/* ============================================================================
   Learn — loaded only on /learn pages, after the four site stylesheets.
   Same tokens, same restraint: the accent marks where you are (HEAD, the
   current branch, success) and nothing else.
   ============================================================================ */

/* --- Learn hub ---------------------------------------------------------------- */

.learn-shelf {
  padding: 0 var(--gutter) clamp(72px, 11vw, 140px);
  max-width: calc(var(--maxw) + var(--gutter) * 2);
  margin-inline: auto;
  display: grid;
  gap: 16px;
}
.learn-course {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
  min-height: 380px;
}
.learn-course__art {
  position: relative;
  border-right: 1px solid var(--line);
  background:
    radial-gradient(circle at 1px 1px, var(--line) 1px, transparent 0) 0 0 / 22px 22px,
    var(--bg);
}
.learn-course__art svg { position: absolute; inset: 0; width: 100%; height: 100%; }
.learn-course__info {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: clamp(24px, 3.5vw, 44px);
}
.learn-course__info p { color: var(--fg-dim); line-height: 1.6; }
.learn-course__num { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--accent); }
.learn-course__tags { display: flex; flex-wrap: wrap; gap: 6px; }
.learn-course__cta { align-self: flex-start; margin-top: auto; }
.learn-course:hover .learn-course__cta .arrow { transform: translateX(4px); }

.learn-watch {
  padding: clamp(32px, 5vw, 64px) clamp(4px, 1vw, 12px);
  border-top: 1px solid var(--line);
  margin-top: clamp(24px, 4vw, 48px);
}

.learn-more {
  display: grid;
  gap: 14px;
  padding: clamp(24px, 3.5vw, 44px);
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-xl);
}
.learn-more p { color: var(--fg-dim); max-width: 60ch; line-height: 1.6; }

@media (max-width: 860px) {
  .learn-course { grid-template-columns: 1fr; }
  .learn-course__art { min-height: 240px; border-right: 0; border-bottom: 1px solid var(--line); }
}

/* --- Course index ----------------------------------------------------------- */

.lab-hero__cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}
.lab-hero__progress {
  flex-basis: 100%;
  color: var(--fg-faint);
  margin-top: 6px;
}

.lab-demo-wrap { padding: 0 var(--gutter); }
.lab-demo {
  max-width: var(--maxw);
  margin-inline: auto;
}
.lab-demo__view { height: clamp(240px, 32vw, 360px); }
.lab-demo .lab-view { pointer-events: none; }
.lab-demo__line {
  display: flex;
  gap: 8px;
  padding: 14px 20px 18px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--fg);
  white-space: nowrap;
  overflow: hidden;
}
.lab-demo__caret {
  width: 8px;
  height: 1.15em;
  background: var(--accent);
  animation: git-blink 1.1s steps(1) infinite;
}
@keyframes git-blink { 50% { opacity: 0; } }

.lab-how {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(20px, 3vw, 40px);
  border-top: 1px solid var(--line);
  padding-top: 32px;
}
.lab-how p { margin-top: 12px; color: var(--fg-dim); line-height: 1.6; }
.lab-how code, .lab-brief__body code, .lab-goal code, .lab-reveal code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  padding: 1px 6px;
  border-radius: var(--radius);
  background: var(--bg-3);
  color: var(--fg);
}
@media (max-width: 760px) { .lab-how { grid-template-columns: 1fr; } }

.lab-chapter {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) 2fr;
  gap: clamp(20px, 4vw, 64px);
  padding: clamp(32px, 4vw, 48px) 0;
  border-top: 1px solid var(--line);
}
.lab-chapter__head { display: flex; gap: 20px; align-items: baseline; }
.lab-chapter__num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--fg-faint);
}
.lab-chapter__title {
  font-size: calc(clamp(28px, 3.2vw, 44px) * var(--display-scale));
}
.lab-chapter__blurb { margin-top: 12px; color: var(--fg-dim); line-height: 1.55; max-width: 36ch; }
.lab-chapter__lessons { display: grid; gap: 2px; }

.lab-row {
  display: grid;
  grid-template-columns: 34px 1fr auto auto;
  align-items: center;
  gap: 16px;
  padding: 16px 4px;
  border-bottom: 1px solid var(--line);
  transition: background-color 0.3s var(--ease), padding 0.3s var(--ease);
}
.lab-row:hover { background: var(--bg-2); padding-inline: 14px; }
.lab-row__num { font-family: var(--font-mono); font-size: 12px; color: var(--fg-faint); }
.lab-row__text { display: grid; gap: 4px; min-width: 0; }
.lab-row__title { font-family: var(--font-display); font-size: 19px; letter-spacing: -0.01em; }
.lab-row__summary { color: var(--fg-dim); font-size: 14px; }
.lab-row__status {
  width: 22px;
  height: 22px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid var(--line-strong);
  color: transparent;
  transition: all 0.4s var(--ease);
}
.lab-row.is-done .lab-row__status { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.lab-row.is-done .lab-row__num { color: var(--accent); }
@media (max-width: 860px) {
  .lab-chapter { grid-template-columns: 1fr; }
  .lab-row { grid-template-columns: 28px 1fr auto; }
  .lab-row .arrow-circle { display: none; }
}

.lab-honesty {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--fg-faint);
  font-size: 14px;
  line-height: 1.6;
  max-width: 72ch;
}

/* --- Lesson layout -------------------------------------------------------------- */

.lab-lesson { padding: 0 var(--gutter) clamp(48px, 7vw, 96px); }
/* base.css gives every svg display:block, which would beat the attribute. */
.lab-lesson [hidden] { display: none !important; }

.lab-lesson__head {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(28px, 4vw, 48px) 0 clamp(20px, 3vw, 32px);
}
.lab-crumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--fg-faint);
}
.lab-crumbs a:hover { color: var(--accent); }
.lab-lesson__title-row {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 24px;
  flex-wrap: wrap;
  margin-top: 16px;
}
.lab-lesson__title {
  font-size: calc(clamp(34px, 5vw, 64px) * var(--display-scale));
  display: flex;
  align-items: baseline;
  gap: 16px;
}
.lab-lesson__num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--accent);
  transform: translateY(-0.6em);
}
.lab-lesson__intro { margin-top: 16px; color: var(--fg-dim); max-width: 64ch; }
.lab-modes { display: flex; gap: 8px; flex-wrap: wrap; }

.lab-meter { display: flex; align-items: center; gap: 12px; }
.lab-meter__text { font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); letter-spacing: 0.1em; }
.lab-meter__track { width: 120px; height: 2px; background: var(--line-strong); border-radius: 2px; overflow: hidden; }
.lab-meter__track span { display: block; height: 100%; width: var(--fill); background: var(--accent); }

.lab-lesson__grid {
  max-width: var(--maxw);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(300px, 380px) minmax(0, 1fr);
  gap: clamp(24px, 3vw, 44px);
  align-items: start;
}
.lab-lesson__grid--wide { grid-template-columns: minmax(0, 1fr); }

/* --- Brief (left column) -------------------------------------------------------- */

