恐怕我不能理解弹性增长。如果你跳到下面的JSFiddle – 我理解它的方式，.big应该是其他.list-item的三倍大小。正如你所看到的，不是这样。为什么？
.flex-container {
display:flex;
padding:0 20%;
}
.flex-item {
flex-grow:1;
list-style-type:none;
border:1px solid black;
}
.big {
flex-grow:3;
}
<ul class="flex-container">
<li class="flex-item big">Why isn't this exactly three times the size of the other one?</li>
<li class="flex-item">Not really working like expected I don't think...</li>
</ul>
