css
body {
    background-color: #f7d7d7;
    color: #fff;
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

a {
    text-decoration: none;
    color: #fff;
    font-size: 24px;
    font-weight: bold;
}

h1, h2, h3, h4 {
    font-family: 'Arial Black', Arial, sans-serif;
    text-shadow: 0 1px 0 #000;
}

body > section {
    padding: 20px;
}

#header {
    background-color: #333;
}

#header a {
    color: #f0f0f0;
}

h1 {
    font-size: 48px;
    line-height: 1.2;
    text-align: center;
    margin: 0 0 20px 0;
}

h2, h3, h4 {
    font-size: 24px;
    margin: 0 0 10px 0;
    line-height: 1.1;
}

h2, h3, h4 {
    text-shadow: 0 1px 0 #000;
}

h2 {
    margin-top: 30px;
}

#footer {
    background-color: #333;
    padding: 10px;
    text-align: center;
    font-size: 18px;
}

#footer a {
    color: #f0f0f0;
}

#footer a:hover {
    text-decoration: underline;
}

/* 
*   Styles specific to /subpages/mermaid-problems
*/

.subpages {
    background-image: url("https://example.com/no-image-here.png");
    background-size: 200px 100px;
    background-position: -20px -10px;
    background-repeat: no-repeat;
}

.subpages a {
    color: #333;
}