Is this how it's supposed to look like?

I’m just a begginer, is this right?

html, body { /* The universe takes up all available space */ width: 100%; height: 100%;

/* The universe is black */
background-color: black;

}

#sun { position: absolute; /* Positions the top-left corner of the image to be * /* in the middle of the box */ top: 50%; left: 50%;

/* Play with these numbers to see what it does */
height: 200px;
width: 200px;
margin-top: -100px; 
margin-left: -100px;

}

#earth { /* Style your earth */ position: absolute; top: 25%; left: 25%; }

#earth-orbit { /* For Section #2 */ }