使用Bootstrap列时引导页面布局问题

Question

我使用Bootstrap列来设置我的页面样式。我的row中有4个主div，我希望它们连续显示，但它们不是，并且页面底部也会插入滚动条。问题是什么？我的代码和JsFiddle如下。

HTML：

<div id="pre-footer" class="row">
        <div class="col-md-9">
            <div class="adv-clickable col-md-3 col-sm-6 col-xs-10 col-xs-offset-1">
                <a href="#"><p>fdhgf</p></a>
                <a href="#"><p>fdgdfg</p></a>
                <a href="#"><p>fgdfg</p></a>
                <a href="#"><p>fgdfg fgdfg</p></a>
                <a href="#"><p>fgdfg gfddg</p></a>
                <a href="#"><p>dgdfgfd</p></a>
                <a href="#"><p>fgdfgdf fgdff gdfgdfg dgdfg</p></a>
            </div>
            <div class="adv-clickable col-md-3 col-sm-6 col-xs-10 col-xs-offset-1">
                <a href="#"><p>fdhgf</p></a>
                <a href="#"><p>fdgdfg</p></a>
                <a href="#"><p>fgdfg</p></a>
                <a href="#"><p>fgdfg fgdfg</p></a>
                <a href="#"><p>fgdfg gfddg</p></a>
                <a href="#"><p>dgdfgfd</p></a>
                <a href="#"><p>fgdfgdf fgdff gdfgdfg dgdfg</p></a>
            </div>
            <div id="pre-footer-nested1" class="col-md-3 col-sm-6 col-xs-10 col-xs-offset-1">
                <img src="images/pre-footer-logo.png">
                <div id="socials" class="col-xs-9 center-block">
                    <a href="#"><i class="fa fa-3x fa-facebook-square"></i></a>
                    <a href="#"><i class="fa fa-3x fa-twitter-square"></i></a>
                    <a href="#"><i class="fa fa-3x fa-linkedin-square"></i></a>
                    <a href="#"><i class="fa fa-3x fa-instagram"></i></a>
                    <a href="#"><i class="fa fa-3x fa-telegram"></i></a>
                </div>
                <form action="#" class="form-group col-xs-9 center-block">
                    <label for="email" class="text-center">ghdfgfdghfghfghfg</label>
                    <input type="email" id="email" class="form-control" placeholder="fdgdfgfdhggfh" >
                    <input type="submit" value="dfghfdghgfhg" class="btn btn-block btn-success">
                </form>
            </div>
            <div id="pre-footer-nested2" class="col-md-3 col-sm-6 col-xs-10 col-xs-offset-1">
                <img src="images/nemad.jpg" >
                <div class="col-md-12">
                    <div class="footer-logos">

                    </div>
                    <div class="footer-logos">

                    </div>
                    <div class="footer-logos">

                    </div>
                    <div class="footer-logos">

                    </div>
                </div>
            </div>
        </div>
    </div>

的CSS：

#pre-footer{
    display: flex;
    justify-content: space-around;
    align-items: center;
    flex-wrap: wrap;
    margin-top: 50px;
    position: relative;
}
.adv-clickable{
    display: flex;
    justify-content: space-around;
    flex-direction: column;
    align-items: center;
}
.adv-clickable a:first-child p{
    margin-bottom: 30px;
}
.adv-clickable p{
    color: #606060;
    font-size: 12px;
    font-weight: bold;
}
.adv-clickable a{
    text-decoration: none;
}
#pre-footer-nested1{
    display: flex;
    flex-direction: column;
    justify-content: center;
}
#pre-footer-nested1 img{
    width: 40px;
    height: 40px;
    margin: 0 auto;
}
#pre-footer-nested2{
    display: flex;
    flex-direction: column;
    justify-content: center;
}
#socials{
    margin-top: 20px;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
}
#socials i{
    color: #01a89e;
}
#pre-footer-nested1 form{
    margin-top: 20px;
    display: flex;
    flex-direction: column;
}
#pre-footer-nested1 form label{
    font-size: 10px;
    font-weight: bold;
    margin-bottom: 10px;
}
#pre-footer-nested1 input:last-child{
    margin-top: 10px;
    background-color: #01a89e;
    font-size: 12px;
}
#pre-footer-nested1 input:last-child:active{
    background-color: #0f8079;
}
#pre-footer-nested2{
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    flex-wrap: wrap;
}
#pre-footer-nested2 img{
    width: 100px;
    height: 120px;
}
#pre-footer-nested2 div{
    display: flex;
    margin-top: 22px;
    justify-content: center;
    flex-wrap: wrap;
}

这是我的JsFiddle