.index_page {
    width: 100%;
    height: 100vh;
    background: url("https://mooc-1300652413.cos.ap-nanjing.myqcloud.com/丝路学院背景图/detail-bg.png") no-repeat center center / cover;
    position: relative;
    display: flex;
    overflow: hidden;
    align-items: center;
}

.section-box {
    width: 1200px;
    height: 440px;
    margin: 0 auto;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
}

.section {
    margin-bottom: 30px;
    position: relative;
    cursor: pointer;
    transition: all 0.5s ease-in-out;
}

.section > img {
    width: 585px;
    height: 280px;
}

.section > img.img1,.section > img.img2 {
    width: 380px;
    height: 340px;
}

.section .btns img {
    width: 320px;
    height: 70px;
}

.section:hover {
    transform: scale(1.05);
}

.section.small {
    cursor: default;
}

.section.small .img2 {
    display: none;
}

.section.small:hover .img2 {
    display: block;
}

.section.small:hover .img1 {
    display: none;
}

.section.small .btns {
    position: absolute;
    top: 90px;
    left: 30px;
    display: flex;
    flex-wrap: wrap;
    display: none;
    transition: all 0.5s ease-in-out;
}

.section.small .btns img {
    cursor: pointer;
    margin-bottom: 5px;
}

.section.small .btns img:hover {
    opacity: 0.8;
}

.section.small:hover .btns {
    display: flex;
}

.back {
    position: absolute;
    right: 50px;
    top: 50px;
    font-size: 24px;
    display: flex;
    align-items: center;
}

.back:hover {
    color: #333;
}

.back img {
    width: 30px;
    margin-right: 8px;
}


@media screen and (min-width: 2999px) {
    .index_page {
        width: 3840px;
        height: 2160px;
    }

    .section-box {
        width: 2000px;
        height: 600px;
        margin: 0 auto;
        display: flex;
        flex-wrap: wrap;
        justify-content: space-between;
        align-items: center;
    }

    .section {
        margin-bottom: 60px;
        position: relative;
        cursor: pointer;
        transition: all 0.5s ease-in-out;
    }

    .section > img {
        width: 960px;
        height: 480px;
    }

    .section > img.img1,.section > img.img2 {
        width: 620px;
        height: 550px;
    }

    .section .btns img {
        width: 560px;
        height: 120px;
    }

    .section:hover {
        transform: scale(1.05);
    }

    .section.small {
        cursor: default;
    }

    .section.small .img2 {
        display: none;
    }

    .section.small:hover .img2 {
        display: block;
    }

    .section.small:hover .img1 {
        display: none;
    }

    .section.small .btns {
        position: absolute;
        top: 130px;
        left: 30px;
        display: flex;
        flex-wrap: wrap;
        display: none;
        transition: all 0.5s ease-in-out;
    }

    .section.small .btns img {
        cursor: pointer;
        margin-bottom: 5px;
    }

    .section.small .btns img:hover {
        opacity: 0.8;
    }

    .section.small:hover .btns {
        display: flex;
    }

    .back {
        position: absolute;
        right: 50px;
        top: 50px;
        font-size: 24px;
        display: flex;
        align-items: center;
    }

    .back:hover {
        color: #333;
    }

    .back img {
        width: 30px;
        margin-right: 8px;
    }
}