柱状图X,Y轴的字体大小怎么修改echarts 柱状配置项内容和展示

      	var timeArr = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24];
	var bgArr = [
		["#cd0252","#7e0022"],
		["#c90384","#9a014e"],
		["#fd524e","#ff0200"],
		["#ffb503","#ff7e01"],
		["#fefe1b","#ffff03"]
	]
	var dataArr = [];
	var barW = ($('#main').width()/timeArr.length)-20;
	
	for(var i=0;i<timeArr.length;i++){
		dataArr.push(
			{
		        value:200+(i*10),
		        itemStyle:{
		            normal:{
		          		color: new echarts.graphic.LinearGradient(0, 0, 0, 1, [
		      				{
		                        offset: 0,
		                        color: bgArr[i%5][0]
		                    }, {
		                        offset: 1,
		                        color: bgArr[i%5][1]
		            		}
			            ])
		      		}
		  		}
		  	}
		)
	}
			
	var option = {  
	    title: {  
	        text: '实时AQI24小时柱状图',
	        x : '4%',
	        y : '5',
	        textStyle:{
	        	color: 'white',
	        	fontSize:'24',
	        	fontWeight: 'normal'
	        }
	    },  
	    tooltip: {  
	        trigger: 'axis'  
	    },  
	    grid: {  
	        left: '5%',  
	        right: '5%',  
	        bottom: '5%', 
	        top: '50px',
	        containLabel: true  
	    },  
	    xAxis: {  
	        type: 'category',  
	        boundaryGap: true,        
	        data:timeArr,
	        axisLine: {
	            lineStyle: {
	                color: "black"
	            }
	        },
	        axisTick : false
	    },  
	    yAxis: {  
	        type: 'value',
	        axisLine: {
	            lineStyle: {
	                color: "black"
	            }
	        },
	        axisTick : false,
	        splitLine : {
	        	show : true,
	        	lineStyle : {
	        		type : 'dashed',
	        		color : '#54575a'
	        	}
	        },
	        isLabel:{ //调整x轴的lable
	            textStyle:{
	                fontSize:25 // 让字体变大
	            }
	        },
	    },  
	    
	    series:[  //统一设置圈圈与线的颜色
	        {
				type:'bar',
				barWidth : barW,
				data:dataArr
	        }           
	        
	
	    ]  
	};  
	    
	myChart.setOption(option); 		
	
	$(window).resize(function(){
		myChart.resize()
	})