how to set DIV position to 200 pixels to left of the center

Question

I want to position a DIV 200 pixels to left of the center.

I am currently using the following code, but on higher resolution displays (e.g. 1920×1080), the DIV was slipping out of position:

.hsonuc {
    position: absolute;  
    top: 20px; 
    margin:auto;
    margin-left:200px;
    display:none;
}

What I want to achieve:

Answer 1

Simply position it 50% from the right (right:50%;), and then push it over using margin-right:200px; (example).

HTML

<div class="hsonuc">DIV</div>

CSS

.hsonuc {
    position:absolute;
    top:20px;
    right:50%; /* Positions 50% from right (right edge will be at center) */
    margin-right:200px; /* Positions 200px to the left of center */
}