为什么我的自举旋转木马两侧有额外的空间？

Question

我相当肯定这是一个简单的解决方法，但我已经花了好几个小时，我不知道为什么我还没能解决它。任何帮助将不胜感激！

我的HTML是标准的bootstrap：

<div class="row">
    <div class="container" id="main">
        <div class=col-md-12>
            <div id="carousel-example-generic" class="carousel slide" data-ride="carousel" data-interval="5000">
            <!-- Indicators -->
                <ol class="carousel-indicators">
                    <li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
                    <li data-target="#carousel-example-generic" data-slide-to="1"></li>
                </ol>
                <!-- Wrapper for slides -->
                <div class="carousel-inner" role="listbox">
                    <div class="item active">
                        <img src="*IMAGE*" alt="Power Grid">
                        <div class="carousel-caption"> 
                            <h3>HELLO</h3>
                            <p>World</p>
                        </div>
                    </div>
                    <div class="item">
                        <img src="*IMAGE*" alt="Power Grid">
                        <div class="carousel-caption"> 
                            <h3>GOODBYE</h3>
                            <p>World</p>
                        </div>
                    </div>
                </div>
            </div>
            <!-- Controls -->
            <a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
                <span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
                <span class="sr-only">Previous</span>
            </a>
            <a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
                <span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
                <span class="sr-only">Next</span>
            </a>
        </div>
    </div>
</div>

这是我目前的CSS：

#main.container {
    padding: 0 10% 5% 10%;
}

.carousel-inner > .item > img,
.carousel-inner > .item > a > img { 
    width: 50%;
    margin: auto;
}

#carousel-example-generic {
    border: #000000 solid 10px; 
    border-radius: 15px;
}