I don't want them to be on the same level. They are both independent divs. The sidebar is fixed.Why doesn't the sidebar stick on top instead of being aligned with the article div ?
body{
margin: 0;
padding: 0;
}

div#sidebar{
background-color: yellow;
margin: 0;
padding: 0;
float: left;
height: 100%;
width: 200px;
position: fixed;
}

div#article{
background-color: blue;
margin-left: 200px;
margin-top: 50px;
height: 500px;
}
HTML :

sidebar



article




Check Solution