body{
    background-image:url(../img/bg2.png);
    min-height: 100vh;
    position: relative;
    box-sizing: border-box;
    padding-bottom: 40px;
    font-family:"Microsoft YaHei";
}


footer{
    text-align:center;
    color:#888;
    height: 40px;
    width: 100%;
    position: absolute;
    bottom: 0;
    left:0;
    vertical-align: middle;
    background-color: #f3f3f3;
}

footer a {
color: #999;
font-size: 14px;
text-decoration: none;
}
footer a:hover {
color: #333;
}

.navbar {
    width:680px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size:20px;
}

.navbar2 {
    width:540px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size:20px;
    margin-right: 50px;
}

a:hover {
    color: red;
    text-decoration: none;
}


.top {
    position: fixed; /* 设置为固定定位 */
    bottom: 200px;; /* 距离底部 */
    right: 200px; /* 距离右侧 */
    opacity:0.5;
}

.top:hover {
            opacity:1;
        }

h2 {
    background: #7991d1;
    border-radius: 6px;     
    text-align: center;
    color: #fff;    
    font-size: 16px;
    height: 24px;
    line-height: 23px;
    margin: 5px 0px 8px 0px;
    padding: 6px 0 7px 0px;
    width:100%;
}   

.image-container{
    display: inline-block;
    position: relative;
    width: 140px;
    margin: auto;
}

.image-container img{
    width: 100%;
    height: 100%;
}

.overlay{
    position: absolute;
    top: 50%;
    left: 50%;
    color: black;
    width: 100%;
    /* 字体居中 */
    transform: translate(-50%,-50%);
    font-size: large;
    /* 悬停前完全透明 */
    opacity: 0;
    transition: 0.3s ease-in-out; 
}

.image-container:hover .overlay{
    transition: 0.3s ease-in-out;
    /* 悬停时完全不透明 */
    opacity: 1;
}

.image-container:hover .trans{

            opacity: 0.3;  
        }