flex实现流式布局， css3

<style>
    .wrapper {
        width: 400px;
        height: 340px;
        margin: 50px auto;
        border: 1px solid #dedede;
        resize: both;
        overflow: hidden;
    }
    .wrapper .title {
        line-height: 40px;
        text-align: center;
        font-size: 20px;
        height: 40px;
        box-sizing: border-box;
        border-bottom: 1px solid #dddd;
    }
    .wrapper .content {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        width: 100%;
        height: 100%;
        align-content: flex-start;
    }
    .wrapper .content .item{
        flex: 0 0 100px;
        border: 1px solid #f0f;
        box-sizing: border-box;
        height: 100px;
        width: 100px;
    }
</style>
<div class="wrapper">
    <div class="title">流式布局</div>
    <div class="content">
        <div class="item">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <div class="item">4</div>
        <div class="item">5</div>
        <div class="item">6</div>
        <div class="item">7</div>
    </div>
</div>