How do I make div fill the corners of the screen? [closed]

I was able to solve my problem! the problem is that when you have an "a href" with an image (eg "img src=" x "" "/ a" inside the div, even if you change the properties in the css, the div does not move anywhere so the solution is:

• Remove «href» with image (use «input type=" image "src=" image.png "onclick=" eventAccessFile () " • And in the css define:

.classe{
  top: 0px;
  left: 0px;
}

This space corresponds to the padding default that browsers apply to BODY, to solve, just reset with the following CSS statement.

body{
    padding: 0;
}