我找不到以此为中心的方法，其他搜索也没有帮助我。这是由css菜单生成的。
我尝试了一些我已经找到的东西，但没有任何效果。希望有人知道如何。
HTML
<body>
<div id='cssmenu'>
<ul>
<li><a href='#'>Home</a></li>
<li class='active'><a href='#'>Products</a>
<ul>
<li><a href='#'>Product 1</a>
<ul>
<li><a href='#'>Sub Product</a></li>
<li><a href='#'>Sub Product</a></li>
</ul>
</li>
<li><a href='#'>Product 2</a>
<ul>
<li><a href='#'>Sub Product</a></li>
<li><a href='#'>Sub Product</a></li>
</ul>
</li>
</ul>
</li>
<li><a href='#'>About</a></li>
<li><a href='#'>Contact</a></li>
</ul>
</div>
</body>
CSS
@import url(http://fonts.googleapis.com/css?family=Montserrat:400,700);
#cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a,
#cssmenu #menu-button {
margin: 0;
padding: 0;
border: 0;
list-style: none;
line-height: 1;
display: block;
position: relative;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}
#cssmenu:after,
#cssmenu > ul:after {
content: ".";
display: block;
clear: both;
visibility: hidden;
line-height: 0;
height: 0;
}
#cssmenu #menu-button {
display: none;
}
#cssmenu {
font-family: Montserrat, sans-serif;
background: #333333;
}
#cssmenu > ul > li {
float: left;
}
#cssmenu.align-center > ul {
font-size: 0;
text-align: center;
}
#cssmenu.align-center > ul > li {
display: inline-block;
float: none;
}
#cssmenu.align-center ul ul {
text-align: left;
}
#cssmenu.align-right > ul > li {
float: right;
}
#cssmenu > ul > li > a {
padding: 17px;
font-size: 12px;
letter-spacing: 1px;
text-decoration: none;
color: #dddddd;
font-weight: 700;
text-transform: uppercase;
}
#cssmenu > ul > li:hover > a {
color: #ffffff;
}
#cssmenu > ul > li.has-sub > a {
padding-right: 30px;
}
#cssmenu > ul > li.has-sub > a:after {
position: absolute;
top: 22px;
right: 11px;
width: 8px;
height: 2px;
display: block;
background: #dddddd;
content: '';
}
#cssmenu > ul > li.has-sub > a:before {
position: absolute;
top: 19px;
right: 14px;
display: block;
width: 2px;
height: 8px;
background: #dddddd;
content: '';
-webkit-transition: all .25s ease;
-moz-transition: all .25s ease;
-ms-transition: all .25s ease;
-o-transition: all .25s ease;
transition: all .25s ease;
}
#cssmenu > ul > li.has-sub:hover > a:before {
top: 23px;
height: 0;
}
#cssmenu ul ul {
position: absolute;
left: -9999px;
}
#cssmenu.align-right ul ul {
text-align: right;
}
#cssmenu ul ul li {
height: 0;
-webkit-transition: all .25s ease;
-moz-transition: all .25s ease;
-ms-transition: all .25s ease;
-o-transition: all .25s ease;
transition: all .25s ease;
}
#cssmenu li:hover > ul {
left: auto;
}
#cssmenu.align-right li:hover > ul {
left: auto;
right: 0;
}
#cssmenu li:hover > ul > li {
height: 35px;
}
#cssmenu ul ul ul {
margin-left: 100%;
top: 0;
}
#cssmenu.align-right ul ul ul {
margin-left: 0;
margin-right: 100%;
}
#cssmenu ul ul li a {
border-bottom: 1px solid rgba(150, 150, 150, 0.15);
padding: 11px 15px;
width: 170px;
font-size: 12px;
text-decoration: none;
color: #dddddd;
font-weight: 400;
background: #333333;
}
#cssmenu ul ul li:last-child > a,
#cssmenu ul ul li.last-item > a {
border-bottom: 0;
}
#cssmenu ul ul li:hover > a,
#cssmenu ul ul li a:hover {
color: #ffffff;
}
#cssmenu ul ul li.has-sub > a:after {
position: absolute;
top: 16px;
right: 11px;
width: 8px;
height: 2px;
display: block;
background: #dddddd;
content: '';
}
#cssmenu.align-right ul ul li.has-sub > a:after {
right: auto;
left: 11px;
}
#cssmenu ul ul li.has-sub > a:before {
position: absolute;
top: 13px;
right: 14px;
display: block;
width: 2px;
height: 8px;
background: #dddddd;
content: '';
-webkit-transition: all .25s ease;
-moz-transition: all .25s ease;
-ms-transition: all .25s ease;
-o-transition: all .25s ease;
transition: all .25s ease;
}
#cssmenu.align-right ul ul li.has-sub > a:before {
right: auto;
left: 14px;
}
