Text Customization ??

Bruhhhh. I just spent like 20 minutes typing html code to change the font and color of the blog entry text.. n when i submitted the post, non of the customization. But it showed in the preview, so I was looking through the code, n what i put down was completely deleted. Idk if i messed up somewhere n the site just automatically formatted the code based on the mistake, or if i am just not able to do it on this platform. but zamn i just wasted hella time