Advice about the header tag in HTML5?

Question

css

I started using tags...

<header></header>
<main></main>
<footer></footer>

I have a website that has a sidebar on the left.
I placed this panel in the tag, then I styled this tag:

header{
    float:left;
    height: 100vh;
  }

In height, what I need, and the rest of the site is displayed to the right of the panel.
Question.
Is it normal to do this? Or not recommended ...
Perhaps in the future, this will backfire on me?

Answer 1

Download any modern book on HTML + CSS in action and read it cover to cover, breaking down each example or take some courses.
It's not okay to do that. You will learn how to do it normally by reading a good textbook or taking a course, reading articles on the topic, analyzing someone else's code and practicing. Otherwise, you are unlikely to get good knowledge on the topic.

Answer 2

Here everything is written.
This is one of the best "textbooks". There is hardly anyone better than them. If it’s tight with bourgeois, this
one helped me out earlier . How they are now, I don't know.