Thanks to all of you for advice.
I agree with you: the header is not exciting, I will try to do better.
You are right, but I do not want to exaggerate with the style; I want to give great importance to the contents of the blog. I use the fixed elements in order to give importance to the main. In that way I could increase the styling of the sidebar ? I need your examples (for example you could send me the link) …
You have the right, but this is only the home page of the blog. Next week, I translate everything in English so understand better what I wrote in the menu, I also add some demo pages.
You are a robber! I am joking! Thanks!
You reason this technique recalls the iframe, but I do not use it for design, but to improve the usability of the blog.
I thank you. I asked your opinion for this very reason. I hope that the final product is beautiful and usable.