浅谈css中渐变衔接

@keyframes looppic{
    from{
        background:url(http://www.005.tv/uploads/allimg/160727/16-160HG44240938.png);
        }
    25%{
        background:url(http://b.zol-img.com.cn/sjbizhi/images/8/750x530/1422008118352.jpg);
        }
    75%{
        background:url(http://img3.duitang.com/uploads/item/201506/11/20150611192600_Stxhe.png);
        }
    to{
        background:url(http://www.005.tv/uploads/allimg/160727/16-160HG44240938.png);

       } 
   } 

.keyframeslp{ width:400px; height:200px; -webkit-animation:looppic 6s ease-in infinite; -moz--animation:looppic 6s ease-in infinite; -o--animation:looppic 6s ease-in infinite; -ms--animation:looppic 6s ease-in infinite; }

@keyframes opa{
    from{
        opacity:1}
        10%{
            opacity:0.75}
            20%{
                opacity:0.5}
                30%{
                    opacity:0.25;
                    content:text content;
                    color:#000000;}
                    40%{
                        opacity:0}
                        50%{
                            opacity:0.25}
                            68%{
                                opacity:0.5}
                                85%{
                                    opacity:0.75}
                                    to{
                                        opacity:1}
                        }
.bc{
    background:#F10E12;
    width:100px;
    height:100px;
    -webkit-animation:opa 5s ease-in-out infinite;
    -o-animation:opa 5s ease-in-out infinite;
    -ms-animation:opa 5s ease-in-out infinite;;
    -moz-animation:opa 5s ease-in-out infinite;
    }