* {
    margin: 0px;
    padding: 0px;
}
.background-container {
    background-image: url('prof_cour_wal.jpg');
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center center;
    position: fixed;
    width: 100vw;
    height: 100vh;
}
.heading {
    height: 14vh;
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    position: inherit;
    filter: drop-shadow(1px -1px 3px black);
    background-color: white;
    box-shadow: inset 0 0 0 200px rgb(14, 154, 216 / 8%);
}

.main-content {
    height: 84vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    opacity: 1;
    align-items: center;
}
.background-container::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.3);
}
.background-container {
    position: fixed; 
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background-image: url('prof_cour_wal.jpg'); 
    background-size: cover; 
    background-position: center; 
    opacity: 0.5; 
}

.container {
    height: 8vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    font-family: "Open Sans", sans-serif;
    width: 300px;
    margin: 9px;
    color: black;
    font-weight: 600;
    filter: drop-shadow(1px 0px 1px black);
    border-radius: 8px;
    background-color: #dedddd;
}
.heading img {
    height: 80%;
}
.main-content a{
    text-decoration: none;
    color: white;
}
.container:hover {
    background-color: #c3c3c3;
    filter: drop-shadow(0px 0px 0px black);
    box-shadow: 0 1px 5px 0px rgba(0, 0, 0, 0.24), 0 15px 46px 0 rgba(0, 0, 0, 0.19);
}