.lab-brief { display: grid; gap: 22px; min-width: 0; }

.lab-goal {
  padding: 18px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--bg-2);
}
.lab-goal__head { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
.lab-goal__state { font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); }
.lab-goal__state.is-done { color: var(--accent); }
.lab-goal__text { margin-top: 10px; line-height: 1.5; }
.lab-goal__view { margin-top: 14px; display: grid; gap: 6px; }
.lab-goal__view:empty { display: none !important; }
.lab-goal__svg {
  width: 100%;
  height: 120px;
  border-radius: var(--radius);
  background: var(--bg);
  border: 1px solid var(--line);
}
.lab-goal__svg:not(:last-child) { height: 84px; }
.lab-goal__todo { margin-top: 12px; display: grid; gap: 6px; }
.lab-goal__todo li {
  font-size: 13px;
  color: var(--fg-dim);
  padding-left: 16px;
  position: relative;
  line-height: 1.45;
}
.lab-goal__todo li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.55em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  border: 1px solid var(--fg-faint);
}

.lab-brief__body { display: grid; gap: 14px; color: var(--fg-dim); line-height: 1.65; font-size: 15.5px; }
.lab-brief__body strong { color: var(--fg); font-weight: 600; }
.lab-brief__body h2 {
  font-size: 13px;
  font-family: var(--font-mono);
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--fg);
  margin-top: 10px;
}
.lab-brief__body blockquote {
  border-left: 2px solid var(--accent);
  padding: 2px 0 2px 16px;
  color: var(--fg);
}

.lab-jump { display: none; }

.lab-reveal {
  border-top: 1px solid var(--line);
  padding-top: 14px;
}
.lab-reveal summary {
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--fg-dim);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
}
.lab-reveal summary::-webkit-details-marker { display: none; }
.lab-reveal summary::before {
  content: "+";
  width: 18px;
  height: 18px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  transition: transform 0.3s var(--ease);
}
.lab-reveal[open] summary::before { transform: rotate(45deg); }
.lab-reveal summary:hover { color: var(--fg); }
.lab-reveal > p, .lab-solution { margin-top: 12px; color: var(--fg-dim); line-height: 1.6; font-size: 14.5px; }
.lab-solution { display: grid; gap: 8px; counter-reset: step; }
.lab-solution li { display: flex; gap: 10px; align-items: baseline; counter-increment: step; }
.lab-solution li::before { content: counter(step); font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); width: 14px; flex: none; }
.lab-solution li.is-note::before { content: "↳"; }
.lab-solution li.is-note code { background: none; padding: 0; color: var(--fg-dim); }
.lab-solution code { word-break: break-word; }
.lab-solution__par { margin-top: 10px; font-size: 12.5px; color: var(--fg-faint); }

.lab-brief__nav { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; border-top: 1px solid var(--line); padding-top: 16px; }
.lab-step {
  display: grid;
  gap: 6px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  font-size: 14px;
  line-height: 1.35;
  transition: border-color 0.3s var(--ease);
}
.lab-step span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--fg-faint);
}
.lab-step--next { grid-column: 2; text-align: right; }
.lab-step--next span { justify-content: flex-end; }
.lab-step:hover { border-color: var(--accent-line); }

/* --- Stage (right column) --------------------------------------------------------- */

.lab-stage { min-width: 0; }
.lab-stage__fallback {
  padding: 20px;
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-lg);
  color: var(--fg-dim);
  line-height: 1.6;
}
.is-live .lab-stage__fallback { display: none; }
.lab-live { display: none !important; }
.is-live .lab-live { display: revert !important; }
.is-live .lab-window.lab-live,
.is-live .lab-goal__view.lab-live,
.is-live .lab-goal__todo.lab-live { display: grid !important; }
.is-live .lab-goal__state.lab-live { display: inline !important; }

@media (min-width: 981px) {
  .lab-lesson:not(.lab-lesson--sandbox) .lab-stage {
    position: sticky;
    top: calc(var(--nav-h) + 12px);
  }
}

.lab-window {
  position: relative;
  display: grid;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-xl);
  background: var(--bg-2);
  box-shadow: var(--shadow-panel);
  overflow: hidden;
}
.lab-window__bar {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  background: var(--bg-3);
  min-width: 0;
}
.lab-window__dots { display: flex; gap: 6px; flex: none; }
.lab-window__dots i { width: 10px; height: 10px; border-radius: 50%; background: var(--line-strong); }
.lab-window__title {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-dim);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.lab-window__moves { margin-left: auto; font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); white-space: nowrap; }
.lab-window__actions { display: flex; gap: 6px; flex: none; }
.lab-window__bar .lab-window__title:last-child { margin-right: auto; }
.lab-tool {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line-strong);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--fg-dim);
  transition: all 0.25s var(--ease);
}
.lab-tool:hover:not(:disabled) { color: var(--fg); border-color: var(--fg-faint); }
.lab-tool:disabled { opacity: 0.4; cursor: default; }

.lab-pane-label {
  position: absolute;
  top: 10px;
  left: 14px;
  z-index: 1;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--fg-faint);
  pointer-events: none;
}
.lab-pane-label b { font-weight: 500; color: var(--fg-dim); margin-right: 6px; text-transform: uppercase; letter-spacing: 0.16em; }

.git-remote { position: relative; border-bottom: 1px dashed var(--line-strong); background: var(--bg); }
.git-remote svg { width: 100%; height: clamp(130px, 18vh, 190px); }
.git-remote[hidden] { display: none; }

.git-canvas {
  position: relative;
  background:
    radial-gradient(circle at 1px 1px, var(--line) 1px, transparent 0) 0 0 / 22px 22px,
    var(--bg);
}
.git-canvas svg { width: 100%; height: clamp(240px, 36vh, 420px); }
.lab-demo .git-canvas, .lab-demo .git-canvas svg { height: 100%; }
.lab-lesson--sandbox .git-canvas svg { height: clamp(280px, 46vh, 520px); }
/* Two graphs and a terminal still have to fit beside the lesson. */
.has-remote .git-remote svg { height: clamp(110px, 15vh, 160px); }
.has-remote .git-canvas svg { height: clamp(170px, 26vh, 300px); }
.has-remote .lab-term__output { height: clamp(120px, 17vh, 200px); }
.lab-inspector {
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--fg-dim);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  pointer-events: none;
}

/* --- Commit graph --------------------------------------------------------------- */

.gg { display: block; overflow: visible; touch-action: pan-y; }
.gg-empty { font-family: var(--font-mono); font-size: 13px; fill: var(--fg-faint); }

.gg-edge {
  fill: none;
  stroke: var(--fg-faint);
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-dasharray: 1;
}
.gg-edge.is-merge { stroke: var(--fg-faint); }
.gg-edge.is-dangling { stroke-dasharray: 0.03 0.03; }
.gg--compact .gg-edge { stroke-width: 1.3; }

.gg-node { cursor: default; }
.gg-node__dot { fill: var(--bg); stroke: var(--fg-dim); stroke-width: 1.8; transition: fill 0.35s var(--ease), stroke 0.35s var(--ease); }
.gg-node__halo { fill: var(--accent-soft); opacity: 0; transition: opacity 0.35s var(--ease); }
.gg-node:hover .gg-node__dot { stroke: var(--fg); }
.gg-node.is-merge .gg-node__dot { stroke-width: 2.4; }
.gg-node.is-head .gg-node__dot { fill: var(--accent); stroke: var(--accent); }
.gg-node.is-head .gg-node__halo { opacity: 1; }
.gg-node.is-dangling .gg-node__dot { stroke-dasharray: 2.5 2.5; }
.gg-node__hash { font-family: var(--font-mono); font-size: 10.5px; fill: var(--fg-faint); letter-spacing: 0.02em; }
.gg-node.is-head .gg-node__hash { fill: var(--fg); }

