.slider {
    width: 1200px;
    height: 550px;
    overflow: hidden;
    margin:0 auto;
}
.slider .slider-main li .img{height: 292px;width:1200px;}
.slider .slider-main li .img1{background:url(../imgs/1.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img2{background:url(../imgs/2.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img3{background:url(../imgs/3.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img4{background:url(../imgs/4.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img5{background:url(../imgs/5.jpg) no-repeat;background-size: cover;}

.slider .slider-main li .img6{background:url(../imgs/6.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img7{background:url(../imgs/7.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img8{background:url(../imgs/8.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img9{background:url(../imgs/9.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img10{background:url(../imgs/10.jpg) no-repeat;background-size: cover;}

.slider .slider-main li .img11{background:url(../imgs/11.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img12{background:url(../imgs/12.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img13{background:url(../imgs/13.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img14{background:url(../imgs/14.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img15{background:url(../imgs/15.jpg) no-repeat;background-size: cover;}

.slider .slider-main li .img16{background:url(../imgs/16.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img17{background:url(../imgs/17.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img18{background:url(../imgs/18.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img19{background:url(../imgs/19.jpg) no-repeat;background-size: cover;}
.slider .slider-main li .img20{background:url(../imgs/20.jpg) no-repeat;background-size: cover;}

.slider .slider-main li .img21{background:url(../imgs/21.jpg) no-repeat;background-size: cover;}

 
/* @media screen and (max-width: 1400px) {
    .slider .slider-main li .img1{background:url(../imgs/13_banner1.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img2{background:url(../imgs/13_banner2.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img3{background:url(../imgs/13_banner3.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img4{background:url(../imgs/13_banner4.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img5{background:url(../imgs/13_banner5.jpg) no-repeat;background-size: cover;}
}
@media screen and (max-width: 1620px) and (min-width: 1400px){
    .slider .slider-main li .img1{background:url(../imgs/16_banner1.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img2{background:url(../imgs/16_banner2.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img3{background:url(../imgs/16_banner3.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img4{background:url(../imgs/16_banner4.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img5{background:url(../imgs/16_banner5.jpg) no-repeat;background-size: cover;}
}
@media screen and (min-width: 1900px){
    .slider .slider-main li .img1{background:url(../imgs/banner1.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img2{background:url(../imgs/banner2.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img3{background:url(../imgs/banner3.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img4{background:url(../imgs/banner4.jpg) no-repeat;background-size: cover;}
    .slider .slider-main li .img5{background:url(../imgs/banner5.jpg) no-repeat;background-size: cover;}
} */