我目前正在为我的基本网站使用 skel 框架。我需要将导航变成多级导航（下拉菜单）。是否有内置功能或者我需要包含一些插件？使用我当前的设置，单级导航运行良好，但是当我嵌套 UL 和 LI 标记时，它会破坏页面。
/* skel-baseline v2.0.3 | (c) n33 | getskel.com | MIT licensed */
(function($) {
skel.init({
reset: 'full',
breakpoints: {
global: {
href: 'assets/css/style.css',
containers: 1400,
grid: { gutters: ['40px', 0] }
},
xlarge: {
media: '(max-width: 1680px)',
href: 'assets/css/style-xlarge.css',
containers: 1200
},
large: {
media: '(max-width: 1280px)',
href: 'assets/css/style-large.css',
containers: 960,
grid: { gutters: ['40px', 0] },
viewport: { scalable: false }
},
medium: {
media: '(max-width: 980px)',
href: 'assets/css/style-medium.css',
containers: '90%'
},
small: {
media: '(max-width: 736px)',
href: 'assets/css/style-small.css',
containers: '90%',
grid: { gutters: ['40px', 0] }
},
xsmall: {
media: '(max-width: 480px)',
href: 'assets/css/style-xsmall.css'
}
},
plugins: {
layers: {
config: {
mode: 'transform'
},
navPanel: {
animation: 'pushX',
breakpoints: 'medium',
clickToHide: true,
height: '100%',
hidden: true,
html: '<div data-action="moveElement" data-args="nav"></div>',
orientation: 'vertical',
position: 'top-right',
side: 'right',
width: 250
},
navButton: {
breakpoints: 'medium',
height: '4em',
html: '<span class="toggle" data-action="toggleLayer" data-args="navPanel"></span>',
position: 'top-right',
side: 'top',
width: '6em'
}
}
}
});
$(function() {
var $window = $(window),
$body = $('body');
// Disable animations/transitions until the page has loaded.
$body.addClass('is-loading');
$window.on('load', function() {
$body.removeClass('is-loading');
});
});
})(jQuery);/* skel-baseline v2.0.3 | (c) n33 | getskel.com | MIT licensed */
/* Resets (http://meyerweb.com/eric/tools/css/reset/ | v2.0 | 20110126 | License: none (public domain)) */
html,body,div,span,applet,object,iframe,h1,h2,h3,h4,h5,h6,p,blockquote,pre,a,abbr,acronym,address,big,cite,code,del,dfn,em,img,ins,kbd,q,s,samp,small,strike,strong,sub,sup,tt,var,b,u,i,center,dl,dt,dd,ol,ul,li,fieldset,form,label,legend,table,caption,tbody,tfoot,thead,tr,th,td,article,aside,canvas,details,embed,figure,figcaption,footer,header,hgroup,menu,nav,output,ruby,section,summary,time,mark,audio,video{margin:0;padding:0;border:0;font-size:100%;font:inherit;vertical-align:baseline;}article,aside,details,figcaption,figure,footer,header,hgroup,menu,nav,section{display:block;}body{line-height:1;}ol,ul{list-style:none;}blockquote,q{quotes:none;}blockquote:before,blockquote:after,q:before,q:after{content:'';content:none;}table{border-collapse:collapse;border-spacing:0;}body{-webkit-text-size-adjust:none}
/* Box Model */
*, *:before, *:after {
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
box-sizing: border-box;
}
/* Container */
.container {
margin-left: auto;
margin-right: auto;
/* width: (containers) */
width: 1200px;
}
/* Modifiers */
/* 125% */
.container.\31 25\25 {
width: 100%;
/* max-width: (containers * 1.25) */
max-width: 1500px;
/* min-width: (containers) */
min-width: 1200px;
}
/* 75% */
.container.\37 5\25 {
/* width: (containers * 0.75) */
width: 900px;
}
/* 50% */
.container.\35 0\25 {
/* width: (containers * 0.50) */
width: 600px;
}
/* 25% */
.container.\32 5\25 {
/* width: (containers * 0.25) */
width: 300px;
}
/* Grid */
.row {
border-bottom: solid 1px transparent;
}
.row > * {
float: left;
}
.row:after, .row:before {
content: '';
display: block;
clear: both;
height: 0;
}
.row.uniform > * > :first-child {
margin-top: 0;
}
.row.uniform > * > :last-child {
margin-bottom: 0;
}
/* Gutters */
/* Normal */
.row > * {
/* padding: (gutters.horizontal) 0 0 (gutters.vertical) */
padding: 0 0 0 2em;
}
.row {
/* margin: -(gutters.horizontal) 0 -1px -(gutters.vertical) */
margin: 0 0 -1px -2em;
}
.row.uniform > * {
/* padding: (gutters.vertical) 0 0 (gutters.vertical) */
