flex grow animation

HTML

<div class="container">
    <div class="item" style="background: red">afffffff</div>
    <div class="item" style="background: green">fffffffb</div>
    <div class="item" style="background: blue">cffffff</div>
    <div class="item" style="background: purple">dffffffff</div>
</div>

CSS

.container {
    flex-grow: 1;
    flex-shrink: 0;
    flex-basis: auto;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.item {
    flex-grow: 20;
    height:25%;
    transition: all 0.5s;
}

.collapse {
    flex-grow: 1;
   
}

html, body {
    width: 100%;    height: 100%;
    margin: 0; padding: 0; border: 0; overflow: hidden;  }

JavaScript

$(".item").click(function() {
    $(this).removeClass('collapse');
    $(".item").not(this).each(function() {
        $(this).addClass("collapse");    
    });
    
    
});