不理解为什么这段代码在谷歌网站HTML Box Gadget中不起作用。

I am messing around with Google sites, trying to get some html code to actually work and I am running into a wall. Basically I want to be able to input html code as well as css styling without having to use inline styling, so I did a little research and sure enough it can be done. Supposedly all one needs is to add a HTML gadget and input the relevant code, click save and shezam! It should work. Problem is when I do it, it doesn't work at all.I am messing around with Google sites, trying t