我想在折叠菜单中使用双箭头（在左侧和右侧），但我不能。
您可以在此处找到折叠菜单示例：http://bootsnipp.com/snippets/b47p2
我想要的例子https://sedo.com/us/＆＃34;＆＃34; HOW IT WORKS＆＃34;部分。
我试图解决sedo的代码，但我无法合并。据我所知，他们使用
_transform: rotate(135deg);_
制作双箭头。
代码想要改变：
HTML：
<div class="container">
<div class="row">
<div class="col-md-8" id="main">
<h3>Doesn't it look better ?</h3>
<div class="panel-group" id="accordion" role="tablist" aria-multiselectable="true">
<div class="panel panel-default">
<div class="panel-heading" role="tab" id="headingOne">
<h4 class="panel-title">
<a role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
Why is it better
</a>
</h4>
</div>
<div id="collapseOne" class="panel-collapse collapse in" role="tabpanel" aria-labelledby="headingOne">
<div class="panel-body">
<ul>
<li>The titles are block, so you don't have to click the text part to activate it</li>
<li>Indicators for expand / collapsing items</li>
<li>Removed title links' obnoxious :hover underlinings, and outlines.</li>
</ul>
</div>
</div>
</div>
<div class="panel panel-default">
<div class="panel-heading" role="tab" id="headingTwo">
<h4 class="panel-title">
<a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
Collapsible Group Item #2
</a>
</h4>
</div>
<div id="collapseTwo" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingTwo">
<div class="panel-body">
Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
</div>
</div>
</div>
<div class="panel panel-default">
<div class="panel-heading" role="tab" id="headingThree">
<h4 class="panel-title">
<a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion" href="#collapseThree" aria-expanded="false" aria-controls="collapseThree">
Collapsible Group Item #3
</a>
</h4>
</div>
<div id="collapseThree" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingThree">
<div class="panel-body">
Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
</div>
</div>
</div>
</div>
<hr />
<h3>Compared to default</h3>
<div class="panel-group" id="accordion_reg" role="tablist" aria-multiselectable="true">
<div class="panel panel-default">
<div class="panel-heading" role="tab" id="headingOne_reg">
<h4 class="panel-title">
<a role="button" data-toggle="collapse" data-parent="#accordion_reg" href="#collapseOne_reg" aria-expanded="true" aria-controls="collapseOne_reg">
Collapsible Group Item #1
</a>
</h4>
</div>
<div id="collapseOne_reg" class="panel-collapse collapse in" role="tabpanel" aria-labelledby="headingOne_reg">
<div class="panel-body">
Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
</div>
</div>
</div>
<div class="panel panel-default">
<div class="panel-heading" role="tab" id="headingTwo_reg">
<h4 class="panel-title">
<a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion_reg" href="#collapseTwo_reg" aria-expanded="false" aria-controls="collapseTwo_reg">
Collapsible Group Item #2
</a>
</h4>
</div>
<div id="collapseTwo_reg" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingTwo_reg">
<div class="panel-body">
Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
</div>
</div>
</div>
<div class="panel panel-default">
<div class="panel-heading" role="tab" id="headingThree_reg">
<h4 class="panel-title">
<a class="collapsed" role="button" data-toggle="collapse" data-parent="#accordion_reg" href="#collapseThree_reg" aria-expanded="false" aria-controls="collapseThree_reg">
Collapsible Group Item #3
</a>
</h4>
</div>
<div id="collapseThree_reg" class="panel-collapse collapse" role="tabpanel" aria-labelledby="headingThree_reg">
<div class="panel-body">
Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
</div>
</div>
</div>
</div>
</div>
<div class="sidebar col-md-4" id="sideright">
<h3>Sidebar</h3>
<p class="well">Some sidebar content</p>
</div>
</div>
<div>
CSS：
#accordion .panel-heading { padding: 0;}
#accordion .panel-title > a {
display: block;
padding: 0.4em 0.6em;
outline: none;
font-weight:bold;
text-decoration: none;
}
#accordion .panel-title > a.accordion-toggle::before, #accordion a[data-toggle="collapse"]::before {
content:"\e113";
float: left;
font-family: 'Glyphicons Halflings';
margin-right :1em;
}
#accordion .panel-title > a.accordion-toggle.collapsed::before, #accordion a.collapsed[data-toggle="collapse"]::before {
content:"\e114";
}
非常感谢..
答案 0 :(得分：4)
将您的CSS更改为下一个
#accordion .panel-heading {
padding: 0;
position: relative;
}
#accordion .panel-title > a {
display: block;
padding: 0.4em 2em;
outline: none;
font-weight:bold;
text-decoration: none;
}
#accordion .panel-title > a.accordion-toggle::before, #accordion a[data-toggle="collapse"]::before,
#accordion .panel-title > a.accordion-toggle::after, #accordion a[data-toggle="collapse"]::after{
content:"\e113";
position: absolute;
font-family: 'Glyphicons Halflings';
top: 0.5em;
}
#accordion .panel-title > a.accordion-toggle.collapsed::before, #accordion a.collapsed[data-toggle="collapse"]::before,
#accordion .panel-title > a.accordion-toggle.collapsed::after, #accordion a.collapsed[data-toggle="collapse"]::after{
content:"\e114";
}
#accordion .panel-title > a.accordion-toggle::before, #accordion a[data-toggle="collapse"]::before,
#accordion .panel-title > a.accordion-toggle.collapsed::before, #accordion a.collapsed[data-toggle="collapse"]::before {
left: 0.5em;
}
#accordion .panel-title > a.accordion-toggle.collapsed::after, #accordion a.collapsed[data-toggle="collapse"]::after,
#accordion .panel-title > a.accordion-toggle::after, #accordion a[data-toggle="collapse"]::after{
right: 0.5em;
}