.gg-pulse {
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.5;
  transform-box: fill-box;
  transform-origin: center;
  animation: gg-pulse 0.9s var(--ease-out) forwards;
}
@keyframes gg-pulse {
  from { transform: scale(1); opacity: 0.9; }
  to { transform: scale(2.6); opacity: 0; }
}

.gg-trail {
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.2;
  stroke-dasharray: 0.02 0.02;
  opacity: 0;
  animation: gg-trail 1.2s var(--ease) forwards;
}
@keyframes gg-trail {
  0% { opacity: 0; }
  20% { opacity: 0.7; }
  100% { opacity: 0; }
}

.gg-ref rect { fill: var(--bg-2); stroke: var(--line-strong); stroke-width: 1; }
.gg-ref text { font-family: var(--font-mono); font-size: 11px; fill: var(--fg-dim); }
.gg--compact .gg-ref text { font-size: 9px; }
.gg-ref--branch rect { stroke: var(--fg-faint); }
.gg-ref--branch text { fill: var(--fg); }
.gg-ref--branch.is-current rect { fill: var(--accent-soft); stroke: var(--accent); }
.gg-ref--branch.is-current text { fill: var(--accent); }
.gg-ref--remote rect { stroke-dasharray: 3 2.5; fill: var(--bg); }
.gg-ref--tag rect { rx: 3px; fill: var(--bg-3); stroke: none; }
.gg-ref--head rect { fill: var(--accent); stroke: var(--accent); }
.gg-ref--head text { fill: var(--accent-ink); font-weight: 500; letter-spacing: 0.06em; }

/* --- Working tree panel ------------------------------------------------------- */

.git-files {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  background: var(--bg-2);
}
.git-files[hidden] { display: none; }
.git-col { padding: 12px 12px 14px; border-right: 1px solid var(--line); min-width: 0; }
.git-col:last-child { border-right: 0; }
.git-col__head { display: grid; gap: 2px; margin-bottom: 10px; }
.git-col__head span { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--fg-dim); }
.git-col__head small { font-size: 11px; color: var(--fg-faint); }
.git-col__list { display: flex; flex-direction: column; gap: 6px; min-height: 30px; }
.git-col.is-empty .git-col__list::after {
  content: "empty";
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--fg-faint);
  opacity: 0.6;
}

.git-file {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
  padding: 6px 8px;
  border-radius: var(--radius);
  border: 1px solid var(--line-strong);
  background: var(--bg);
  font-family: var(--font-mono);
  font-size: 11.5px;
  will-change: transform;
}
.git-file__name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.git-file__badge { font-size: 10px; color: var(--fg-faint); flex: none; }
.git-file--new { border-style: dashed; color: var(--fg-dim); }
.git-file--modified .git-file__badge { color: var(--fg); }
.git-file--staged_new, .git-file--staged_modified { border-color: var(--accent-line); background: var(--accent-soft); }
.git-file--staged_new .git-file__badge, .git-file--staged_modified .git-file__badge { color: var(--accent); }
.git-file--clean { color: var(--fg-faint); border-color: var(--line); background: transparent; }
.git-file--stash { color: var(--fg-dim); background: var(--bg-3); border-color: transparent; }

@media (max-width: 640px) {
  .git-files { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .git-col:nth-child(2) { border-right: 0; }
  .git-col:nth-child(-n + 2) { border-bottom: 1px solid var(--line); }
}

/* --- Terminal ------------------------------------------------------------------ */

.lab-term {
  display: grid;
  border-top: 1px solid var(--line);
  background: var(--bg);
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
}
.lab-term__output {
  height: clamp(150px, 22vh, 230px);
  overflow-y: auto;
  padding: 12px 16px 4px;
  overscroll-behavior: contain;
  scrollbar-width: thin;
}
.lab-out { white-space: pre-wrap; word-break: break-word; color: var(--fg-dim); animation: git-line 0.35s var(--ease) both; animation-delay: calc(var(--i, 0) * 18ms); }
.lab-out--cmd { color: var(--fg); margin-top: 6px; animation: none; }
.lab-out--err { color: var(--fg); }
.lab-out--err::before { content: "│ "; color: var(--fg-faint); }
.lab-out--dim { color: var(--fg-faint); }
.lab-out--goal { color: var(--fg); }
.lab-out--ok { color: var(--accent); }
.lab-out--log { color: var(--fg); }
@keyframes git-line { from { opacity: 0; transform: translateY(3px); } }

.lab-term__line { display: flex; align-items: center; gap: 8px; padding: 6px 16px 12px; }
.lab-term__prompt { white-space: nowrap; color: var(--fg-faint); flex: none; }
.lab-term__path { color: var(--fg-dim); }
.lab-term__branch { color: var(--accent); }
.lab-term__branch.is-detached { color: var(--fg); }
.lab-term__input {
  flex: 1;
  min-width: 0;
  background: transparent;
  border: 0;
  outline: 0;
  color: var(--fg);
  font: inherit;
  caret-color: var(--accent);
  padding: 4px 0;
}
.lab-term__input::placeholder { color: var(--fg-faint); opacity: 0.7; }
.lab-term__line:focus-within { box-shadow: inset 2px 0 0 var(--accent); }
.lab-term__chips {
  display: flex;
  gap: 6px;
  padding: 0 16px 12px;
  overflow-x: auto;
  scrollbar-width: none;
}
.lab-chip {
  flex: none;
  padding: 5px 10px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line);
  color: var(--fg-dim);
  font-family: var(--font-mono);
  font-size: 11px;
  white-space: nowrap;
  transition: all 0.25s var(--ease);
}
.lab-chip:hover { border-color: var(--accent-line); color: var(--fg); }

@media (max-width: 520px) {
  .lab-term__prompt .lab-term__path { display: none; }
  .lab-window__moves { display: none; }
}

/* --- Rebase editor --------------------------------------------------------------- */

.lab-editor {
  position: absolute;
  inset: 44px 0 0;
  z-index: 3;
  display: grid;
  grid-template-rows: auto 1fr auto;
  background: var(--bg);
  animation: git-rise 0.4s var(--ease-out);
}
.lab-editor[hidden] { display: none; }
.lab-editor__head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--fg-dim);
}
.lab-editor__keys { color: var(--fg-faint); }
.lab-editor__text {
  width: 100%;
  min-height: 220px;
  resize: none;
  padding: 14px 16px;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--fg);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  caret-color: var(--accent);
}
.lab-editor__actions { display: flex; justify-content: flex-end; gap: 10px; padding: 12px 16px; border-top: 1px solid var(--line); flex-wrap: wrap; }
@keyframes git-rise { from { opacity: 0; transform: translateY(12px); } }

/* --- Success ------------------------------------------------------------------- */

