<分区>
我正在摆弄 this menu对于触摸屏:
#nav span:after 以某种方式导致跨度上出现向下箭头 - 怎么办？它从何而来？如何更改此图标/字符？
它似乎不是来自 content 属性，而且任何地方都没有图像文件。当我在自己的系统中复制它时，我在 IE 和 FF 中也得到了箭头。如果我们将 nav 标记更改为 div 并且如果我们删除 aria-haspopup，它就会出现。如果我在 IE 或 FF 中按 F12，我找不到它以查看它被引入的位置，除非它是使用边框或其他东西的一些奇怪的怪癖。
HTML:
<nav id="nav" role="navigation">
<span href="#nav" title="Show navigation">Show navigation</span>
<span href="#" title="Hide navigation">Hide navigation</span>
<ul class="clearfix">
<li><a href="">Home</a>
</li>
<li> <a href="" aria-haspopup="true"><span>Blog</span></a>
<ul>
<li><a href="">Design</a>
</li>
<li><a href="">HTML</a>
</li>
<li><a href="">CSS</a>
</li>
<li><a href="">JavaScript</a>
</li>
</ul>
</li>
<li> <a href="" aria-haspopup="true"><span>Work</span></a>
<ul>
<li><a href="">Web Design</a>
</li>
<li><a href="">Typography</a>
</li>
<li><a href="">Front-End</a>
</li>
</ul>
</li>
<li><a href="">About</a>
</li>
</ul>
</nav>
CSS:
#nav {
width: 60em;
/* 1000 */
font-family:'Open Sans', sans-serif;
font-weight: 400;
position: absolute;
top: 25%;
left: 50%;
margin-left: -30em;
/* 30 480 */
}
#nav > span {
display: none;
}
#nav li {
position: relative;
}
#nav li a {
color: #fff;
display: block;
}
#nav li a:active {
background-color: #c00 !important;
}
#nav span:after {
width: 0;
height: 0;
border: 0.313em solid transparent;
/* 5 */
border-bottom: none;
border-top-color: #efa585;
content:'';
vertical-align: middle;
display: inline-block;
position: relative;
right: -0.313em;
/* 5 */
}
/* first level */
#nav > ul {
height: 3.75em;
/* 60 */
background-color: #e15a1f;
}
#nav > ul > li {
width: 25%;
height: 100%;
float: left;
}
#nav > ul > li > a {
height: 100%;
font-size: 1.5em;
/* 24 */
line-height: 2.5em;
/* 60 (24) */
text-align: center;
}
#nav > ul > li:not(:last-child) > a {
border-right: 1px solid #cc470d;
}
#nav > ul > li:hover > a, #nav > ul:not(:hover) > li.active > a {
background-color: #cc470d;
}
/* second level */
#nav li ul {
background-color: #cc470d;
display: none;
position: absolute;
top: 100%;
}
#nav li:hover ul {
display: block;
left: 0;
right: 0;
}
#nav li:not(:first-child):hover ul {
left: -1px;
}
#nav li ul a {
font-size: 1.25em;
/* 20 */
border-top: 1px solid #e15a1f;
padding: 0.75em;
/* 15 (20) */
}
#nav li ul li a:hover, #nav li ul:not(:hover) li.active a {
background-color: #e15a1f;
}
@media only screen and (max-width: 62.5em)
/* 1000 */
{
#nav {
width: 100%;
position: static;
margin: 0;
}
}
@media only screen and (max-width: 40em)
/* 640 */
{
html {
font-size: 75%;
/* 12 */
}
#nav {
position: relative;
top: auto;
left: auto;
}
#nav > span {
width: 3.125em;
/* 50 */
height: 3.125em;
/* 50 */
text-align: left;
text-indent: -9999px;
background-color: #e15a1f;
position: relative;
}
#nav > span:before, #nav > span:after {
position: absolute;
border: 2px solid #fff;
top: 35%;
left: 25%;
right: 25%;
content:'';
}
#nav > span:after {
top: 60%;
}
#nav:not(:target) > span:first-of-type, #nav:target > span:last-of-type {
display: block;
}
/* first level */
#nav > ul {
height: auto;
display: none;
position: absolute;
left: 0;
right: 0;
}
#nav:target > ul {
display: block;
}
#nav > ul > li {
width: 100%;
float: none;
}
#nav > ul > li > span {
height: auto;
text-align: left;
padding: 0 0.833em;
/* 20 (24) */
}
#nav > ul > li:not(:last-child) > span {
border-right: none;
border-bottom: 1px solid #cc470d;
}
/* second level */
#nav li ul {
position: static;
padding: 1.25em;
/* 20 */
padding-top: 0;
}
}