body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
    margin: 0;
    padding: 0; }
header {
    background-color: saddlebrown;
    color: black;
    text-align: center;
    padding: 20px;
    border-bottom: 5px solid darkgoldenrod;
    border-radius: 0 0 50px 50px; }
h1 {
    margin: 0;
    font-size: 28px;
    font-weight: bold;
    letter-spacing: 2px;
}
nav {
    background-color: darkslategray;
    text-align: center;
    padding: 10px 0;
}
nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: inline-flex;
}
nav ul li {
    margin: 0 15px;
}
nav ul li a {
    color: white;
    text-decoration: none;
    font-weight: bold;
    padding: 8px 16px;
    background-color: blue;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}
nav ul li a:hover {
    background-color: darkblue; }
h2 {
    margin: 0;
    font-size: 28px;
    font-weight: bold;
    letter-spacing: 2px;
    text-align: center;
}
#panel, #flip {
    padding: 5px;
    text-align: center;
    background-color: #e5eecc;
    border: solid 1px #c3c3c3;
}
#panel {
    padding: 50px;
    display: none;
}