section.section_first {
    height: 50vh;
    background-image: linear-gradient(to bottom, #000000, #000000, #0c5449);
}

.main_image_box {
    border-radius: 10px;
    overflow: hidden;
}

.main_image_box:hover {
    box-shadow: 0px 0px 20px gray;
}

.main_image_box img:hover {
    transform: scale(1.2);
}

.col-6.col-sm-4.col-md-3.col-lg-2:nth-child(1n) .main_image_box {
    background-color: #1abc9c;
}

.col-6.col-sm-4.col-md-3.col-lg-2:nth-child(2n) .main_image_box {
    background-color: #884a79;
}

.col-6.col-sm-4.col-md-3.col-lg-2:nth-child(3n) .main_image_box {
    background-color: #2076bd;
}

.col-6.col-sm-4.col-md-3.col-lg-2:nth-child(5n) .main_image_box {
    background-color: #de366b;
}



.col-6.col-sm-4.col-md-3.col-lg-2:nth-child(9n) .main_image_box {
    background-color: #5644a5;
}

@media screen and (max-width: 560px) {
    section.section_first h1 {
        font-size: 40px;
    }

    section.section_first {
        height: 70vh;
        background: linear-gradient(to bottom, #000000, #1abc9c);
        padding: 10px;
        overflow: hidden;
    }

    section.second_client {
        padding: 28px;
    }
}