body {
  --background-color: white;
  --text-color: black;
  --link-color: #36f;
  --header-color: #ddd;
  --toc-color: #eee;
  --hover-color: #aaa;

  --font-headers: Courier, Courier New, monospace;
  --font-body: Courier, Courier New, monospace;
  --font-code: Courier, Courier New, monospace;
  --font-page: -apple-system, BlinkMacSystemFont, Segoe UI, Roboto, Ubuntu, Arial, Helvetica Neue, sans-serif;

  margin: 0;

  color: var(--text-color);
  background-color: var(--background-color);
}

body {
  font-family: var(--font-body);
}

h1, h2, h3, h4, h5 {
  font-family: var(--font-headers);
}

pre, code {
  font-family: var(--font-code);
}

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

td, p, ul {
  max-width: 60rem;
}

th, td {
  padding-right: 1rem;
  vertical-align: baseline;
}

th {
  text-align: left;
  white-space: nowrap;
}

h1 {
  margin-top: 0;
}

.main {
  padding: 1rem;
}

/* header */

.header {
  background-color: var(--header-color);
  display: flex;
}

.flex {
  flex-grow: 1;
}

.header-spacer {
  width: 22rem;
}

.header a {
  padding: 1rem;
  text-decoration: none;
  color: var(--text-color);
  cursor: pointer;
}

.header a:hover {
  background-color: var(--hover-color);
}

/* tabs */

.tab-buttons {
  display: flex;
  margin: 0.5rem 0;
}

.tab-button {
  border: 1px solid var(--link-color);
  padding: 0.5rem 1rem;
  cursor: pointer;
}

.tab-button-active {
  background-color: var(--link-color);
  color: white;
}

.tab {
  display: none;
}

.tab-active {
  display: block;
}

/* page */

#page p, #page ul {
  font-family: var(--font-page);
}

/* toc */

.menu-button {
  display: none;
}

.page-with-toc .content {
  margin-right: 22rem;
  padding: 1rem;
}

.page-with-toc aside {
  position: fixed;
  z-index: 1;
  top: 0;
  bottom: 0;
  right: 0;
  width: 20rem;
  padding: 1rem;
  background-color: var(--toc-color);
}

.page-with-toc nav ul {
  padding-left: 0;
}

.page-with-toc nav li {
  font-family: var(--font-headers);
  list-style: none;
}

.page-with-toc nav a {
  color: var(--text-color);
  text-decoration: none;
}

/* h1 */
.page-with-toc nav > ul > li > a {
  display: none;
}

/* h2 */
.page-with-toc nav > ul > li > ul > li > a {
  display: block;
  margin-top: 1rem;
  margin-bottom: 0.5rem;
  font-size: 110%;
  font-weight: bold;
}

/* h3 */
.page-with-toc nav > ul > li > ul > li > ul > li > a {
  display: block;
  margin-left: 1rem;
  margin-bottom: 0.5rem;
}

@media (max-width: 1020px) {
  .header-spacer {
    width: 3rem;
  }

  .page-with-toc .content {
    margin-right: 0;
  }

  .page-with-toc aside {
    transition: right 0.2s;
    right: -22rem;
  }

  .page-with-toc.show-toc aside {
    right: 0;
  }

  .menu-button {
    display: block;
    padding: 0.5rem 1rem;
    font-family: Arial, Helvetica, sans-serif;
    font-size: 2rem;
    line-height: 2rem;
    cursor: pointer;
  }

  .menu-button:hover {
    background-color: var(--hover-color);
  }

  .menu-open {
    position: fixed;
    right: 0;
    top: 0;
    width: 1rem;
    background-color: var(--header-color);
  }

  .menu-close {
    position: absolute;
    right: 0;
    top: 0;
    background-color: var(--toc-color);
  }
}

/* dark mode */

a.theme {
  padding: 0.5rem;
  margin: 0.5rem 0;
  line-height: 1rem;
}

a.theme-light {
  background-color: white;
  color: black;
}

a.theme-dark {
  background-color: black;
  color: white;
}

a.theme-crazy {
  background-color: pink;
  color: rebeccapurple;
  font-family: Comic Sans MS, serif;
  margin-right: 0.5rem;
}

@media (prefers-color-scheme: dark) {
  body:not(.theme-light) {
    --background-color: black;
    --text-color: white;
    --link-color: #8cf;
    --header-color: #333;
    --toc-color: #222;
    --hover-color: #555;
  }
}

body.theme-dark {
  --background-color: black;
  --text-color: white;
  --link-color: #8cf;
  --header-color: #333;
  --toc-color: #222;
  --hover-color: #555;
}

body.theme-crazy {
  --background-color: pink;
  --text-color: rebeccapurple;
  --link-color: darkcyan;
  --header-color: lightsalmon;
  --toc-color: lightcoral;
  --hover-color: lightseagreen;

  --font-headers: Comic Sans MS, serif;
  --font-page: Optima, -apple-system, BlinkMacSystemFont, Segoe UI, Roboto, Ubuntu, Arial, Helvetica Neue, sans-serif;

  background-image: linear-gradient(pink, lightyellow);
  min-height: 100vh;
}