.lab-success {
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 12px;
  z-index: 4;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 4px 18px;
  padding: 18px 20px;
  border: 1px solid var(--accent-line);
  border-radius: var(--radius-lg);
  background: var(--bg-2);
  box-shadow: var(--shadow-lift);
  animation: git-rise 0.55s var(--ease-out);
}
.lab-success[hidden] { display: none; }
.lab-success > p { grid-column: 2; }
.lab-success__mark { grid-row: 1 / span 2; }
.lab-success__actions { grid-column: 3; grid-row: 1 / span 2; }
@media (max-width: 760px) {
  .lab-success { grid-template-columns: auto 1fr; }
  .lab-success__actions { grid-column: 1 / -1; grid-row: auto; justify-content: stretch; }
  .lab-success__actions .btn { flex: 1; }
}
.lab-success__mark { width: 44px; height: 44px; }
.lab-success__mark circle, .lab-success__mark path {
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  animation: git-draw 0.7s var(--ease-out) forwards;
}
.lab-success__mark path { animation-delay: 0.35s; }
.lab-success__title { font-family: var(--font-display); font-size: 22px; letter-spacing: -0.01em; white-space: nowrap; }
.lab-success__score { color: var(--fg-dim); font-size: 14px; }
.lab-success__actions { display: flex; gap: 10px; flex-wrap: wrap; justify-content: flex-end; }
@keyframes git-draw { to { stroke-dashoffset: 0; } }
@keyframes git-fade { from { opacity: 0; } }

/* --- Narrow screens -------------------------------------------------------------- */

@media (max-width: 980px) {
  .lab-lesson__grid { grid-template-columns: minmax(0, 1fr); }
  .lab-jump {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--accent);
  }
  .lab-stage { scroll-margin-top: calc(var(--nav-h) + 8px); }
}

@media (prefers-reduced-motion: reduce) {
  .lab-demo__caret { animation: none; }
  .lab-success__mark circle, .lab-success__mark path { stroke-dashoffset: 0; animation: none; }
}

/* ==========================================================================
   Framework pieces shared by every course
   ========================================================================== */

.lab-view {
  position: relative;
  min-height: 180px;
  background:
    radial-gradient(circle at 1px 1px, var(--line) 1px, transparent 0) 0 0 / 22px 22px,
    var(--bg);
  overflow: hidden;
}
.lab-view__loading {
  padding: 48px 20px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-faint);
}
.lab-term__user { color: var(--fg-dim); }
.lab-term__detached { color: var(--fg); }
.lab-term__dim { color: var(--fg-faint); }

/* A copy of an element flying from one place to another (rows into results). */
.lab-ghost { border-radius: var(--radius); box-shadow: 0 0 0 1px var(--accent-line), var(--shadow-lift); background: var(--bg-2); }

@keyframes lab-pulse {
  0% { box-shadow: 0 0 0 0 var(--accent-line); background-color: var(--accent-soft); }
  100% { box-shadow: 0 0 0 10px transparent; background-color: transparent; }
}
@keyframes lab-born {
  0% { background-color: var(--accent-soft); box-shadow: inset 2px 0 0 var(--accent); }
  100% { background-color: transparent; box-shadow: inset 2px 0 0 transparent; }
}
.is-pulse { animation: lab-pulse 0.9s var(--ease-out); }
.is-born { animation: lab-born 1.6s var(--ease-out); }

/* --- Learn hub: tracks and course cards ------------------------------------ */

.learn-total { color: var(--fg-faint); }
.learn-tracks {
  max-width: calc(var(--maxw) + var(--gutter) * 2);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: grid;
  gap: clamp(48px, 7vw, 96px);
}
.learn-track__head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr);
  gap: 24px;
  align-items: end;
  padding-bottom: 20px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line);
}
.learn-track__title { font-size: calc(clamp(30px, 3.6vw, 52px) * var(--display-scale)); }
.learn-track__head p { color: var(--fg-dim); max-width: 52ch; line-height: 1.55; }
.learn-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 340px), 1fr));
  gap: 16px;
}
.learn-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius-xl);
  background: var(--bg-2);
  overflow: hidden;
  transition: border-color 0.4s var(--ease), transform 0.4s var(--ease), background-color 0.4s var(--ease);
}
.learn-card:hover { border-color: var(--accent-line); transform: translateY(-3px); }
.learn-card__art {
  height: 120px;
  margin: -24px -24px 8px;
  display: grid;
  place-items: center;
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(circle at 1px 1px, var(--line) 1px, transparent 0) 0 0 / 18px 18px,
    var(--bg);
}
.learn-emblem { width: 120px; height: 80px; fill: none; stroke: var(--fg-dim); stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; transition: transform 0.6s var(--ease), stroke 0.4s var(--ease); }
.learn-emblem .is-on { fill: var(--accent); stroke: var(--accent); }
.learn-emblem .is-on-stroke { stroke: var(--accent); stroke-width: 2.4; }
.learn-card:hover .learn-emblem { transform: scale(1.06); stroke: var(--fg); }
.learn-card__num { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--accent); }
.learn-card__title { font-size: 24px; letter-spacing: -0.015em; }
.learn-card__summary { color: var(--fg-dim); font-size: 14.5px; line-height: 1.55; }
.learn-card__foot { margin-top: auto; padding-top: 12px; display: flex; justify-content: space-between; align-items: center; gap: 10px; }
.learn-card__meta { font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); letter-spacing: 0.04em; }
.learn-card__progress {
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--accent);
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--accent-soft) var(--done, 0%), transparent var(--done, 0%));
  border: 1px solid var(--accent-line);
}
.learn-card.is-complete .learn-card__progress { background: var(--accent); color: var(--accent-ink); }
@media (max-width: 760px) {
  .learn-track__head { grid-template-columns: 1fr; }
}
.learn-shelf { margin-top: clamp(48px, 7vw, 96px); }

/* ==========================================================================
   Course: the command line
   ========================================================================== */

.cli { display: grid; height: clamp(260px, 40vh, 440px); grid-template-rows: minmax(0, 1fr) auto; }
.lab-lesson--sandbox .cli { height: clamp(300px, 50vh, 560px); }
.lab-demo .cli { height: 100%; }
.cli-tree-wrap { position: relative; overflow: auto; padding: 14px 0 14px; scrollbar-width: thin; }
.cli-tree { display: grid; font-family: var(--font-mono); font-size: 12.5px; }
.cli-node {
  --indent: 18px;
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  height: 28px;
  padding: 0 16px 0 calc(110px + var(--depth) * var(--indent));
  color: var(--fg-dim);
  white-space: nowrap;
  border-radius: 2px;
}
.cli-node__guides {
  position: absolute;
  left: 110px;
  top: 0;
  bottom: 0;
  width: calc(var(--depth) * var(--indent));
  background: repeating-linear-gradient(90deg, var(--line) 0 1px, transparent 1px var(--indent));
  background-position: 6px 0;
}
.cli-node--dir { color: var(--fg); }
.cli-node.is-hidden { opacity: 0.55; }
.cli-node.is-cwd { color: var(--accent); }
.cli-node.is-cwd::before {
  content: "";
  position: absolute;
  inset: 2px 8px 2px calc(104px + var(--depth) * var(--indent));
  border-radius: var(--radius);
  background: var(--accent-soft);
  box-shadow: inset 0 0 0 1px var(--accent-line);
  z-index: -1;
}
.cli-icon { display: inline-grid; color: var(--fg-faint); flex: none; }
.cli-node--dir .cli-icon { color: var(--fg-dim); }
.cli-node.is-cwd .cli-icon { color: var(--accent); }
.cli-icon--exec { color: var(--accent); }
.cli-node__name { overflow: hidden; text-overflow: ellipsis; }
.cli-node__meta { margin-left: auto; display: flex; gap: 14px; color: var(--fg-faint); font-size: 11px; }
.cli-node__mode { letter-spacing: 0.02em; }
.cli-node__size { min-width: 56px; text-align: right; }
.cli-node--leaving { color: var(--fg-faint); text-decoration: line-through; pointer-events: none; }
.cli-node.is-pulse { animation: lab-born 1.4s var(--ease-out); }

