.container {
    margin: 0 auto;
    max-width: 960px;
    padding: 20px 50px;
}

nav ul {
    list-style-position: inside;
    padding: 0;
}

nav ul li {
    display: inline-block;
    list-style-type: none;
    text-align: center;

}
nav ul li a {
    width: 50px;
    display: block;
    padding: 10px;
    background-color: darkgrey;
    color: white;
    margin-bottom: 8px;
}
nav ul li a:hover,
nav ul li a.active:hover
{
    background-color: #535353;
}
nav ul li a.active {
    background-color: black;
}
.col {
    float: left;
    width: 40%;
}

.sum {
    font-family: monospace;
    font-size: 26px;
    line-height: 42px;
}
@media (max-width: 800px){
    .col {
        margin-bottom: 14px;
        width: 100%;
    }

}
@media print {
    nav {
        display: none;
    }
    .sum {
        font-size: 22px;
        line-height: 34px;
    }

    .col {
        width: 48%;
    }

}