.course_info {
    width: 1440px;
    margin: 0 auto;
}

@media screen and (max-width:1024px) {
    .course_info {
        width: auto;
        margin: 0 auto;
    }
    .course_info .data-info img {
        max-width: 100%;
    }
}

.course_info .data-con {
    margin: 50px auto;
}

.course_info .data-con::before,
.course_info .data-con::after {
    display: block;
    content: "";
    width: 0;
    height: 0;
    visibility: hidden;
    clear: both;
}

.course_info .data-con ul {
    width: 100%;
}

.course_info .data-con ul li {
    box-sizing: border-box;
    padding: 10px;
    width: 479px;
    height: 426px;
}

.course_info .data-con ul li>a {
    display: block;
}

.course_info .data-info {
    padding: 20px;
    text-align: left;
}

.course_info .data-info h3 {
    display: inline-block;
    font-size: 18px;
    color: #333;
    font-weight: 400;
    line-height: 2;
    margin-top: 35px;
    width: 100%;
    white-space: nowrap;
    text-overflow: ellipsis;
    overflow: hidden;
    float: left;
    text-align: left;
}

.course_info .data-info p {
    font-size: 14px;
    color: #999;
    line-height: 2;
    width: 90%;
    height: 40px;
    text-overflow: ellipsis;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    text-align: right;
}

.course_info .data-info img {
    width: 419px;
    height: 255px;
}

.course_info .data-con ul li .data-info {
    background-color: #f8f8f8;
    text-align: center;
}

@media screen and (min-width:1024px) {
    .course_info .data-con {
        width: 100%;
        margin: 50px auto;
    }
    .course_info .data-con ul {
        width: 100%;
    }
    .course_info .data-con ul li {
        width: 33.3%;
        float: left;
        box-sizing: border-box;
    }
    .course_info .data-con ul li {
        padding: 10px;
    }
}

@media screen and (max-width:1023px) {
    .course_info .data-con {
        width: 100%;
        margin: 50px auto;
    }
    .course_info .data-con ul {
        width: 100%;
    }
    .course_info .data-con ul li {
        padding: 2%;
        width: 50%;
        float: left;
        box-sizing: border-box;
    }
    .course_info .data-info img {
        max-width: 100%;
    }
}

@media screen and (max-width:500px) {
    .course_info .data-con {
        width: 100%;
        margin: 50px auto;
    }
    .course_info .data-con ul {
        width: 100%;
    }
    .course_info .data-con ul li {
        padding: 2%;
        width: 100%;
        box-sizing: border-box;
    }
}