First flexbox-fiddle
by agib
HTML
<div class="container">
<div class="row">
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
</div>
<div class="row">
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
</div>
<div class="row">
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
</div>
<div class="row">
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>
</div>
</div>
CSS
.container {
/*padding: 20px;
display: -webkit-box;
display: -moz-box;
display: -ms-flexbox;
display: -webkit-flex;
display: flex;
width: 100%;
-webkit-flex-flow: column;*/
}
.row {
display: -webkit-box;
display: -moz-box;
display: -ms-flexbox;
display: -webkit-flex;
display: flex;
-webkit-flex-flow: row wrap;
}
.box {
background-color: #e3e3e3;
outline: 1px solid #777;
min-height: 80px;
margin-left: 20px;
margin-bottom: 20px;
min-width: 160px;
flex: 1;
}