css - 固定元素溢出

Question

我试图让#sidebar 元素在浏览器窗口短于它的最小高度时滚动溢出，但似乎无法让它工作。知道为什么吗？

http://jsfiddle.net/q5jKM/1/

CSS - 抱歉，我无法使用这种时髦的格式。

html,body{height:100%;margin:0}
#sidebar {
    width: 20em;
    position:fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index:2;
    color: #ffffff;
    background-color: #333333;  
    overflow:auto;
    min-height: 34em;
}

#sidebar .nav {
    width: 3em;
    float: right;
    overflow: auto;
    background-color: #2e2e2e;
    border-left: 2px groove #454545;
    height: 100%;
    position:relative;  
}

#sidebar .content {
    height: 100%; 
    width: 16.875em; /*    17-(2/16)   - 20em - .nav - nav border*/
    float:left; 
    position:relative;
}

#sidebar .top {
    position:absolute;
    top:0;
}
#sidebar .bottom {
    position:absolute;
    bottom:0;
}

#sidebar .middle {
    position: absolute;
    bottom: 12em;       /*  3.125*3  */
    top: 16em;          /*  3.125*4  */
    background: green;
}

.content .middle {
    overflow:auto;
}


#sidebar .content > div {width: 16.875em; } /*.top .middle .bottom*/
#sidebar .nav > div {width:3em; } /*.top .middle .bottom*/


    /*table-cell trying get vertical-align working*/
#sidebar .table-cell {display:table-cell;}
#sidebar .middle .table-cell {vertical-align: middle;}


#sidebar .content p, #sidebar .content li, #sidebar .content img {font-size: .75em; color: #dddddd;}

#sidebar ul {margin:0; padding: 0;}






#sidebar .nav li {
    padding: .5625em;
    list-style:none;
}
#sidebar .nav li img {
    height: 1.875em;
    width: 1.875em
}

#sidebar .nav .top li { border-bottom: 2px groove #454545 }
#sidebar .nav .bottom li { border-top:  2px groove #454545 }




.content li {
    position:relative;
    display:block;
    background-color: #444;
    padding: .72em;
    border-radius: .8em;
    border-bottom: 1px solid #292929;
    border-top: 1px solid #4c4c4c;
    text-align: center;
    font-size: 1em;
    letter-spacing: .1em;
    font-weight: normal;
    height: 1.2em;
}

.content li:after {
    content:"";
    position:absolute;
    display:block; 
    width:0;
    top:.11em; /* controls vertical position */
    right:-.852em; /* value = - border-left-width - border-right-width */
    border-style:solid;
    border-width:1.2em 0 1.2em 1.2em;
    border-color:transparent #444;
}

.content .top li{margin: .95em 0 1.9em 0;}
.content .bottom li{margin: 1.9em 0 .95em 0;}

.content .logo {
    text-align: center;
    padding: 1em 0 2em 0;
    width: 100%;
    border-bottom: 2px groove #454545;
}
.content p.welcome {
    text-align: center;
    line-height: 1.5em;
    margin: 1em 0;
}

HTML

    <div id="sidebar">


            <div class="nav">
            <div class="top">
            <ul>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
            </ul>
            </div>
            <div class="middle"><div class="table-cell"><p>test</p></div></div>
            <div class="bottom">
            <ul>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
                <li><img src="_images/attributes/attribute2.svg"></li>
            </ul>
            </div>
            </div>



            <div class="content">
                <div class="top">
                <ul>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                </ul>
                </div>
                <div class="middle"><div class="table-cell">
                <div class="logo"><img src="_images/g.svg"></div>
                <p class="welcome">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris dictum tellus viverra neque bibendum in mattis ante dignissim. Nam mattis feugiat lorem porttitor adipiscing. Aliquam erat volutpat. Nunc feugiat magna vitae mauris egestas euismod. In hac habitasse platea dictumst. Praesent magna sem, malesuada non fermentum vel, luctus quis mauris. Duis quam purus, ornare vitae eleifend sed, malesuada eget libero. Phasellus sed lorem risus, nec placerat urna. In magna turpis, accumsan ac egestas quis, dictum vel massa. Nulla vitae magna arcu. Maecenas sit amet vestibulum urna. Integer feugiat dignissim leo sed ornare. Maecenas auctor ultricies dui, pulvinar tincidunt velit feugiat quis. Sed egestas ornare elit, et fringilla quam viverra ut.</p>
                </div></div>
                <div class="bottom">
                <ul>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                    <li>SIDEBAR LINK</li>
                </ul>
                </div>
                </div>
    </div>

Answer 1

知道了!

添加:- 这样#sidebar 就等于浏览器窗口。

#sidebar{height:100%}

并添加:- 提供溢出的内容。

#sidebar .nav, #sidebar .content {min-height:34em}

一旦浏览器窗口变得小于 34ems #sidebar 就会溢出。