/* The Learn pages' own frame: the bar, the contents, the article column, the term drawer, the
   search. Loaded after tokens.css only (layout.css and page.css both lay out `body` for other
   pages); the words themselves are styled by learn-content.css, shared with the player's lightbox.
   A few small pieces are copied from page.css and layout.css, each marked. */

body.learn {
  min-height: 100dvh;
  display: grid;
  grid-template-rows: auto 1fr auto;
  font-size: 15px;
  overflow-x: hidden;
}
/* a grid's rows would otherwise grow to the widest line of code */
body.learn > *,
.learn__main > * {
  min-width: 0;
}
.skip {
  position: absolute;
  top: -40px;
  left: 12px;
  z-index: 60;
  padding: 8px 12px;
  border-radius: 6px;
  background: var(--hb-ink);
  color: var(--hb-bg-deep);
  text-decoration: none;
}
.skip:focus {
  top: 8px;
}

/* ---------- the bar ---------- */

.learnbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 14px;
  min-height: var(--hb-topbar);
  padding: 0 var(--hb-gutter);
  background: var(--hb-bg-deep);
  border-bottom: 1px solid var(--hb-line-soft);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--hb-ink);
  text-decoration: none;
}
.brand__mark {
  width: 20px;
  height: 20px;
  fill: var(--hb-ink);
}
.brand__dot {
  fill: var(--hb-accent);
}
.brand__name {
  font: 500 10.5px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
}
.learnbar__kicker {
  padding-left: 14px;
  border-left: 1px solid var(--hb-line);
  font: 500 10.5px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
  text-decoration: none;
}
.learnbar__kicker:hover {
  color: var(--hb-ink);
}
.learnbar__player {
  margin-left: auto;
  padding: 7px 13px;
  border: 1px solid var(--hb-line);
  border-radius: 999px;
  font: 500 12px/1 var(--hb-sans);
  color: var(--hb-ink);
  text-decoration: none;
  white-space: nowrap;
  transition: background 0.15s, border-color 0.15s;
}
.learnbar__player:hover {
  background: var(--hb-raise);
  border-color: var(--hb-ink-4);
}
.learnbar__contents {
  display: none;
}

/* (headings and labels are orange on these pages, at the user's request) */
/* layout.css .iconbtn */
.iconbtn {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  flex: none;
  border-radius: 50%;
  color: var(--hb-ink-3);
  transition: color 0.15s, background 0.15s;
}
.iconbtn:hover {
  color: var(--hb-ink);
  background: var(--hb-raise);
}
.iconbtn svg {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
/* layout.css .pillbtn */
.pillbtn {
  display: inline-block;
  padding: 8px 14px;
  border: 1px solid var(--hb-line);
  border-radius: 999px;
  font: 500 12px/1 var(--hb-sans);
  color: var(--hb-ink);
  text-decoration: none;
  transition: background 0.15s, border-color 0.15s;
}
.pillbtn:hover {
  background: var(--hb-raise);
  border-color: var(--hb-ink-4);
}

/* ---------- search ---------- */

.search {
  position: relative;
  display: flex;
  align-items: center;
  margin-left: 8px;
}
.search input {
  width: min(320px, 32vw);
  padding: 8px 34px 8px 12px;
  border: 1px solid var(--hb-line);
  border-radius: 999px;
  background: var(--hb-bg);
  color: var(--hb-ink);
  font: 400 13px/1.3 var(--hb-sans);
  transition: border-color 0.15s, width 0.2s var(--hb-ease);
}
.search input::placeholder {
  color: var(--hb-ink-4);
}
.search input:focus {
  outline: none;
  border-color: var(--hb-ink-3);
  width: min(420px, 40vw);
}
.search input::-webkit-search-cancel-button {
  -webkit-appearance: none;
}
.search__hint {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
  color: var(--hb-ink-4);
  font-size: 11px;
}
.search input:focus ~ .search__hint {
  display: none;
}
.search__open,
.search__close {
  display: none;
}
.search__panel {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  z-index: 50;
  width: min(560px, calc(100vw - 2 * var(--hb-gutter)));
  max-height: min(70vh, 560px);
  overflow-y: auto;
  padding: 6px;
  border: 1px solid var(--hb-line);
  border-radius: 10px;
  background: var(--hb-bg-deep);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.5);
}
.search__results {
  margin: 0;
  padding: 0;
  list-style: none;
}
.search__group {
  padding: 10px 10px 4px;
  font: 500 10.5px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.search__result {
  display: block;
  padding: 8px 10px;
  border-radius: 6px;
  color: var(--hb-ink-2);
  text-decoration: none;
  cursor: pointer;
}
.search__result:hover,
.search__result.is-active {
  background: var(--hb-raise);
}
.search__title {
  display: flex;
  align-items: baseline;
  gap: 8px;
  color: var(--hb-ink);
  font-weight: 500;
}
.search__kind {
  font: 500 9.5px/1 var(--hb-mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--hb-ink-4);
}
.search__snippet {
  margin-top: 2px;
  font-size: 13px;
  line-height: 1.45;
  color: var(--hb-ink-3);
}
.search__note {
  margin: 0;
  padding: 10px 12px;
  font-size: 13px;
  color: var(--hb-ink-3);
}
mark {
  background: none;
  color: var(--hb-ink);
  text-decoration: underline;
  text-decoration-color: var(--hb-ink-4);
  text-underline-offset: 2px;
}

