我试图将蓝色框居中在灰色框内，但是一旦我将它们居中，它们甚至都不是水平的。我无法弄清楚是什么导致它们不均匀。谁能看到是什么原因造成的？
div.event_container{
width:100%;
overflow: hidden;
height:245px;
padding: 5px;
margin-top: 0px;
margin-bottom: 5px;
margin-left: auto;
margin-right: auto;
background-color:#999;
border-top: 0px;
position:relative;
top: 65px;
left: 0px;
clip: rect(5px, 0px, 0px, 0px);
z-index: 1;
}
div.event_box{
display: inline-block;
width:27%;
height:190px;
padding: 10px;
margin: 10px auto;
background-color:#B9DAF4;
position: relative;
border-top: 0px;
border-radius: 5px 10px 5px 10px / 10px 5px 10px 5px;
}
.event_text {
width:90%;
min-width:700px;
max-width:2000px;
min-height:100px;
position: relative;
top: 40px;
padding: 15px;
margin-top: 60px;
margin-bottom: 0px;
margin-left: auto;
margin-right: auto;
background-color:#fff;
text-align: left;
border-top: 1px solid #A3A3A3;
z-index:1;
}
.div_center3 {
margin:0 auto;
width:850px;
background-color: #666;
text-align: center;
position: relative;
}
#content{
width:99%;
max-width: 1200px;
height:100%;
margin-top: 0px;
margin-bottom: 5px;
margin-left: auto;
margin-right: auto;
text-align:center;
background-color:222;
border-top: 0px;
position:relative;
z-index:1px;
padding-bottom: 130px;
}
编码
<div id="content">
<div class="div_center3">
<!--Start header text-->
<div class="event_text">
<p class="htext"> Information & Innovation at USM hosts a variety of business and industry tours through the academic year,
as well as showcases projects and hosting job fairs. I&I is very active in coordinating efforts with Maine business and industry
leaders in many capacities.</p>
<p class="htext">I&I hosts tours of local IT industry leaders, such as Texas Instruments and Wright Express in South Portland.
In December of 2010, I&I showcased an array of research and development projects at the fifth Business and Industry Homecoming event
where technology leaders and staffing specialists from major Maine corporations were in attendance for the corporate event at the John
Mitchell Center at USM Gorham's campus.</p>
</div><!--End event_text div-->
<!--End Header text-->
<!--Start event boxes-->
<div class="event_container">
<div class="event_box">
<h3>State of IT in Maine Conference</h3>
Oct 18, 2012
<p style="text-align: justify;">Stay Tuned for more information!!</p>
<!--<a href="#">Read more</a>-->
</div>
<div class="event_box">
<h3>Business & Industry Tours</h3>
Fall of 2012
<p style="text-align: justify;">Each year, company representatives conduct business tours for IT students where they describe their
particular industry, as well as types of jobs and needed skills. This is a great opportunity for students to network and
get real world knowledge of the workforce.</p>
<p>Stay tuned for more information!! </p>
<!--<a href="#">Read more</a>-->
</div>
<div class="event_box">
<h3>IT Job Fair</h3>
Fall of 2012
<p style="text-align: justify;">This is an exclusive opportunity for IT and Computer Science students.<br />
Come meet potential employers offering internships and employment in Information Technology and Computer Science feilds.
</p>
<p style="text-align: justify;">Stay Tuned for more information!!</p>
<!--<a href="#">Read more</a>-->
</div>
</div>
<div id="pipe_container">
<div id="event_pipe">
<script src="http://l.yimg.com/a/i/us/pps/listbadge_1.6.js"> {"pipe_id":"2a44070dcf6974aea04ad155a76caef4","_btype":"list","width":"80%","height":"350px ", "margin":"auto"}</script>
</div>
</div>
</div>
</div>
<!--end holder-->