.xm-about{
    -webkit-font-smoothing:antialiased
}
.xm-about h1,.xm-about h2,.xm-about h3,.xm-about h4,.xm-about h5{
    margin:0;
    padding:0
}
.xm-about ul{
    margin:0;
    padding:0;
    overflow:hidden;
    _zoom:1
}
.xm-about ul li{
    list-style:none
}
.xm-about .nav{
    height:82px;
    line-height:82px
}
.xm-about .nav ul{
    margin:0 0 0 80px
}
.xm-about .nav ul li{
    float:left;
    text-align:center
}
.xm-about .nav ul li a{
    color:#b0b0b0;
    font-size:16px;
    font-weight:600;
    text-align:center;
    display:inline-block;
    *zoom:1;
    *display:inline;
    height:82px
}
.xm-about .nav ul li a:hover{
    color:#424242
}
.xm-about .nav ul li span{
    color:#e0e0e0;
    padding:0 34px;
    display:inline-block;
    *zoom:1;*display:inline
}
.xm-about .nav ul li.last{
    margin-right:0
}
.xm-about .nav ul li.cur a{
    color:#ff6700
}
.xm-about .news{
    background:#fff;
    margin-bottom:100px
}
.xm-about .news .news_header{
    background:url("../images/news.jpg") no-repeat;
    height:450px
}
.xm-about .news .news_header .text{
    padding:126px 0 0 215px;
    color:#fff;
    width:240px;
    text-align:center
}
.xm-about .news .news_header .text h1{
    font-weight:normal;
    font-size:40px
}
/*
.xm-about .news .news_header .text .btn{
    margin:20px auto 30px auto;
border:2px solid #fff;
color:#fff;
font-size:16px;
width:160px;
height:40px;
font-weight:bold
}*/

/*追加的，实现字条颜色变动*/

.xm-about .news .news_header .text .btn {
    background: none;
    border: 0;
    outline: 0;
    color: aquamarine;
    font-family: 'JetBrains Mono';
    font-size: 18px;
    cursor: pointer;
    border: 2px solid aquamarine;
    width: 180px;
    height: 50px;
    position: relative;
}

.xm-about .news .news_header .text .btn label {
    position: absolute;
    left: 0;
    top: 0;
    line-height: 50px;
    width: 100%;
    height: 100%;
    z-index: 1;
    background-color: rgb(51,51,51);
}

.xm-about .news .news_header .text .btn::before {
    content: '';
    position: absolute;
    left: -2px;
    top: -2px;
    width: 0px;
    height: 0;
    z-index: 0;
    background-color: #3ea510;
    transition: width .5s,height .5s;
}

.xm-about .news .news_header .text .btn::after {
    content: '';
    position: absolute;
    right: -2px;
    bottom: -2px;
    width: 0;
    height: 0;
    z-index: 0;
    background-color: #3ea510;
    transition: width .5s,height .5s;

    /*width: calc(100% + 4px);
    height: calc(100% + 4px); */
}

.xm-about .news .news_header .text .btn:hover {
    color: #3ea510;
}

.btn:hover::before {
    width: calc(100% + 4px);
    height: calc(100% + 4px);
}

.xm-about .news .news_header .text .btn:hover::after {
    width: calc(100% + 4px);
    height: calc(100% + 4px);
}