/* ---------- the two columns ---------- */

.learn__main {
  display: grid;
  grid-template-columns: 248px minmax(0, 1fr);
  gap: 0 48px;
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 var(--hb-gutter);
}
.learnnav {
  position: sticky;
  top: var(--hb-topbar);
  align-self: start;
  max-height: calc(100dvh - var(--hb-topbar));
  overflow-y: auto;
  padding: 28px 16px 40px 0;
  border-right: 1px solid var(--hb-line-soft);
  font-size: 13.5px;
}
.learnnav ol {
  margin: 0;
  padding: 0;
  list-style: none;
}
.learnnav a {
  display: block;
  padding: 5px 0;
  color: var(--hb-ink-3);
  text-decoration: none;
}
.learnnav a:hover {
  color: var(--hb-ink);
}
.learnnav a[aria-current='page'] {
  color: var(--hb-ink);
  font-weight: 500;
}
.learnnav__home {
  margin: 0 0 16px;
}
.learnnav__home a {
  font: 500 11px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  color: var(--hb-accent);
  text-transform: uppercase;
}
.learnnav__group {
  margin-bottom: 18px;
}
.learnnav__label {
  margin: 0 0 4px;
  font: 500 10px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.learnnav__sections {
  margin: 2px 0 6px 2px;
  padding-left: 0;
}
.learnnav__sections a {
  padding: 3px 0 3px 10px;
  border-left: 2px solid var(--hb-line-soft);
  font-size: 12.5px;
  color: var(--hb-ink-4);
}
.learnnav__sections a.is-active {
  border-left-color: var(--hb-ink);
  color: var(--hb-ink);
}

.learn__body {
  max-width: 72ch;
  padding: 36px 0 64px;
  outline: none;
}

/* the landing: paths and areas */
.paths {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 8px 0 28px;
}
.paths__title {
  grid-column: 1 / -1;
  margin: 0 0 2px;
  padding: 0;
  border: 0;
  font: 500 11px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.path {
  display: grid;
  gap: 4px;
  padding: 16px;
  border: 1px solid var(--hb-line-soft);
  border-radius: 10px;
  background: var(--hb-panel);
  color: var(--hb-ink-2);
  text-decoration: none;
  transition: border-color 0.15s, background 0.15s;
}
.path:hover {
  border-color: var(--hb-ink-4);
  background: var(--hb-raise);
}
.path__kicker {
  font: 500 10px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.path__title {
  font: 500 16px/1.3 var(--hb-sans);
  color: var(--hb-ink);
}
.path__text {
  font-size: 13.5px;
  line-height: 1.5;
}
.areas {
  margin-top: 36px;
}
.areas__label {
  margin: 0 0 10px;
  padding: 0;
  border: 0;
  font: 500 11px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.areas__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}
.area {
  padding: 16px 18px;
  border: 1px solid var(--hb-line-soft);
  border-radius: 10px;
}
.area__title {
  margin: 0 0 6px;
  font: 300 20px/1.2 var(--hb-sans);
  letter-spacing: -0.01em;
}
.area__title a {
  color: var(--hb-ink);
  text-decoration: none;
}
.area__title a:hover {
  text-decoration: underline;
  text-decoration-color: var(--hb-ink-4);
}
.area__text {
  margin: 0 0 8px;
  font-size: 13.5px;
  color: var(--hb-ink-3);
}
.area__sections {
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 13px;
}
.area__sections li {
  margin: 0 0 2px;
}
.area__sections a {
  color: var(--hb-ink-2);
  text-decoration: none;
}
.area__sections a:hover {
  color: var(--hb-ink);
  text-decoration: underline;
  text-decoration-color: var(--hb-ink-4);
}

/* previous and next */
.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 56px;
  padding-top: 20px;
  border-top: 1px solid var(--hb-line-soft);
}
.pager a {
  display: grid;
  gap: 4px;
  padding: 12px 14px;
  border: 1px solid var(--hb-line-soft);
  border-radius: 8px;
  text-decoration: none;
  color: var(--hb-ink);
  transition: border-color 0.15s, background 0.15s;
}
.pager a:hover {
  border-color: var(--hb-ink-4);
  background: var(--hb-raise);
}
.pager__next {
  text-align: right;
}
.pager__kicker {
  font: 500 10px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.pager__title {
  font: 300 18px/1.2 var(--hb-sans);
}

