Highcharts X轴纵向显示

xAxis: {
            categories: ['苹果', '橘子', '梨', '葡萄', '香蕉'],
            labels:{
                rotation: 90,
                style:{
                    fontSize: '13px',
                    fontFamily: 'Verdana, sans-serif',
                    writingMode:'tb-rl'
                }}
        },