* { box-sizing: border-box; }

body {
    font-family: Arial, Helvetica, sans-serif;
}

#wrapper {
    width: 80%;
    margin: auto;
    border: thin solid black;
}

header {
    margin: 10px;
    padding: 10px;
    background: grey;
    color: white;
}

header img {
    width: 20%;
    float: right;
}

.clearright { clear: right; }

nav {
    display: flex;
    justify-content: center;
}

nav div {
    background: #f1f1f1;
    margin: 10px;
    padding: 10px 20px;
}

nav a {
    text-decoration: none;
    color: steelblue;
    font-weight: bold;
}

nav a:hover {
    color: red;
}

main {
    display: flex;
}

main div {
    margin: 10px;
    padding: 10px;
    background: #f1f1f1;
}

.left { flex: 1; }

.right {
    flex: 2;
    border: 1px solid #dddddd;
    background: white;
}

table {
    border-collapse: collapse;
    width: 90%;
    margin: auto;
}

td, th {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: left;
}

tr:nth-child(even) {
    background: whitesmoke;
}

.grad {
    background: linear-gradient(CornflowerBlue, crimson);
    height: 200px;
}

.shad {
    box-shadow: 10px 10px 5px grey;
    margin: 15px;
}

.shadow {
    color: white;
    text-shadow: 2px 2px 4px black;
}

.roundcorner {
    border-radius: 25px;
}

.whitetext {
    color: white;
    padding: 20px;
    font-size: 1.3em;
}

footer {
    background: gainsboro;
    margin: 10px;
    padding: 10px;
    text-align: center;
}

@media (max-width: 900px) {
    #wrapper { width: 100%; border: none; }
    header img { width: 25%; }
}

@media (max-width: 510px) {
    nav { flex-direction: column; }
    main { flex-direction: column; }
    header img { width: 40%; }
}