我不明白为什么这些div的边距重叠

.alignright {float: right}

#header .social {margin-top: 50px;}

#header .social a {display: inline-block;}

#header .social .fb {width: 64px; height: 1px; padding-top: 60px; overflow: hidden;}

#header .social .twit {width: 64px; height: 1px; padding-top: 60px; overflow: hidden;}

#header .contact {margin: 20px 70px 20px 0; font-size: 14px; font-weight: bold;}

#header .contact span {color: #FFFFFF;}

#header .search {margin: 10px 0 0;}


<div class="alignright">

    <div class="social">

        <a href="#" class="twit"></a>

        <a href="#" class="fb"></a>

    </div><!-- social -->

    <div class="contact">

        Get in Touch: <span>+44 10012 12345</span>

    </div><!-- contact -->

    <div class="search">

        <form method="post" action="">

            <input type="text" value="" name="s" gtbfieldid="28">

        </form>

    </div><!-- search -->

</div>