/*最外层的容器开始*/
.mqjy {
    width: 100%;
    max-width: 1920px;
    min-width: 1280px;
    margin: 0px auto;
}

/*最外层的容器结束*/

a{
    color: #333333;
    text-decoration: none;
    outline: none;
    font-weight: normal ;
}

/*头部样式开始*/

.nav {
    position: relative;
    top: 0;
    left: 0;
    width: 100%;
    height: 60px;
}

.nav-wrap {
    margin: 0 auto;
    width: 1180px;
    height: 60px;
    line-height: 60px;
}

.nav-wrap li {
    float: left;
    /*导航栏间隔距离*/
    width: 160px;
    /*字体大小*/
    font-size: 18px;
    text-align: center;
}
/*鼠标移动上去变色*/ 
.nav-wrap li:hover {
    background-color: #00BFFF;
    cursor: pointer;
    transition: 0.6s;
}

/*回到顶端*/
.btn{
    position: fixed;
    bottom: 20px;
    left: 50%;
    margin-left: 850px;
}