I suggest actually putting it in the HTML where you want it placed, as opposed to positioning it from another place...
You can use:
.positionedSearch {
width: 400px;
height: 45px;
position: absolute;
z-index: 2;
left: 40%;
top: 330px;
}
This only works for the full screen media query. Needs to be adjusted for the smaller screens.
Like I said, it would be much better just to place it in that relative area via the JS.. then you can avoid using absolute positioning.
Based on your other question:
Find this line in your CSS and modify it to this:
.sqs-search-ui-button-wrapper {
background: rgba(255, 255, 255, 0.66);
max-width: 280px;
}