/* ---------- support the site (css/support.css), and the Donate button that leads to it ---------- */

.learn__support,
.learn__support .support {
  scroll-margin-top: calc(var(--hb-topbar) + 16px);
}
.learn__support {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 var(--hb-gutter) 40px;
  scroll-margin-top: calc(var(--hb-topbar) + 16px);
}
.learn__support .support {
  max-width: 72ch;
  margin-left: calc(248px + 48px);
}
/* layout.css .about__donate */
.learnbar__donate {
  margin-left: auto;
  padding: 8px 16px;
  border-radius: 999px;
  background: var(--hb-accent);
  font: 600 11px/1 var(--hb-mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--hb-accent-ink);
  text-decoration: none;
  white-space: nowrap;
  transition: background 0.15s, box-shadow 0.25s;
}
.learnbar__donate:hover {
  background: color-mix(in srgb, var(--hb-accent) 86%, white);
  box-shadow: 0 0 18px 1px rgb(255 107 53 / 0.4);
}
.learnbar__donate + .learnbar__player {
  margin-left: 0;
}

/* ---------- footer (page.css .pagefoot and .signal) ---------- */

.pagefoot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 20px;
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 16px var(--hb-gutter) 28px;
  border-top: 1px solid var(--hb-line-soft);
  color: var(--hb-ink-4);
  font-size: 13px;
}
.pagefoot p {
  margin: 0;
}
.signal {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--hb-ink-3);
  text-decoration: none;
  font: 400 11px/1 var(--hb-mono);
  letter-spacing: 0.04em;
}
.signal:hover {
  color: var(--hb-ink);
}
.signal__mark {
  width: 18px;
  height: 18px;
  border-radius: 3px;
  box-shadow: 0 0 0 1px var(--hb-line);
}
.signal strong {
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--hb-ink-2);
}

/* ---------- dialogs: the term drawer and the contents sheet ---------- */

dialog {
  color: var(--hb-ink);
  background: var(--hb-bg-deep);
  border: 1px solid var(--hb-line);
  padding: 0;
}
dialog::backdrop {
  background: rgba(10, 10, 10, 0.62);
  backdrop-filter: blur(3px);
}

.termdrawer {
  position: fixed;
  inset: var(--hb-topbar) 0 0 auto;
  z-index: 45;
  width: min(380px, 92vw);
  height: auto;
  max-height: none;
  margin: 0;
  border-width: 0 0 0 1px;
  box-shadow: -16px 0 40px rgba(0, 0, 0, 0.35);
  overflow: hidden;
}
.termdrawer[open] {
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr) auto auto;
  animation: hb-slide-in 0.26s var(--hb-ease);
}
@keyframes hb-slide-in {
  from {
    transform: translateX(24px);
    opacity: 0;
  }
}
.termdrawer__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 10px 0 var(--hb-gutter);
}
.termdrawer__kicker {
  margin: 0;
  font: 500 10.5px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.termdrawer__title {
  margin: 6px 0 0;
  padding: 0 var(--hb-gutter);
  font: 300 26px/1.15 var(--hb-sans);
  letter-spacing: -0.02em;
  color: var(--hb-accent);
  outline: none;
}
.termdrawer__body {
  overflow-y: auto;
  padding: 10px var(--hb-gutter) 6px;
}
.termdrawer__body .entry__more {
  display: none;
}
.termdrawer__related {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0;
  padding: 0 var(--hb-gutter) 10px;
  font-size: 13px;
  color: var(--hb-ink-4);
}
.termdrawer__related button {
  padding: 4px 10px;
  border: 1px solid var(--hb-line);
  border-radius: 999px;
  font: 500 11px/1 var(--hb-sans);
  color: var(--hb-ink-2);
}
.termdrawer__related button:hover {
  background: var(--hb-raise);
  color: var(--hb-ink);
}
.termdrawer__foot {
  padding: 10px var(--hb-gutter) 18px;
  border-top: 1px solid var(--hb-line-soft);
}

