I'm having problems with my page layout on flexbox and wonder if anyone can help! I've got the below code in a JSFiddle here https://jsfiddle.net/smvrn7to/1/
I'm trying to make the div with the ID 'notheader' stretch to the bottom of the screen, but I'm having no luck. As I understand it if I use align-content:stretch on the "notheader" div should work, but I'm getting nothing.
I've tried changing the height to 100% as well, but again its made no difference.
body{
    background-color: blueviolet;
    margin: 0px;
    padding: 0px;
    display: flex;
    align-content: stretch;
    height: 100%;
}
html{
    height: 100%;
}
nav{
    background-color: aqua;
    width: 80px;
    height: 100%;
}
main{
    background: yellow;
    width: 100%
}
header{
    height: 100px;
    background-color: teal;
}
#controls{
    background: tomato;
}
#notnav{
    width: 100%;
    background-color: chartreuse;
    display: flex;
    flex-direction: column;
    height: 100%;
}
#notheader{
    background: white;
}<nav>
    <p>Nav Bar</p>
</nav>
<div id="notnav">
    <header>Header</header>
    <div id="notheader">not header</div>
    <!-- <div id="controls">controls</div> -->
</div> 
    