body {
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    font-size: 20;
}
nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 220px;
    height: 100%;
    background-color: rgb(25, 0, 255);
    color: white;
    padding: 40px 30px;
    box-sizing: border-box;
}
nav ul {
    list-style: none;
    padding: 0;
}
nav a {
    text-decoration: none;
    color:rgb(255, 255, 255);
    padding: 12px 4px;
    display: block;
}
nav ul :hover {
    background-color: orange;
    border-radius: 10px;
}
main {
    margin-left: 250px;
}
.container {
    max-width: 800px;
}
.zdroj {
    text-decoration: dotted;
    font-style: italic;
}
img {
    max-width: 400px;
}
@media screen and (max-width: 760px) {
    nav {
        width: 100;
        height: 240px;
        padding-bottom: 0;
    }
    nav a {
        display: inline;
    }
    nav li {
        display: inline-block;
        padding: 8px 8px;
    }
    main {
        margin-left: 0;
        margin-top: 100px;
    }
}