BBEdit Markdown stylesheet (~/Library/Application Support/BBEdit/Preview CSS/clean.css)

clean.css

body {
  font-family: "Helvetica Neue", Helvetica, sans-serif;
  font-size: 12pt;
  line-height: 1.45;
  padding: 0 1rem;
  max-width: 60em;
}
a {
  color: rgba(0, 122, 255, 1);
}
a:visited {
  color: rgba(88, 86, 214, 1);
}
pre, code {
  font-family: "SF Mono", "Input Mono", "Inconsolata", "Consolas", monospaced;
  font-size: 10pt;
  color: rgba(255, 45, 85, 1);
  border: solid 0.5px #ccc;
  border-radius: 0.25em;
}
pre {
  margin: 1em;
  padding: 0.75em;
  line-height: 1.55;
}
code {
  padding: 0.1em 0.35em;
  
  white-space: nowrap;
}
pre > code  { 
  white-space: pre;
  border: none;
}
pre {
  width: 100%;
  overflow: scroll;
}

blockquote {
  border-left: solid 0.25em #ddd;
  padding: 0.5em 1em;
  font-style: italic;
  color: #999;
}

footer {
  border-top: solid 0.5px #ccc;
  padding-top: 0.5em;
  font-size: 0.75em;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: bold;
  line-height: 1.1;
}
h1 { font-size: 1.75rem; }
h2 { font-size: 1.5rem; }
h3, h4, h5, h6 { font-size: 1rem; }

/* Indentation of “child” content */
h2 ~ *:not(h1, h2) {
  margin-left: 1rem;
}
h3 ~ *:not(h1, h2, h3) {
  margin-left: 2rem;
}
h4 ~ *:not(h1, h2, h3, h4) {
  margin-left: 3rem;
}
h5 ~ *:not(h1, h2, h3, h4, h5) {
  margin-left: 4rem;
}
h6 ~ *:not(h1, h2, h3, h4, h5, h6) {
  margin-left: 5rem;
}