simpletheme/static/css/style.css

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.5em;
  font-size: 1.1em;
  color: #222;
  max-width: 40rem;
  padding: 2rem;
  margin: auto;
  background: #fafafa; 
  overscroll-behavior-y: none;
}

img {
  max-width: 100%; }

a {
  color: #0074D9; }

h1, h2, strong {
  color: #111; }

h1 {
  font-size: 1.6em; }

h2 {
  font-size: 1.2em; }

h3 {
  font-size: 1.1em; }

.muted {
  color: #aaa;
  text-decoration: none; }

.small {
  font-size: .8em; }

hr {
  border: 0px;
  border: 1px solid #eee; 
}