[]HTMLDivElement 设置字体

HTMLDivElement 设置字体不生效，需要怎样设置的？多谢
 


let html:laya.html.dom.HTMLDivElement = new laya.html.dom.HTMLDivElement();
            html.innerHTML = "<span style='font-weight:bold; font:24px SimHei' color='#ff0000'>欢迎你的加入</span>"
            +"<span style='font-weight:bold; font:24px Arial' color='#ff0000'>欢迎你的加入</span>";
            this.addChild(html);