SEO of Blogspot

I think div and css is the best SEO method while building a site, and I familiar with div and css.

Due to the style information is included by css file, most of html file are real content,which is visual for viewers.

But blogspot and wordpress is different with above principle. There are so much style and js script in html file that proportion of the real content is low. did it be friendly with Search engine like google?

Another question is that the size of any page is over 50k,which is friendly with viewers while less than 20k.