最近我为菜单栏添加了响应式下拉菜单以支持触摸设备，但我遇到了一个有趣的问题，无法找出根本原因。基本上，下拉列表似乎是透明的，并且受到内容部分中背景提要帖子的文本的影响。似乎该下拉列表会读取背景文本标题，因为如果我将鼠标悬停在该文本上，则下拉列表会关闭，就像它认为我正在尝试将焦点放在标题上一样。
Click to see the image and it will all make sense.
#nav {
display: block;
cursor: pointer;
background-color: #4085C6;
padding: 6px;
color: #000;
text-decoration: none;
border-top-color: #4085C6;
border-right-color: #4085C6;
border-bottom-color: #4085C6;
border-left-color: #4085C6;
margin: 0px;
width: 960px;
}
#nav > a {
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: #4086C4;
content: '';
vertical-align: middle;
display: inline-block;
position: relative;
right: -0.313em; /* 5 */
}
/* first level */
#nav > ul {
height: 3.75em;
background-color: #4086C4;
list-style-type: none;
}
#nav > ul > li {
width: 157px;
float: left;
}
#nav > ul > li > a {
height: 100%;
font-size: 1.5em;
line-height: 2.5em;
text-align: center;
text-decoration: none;
}
#nav > ul > li:not( :last-child ) > a {
border-right-width: 8px;
border-right-color: #3779b3;
border-right-style: solid;
}
#nav > ul > li:hover > a,
#nav > ul:not( :hover ) > li.active > a {
background-color: #3779b3;
color: #FFF;
list-style-type: none;
}
/* second level */
#nav li ul {
background-color: #3779b3;
display: none;
position: absolute;
top: 100%;
width: 20em;
list-style-type: none;
}
#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;
border-top: 1px solid #4086C4;
padding: 0.75em;
text-decoration: none;
}
#nav li ul li a:hover,
#nav li ul:not( :hover ) li.active a {
background-color: #4086C4;
list-style-type: none;
}
@media only screen and ( max-width: 62.5em ) /* 1000 */
{
#nav {
width: 100%;
position: static;
box-shadow: 6px 6px #4785C6;
margin-top: 0px;
margin-right: 0px;
margin-bottom: 0px;
margin-left: 0px;
outline-color: #4086C4;
outline-style: solid;
background-color: #4086C4;
color: #4086C4;
padding: 0px;
border-top-color: #4086C4;
border-right-color: #4086C4;
border-bottom-color: #4086C4;
border-left-color: #4086C4;
}
}
@media only screen and ( max-width: 40em ) /* 640 */
{
html {
font-size: 75%; /* 12 */
}
#nav {
position: relative;
top: auto;
left: auto;
}
#nav > a {
width: 3.125em;
height: 3.125em;
text-align: left;
text-indent: -9999px;
background-color: #4086C4;
position: relative;
}
#nav > a:before,
#nav > a:after {
position: absolute;
border: 2px solid #fff;
top: 35%;
left: 25%;
right: 25%;
content: '';
}
#nav > a:after {
top: 60%;
}
#nav:not( :target ) > a:first-of-type,
#nav:target > a: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 > a {
height: auto;
text-align: left;
padding: 0 0.833em;
}
#nav > ul > li:not( :last-child ) > a {
border-right: none;
border-bottom: 1px solid #3779b3;
}
/* second level */
#nav li ul {
position: static;
padding: 1.25em;
padding-top: 0;
}
} <nav id="nav" role="navigation">
<a href="#nav" title="Show navigation">Show navigation</a>
<a href="#" title="Hide navigation">Hide navigation</a>
<ul>
<li><a href="home.html">Home</a></li>
<li>
<a href="#" aria-haspopup="true"><span>Adult</span></a>
<ul>
<li><a href="adult/indoor_soccer.html">Indoor</a></li>
<li><a href="adult/indoor_league.html">Indoor League</a></li>
<li><a href="adult/outdoor_soccer.html">Outdoor</a></li>
<li><a href="adult/wsl_schedules.html">WSL Schedule</a></li>
<li><a href="adult/srbijada2014.html">Srbijada 2014</a></li>
<li><a href="adult/contact_us.html">Contact</a></li>
</ul>
</li>
<li>
<a href="#" aria-haspopup="true"><span>Youth</span></a>
<ul>
<li><a href="youth/code_of_ethics.html">Code of Ethics</a></li>
<li><a href="youth/team_tryouts.html">Team Tryouts</a></li>
<li><a href="youth/team_camp.html">Team Camp</a></li>
<li><a href="youth/team_registration.html">Team Registration and Payments</a></li>
<li><a href="youth/mikro_soccer.html">MiKro Soccer</a></li>
<li><a href="youth/tournaments.html">Tournaments</a></li>
<li><a href="youth/contact_us.html">Contact</a></li>
</ul>
</li>
<li><a href="about_us.html">About Us</a></li>
<li><a href="board_members.html">Board</a></li>
<li><a href="links.html">Links</a></li>
</ul>
</nav>
答案 0 :(得分：1)
您应该在CSS中使用z-index属性。
#nav li ul {
background-color: #3779b3;
display: none;
position: absolute;
top: 100%;
width: 20em;
list-style-type: none;
z-index: 1;
}