利用CSS實現Family tree（族譜）效果

Family tree（族譜），也稱家譜，用來記錄家族世系繁衍輩份關係。本文結合執行個體，不藉助任何js指令碼，使用純CSS打造一個漂亮的Family tree（族譜），也可以應用的企業組織架構圖中。

HTML
我們使用div#tree來包含整個族譜結構，內部以ul和li元素構建資料來源。實際開發中這些族譜資料來源可以從資料庫中讀取，就像得到一個無限級的分類列表，以下是主要的html結構。
 
<div class="tree">
    <ul>
        <li>
            <a href="#">Parent</a>
            <ul>
                <li>
                    <a href="#">Child</a>
                    <ul>
                        <li><a href="#">Grand Child</a></li>
                    </ul>
                </li>
                <li>
                    <a href="#">Child</a>
                    <ul>
                        <li><a href="#">Grand Child</a></li>
                        <li>
                            <a href="#">Grand Child</a>
                            <ul>
                                <li><a href="#">Great Grand Child</a></li>
                                <li><a href="#">Great Grand Child</a></li>
                                <li><a href="#">Great Grand Child</a></li>
                            </ul>
                        </li>
                        <li><a href="#">Grand Child</a></li>
                    </ul>
                </li>
            </ul>
        </li>
    </ul>
</div>

CSS

我們使用css中的 :before、:after 兩個偽類的content屬性來構建元素間的連接線，同時使用了css3實現元素的圓角效果，並加上了滑鼠滑上hover效果，這樣滑鼠滑向族譜中的一個節點元素，與之相關的後輩元素都會有hover效果，完整的css代碼如下：
 
.tree ul {
    padding-top: 20px; position: relative;
    
    transition: all 0.5s;
    -webkit-transition: all 0.5s;
    -moz-transition: all 0.5s;
}
 
.tree li {
    float: left; text-align: center;
    list-style-type: none;
    position: relative;
    padding: 20px 5px 0 5px;
    
    transition: all 0.5s;
    -webkit-transition: all 0.5s;
    -moz-transition: all 0.5s;
}
 
/*We will use ::before and ::after to draw the connectors*/
 
.tree li::before, .tree li::after{
    content: '';
    position: absolute; top: 0; right: 50%;
    border-top: 1px solid #ccc;
    width: 50%; height: 20px;
}
.tree li::after{
    right: auto; left: 50%;
    border-left: 1px solid #ccc;
}
 
/*We need to remove left-right connectors from elements without 
any siblings*/
.tree li:only-child::after, .tree li:only-child::before {
    display: none;
}
 
/*Remove space from the top of single children*/
.tree li:only-child{ padding-top: 0;}
 
/*Remove left connector from first child and 
right connector from last child*/
.tree li:first-child::before, .tree li:last-child::after{
    border: 0 none;
}
/*Adding back the vertical connector to the last nodes*/
.tree li:last-child::before{
    border-right: 1px solid #ccc;
    border-radius: 0 5px 0 0;
    -webkit-border-radius: 0 5px 0 0;
    -moz-border-radius: 0 5px 0 0;
}
.tree li:first-child::after{
    border-radius: 5px 0 0 0;
    -webkit-border-radius: 5px 0 0 0;
    -moz-border-radius: 5px 0 0 0;
}
 
/*Time to add downward connectors from parents*/
.tree ul ul::before{
    content: '';
    position: absolute; top: 0; left: 50%;
    border-left: 1px solid #ccc;
    width: 0; height: 20px;
}
 
.tree li a{
    border: 1px solid #ccc;
    padding: 5px 10px;
    text-decoration: none;
    color: #666;
    font-family: arial, verdana, tahoma;
    font-size: 11px;
    display: inline-block;
    
    border-radius: 5px;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    
    transition: all 0.5s;
    -webkit-transition: all 0.5s;
    -moz-transition: all 0.5s;
}
 
/*Time for some hover effects*/
/*We will apply the hover effect the the lineage of the element also*/
.tree li a:hover, .tree li a:hover+ul li a {
    background: #c8e4f8; color: #000; border: 1px solid #94a0b4;
}
/*Connector styles on hover*/
.tree li a:hover+ul li::after, 
.tree li a:hover+ul li::before, 
.tree li a:hover+ul::before, 
.tree li a:hover+ul ul::before{
    border-color:  #94a0b4;
}