对于最大宽度为480px的设备，我使用以下HTML和CSS代码。
我怎么能：
请注意，我对网页设计的了解仅限于基本的HTML和CSS。这是我第一次设计网站。
非常感谢任何帮助或建议。
#menu {
position: relative;
top: 0;
margin: 0;
padding: 0;
width: 100%;
height: 3rem;
font-size: 0.8rem;
z-index: 999;
}
#menu ul {
position: absolute;
margin: 0;
padding: 0;
height: 100%;
width: 100%;
list-style-type: none;
background-color: #0000ff;
color: #ffffff;
}
#menu ul > li {
display: block;
float: left;
height: auto;
width: 20%;
overflow: hidden;
}
#menu li > a {
display: block;
height: 100%;
width: 100%;
line-height: 3rem;
text-align: center;
text-decoration: none;
background-color: #0000ff;
color: #ffffff;
}
#menu li > span {
display: block;
height: 100%;
width: 100%;
line-height: 3rem;
text-align: center;
text-decoration: none;
background-color: #0000ff;
color: #ffffff;
}
#menu ul ul {
display: none;
position: static;
height: auto;
width: 100%;
margin: 0;
}
#menu ul ul li {
position: relative;
float: none;
display: block;
height: 100%;
width: 100%;
}
#menu ul ul li > a {
height: 100%;
width: 100%;
text-align: center;
}
#menu li:hover > a {
color: #0000ff;
background-color: #ffffff;
}
#menu li:hover > span {
color: #0000ff;
background-color: #ffffff;
}
#menu li:hover > ul {
display: block;
}<nav id="menu">
<ul>
<li><a href="index.html">HOME</a></li>
<li><span>ABOUT</span>
<ul>
<li><a href="about/history.html">History</a></li>
<li><a href="about/champions.html">Champions</a></li>
<li><a href="about/presidents.html">Presidents</a></li>
<li><a href="about/committee.html">Committee</a></li>
<li><a href="about/rules.html">Rules</a></li>
</ul>
</li>
<li><span>BOOK</span>
<ul>
<li><a href="book/functions.html">Functions</a></li>
<li><a href="book/suite.html">Suite</a></li>
<li><a href="book/lounge.html">Lounge</a></li>
<li><a href="book/bar.html">Bar</a></li>
</ul>
</li>
<li><span>COMPS</span>
<ul>
<li><a href="comps/fixtures.html">Fixtures</a></li>
<li><a href="comps/gents.html">Gents</a></li>
<li><a href="comps/ladies.html">Ladies</a></li>
<li><a href="comps/winners.html">Winners</a></li>
</ul>
</li>
<li><span>CONTACT</span>
<ul>
<li><a href="contact/details.html">Details</a></li>
<li><a href="membership/join.html">Join</a></li>
<li><a href="contact/map.html">Map</a></li>
</ul>
</li>
</ul>
</nav>
答案 0 :(得分：2)
请查看以下示例
/********** Start RESET **********
AUTHOR: Osvaldas Valutis, www.osvaldas.info
*/
* {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
*behavior: url( '/theme/js/boxsizing.htc' );
-webkit-tap-highlight-color: rgba( 0, 0, 0, 0 );
-webkit-overflow-scrolling: touch;
}
html, body, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sup, sub, tt, var, b, u, i, center, ul, ol, li, dl, dt, dd, table, tr, th, td, thead, tbody, tfoot, caption, form, fieldset, legend, input, textarea, select, label, applet, object, iframe, audio, video, canvas, article, aside, canvas, details, figcaption, figure, footer, header, hgroup, menu, nav, section, summary {
font-size: 100%;
font-family: inherit;
font-weight: inherit;
font-style: inherit;
line-height: inherit;
vertical-align: baseline;
border: 0;
outline: 0;
padding: 0;
margin: 0;
}
html {
font-size: 100%;
-webkit-text-size-adjust: 100%;
-moz-text-size-adjust: 100%;
-ms-text-size-adjust: 100%;
-o-text-size-adjust: 100%;
text-size-adjust: 100%;
}
body {
font-family: Helvetica, Arial, sans-serif;
line-height: 1;
color: #000;
background-color: #fff;
}
article, aside, canvas, details, figcaption, figure, footer, header, hgroup, menu, nav, section, summary {
display: block;
}
audio, canvas, video {
display: inline-block;
*display: inline;
