我是一个CSS新手。我创建了一个菜单,其中菜单和下拉菜单之间出现了一个小空间,导致悬停效果中断。请帮帮我。谢谢
#menu, #menu ul {
margin: 0;
padding: 0;
list-style: none;
}
#menu {
width: 958px;
/*margin: 60px auto;*/
border: 1px solid #222;
background-color: #111;
background-image: linear-gradient(#444, #111);
box-shadow: 0 1px 1px #777;
}
#menu:before,
#menu:after {
content: "";
display: table;
}
#menu:after {
clear: both;
}
#menu {
zoom:1;
}
#menu li {
float: left;
/* border-right: 1px solid #222;*/
box-shadow: 1px 0 0 #444;
position: relative;
box-sizing: border-box;
width: 20%;
}
#menu a {
float: left;
padding: 11px 64px;
color: #999;
text-transform: uppercase;
text-decoration: none;
text-shadow: 0 1px 0 #000;
}
#menu li:hover > a {
color: #fafafa;
}
*html #menu li a:hover { /* IE6 only */
color: #fafafa;
}
#menu ul {
margin: 20px 0 0 0;
_margin: 0; /*IE6 only*/
opacity: 0;
visibility: hidden;
position: absolute;
top: 38px;
left: 0;
z-index: 1000000;
background: #444;
background: linear-gradient(#444, #111);
box-shadow: 0 -1px 0 rgba(255,255,255,.3);
transition: all .2s ease-in-out;
width: 100%;
}
#menu li:hover > ul {
opacity: 1;
visibility: visible;
margin: 0;
}
#menu ul ul {
top: 0;
left: 150px;
margin: 0 0 0 20px;
width:100%;
_margin: 0; /*IE6 only*/
box-shadow: -1px 0 0 rgba(255,255,255,.3);
}
#menu ul li {
float: none;
display: block;
border: 0;
_line-height: 0; /*IE6 only*/
box-shadow: 0 1px 0 #111, 0 2px 0 #666;
}
#menu ul li:last-child {
box-shadow: none;
}
#menu ul a {
padding: 10px;
width: 130px;
_height: 10px; /*IE6 only*/
display: block;
white-space: nowrap;
float: none;
text-transform: none;
}
#menu ul a:hover {
background-color: #111;
}
#menu ul li:first-child > a {
/*border-radius: 3px 3px 0 0;*/
}
#menu ul li:first-child > a:after {
content: '';
position: absolute;
left: 40px;
top: -6px;
}
#menu ul ul li:first-child a:after {
left: -6px;
top: 50%;
margin-top: -6px;
border-left: 0;
}
#menu ul li:first-child a:hover:after {
}
#menu ul ul li:first-child a:hover:after {
border-right-color: #000;
border-bottom-color: transparent;
}
#menu ul li:last-child > a {
/*border-radius: 0 0 3px 3px*/;
}
这是html,
<ul id="menu">
<li><a href="#">About </a></li>
<li><a href="#">Programmes</a><ul>
<li><a href="#">Undergraduate</a></li>
<li><a href="#">Postgraduate</a></li>
</ul></li>
<li><a href="#">Academics</a></li>
<li><a href="#">Research</a></li>
<li><a href="#">Facilities</a></li>
</ul>