body {
    margin: 0;
    display: flex;
    flex-direction: column;
}

header {
    width: 100%;
    height: 50vh;
    align-content: center;
    text-align: center;
    display:block;
    position: relative;
    top: 0;
    left: 0;
    background-color: black;
}

#main-menu {
    box-sizing: border-box;
    width: 90%;
    display: flex;
    margin-top: 2%;
    align-self: center;
    text-align: center;
    align-items: start;
    position: sticky;
    border-radius: 40px;
    border: 5px solid black;
}

#left-menu {
    border-top-left-radius: 33px;
    border-bottom-left-radius: 33px;
}
#right-menu {
    border-top-right-radius: 33px;
    border-bottom-right-radius: 33px;
}

@media screen and (max-width: 700px) {

    header {
        height: 46vh;
    }
    #main-menu {
        margin-top: 5%;
        flex-direction: column;
        height: 40vh;
    }
    #left-menu {
        border-bottom-left-radius: 0px;
        border-top-right-radius: 33px;
    }
    #right-menu {
        border-top-right-radius: 0;
        border-bottom-left-radius: 33px;
    }
}

#main-menu a {
    box-sizing: border-box;
    background-color: green;
    width: 100%;
    text-decoration: none;
    color: black;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    font-size: x-large;
    height: 100px;
    margin: 0;
    text-align: center;
    align-content: center;
}

#main-menu a:hover {
    background-color: aquamarine;
}


#start-picture {
    height: 50vh;
}

#start-picture-attribution {
    position: absolute;
    bottom: 0;
    right: 2%;
}

@media screen and (max-width: 700px) {
    #start-picture {
        width: 100%;
        height: auto;
    }
}

header p {
    color: white;
}

footer {
    padding-left: 2%;
}

footer p {
    color: white;
}