Reading the HTML in the MDN

  • Content categories;
  • Permitted content;
  • Tag omission: if the start or end tag can be omit;
  • Permitted parents;
  • Permitted ARIA roles;
  • DOM interface;

Content categories

Question 1: What is the height of span?

<span style="font-size: 16px; line-height: 1">hello</span>

From Rules Between Block Elements And Inline Blocks, we can learn that you can't set any with/height/line-height css property to inline-element. So the height of span is depende on the default browser.