.cli-here {
  position: absolute;
  top: 14px;
  left: 14px;
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  background: var(--accent);
  color: var(--accent-ink);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  white-space: nowrap;
  transition: transform 0.65s cubic-bezier(0.34, 1.35, 0.5, 1);
  pointer-events: none;
}
.cli-here::after {
  content: "";
  position: absolute;
  right: -5px;
  top: 50%;
  border: 5px solid transparent;
  border-left-color: var(--accent);
  border-right: 0;
  transform: translateY(-50%);
}

.cli-flow {
  display: flex;
  align-items: center;
  gap: 0;
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  background: var(--bg-2);
  overflow-x: auto;
  scrollbar-width: none;
}
.cli-flow[hidden] { display: none; }
.cli-flow__stage {
  flex: none;
  display: grid;
  gap: 2px;
  padding: 8px 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--bg);
  animation: cli-stage 0.5s var(--ease-out) both;
  animation-delay: calc(var(--i) * 0.28s);
}
.cli-flow__stage code { font-family: var(--font-mono); font-size: 12px; color: var(--fg); }
.cli-flow__stage small { font-family: var(--font-mono); font-size: 10.5px; color: var(--accent); }
.cli-flow__stage--file { border-color: var(--accent-line); display: grid; grid-template-columns: auto 1fr; column-gap: 8px; align-items: center; }
.cli-flow__stage--file small { grid-column: 2; }
.cli-flow__pipe {
  position: relative;
  flex: none;
  width: 44px;
  height: 2px;
  background: var(--line-strong);
  animation: cli-stage 0.3s var(--ease-out) both;
  animation-delay: calc(var(--i) * 0.28s - 0.1s);
}
.cli-flow__pipe i {
  position: absolute;
  top: -2px;
  left: 0;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  animation: cli-data 1.2s linear infinite;
  animation-delay: calc(var(--i) * 0.28s);
}
.cli-flow__pipe i:nth-child(2) { animation-delay: calc(var(--i) * 0.28s + 0.4s); }
.cli-flow__pipe i:nth-child(3) { animation-delay: calc(var(--i) * 0.28s + 0.8s); }
@keyframes cli-stage { from { opacity: 0; transform: translateX(-8px); } }
@keyframes cli-data {
  0% { transform: translateX(0); opacity: 0; }
  15%, 85% { opacity: 1; }
  100% { transform: translateX(38px); opacity: 0; }
}

.cli-tree--compact { font-size: 11px; max-height: 220px; overflow: auto; padding: 8px 0; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg); }
.cli-tree--compact .cli-node { height: 22px; padding-left: calc(10px + var(--depth) * 14px); --indent: 14px; }
.cli-tree--compact .cli-node__guides { left: 10px; }
.cli-tree--compact .cli-node.is-cwd::before { inset: 1px 4px 1px calc(6px + var(--depth) * 14px); }

@media (max-width: 640px) {
  .cli-node { padding-left: calc(92px + var(--depth) * 14px); --indent: 14px; }
  .cli-node__guides { left: 92px; }
  .cli-node.is-cwd::before { left: calc(86px + var(--depth) * 14px); }
  .cli-node__mode { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  .cli-flow__pipe i { animation: none; opacity: 0.6; }
}

/* ==========================================================================
   Course: SQL
   ========================================================================== */

.sql {
  display: grid;
  gap: 14px;
  padding: 16px;
  height: clamp(320px, 46vh, 520px);
  grid-template-rows: auto auto minmax(0, 1fr);
  overflow: auto;
  scrollbar-width: thin;
}
.lab-lesson--sandbox .sql { height: clamp(360px, 54vh, 600px); }
.lab-demo .sql { height: 100%; }
.sql-sources { display: flex; gap: 12px; flex-wrap: wrap; align-items: flex-start; }
.sql-sources > .sql-card { flex: 1 1 240px; min-width: 0; max-width: 100%; }
.sql-result:empty { display: none; }
.sql-result__empty { font-family: var(--font-mono); font-size: 11.5px; color: var(--fg-faint); padding: 6px 2px; }

.sql-card {
  margin: 0;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--bg-2);
  overflow: hidden;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  max-height: 230px;
  transition: box-shadow 0.4s var(--ease), border-color 0.4s var(--ease);
}
.sql-card--result { max-height: 260px; border-color: var(--accent-line); box-shadow: 0 0 0 4px var(--accent-soft); }
.sql-card--goal { max-height: 200px; background: var(--bg); }
.sql-card__head {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 7px 10px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
}
.sql-card__name { color: var(--fg); letter-spacing: 0.04em; }
.sql-card--result .sql-card__name { color: var(--accent); text-transform: uppercase; letter-spacing: 0.14em; }
.sql-card__count { color: var(--fg-faint); }
.sql-card__scroll { overflow: auto; scrollbar-width: thin; }
.sql-card__more { padding: 5px 10px; font-family: var(--font-mono); font-size: 10.5px; color: var(--fg-faint); border-top: 1px solid var(--line); }

.sql-table { width: 100%; border-collapse: collapse; font-family: var(--font-mono); font-size: 11.5px; }
.sql-table th {
  position: sticky;
  top: 0;
  background: var(--bg-3);
  text-align: left;
  font-weight: 500;
  color: var(--fg-dim);
  padding: 5px 10px;
  white-space: nowrap;
}
.sql-table td { padding: 4px 10px; color: var(--fg-dim); white-space: nowrap; border-top: 1px solid var(--line); }
.sql-table td.is-num { text-align: right; font-variant-numeric: tabular-nums; }
.sql-table td.is-null { color: var(--fg-faint); font-style: italic; }
.sql-card--result td { color: var(--fg); }
.sql-table tr { transition: background-color 0.35s var(--ease), opacity 0.35s var(--ease); }
.sql-table tr.is-hit td { background: var(--accent-soft); color: var(--fg); }
.sql-table tr.is-waiting { opacity: 0; }
.sql-table tr.is-land td { animation: sql-land 0.7s var(--ease-out); }
.sql-table tr.is-inserted td { animation: sql-insert 1.6s var(--ease-out) both; animation-delay: calc(var(--i, 0) * 80ms); }
.sql-table tr.is-deleted td { animation: sql-delete 1.1s var(--ease) forwards; animation-delay: calc(var(--i, 0) * 70ms); text-decoration: line-through; }
.sql-table td.is-changed { animation: sql-changed 1.4s var(--ease-out); }
.sql-table tr.is-scan td { animation: sql-scan 0.5s var(--ease) both; animation-delay: calc(var(--i, 0) * 70ms); }
@keyframes sql-land { from { background: var(--accent-soft); } }
@keyframes sql-insert {
  0% { opacity: 0; transform: translateX(-14px); background: var(--accent-soft); }
  30% { opacity: 1; transform: none; background: var(--accent-soft); }
  100% { background: transparent; }
}
@keyframes sql-delete {
  0% { background: var(--bg-3); }
  60% { opacity: 0.6; }
  100% { opacity: 0; line-height: 0; padding-top: 0; padding-bottom: 0; font-size: 0; }
}
@keyframes sql-changed { 0%, 30% { background: var(--accent); color: var(--accent-ink); } }
@keyframes sql-scan { 0% { background: transparent; } 40% { background: var(--accent-soft); box-shadow: inset 2px 0 0 var(--accent); } 100% { background: transparent; } }
.sql-card.is-seek { border-color: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); }

