body {
    line-height: 1.5; 
    max-width: 60ch; 
    margin: auto;
    font-family: Sans-Serif;
    font-size: 20px;
}

header {
    top: 0px;
    height: auto;
    width: 100%;
    padding: 10px;
    position: fixed;
    background: white;
}

@media (prefers-color-scheme: dark) {
    body {
	background: #000;
	color: #eee;
    }

    header {
	background: #000;
	color: #eee;
    }

    a:visited {
	color: lightgreen;
    }

    a:link {
	color:lightblue;
    }
}

img {
    max-width: 100%;
    margin: auto;
}