css3选择器（上）
.nav li::before,.nav li::after{
content:"";
position:absolute;
top:14px;
height:25px;
width:1px;
}
.nav li::before{
left:0;
background:-webkit-linear-gradient(to bottom,#f06254,#ffffff,#f06254);
background:-moz-linear-gradient(to bottom,#f06254,#ffffff,#f06254);
background:-o-linear-gradient(to bottom,#f06254,#ffffff,#f06254);
background:-ms-linear-gradient(to bottom,#f06254,#ffffff,#f06254);
background:linear-gradient(to bottom,#f06254,#ffffff,#f06254);
}
.nav li::after{
right:0;
background:-webkit-linear-gradient(to bottom,#f06254,#bf554c,#f06254);
background:-moz-linear-gradient(to bottom,#f06254,#bf554c,#f06254);
background:-o-linear-gradient(to bottom,#f06254,#bf554c,#f06254);
background:-ms-linear-gradient(to bottom,#f06254,#bf554c,#f06254);
background:linear-gradient(to bottom,#f06254,#bf554c,#f06254);
}
.nav li:first-child::before{ background:none;}
.nav li:last-child::after{ background:none;}
2、
html代码：