Павел

.menu > li > a, .menu > li > a:after {-webkit-transition: all .3s ease-in-out;
    -moz-transition: all .3s ease-in-out;
    -o-transition: all .3s ease-in-out;
    -ms-transition: all .3s ease-in-out;
    transition: all .3s ease-in-out;}
.menu > li > a:after {
    content: "";
    height: 4px;
    background: #000;
    width: 100%;
    position: absolute;
    left: 0;
    top: -4px;
    z-index: 203;
    opacity: 0;
    filter: alpha(opacity=0);
}
.menu > li.hover > a:after {
    opacity: 1;
    filter: alpha(opacity=100);
}

{
  justify-content: center;
  flex-direction: column;
  overflow:hidden;}

.post_content {
    margin-top: 10px;
    box-sizing: border-box;
    overflow: hidden;
    max-height: 55px;
}

<style>
.wrap {width:100%;margin: auto;}
.wrap .col {width:25%;float:left;}
</style>
<div class="wrap">
<div class="col">1</div>
<div class="col">2</div>
<div class="col">3</div>
<div class="col">4</div>
</div>

list {
  overflow: scroll;
  height: 300px;
}