纯CSS3实现动态导航栏目

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>测试一下</title>
</head>
<style>
    *{
        padding:0;
        margin: 0;
    }
      .top-nav{
         width:900px;
         margin:0 auto;
         border: 1px solid #222;
         background-image:linear-gradient(#444,#111);
         border-radius: 6px;
         box-shadow: 0 1px 1px #777;
         padding:0;
         list-style: none;
          /*overflow: hidden;*/
          overflow: visible;
     }
      .top-nav:before,.top-nav:after{
          content: "";
          display:table;
      }
      .top-nav:after{
          clear:both;
      }
    .top-nav li{
        float: left;
        border-right: 1px solid #222;
        box-shadow: 1px 0 0 #444;
        position:relative;
    }
    .top-nav li a {
        float:left;
        padding:12px 30px;
        color:#999;
        font:bold 12px;
        text-decoration: none;
        text-shadow: 0 1px 0 #000;
    }
    .top-nav li a:hover{
        color:#fafafa;
    }
    .top-nav li ul{
        visibility:hidden;
        position: absolute;
        list-style: none;
        top:41px;
        left:0;
        z-index: 1;
        padding:0;
        background-color: #444;
        background-image: linear-gradient(#444,#111);
        box-shadow: 0 -1 0 rgba(255,255,255,.3);
        border-radius: 3px;
        opacity: 0;
        margin:20px 0 0 0;
        transition:all .2s ease-in-out;

    }
      .top-nav li:hover >ul{
          opacity:1;
          visibility: visible;
          margin: 0;
      }
    .top-nav ul li{
        float: none;
        display:block;
        border:0;
        box-shadow: 0 1px 0 #111 ,0 2px 0 #666;
    }
    .top-nav ul a{
        padding:10px;
        width:130px;
        display: block;
        float: none;
    }
    .top-nav ul a:hover{
        background-color: #0186ba;
        background-image:liner-gradient(#04acec,#0186ba);

    }
    .top-nav ul li:first-child>a{
        border-radius: 3px 3px 0 0;

    }
   .top-nav ul li :last-child>a{
       border-radius:0 0 3px 3px;
   }
    .top-nav ul li :first-child > a:before{
        content:"";
        position:absolute;
        left:40px;
        top:-6px;
        border-bottom:6px solid #0299d3;
        border-left:6px solid transparent;
        border-right:6px solid transparent;

    }
    .top-nav ul li :first-child > a:before{
        border-bottom-color:#04acec;
    }
    .top-nav ul ul {
        top:0;
        left:150px;
        margin:0 0 0 20px;
        box-shadow: -1px 0 0 rgba(255,255,255,.3);
    }
    .top-nav ul ul li:first-child a:before{
        left:-6px;
        top:50%;
        margin-top:-6px;
        border-left: 0;
        border-bottom: 6px solid transparent;
        border-top: 6px solid transparent;
        border-right: 6px solid #3b3b3b;
    }
    .top-nav ul ul li:first-child a:hover:before{
        border-right-color: #0299d3;
        border-bottom-color:transparent;
    }
</style>
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css3实现动画导航菜单尖角

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>动画导航尖角</title>
    <style>
        .box{
            display: block;
            width: 0;
            border-bottom: 10px solid  red;
            border-left:10px solid transparent;
            border-right:10px solid transparent;
            border-top:10px solid transparent;
        }


    </style>
</head>
<body>
   <div class="box"></div>
</body>
</html>
原文地址:https://www.cnblogs.com/kangshuai/p/5955512.html