《HTML5与CSS3基础教程》学习笔记 --Three Day_html/css_WEB-ITnose

 body{font-family:’ pt_sansregular’;}@font-face{ font-family: 'pt_sansregular';src: url('PTS55F-webfont.eot');src: url('PTS55F-webfont.eot?#iefix') format('embedded-opentype'),url('PTS55F-webfont.woff') format('woff'),url('PTS55F-webfont.ttf') format('truetype');font-weight: normal;font-style: normal;}

background: aqua;//要放在前面background: linear-gradient(to top right,blue,green);background: linear-gradient(90deg,blue,green);(起点：中上线)

/* 默认 */background: red;background: radial-gradient(yellow, red); background: radial-gradient(at top,yellow, red); background: radial-gradient(closest-side at 70px 60px, yellow, lime, red);background: radial-gradient(30px 30px at 65% 70%, yellow, lime, red)

:before和：after.more:after {content: " »";}

.icon:before {background-image: url(sprite.png);content: " ";//-------------------------------------------------display: block;//height: 16px; /* 图标高度 */position: absolute;width: 16px; /* 图标宽度 */}a[href$=".xls"]:before {background-position: -17px 0;}a[href$=".docx"]:before {background-position: -34px 0;}

ul{   list-style: none;   margin-left: 0;padding-left: 0;}li{   background: url(../img/done_square.png) no-repeat 0 .1em;   padding-left: 15px;   line-height: 24px;}

<nav role="navigation">         <ul class="nav">            <li><a href="/">Home</a></li>            <li><a href="#">Products</a>                <ul class="subnav">                   <li><a href="#">Phones</a></li>                   <li><a href="#">Accessories</a></li>                </ul>            </li>            <li><a href="#">Support</a>                <ul class="subnav">                   <li><a href="#">Community Forum</a></li>                   <li><a href="#">Contact Us</a></li>                   <li><a href="#">How-to Guides</a></li>                </ul>            </li>            <li><a href="#">About Us</a></li>         </ul>         <!-- end .nav -->      </nav>

/* 子菜单的默认状态 */.nav .subnav {left: -999em;/* 将子菜单移出屏幕 */position: absolute;z-index: 1000;}a,a:hover {text-decoration: none;}ul {list-style: none;margin-left: 0;padding-left: 0;}.nav {background: #fff;}.nav>li {float: left;padding-right: 10px;}.nav ul {background: #fff;z-index: 1000;border-bottom: 1px solid #fff;}.nav ul li {border-bottom: 1px solid gray;line-height: 24px;padding: 2px 5px;}/* 当鼠标停留在父元素li上时子菜单的状态 */.nav li:hover .subnav {left: auto;/* 让子菜单回到自然状态 */}