padding: 2em 0 0 2em;
}
.row.uniform {
/* margin: -(gutters.vertical) 0 -1px -(gutters.vertical) */
margin: -2em 0 -1px -2em;
}
/* 200% */
.row.\32 00\25 > * {
/* padding: (gutters.horizontal) 0 0 (gutters.vertical) */
padding: 0 0 0 4em;
}
.row.\32 00\25 {
/* margin: -(gutters.horizontal) 0 -1px -(gutters.vertical) */
margin: 0 0 -1px -4em;
}
.row.uniform.\32 00\25 > * {
/* padding: (gutters.vertical) 0 0 (gutters.vertical) */
padding: 4em 0 0 4em;
}
.row.uniform.\32 00\25 {
/* margin: -(gutters.vertical) 0 -1px -(gutters.vertical) */
margin: -4em 0 -1px -4em;
}
/* 150% */
.row.\31 50\25 > * {
/* padding: (gutters.horizontal) 0 0 (gutters.vertical) */
padding: 0 0 0 1.5em;
}
.row.\31 50\25 {
/* margin: -(gutters.horizontal) 0 -1px -(gutters.vertical) */
margin: 0 0 -1px -1.5em;
}
.row.uniform.\31 50\25 > * {
/* padding: (gutters.vertical) 0 0 (gutters.vertical) */
padding: 1.5em 0 0 1.5em;
}
.row.uniform.\31 50\25 {
/* margin: -(gutters.vertical) 0 -1px -(gutters.vertical) */
margin: -1.5em 0 -1px -1.5em;
}
/* 50% */
.row.\35 0\25 > * {
/* padding: (gutters.horizontal) 0 0 (gutters.vertical) */
padding: 0 0 0 1em;
}
.row.\35 0\25 {
/* margin: -(gutters.horizontal) 0 -1px -(gutters.vertical) */
margin: 0 0 -1px -1em;
}
.row.uniform.\35 0\25 > * {
/* padding: (gutters.vertical) 0 0 (gutters.vertical) */
padding: 1em 0 0 1em;
}
.row.uniform.\35 0\25 {
/* margin: -(gutters.vertical) 0 -1px -(gutters.vertical) */
margin: -1em 0 -1px -1em;
}
/* 25% */
.row.\32 5\25 > * {
/* padding: (gutters.horizontal) 0 0 (gutters.vertical) */
padding: 0 0 0 0.5em;
}
.row.\32 5\25 {
/* margin: -(gutters.horizontal) 0 -1px -(gutters.vertical) */
margin: 0 0 -1px -0.5em;
}
.row.uniform.\32 5\25 > * {
/* padding: (gutters.vertical) 0 0 (gutters.vertical) */
padding: 0.5em 0 0 0.5em;
}
.row.uniform.\32 5\25 {
/* margin: -(gutters.vertical) 0 -1px -(gutters.vertical) */
margin: -0.5em 0 -1px -0.5em;
}
/* 0% */
.row.\30 \25 > * {
padding: 0;
}
.row.\30 \25 {
margin: 0 0 -1px 0;
}
/* Cells */
.\31 2u, .\31 2u\24 { width: 100%; clear: none; margin-left: 0; }
.\31 1u, .\31 1u\24 { width: 91.6666666667%; clear: none; margin-left: 0; }
.\31 0u, .\31 0u\24 { width: 83.3333333333%; clear: none; margin-left: 0; }
.\39 u, .\39 u\24 { width: 75%; clear: none; margin-left: 0; }
.\38 u, .\38 u\24 { width: 66.6666666667%; clear: none; margin-left: 0; }
.\37 u, .\37 u\24 { width: 58.3333333333%; clear: none; margin-left: 0; }
.\36 u, .\36 u\24 { width: 50%; clear: none; margin-left: 0; }
.\35 u, .\35 u\24 { width: 41.6666666667%; clear: none; margin-left: 0; }
.\34 u, .\34 u\24 { width: 33.3333333333%; clear: none; margin-left: 0; }
.\33 u, .\33 u\24 { width: 25%; clear: none; margin-left: 0; }
.\32 u, .\32 u\24 { width: 16.6666666667%; clear: none; margin-left: 0; }
.\31 u, .\31 u\24 { width: 8.3333333333%; clear: none; margin-left: 0; }
.\31 2u\24 + *,
.\31 1u\24 + *,
.\31 0u\24 + *,
.\39 u\24 + *,
.\38 u\24 + *,
.\37 u\24 + *,
.\36 u\24 + *,
.\35 u\24 + *,
.\34 u\24 + *,
.\33 u\24 + *,
.\32 u\24 + *,
.\31 u\24 + * {
clear: left;
}
.\-11u { margin-left: 91.6666666667% }
.\-10u { margin-left: 83.3333333333% }
.\-9u { margin-left: 75% }
.\-8u { margin-left: 66.6666666667% }
.\-7u { margin-left: 58.3333333333% }
.\-6u { margin-left: 50% }
.\-5u { margin-left: 41.6666666667% }
.\-4u { margin-left: 33.3333333333% }
.\-3u { margin-left: 25% }
.\-2u { margin-left: 16.6666666667% }
.\-1u { margin-left: 8.3333333333% }<nav id="nav">
<ul>
<li><a href="#top">Top</a></li>
<li><a href="#content">Content</a></li>
<li><a href="#elements">Elements</a>
<ul><li>Link 1</li><li>link 2</li><li>Link 3</li></ul>
</li>
<li><a href="#grid">Grid System</a></li>
<li><a href="http://getskel.com" class="button special">Download</a></li>
</ul>
</nav>