main {
    padding-top: 2rem;
    position: relative;
}
main::after {
    content: "";
    background-image: url("/images/background.jpg");
    opacity: 0.15;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    position: absolute;
    z-index: -1; 
    display: fixed;
    position: fixed;  
    }

.advertisement_up {
    display: none;

} 


.advertisement {
    width: 728px;
    height: 90px;
    margin: auto;
    background-color: #f8f9fa;
    color: #fff;
    text-align: center;
    margin-bottom: 2rem;
}


.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
}

.navbar-nav {
    margin: auto;
}

.main_title {

    text-align: center;
    color: #544a4a;
    margin-bottom: 3rem;
}

.main {
    margin-bottom: 2rem;
    display: flex;
    justify-content: space-between;
    gap: 20px;

}


.card {
    width: 16rem;
    -webkit-box-shadow: 0px 5px 10px 2px rgba(34, 60, 80, 0.2);
-moz-box-shadow: 0px 5px 10px 2px rgba(34, 60, 80, 0.2);
box-shadow: 0px 5px 10px 2px rgba(34, 60, 80, 0.2);

}

.card-body {
    text-align: center;
}



.main {
    @media (max-width: 800px) {
        flex-direction: column;
        align-items: center;
      };

}

.advertisement {
    @media (max-width: 800px) {
        width: 300px;
        height: 50px;
    }
}