header {
    background-color: dodgerblue;
    opacity: 90%;
    text-align: center;
    padding: 6px;
    height: 160px;
    font-family: Tahoma, Verdana, sans-serif;
    font-size: 1.3rem;
    background-repeat: no-repeat;
    background-size: 300px;
    color: lightgoldenrodyellow;
    text-shadow: 2px 2px;
    border-radius: 15px;
}


body {
    color: blue;
    background-color: #dddddd;
    background-image: url('.//images//pexels-mikhail-nilov-8108712.jpg');
}

.light {
    background-color: hotpink;
    font-family: Tahoma, Verdana, sans-serif;
    font-size: 1.5rem;
    color: black;
    padding: 20px;
    height: 240px;
    text-align: left;
}

.dark {
    background-color: indigo;
    font-family: Tahoma, Verdana, sans-serif;
    font-size: 1.5rem;
    color: white;
    padding: 20px;
    height: 240px;
}

p {
    font-family: Tahoma, Verdana, sans-serif;
    font-size: 0.8rem;
}

H3 {
    font-family: Tahoma, Verdana, sans-serif;
    font-size: 1rem;
}

footer {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: #f1f1f1;
    padding: 8px;
    text-align: center;
    z-index: 1000;
}