由灰色渐变成蓝色，样式如下
?
a {
? color: #999999;
? color: rgba(155,155,155,.5);
? -webkit-transition: all .2s ease-in-out;
? ? ?-moz-transition: all .2s ease-in-out;
? ? ? ? ? transition: all .2s ease-in-out;
}
a:hover {
? color: #7777FF;
? text-shadow: 0 0 10px rgba(125,125,125,.25);
}