CSS Help Floating a div to center when enough space - html

Question

I'm trying to center a div in the web browser when there is enough space. If not it should be collapsed between 2 divs.
This is the collapsed view
And this would be the expanded view
I've tried so many different things but nothing seems to work right. When I get something that looks right, the filterDiv ends up going over the top of titleDiv or buttonDiv or both.
Here's some code that I started with and should represent the collapsed view when the browser isn't very wide.
<style type="text/css">
.controlsDiv{
background-color:yellow;
border: 1px solid black;
}
.titleDiv{
background-color:Red;
width:25em;
height: 5em;
border: 1px solid black;
}
.filterDiv {
background-color: gainsboro;
width: 600px;
height: 10em;
border: 1px solid black;
}
.buttonDiv{
width:25em;
height:5em;
background-color:green;
border: 1px solid black;
}
</style>
<div class="controlsDiv" >
<div class="titleDiv">
<h2>titleDiv</h2>
</div>
<div class="filterDiv">
<h2>filterDiv</h2>
<h2>Centered in Browser Window</h2>
<h2>titleDiv and ButtonDiv Collapsed</h2>
</div>
<div style:clear:both></div>
<div class="buttonDiv">
<h2>buttonDiv</h2>
</div>
</div>
Thank you in advance!

Answer 1

You can always position absolute required div:
<style type="text/css">
.controlsDiv{
background-color:yellow;
border: 1px solid black;
}
.titleDiv{
background-color:Red;
width:25em;
height: 5em;
border: 1px solid black;
}
.filterDiv {
background-color: gainsboro;
width: 600px;
height: 10em;
border: 1px solid black;
}
#media(min-width: 900px) {
.filterDiv {
position: absolute;
left: calc(50% - 300px);
top: 0;
}
}
.buttonDiv{
width:25em;
height:5em;
background-color:green;
border: 1px solid black;
}
</style>