.sql-plan { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.sql-plan[hidden] { display: none; }
.sql-plan__label { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.16em; text-transform: uppercase; color: var(--fg-faint); }
.sql-plan code {
  font-family: var(--font-mono);
  font-size: 11.5px;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line-strong);
  color: var(--fg-dim);
  animation: cli-stage 0.5s var(--ease-out) both;
}
.sql-plan code.is-scan { border-color: var(--fg-faint); color: var(--fg); }
.sql-plan code.is-index { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.sql-plan--goal { padding: 10px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg); }

@media (prefers-reduced-motion: reduce) {
  .sql-table tr.is-waiting { opacity: 1; }
}

/* ==========================================================================
   Course: regex
   ========================================================================== */

.rx {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 16px;
  height: clamp(340px, 48vh, 540px);
  overflow: auto;
  scrollbar-width: thin;
}
.lab-demo .rx { height: 100%; }
.rx > * { flex: none; }
.rx-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.rx-current { font-family: var(--font-mono); font-size: 18px; color: var(--accent); word-break: break-all; }
.rx-current.is-empty { color: var(--fg-faint); font-size: 13px; }
.rx-current.is-error { color: var(--fg); text-decoration: wavy underline var(--fg-faint); }
.rx-status { font-family: var(--font-mono); font-size: 11.5px; color: var(--fg-faint); }

.rx-diagram {
  overflow-x: auto;
  padding: 6px 4px 2px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--bg-2);
  scrollbar-width: thin;
  min-height: 70px;
}
.rx-diagram.is-empty { display: none; }
.rr { display: block; height: auto; width: min(100%, var(--rr-w, 100%)); min-width: min(var(--rr-w, 0px), 760px); margin: 0 auto; overflow: visible; }
.rr-line { fill: none; stroke: var(--fg-faint); stroke-width: 1.6; stroke-linecap: round; stroke-dasharray: 1; stroke-dashoffset: 0; }
.rr.is-drawn .rr-line { animation: rr-draw 0.55s var(--ease-out) both; animation-delay: calc(var(--i, 0) * 22ms); }
.rr-loop { stroke-dasharray: none; }
.rr.is-drawn .rr-loop { animation: rr-fade 0.6s var(--ease) both; }
.rr-skip { stroke: var(--fg-faint); opacity: 0.7; }
.rr-end { fill: var(--bg); stroke: var(--fg-dim); stroke-width: 1.6; }
.rr-end--out { fill: var(--fg-dim); }
.rr-node rect { fill: var(--bg); stroke: var(--fg-dim); stroke-width: 1.3; }
.rr-node text { font-family: var(--font-mono); font-size: 12px; fill: var(--fg); }
.rr-node--class rect { fill: var(--accent-soft); stroke: var(--accent-line); }
.rr-node--class text { fill: var(--accent); }
.rr-node--anchor rect { fill: var(--bg-3); stroke: none; }
.rr-node--anchor text { fill: var(--fg-dim); font-size: 10.5px; letter-spacing: 0.04em; }
.rr-node--ref rect { stroke-dasharray: 3 3; }
.rr.is-drawn .rr-node { animation: rr-pop 0.5s cubic-bezier(0.34, 1.4, 0.5, 1) both; transform-box: fill-box; transform-origin: center; }
.rr-group { fill: none; stroke: var(--line-strong); stroke-dasharray: 4 3; }
.rr-group--capture { stroke: var(--accent-line); }
.rr-group-label { font-family: var(--font-mono); font-size: 10px; fill: var(--fg-faint); letter-spacing: 0.06em; }
.rr-group--capture + .rr-group-label { fill: var(--accent); }
.rr-note { font-family: var(--font-mono); font-size: 10px; fill: var(--fg-faint); }
@keyframes rr-draw { from { stroke-dashoffset: 1; } }
@keyframes rr-fade { from { opacity: 0; } }
@keyframes rr-pop { from { opacity: 0; transform: scale(0.8); } }

.rx-cases { display: grid; gap: 6px; align-content: start; }
.rx-cases[hidden] { display: none; }
.rx-case {
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr) auto;
  gap: 10px;
  align-items: center;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-2);
  transition: border-color 0.3s var(--ease), background-color 0.3s var(--ease);
}
.rx-case.is-pass { border-color: var(--accent-line); }
.rx-case__mark {
  width: 20px;
  height: 20px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  font-size: 11px;
  border: 1px solid var(--line-strong);
  color: var(--fg-faint);
  transition: all 0.3s var(--ease);
}
.rx-case.is-pass .rx-case__mark { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.rx-case.is-checked { animation: rx-check 0.5s var(--ease-out) both; animation-delay: calc(var(--i) * 45ms); }
.rx-case.is-checked.is-pass .rx-case__mark { animation: rx-tick 0.5s cubic-bezier(0.34, 1.6, 0.5, 1) both; animation-delay: calc(var(--i) * 45ms + 0.1s); }
@keyframes rx-check { 0% { transform: translateX(-4px); opacity: 0.6; } }
@keyframes rx-tick { 0% { transform: scale(0.4); } }
.rx-case__text { font-family: var(--font-mono); font-size: 13px; color: var(--fg); white-space: pre-wrap; word-break: break-word; }
.rx-case--no .rx-case__text { color: var(--fg-dim); }
.rx-case__want { font-family: var(--font-mono); font-size: 10.5px; color: var(--fg-faint); white-space: nowrap; }
.rx-match {
  background: var(--accent-soft);
  color: inherit;
  border-radius: 3px;
  box-shadow: 0 0 0 1px var(--accent-line);
  padding: 0 1px;
}
.rx-match.is-empty { box-shadow: -1px 0 0 0 var(--accent); padding: 0; }
.rx-group { border-bottom: 2px solid var(--accent); position: relative; }
.rx-group::after {
  content: attr(data-n);
  position: absolute;
  top: -9px;
  right: -5px;
  font-size: 8px;
  color: var(--accent);
}
.rx-group--2 { border-bottom-style: dashed; }
.rx-group--3 { border-bottom-style: dotted; }
.rx-group--4 { border-bottom-style: double; }