.learnnav-sheet {
  position: fixed;
  inset: 0 auto 0 0;
  width: min(360px, 92vw);
  height: 100dvh;
  max-height: none;
  margin: 0;
  border-width: 0 1px 0 0;
  overflow: hidden;
}
.learnnav-sheet[open] {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  animation: hb-slide-left 0.26s var(--hb-ease);
}
@keyframes hb-slide-left {
  from {
    transform: translateX(-24px);
    opacity: 0;
  }
}
.learnnav-sheet__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 10px 10px var(--hb-gutter);
  border-bottom: 1px solid var(--hb-line-soft);
}
.learnnav-sheet__title {
  margin: 0;
  font: 300 22px/1.2 var(--hb-sans);
}
.learnnav-sheet__body {
  overflow-y: auto;
  padding: 8px var(--hb-gutter) 32px;
  font-size: 14px;
}
.learnnav-sheet__body ol {
  margin: 0;
  padding: 0;
  list-style: none;
}
.learnnav-sheet__body a {
  display: block;
  padding: 7px 0;
  color: var(--hb-ink-2);
  text-decoration: none;
}
.learnnav-sheet__body a[aria-current='page'] {
  color: var(--hb-ink);
  font-weight: 500;
}
.learnnav-sheet__body .learnnav__home {
  margin: 8px 0 12px;
}
.learnnav-sheet__body .learnnav__label {
  margin: 14px 0 2px;
  font: 500 10px/1 var(--hb-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hb-accent);
}
.learnnav-sheet__body .learnnav__sections {
  margin: 0 0 6px;
  padding-left: 14px;
  border-left: 1px solid var(--hb-line-soft);
}
.learnnav-sheet__body .learnnav__sections a {
  font-size: 13px;
  color: var(--hb-ink-3);
}

/* ---------- narrower windows ---------- */

@media (max-width: 1180px) {
  .learn__main {
    grid-template-columns: 208px minmax(0, 1fr);
    gap: 0 32px;
  }
  .learn__support .support {
    margin-left: calc(208px + 32px);
  }
}
@media (max-width: 860px) {
  :root {
    --hb-gutter: 16px;
  }
  .learn__main {
    display: block;
  }
  .learnnav {
    display: none;
  }
  .learnbar {
    gap: 10px;
  }
  .learnbar__contents {
    display: grid;
    margin-left: auto;
  }
  .learnbar__player {
    display: none;
  }
  .learnbar__donate {
    margin-left: auto;
    padding: 7px 12px;
  }
  .learnbar__contents {
    margin-left: 0;
  }
  .learn__support .support {
    max-width: none;
    margin-left: 0;
  }
  .search {
    margin-left: 0;
  }
  .search input,
  .search__hint,
  .search__close {
    display: none;
  }
  .search__open {
    display: grid;
  }
  body.is-searching .learnbar > :not(.search) {
    display: none;
  }
  body.is-searching .search {
    flex: 1;
    gap: 6px;
  }
  body.is-searching .search input {
    display: block;
    flex: 1;
    width: auto;
  }
  body.is-searching .search input:focus {
    width: auto;
  }
  body.is-searching .search__open {
    display: none;
  }
  body.is-searching .search__close {
    display: grid;
  }
  body.is-searching .search__panel {
    position: fixed;
    inset: var(--hb-topbar) 0 0 0;
    width: auto;
    max-height: none;
    border-radius: 0;
    border-width: 0;
  }
  .learn__body {
    max-width: none;
    padding-top: 24px;
  }
  .paths,
  .areas__grid {
    grid-template-columns: 1fr;
  }
  .termdrawer {
    inset: auto 0 0 0;
    width: auto;
    max-height: 70dvh;
    border-width: 1px 0 0;
    border-radius: 12px 12px 0 0;
    box-shadow: 0 -16px 40px rgba(0, 0, 0, 0.45);
  }
  .termdrawer[open] {
    animation: hb-slide-up 0.26s var(--hb-ease);
  }
  body:has(.termdrawer[open]) {
    overflow: hidden;
  }
  @keyframes hb-slide-up {
    from {
      transform: translateY(24px);
      opacity: 0;
    }
  }
}
@media (max-width: 560px) {
  .pager {
    grid-template-columns: 1fr;
  }
  .pager__next {
    text-align: left;
  }
  .pagefoot {
    font-size: 12px;
  }
}
@media (max-width: 480px) {
  .brand__name,
  .learnbar__kicker {
    display: none;
  }
}

/* layout.css: nothing moves for people who ask for that */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001s !important;
    transition-duration: 0.001s !important;
  }
  html {
    scroll-behavior: auto;
  }
}
html {
  scroll-behavior: smooth;
}

@media print {
  .learnbar,
  .learnnav,
  .termdrawer,
  .learnnav-sheet,
  .pager,
  .pagefoot,
  .skip,
  .code__open {
    display: none !important;
  }
  body.learn,
  .learn-content {
    background: #fff;
    color: #111;
  }
  .learn__main {
    display: block;
    max-width: none;
  }
  .learn__body {
    max-width: none;
  }
  .learn-content a[href^='http']::after {
    content: ' (' attr(href) ')';
    font-size: 0.85em;
  }
}