In other words, is it possible to achieve this?
Note: This is the best I could get:
html, body, .container {
height: 100%;
}
.container {
border: 1px solid green;
display: flex;
flex-wrap: wrap;
}
.container > div {
border: 1px solid black;
background: #ececec;
flex: 1;
}
.container > div:nth-of-type(1) {
flex: 1 1 100%;
}
.container>div:nth-of-type(4) {
flex: 1 1 100%;
}
<div class="container">
<div>Div 1</div>
<div>Div 2</div>
<div>Div 3</div>
<div>Div 4</div>
</div>