.rx-text {
  margin: 0;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--bg-2);
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.9;
  white-space: pre-wrap;
  word-break: break-word;
  color: var(--fg-dim);
}
.rx-text[hidden] { display: none; }

.rx-explain { display: grid; gap: 3px; font-size: 12.5px; color: var(--fg-dim); border-top: 1px solid var(--line); padding-top: 10px; }
.rx-explain:empty { display: none; }
.rx-explain li { display: flex; gap: 10px; padding-left: calc(var(--depth) * 16px); }
.rx-explain code { flex: none; min-width: 52px; font-family: var(--font-mono); font-size: 11.5px; color: var(--accent); }
.lab-demo .rx-explain { display: none; }

.rx-goal { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.rx-goal__col ul { display: grid; gap: 4px; margin-top: 6px; }
.rx-goal__col li { font-size: 12.5px; color: var(--fg-dim); }
.rx-goal__col code { font-family: var(--font-mono); font-size: 12px; color: var(--fg); background: var(--bg); padding: 1px 6px; border-radius: var(--radius); }
.rx-goal__col small { color: var(--fg-faint); font-family: var(--font-mono); font-size: 10.5px; }
@media (max-width: 520px) { .rx-goal { grid-template-columns: 1fr; } .rx-case { grid-template-columns: 22px minmax(0, 1fr); } .rx-case__want { grid-column: 2; } }

/* ==========================================================================
   Course: Docker
   ========================================================================== */

.dk {
  position: relative;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: 18px;
  padding: 14px 16px 16px;
  height: clamp(360px, 50vh, 560px);
  overflow: auto;
  scrollbar-width: thin;
}
.lab-demo .dk { height: 100%; }
.lab-lesson--sandbox .dk { height: clamp(400px, 56vh, 640px); }
.dk-label { font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.18em; text-transform: uppercase; color: var(--fg-faint); }
.dk-host {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 8px 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--bg-2);
}
.dk-sockets { display: flex; gap: 8px; flex-wrap: wrap; }
.dk-socket {
  font-family: var(--font-mono);
  font-size: 11px;
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  background: var(--accent);
  color: var(--accent-ink);
  animation: rr-pop 0.5s cubic-bezier(0.34, 1.4, 0.5, 1) both;
}
.dk-body { position: relative; z-index: 1; display: grid; grid-template-columns: minmax(150px, 0.8fr) minmax(0, 2fr); gap: 16px; min-height: 0; }
.dk-col { display: grid; gap: 8px; align-content: start; min-width: 0; }
.dk-images { display: flex; flex-wrap: wrap; gap: 10px; align-items: flex-end; }
.dk-img { display: grid; justify-items: center; gap: 6px; width: 92px; }
.dk-img__meta { display: grid; text-align: center; font-family: var(--font-mono); }
.dk-img__meta strong { font-size: 11px; font-weight: 500; color: var(--fg); word-break: break-all; }
.dk-img__meta small { font-size: 9.5px; color: var(--fg-faint); }
.dk-layers { display: flex; flex-direction: column; gap: 2px; width: 72px; }
.dk-layer {
  height: var(--h);
  border-radius: 2px;
  background: var(--bg-3);
  border: 1px solid var(--line-strong);
  transition: background-color 0.4s var(--ease);
}
.dk-layer.is-shared { background: var(--line-strong); }
.dk-layer.is-built { background: var(--accent-soft); border-color: var(--accent-line); }
.dk-layer.is-arriving, .dk-layer.is-fresh { animation: dk-drop 0.55s cubic-bezier(0.34, 1.3, 0.5, 1) both; animation-delay: calc(var(--i) * 110ms); }
.dk-layer.is-cached { animation: dk-cached 1.2s var(--ease-out) both; animation-delay: calc(var(--i) * 60ms); }
@keyframes dk-drop { from { opacity: 0; transform: translateY(-22px); } }
@keyframes dk-cached { 0%, 40% { box-shadow: 0 0 0 2px var(--accent); } }

.dk-containers { display: grid; gap: 12px; align-content: start; }
.dk-net { display: flex; flex-wrap: wrap; gap: 10px; align-content: flex-start; position: relative; padding: 18px 10px 10px; border: 1px dashed var(--accent-line); border-radius: var(--radius-lg); }
.dk-net--bridge { padding: 0; border: 0; }
.dk-net__label { position: absolute; top: -8px; left: 10px; padding: 0 6px; background: var(--bg); font-family: var(--font-mono); font-size: 10px; color: var(--accent); letter-spacing: 0.06em; }
.dk-ctr {
  width: 188px;
  display: grid;
  gap: 6px;
  padding: 10px 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--bg-2);
  box-shadow: var(--shadow-lift);
  transition: opacity 0.4s var(--ease), border-color 0.4s var(--ease);
}
.dk-ctr.is-running { border-color: var(--accent-line); }
.dk-ctr.is-exited, .dk-ctr.is-created { opacity: 0.62; box-shadow: none; }
.dk-ctr__head { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: 8px; align-items: center; }
.dk-ctr__light { width: 8px; height: 8px; border-radius: 50%; background: var(--fg-faint); transition: background-color 0.4s var(--ease), box-shadow 0.4s var(--ease); }
.is-running .dk-ctr__light, .dk-goal__item.is-running .dk-ctr__light { background: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); animation: pulse 2.4s ease-in-out infinite; }
.dk-ctr__name { font-family: var(--font-mono); font-size: 12px; font-weight: 500; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.dk-ctr__state { font-family: var(--font-mono); font-size: 9.5px; color: var(--fg-faint); white-space: nowrap; }
.dk-ctr__image { font-family: var(--font-mono); font-size: 10.5px; color: var(--fg-dim); }
.dk-ctr__chips { display: flex; flex-wrap: wrap; gap: 4px; min-width: 0; }
.dk-ctr { min-width: 0; overflow: hidden; }
.dk-chip { font-family: var(--font-mono); font-size: 9.5px; padding: 2px 6px; border-radius: var(--radius); background: var(--bg-3); color: var(--fg-dim); max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.dk-chip--port { background: var(--accent-soft); color: var(--accent); }
.dk-chip--mount { border: 1px solid var(--line-strong); background: transparent; }
.dk-ctr.is-pulse { animation: lab-pulse 0.9s var(--ease-out); }

.dk-volumes { position: relative; z-index: 1; display: flex; gap: 12px; flex-wrap: wrap; padding-top: 4px; border-top: 1px dashed var(--line); }
.dk-volumes[hidden] { display: none; }
.dk-disk { display: grid; grid-template-columns: auto auto; column-gap: 8px; align-items: center; padding: 6px 10px; border: 1px solid var(--line-strong); border-radius: var(--radius-lg); background: var(--bg-2); animation: rr-pop 0.5s cubic-bezier(0.34, 1.4, 0.5, 1) both; }
.dk-disk__icon { grid-row: span 2; width: 22px; height: 16px; border-radius: 50% / 30%; border: 1.5px solid var(--fg-dim); box-shadow: inset 0 -6px 0 -4px var(--fg-faint); }
.dk-disk strong { font-family: var(--font-mono); font-size: 11px; font-weight: 500; }
.dk-disk small { font-family: var(--font-mono); font-size: 9.5px; color: var(--fg-faint); }
.dk-empty { font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); }

