:root {
  --bg-color: #fefefe;
  --text-color: #222;
  --heading-color: #1e2d50;
  --heading-hover-color: #4e91ff;
  --heading-active-color: #7e5ca9;
  --link-color: #1a73e8;
  --link-hover-color: #1a73e8;
  --font-family: Cambria, serif;
}

body.dark {
  --bg-color: #1a1a1a;
  --text-color: #ddd;
  --heading-color: #e0e0ff;
  --heading-hover-color: #7ca9ff;
  --heading-active-color: #c39fff;
  --link-color: #70a8ff;
  --link-hover-color: #9ec9ff;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.7;
  padding: 2rem;
  margin: 0;
  transition: background-color 0.3s, color 0.3s;
}

#content {
  max-width: 800px;
  margin: auto;
  word-break: break-word;
}

.heading {
  margin-top: 2rem;
  margin-bottom: 1rem;
  color: var(--heading-color);
  font-weight: bold;
}

.heading a.anchor-link {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s;
  cursor: pointer;
}

.heading a.anchor-link:hover {
  color: var(--heading-hover-color);
}

.heading a.anchor-link:active {
  color: var(--heading-active-color);
}

a {
  color: var(--link-color);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

a:visited {
  color: var(--link-color);
}

#toggle-dark-mode {
  position: fixed;
  top: 1rem;
  right: 1rem;
  font-size: 1.5rem;
  cursor: pointer;
  user-select: none;
  background: none;
  border: none;
  outline: none;
  padding: 0;
}