Flexbox Article 1

HTML

<div class="container">
<div class="item0">item 1</div>
<div class="item0">item 2</div>
<div class="item2">item 3</div>
<div class="item0">item 4</div>
<div class="item1">item 5</div>
<div class="item0">item 6</div>
<div class="item0">item7</div>
</div>

CSS

.container {
    margin: 0 auto; 
    column-count: 3;
    width: 350px;
    background-color: white;
}
.item0 {
    background-color: DeepSkyBlue;
    width: 100px;
    height: 100px;
    margin: 2px 0 0 2px;
}
.item1 {
    background-color: DeepSkyBlue;
    width: 100px;
    height: 400px;
    margin: 2px;
}
.item2 {
    background-color: DeepSkyBlue;
    width: 100px;
    height: 20px;
    margin: 2px;
}