@media (prefers-color-scheme: dark) {
  body { filter: invert(1); }
  img { filter: invert(1); }
}

html, body { background: white; }
html { height: 100%; scroll-behavior: smooth; }

body {
  color: black;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  margin: 0;
  min-height: 100%;
  overflow-wrap: break-word;
}

.w {
  max-width: 640px;
  margin: 0 auto;
  padding: 4rem 2rem;
}

footer {
  margin-top: 4rem;
  text-align: center;
}

h2, h3, h4, h5, h6 { margin-top: 3rem; }

hr {
  text-align: center;
  border: 0;
  margin: 0.5rem 0;
}
hr::before { content: "-----"; }

p { margin: 1rem 0; }
li { margin: 0.4rem 0; }

*:target { background: yellow; }

table { width: 100%; }
table, th, td {
  border: thin solid black;
  border-collapse: collapse;
  padding: 0.4rem;
}

code { color: white; background: black; }

pre code {
  display: block;
  overflow-x: auto;
  white-space: pre-wrap;
  padding: 1rem;
}

blockquote {
  font-style: italic;
  border: thin solid black;
  padding: 1rem;
}
blockquote p { margin: 0; }

img { max-width: 100%; display: block; margin: 0 auto; }