*zoom: 1;
}
audio:not([controls]) {
display: none;
}
canvas {
-ms-touch-action: double-tap-zoom;
}
[hidden] {
display: none;
}
a {
text-decoration: underline;
color: #000;
}
a:hover {
text-decoration: none;
}
small {
font-size: 75%;
}
big {
font-size: 125%;
}
em {
font-style: italic;
}
strong {
font-weight: bold;
}
ins {
text-decoration: none;
}
del {
text-decoration: line-through;
}
sup, sub {
font-size: 75%;
line-height: 0;
}
sup {
vertical-align: super;
}
sub {
vertical-align: sub;
}
pre {
display: block;
overflow: auto;
}
code {
font-family: 'Courier New', Courier, monospace;
}
ul, ol {
list-style: none;
}
table {
table-layout: auto;
border-collapse: separate;
border-spacing: 0;
empty-cells: hide;
}
img {
vertical-align: middle;
-ms-interpolation-mode: bicubic;
}
svg:not(:root) {
overflow: hidden;
}
blockquote, q {
quotes: none;
}
blockquote:before, blockquote:after, q:before, q:after {
content: '';
content: none;
}
input, textarea {
-webkit-appearance: none;
}
button, input, select, textarea {
vertical-align: baseline;
*vertical-align: middle;
-webkit-border-radius: 0;
}
button, input {
line-height: normal;
*overflow: visible;
}
table button, table input {
*overflow: auto;
}
button, input[type='button'], input[type='reset'], input[type='submit'] {
cursor: pointer;
-webkit-appearance: button;
}
textarea {
overflow: auto;
vertical-align: top;
}
input[type='search']::-webkit-search-decoration, input[type='search']::-webkit-search-cancel-button, input[type='search']::-webkit-search-results-button, input[type='search']::-webkit-search-results-decoration {
display: none;
}
input[type='search'] {
-webkit-appearance: textfield;
}
input[type='radio'] {
-webkit-appearance: radio;
}
input[type='checkbox'] {
-webkit-appearance: checkbox;
}
input::-ms-clear {
display: none;
}
input[type='password']::-ms-reveal {
display: none;
}
.clearfix:after {
visibility: hidden;
display: block;
font-size: 0;
content: " ";
clear: both;
height: 0;
}
* html .clearfix {
zoom: 1;
}
*:first-child+html .clearfix {
zoom: 1;
}
.cleaner {
height: 0;
line-height: 0;
clear: both;
}
/********** End RESET **********/
html {
font-size: 100%;
}
body {
font-family: 'Noticia Text', serif;
font-weight: 400;
-webkit-font-smoothing: antialiased;
background-color: #f7efeb;
padding: 1.25em; /* 20 */
}
body, a, a:hover {
color: #111;
}
a {
-webkit-transition: color .3s ease;
-moz-transition: color .3s ease;
-ms-transition: color .3s ease;
-o-transition: color .3s ease;
transition: color .3s ease;
}
a, a:hover {
text-decoration: none;
}
#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 > 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: #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 > a {
width: 3.125em; /* 50 */
height: 3.125em; /* 50 */
text-align: left;
text-indent: -9999px;
background-color: #e15a1f;
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; /* 20 (24) */
}
#nav > ul > li:not( :last-child ) > a {
border-right: none;
border-bottom: 1px solid #cc470d;
}
/* second level */
#nav li ul {
position: static;
padding: 1.25em; /* 20 */
padding-top: 0;
}
}<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<meta name="viewport" content="width=device-width,initial-scale=1" />
<nav id="nav" role="navigation"> <a href="#nav" title="Show navigation">Show navigation</a> <a href="#" title="Hide navigation">Hide navigation</a>
<ul class="clearfix">
<li><a href="">Home</a></li>
<li> <a href=""><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=""><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>