#cssmenu ul ul > li.has-sub:hover > a:before {
top: 17px;
height: 0;
}
@media all and (max-width: 768px), only screen and (-webkit-min-device-pixel-ratio: 2) and (max-width: 1024px), only screen and (min--moz-device-pixel-ratio: 2) and (max-width: 1024px), only screen and (-o-min-device-pixel-ratio: 2/1) and (max-width: 1024px), only screen and (min-device-pixel-ratio: 2) and (max-width: 1024px), only screen and (min-resolution: 192dpi) and (max-width: 1024px), only screen and (min-resolution: 2dppx) and (max-width: 1024px) {
#cssmenu {
width: 100%;
}
#cssmenu ul {
width: 100%;
display: none;
}
#cssmenu.align-center > ul {
text-align: left;
}
#cssmenu ul li {
width: 100%;
border-top: 1px solid rgba(120, 120, 120, 0.2);
}
#cssmenu ul ul li,
#cssmenu li:hover > ul > li {
height: auto;
}
#cssmenu ul li a,
#cssmenu ul ul li a {
width: 100%;
border-bottom: 0;
}
#cssmenu > ul > li {
float: none;
}
#cssmenu ul ul li a {
padding-left: 25px;
}
#cssmenu ul ul ul li a {
padding-left: 35px;
}
#cssmenu ul ul li a {
color: #dddddd;
background: none;
}
#cssmenu ul ul li:hover > a,
#cssmenu ul ul li.active > a {
color: #ffffff;
}
#cssmenu ul ul,
#cssmenu ul ul ul,
#cssmenu.align-right ul ul {
position: relative;
left: 0;
width: 100%;
margin: 0;
text-align: left;
}
#cssmenu > ul > li.has-sub > a:after,
#cssmenu > ul > li.has-sub > a:before,
#cssmenu ul ul > li.has-sub > a:after,
#cssmenu ul ul > li.has-sub > a:before {
display: none;
}
#cssmenu #menu-button {
display: block;
padding: 17px;
color: #dddddd;
cursor: pointer;
font-size: 12px;
text-transform: uppercase;
font-weight: 700;
}
#cssmenu #menu-button:after {
position: absolute;
top: 22px;
right: 17px;
display: block;
height: 4px;
width: 20px;
border-top: 2px solid #dddddd;
border-bottom: 2px solid #dddddd;
content: '';
}
#cssmenu #menu-button:before {
position: absolute;
top: 16px;
right: 17px;
display: block;
height: 2px;
width: 20px;
background: #dddddd;
content: '';
}
#cssmenu #menu-button.menu-opened:after {
top: 23px;
border: 0;
height: 2px;
width: 15px;
background: #ffffff;
-webkit-transform: rotate(45deg);
-moz-transform: rotate(45deg);
-ms-transform: rotate(45deg);
-o-transform: rotate(45deg);
transform: rotate(45deg);
}
#cssmenu #menu-button.menu-opened:before {
top: 23px;
background: #ffffff;
width: 15px;
-webkit-transform: rotate(-45deg);
-moz-transform: rotate(-45deg);
-ms-transform: rotate(-45deg);
-o-transform: rotate(-45deg);
transform: rotate(-45deg);
}
#cssmenu .submenu-button {
position: absolute;
z-index: 99;
right: 0;
top: 0;
display: block;
border-left: 1px solid rgba(120, 120, 120, 0.2);
height: 46px;
width: 46px;
cursor: pointer;
}
#cssmenu .submenu-button.submenu-opened {
background: #262626;
}
#cssmenu ul ul .submenu-button {
height: 34px;
width: 34px;
}
#cssmenu .submenu-button:after {
position: absolute;
top: 22px;
right: 19px;
width: 8px;
height: 2px;
display: block;
background: #dddddd;
content: '';
}
#cssmenu ul ul .submenu-button:after {
top: 15px;
right: 13px;
}
#cssmenu .submenu-button.submenu-opened:after {
background: #ffffff;
}
#cssmenu .submenu-button:before {
position: absolute;
top: 19px;
right: 22px;
display: block;
width: 2px;
height: 8px;
background: #dddddd;
content: '';
}
#cssmenu ul ul .submenu-button:before {
top: 12px;
right: 16px;
}
#cssmenu .submenu-button.submenu-opened:before {
display: none;
}
}
答案 0 :(得分：2)
一种解决方案是更改以下内容：
#cssmenu #menu-button {
margin: 0;
padding: 0;
border: 0;
list-style: none;
line-height: 1;
display: inline-block;/*Change display to inline block*/
position: relative;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
text-align: center;/*Add text-align center*/
}
#cssmenu {
font-family: Montserrat, sans-serif;
background: #333333;
width: 100%;/*Add width 100%*/
}