" : "http://json-schema.org/draft-04/schema#",
     "title" : "style",
     "type" : "object",
     "properties" : {
         "wholeSlicerStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "headerStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "selectedItemWithDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "selectedItemWithNoDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "unSelectedItemWithDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "unSelectedItemWithNoDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "hoveredSelectedItemWithDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "hoveredSelectedItemWithNoDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "hoveredUnSelectedItemWithDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         },
         "hoveredUnSelectedItemWithNoDataStyle" : {
             "$ref" : "#/definitions/StyleInfo"
         }
     },
     "definitions" : {
         "StyleInfo" : {
             "type" : "object",
             "properties" : {
                     "backColor" : {
                             "type" : "string"
                     },
                     "foreColor" : {
                             "type" : "string"
                     },
                     "font" : {
                             "type" : "string"
                     },
                     "borderLeft" : {
                             "$ref" : "#/definitions/SlicerBorder"
                     },
                     "borderTop" : {
                             "$ref" : "#/definitions/SlicerBorder"
                     },
                     "borderRight" : {
                             "$ref" : "#/definitions/SlicerBorder"
                     },
                     "borderBottom" : {
                             "$ref" : "#/definitions/SlicerBorder"
                     },
                 "textDecoration":{
                     "type" : "string"
                 }
             }
         },
         "SlicerBorder":{
             "type":"object",
             "properties":{
                 "borderWidth":{
                         "type":"number"
                 },
                 "borderStyle":{
                         "type":"string"
                 },
                 "borderColor":{
                         "type":"string"
                 }
          }
         }
     }
 }