To create the desired effect, it is recommended to allow the left-hand content to overlap with the right-hand content instead of relying on margins. See the example code provided below.
div.map {
position: absolute;
display: inline-block;
z-index: 10;
background-color: rgba(255, 0, 0, 0.25);
margin-top: 16px;
}
div.controls {
position: absolute;
z-index: 0;
background-color: rgba(0, 255, 0, 0.25);
display: flex;
width: 100%;
}
<div class="container">
<div class="map">
<a href='#'>My occupied link</a>
</div>
<div class="controls">
<div class="main-controls">
Here goes some more controls
</div>
<div class="actual-controls">
<a href='#'>toolbox link</a><br />
<a href='#'>toolbox link</a><br />
</div>
</div>
</div>