.caseService20 {
    max-width: 1200px;
    margin: 0 auto;
}

.caseService20 * {
    box-sizing: border-box;
}

.caseService20 img {
    max-width: 100%;
    display: block;
    border: none;
    position: absolute;
    width: 60px;
    height: 60px;
    top: -30px;
    left: 50%;
    margin-left: -30px;
    background-repeat: no-repeat;
    transition: all .5s;
    object-fit: cover;
}

.caseService20 ul {
    overflow: hidden;
    padding: 0;
    margin: 0;
    list-style: none;
}

.caseService20 ul li {
    width: 35%;
    height: 200px;
    float: left;
    margin-top: 72px;
   
}

.caseService20 ul li:nth-child(3n) {
    margin-right: 0;
}

.caseService20 ul li:nth-child(2) {
    margin-left: 350px;
}

.caseService20 ul li:nth-child(4) {
    margin-left: 350px;
}

.caseService20 ul li a {
    display: block;
    text-decoration: none;
    color: #333333;
    text-align: center;
    width: 100%;
    height: 100%;
    padding: 0 50px;
    background: #fff;
    position: relative;
    border-radius: 15px;
    transition: all .5s;
}

.caseService20 ul li a:hover {
    background: #c21528;
    color: #fff;
}

.caseService20 ul li a:hover .normal_img {
    display: none;
}

.caseService20 ul li a:hover .hover_img {
    display: block;
}

.caseService20 ul li a .normal_img {
    display: block;
}

.caseService20 ul li a .hover_img {
    display: none;
}

.caseService20 ul li a .title {
    font-size: 16px;
    padding: 55px 0 20px;
    font-weight: bold;
}

.caseService20 ul li a .dec {
    font-size: 12px;
    line-height: 1.8;
    overflow: hidden;
    height: 90px;
}