.dk-wires { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; z-index: 0; overflow: visible; }
.dk-wire { fill: none; stroke: var(--accent-line); stroke-width: 1.5; stroke-dasharray: 1; animation: rr-draw 0.6s var(--ease-out) both; }
.dk-wire--volume { stroke: var(--fg-faint); stroke-dasharray: 0.02 0.015; animation: rr-fade 0.6s var(--ease) both; }
.dk-packet { fill: var(--accent); filter: drop-shadow(0 0 4px var(--accent)); }

.dk-goal { display: grid; gap: 6px; }
.dk-goal__item { display: grid; grid-template-columns: auto auto minmax(0, 1fr); gap: 8px; align-items: center; padding: 6px 8px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg); }
.dk-goal__item code { font-family: var(--font-mono); font-size: 11.5px; }
.dk-goal__item small { font-family: var(--font-mono); font-size: 10px; color: var(--fg-faint); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
@media (max-width: 640px) {
  .dk-body { grid-template-columns: 1fr; }
  .dk-ctr { width: 100%; }
}

/* ==========================================================================
   Course: LLMs, under the hood
   ========================================================================== */

.llm { display: flex; flex-direction: column; gap: 14px; padding: 16px; height: clamp(340px, 50vh, 560px); overflow: auto; scrollbar-width: thin; }
.lab-demo .llm { height: 100%; }
.llm > * { flex: none; }
.llm-panel { display: grid; gap: 10px; padding: 12px 14px; border: 1px solid var(--line-strong); border-radius: var(--radius-lg); background: var(--bg-2); }
.llm-panel[hidden] { display: none; }
.llm-panel__head { display: flex; justify-content: space-between; align-items: center; gap: 10px; flex-wrap: wrap; }
.llm-meta { font-family: var(--font-mono); font-size: 11px; color: var(--fg-faint); }

.llm-strip { display: flex; flex-wrap: wrap; gap: 4px; }
.llm-token {
  display: inline-grid;
  justify-items: center;
  padding: 3px 6px 2px;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.3;
  color: var(--fg);
  border: 1px solid var(--line-strong);
  background: var(--bg);
}
.llm-token small { font-size: 8.5px; color: var(--fg-faint); }
.llm-token--1 { background: var(--accent-soft); }
.llm-token--2 { background: var(--bg-3); }
.llm-token--3 { background: color-mix(in srgb, var(--accent-soft) 50%, var(--bg-3)); }
.llm-token.is-new { animation: llm-split 0.5s cubic-bezier(0.34, 1.4, 0.5, 1) both; animation-delay: calc(var(--i) * 28ms); }
@keyframes llm-split { from { opacity: 0; transform: translateX(calc(var(--i) * -2px)) scale(0.85); letter-spacing: -0.2em; } }

.llm-dials { display: flex; gap: 6px; flex-wrap: wrap; }
.llm-dial { display: inline-flex; gap: 6px; align-items: baseline; padding: 3px 8px; border-radius: var(--radius-pill); border: 1px solid var(--line-strong); font-family: var(--font-mono); }
.llm-dial small { font-size: 9.5px; color: var(--fg-faint); }
.llm-dial b { font-size: 11px; font-weight: 500; color: var(--accent); }
.llm-dial:first-child { background: linear-gradient(90deg, var(--accent-soft) calc(var(--t) * 100%), transparent calc(var(--t) * 100%)); transition: background 0.5s var(--ease); }

.llm-text { font-family: var(--font-display); font-size: clamp(17px, 1.6vw, 21px); line-height: 1.5; color: var(--fg-dim); }
.llm-text__prompt { color: var(--fg); }
.llm-text__gen { color: var(--accent); }
.llm-text__gen.is-new { animation: llm-word 0.35s var(--ease-out) both; }
@keyframes llm-word { from { opacity: 0; filter: blur(3px); } }
.llm-caret { display: inline-block; width: 2px; height: 1em; margin-left: 2px; vertical-align: -0.12em; background: var(--accent); animation: git-blink 1.1s steps(1) infinite; }

.llm-bars { display: grid; gap: 4px; }
.llm-bar { display: grid; grid-template-columns: minmax(70px, 120px) minmax(0, 1fr) 64px; gap: 10px; align-items: center; font-family: var(--font-mono); font-size: 12px; }
.llm-bar__token { color: var(--fg); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; text-align: right; }
.llm-bar__track { position: relative; height: 12px; border-radius: 3px; background: var(--bg-3); overflow: hidden; }
.llm-bar__fill {
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--w);
  background: var(--fg-faint);
  border-radius: 3px;
  transition: width 0.6s cubic-bezier(0.34, 1.2, 0.5, 1), background-color 0.3s var(--ease);
}
.llm-bar__p { color: var(--fg-dim); font-size: 11px; text-align: right; }
.llm-bar.is-cut { opacity: 0.4; }
.llm-bar.is-cut .llm-bar__track { background: repeating-linear-gradient(135deg, var(--bg-3) 0 4px, transparent 4px 8px); }
.llm-bar.is-cut .llm-bar__fill { width: 0; }
.llm-bar.is-chosen .llm-bar__fill { background: var(--accent); }
.llm-bar.is-chosen .llm-bar__token { color: var(--accent); }
.llm-bar.is-chosen { animation: llm-pick 0.4s var(--ease-out); }
@keyframes llm-pick { from { transform: translateX(4px); } }

.llm-window { position: relative; display: flex; gap: 2px; height: 54px; align-items: stretch; }
.llm-window__frame {
  position: absolute;
  top: -6px;
  bottom: -6px;
  right: 0;
  width: var(--window);
  border: 2px solid var(--accent);
  border-radius: var(--radius-lg);
  pointer-events: none;
  transition: width 0.7s var(--ease);
}
.llm-msg {
  flex: none;
  width: var(--w);
  min-width: 26px;
  display: grid;
  align-content: center;
  justify-items: center;
  border-radius: 4px;
  background: var(--bg-3);
  font-family: var(--font-mono);
  overflow: hidden;
  transition: width 0.6s var(--ease), opacity 0.5s var(--ease), transform 0.5s var(--ease);
}
.llm-msg small { font-size: 8.5px; color: var(--fg-faint); }
.llm-msg b { font-size: 10.5px; font-weight: 500; }
.llm-msg--system { background: var(--accent-soft); box-shadow: inset 0 0 0 1px var(--accent-line); }
.llm-msg--system.is-pinned { box-shadow: inset 0 0 0 2px var(--accent); }
.llm-msg--reply { background: repeating-linear-gradient(135deg, var(--accent-soft) 0 5px, transparent 5px 10px); border: 1px dashed var(--accent-line); }
.llm-msg.is-out { opacity: 0.3; transform: translateY(6px); text-decoration: line-through; }

/* ==========================================================================
   Course: RAG & vector search
   ========================================================================== */

.rag {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  grid-template-rows: auto minmax(0, 1fr);
  gap: 12px;
  padding: 14px;
  height: clamp(400px, 56vh, 600px);
  overflow: auto;
  scrollbar-width: thin;
}
.lab-demo .rag { height: 100%; }
.rag-panel { display: grid; gap: 8px; align-content: start; padding: 10px 12px; border: 1px solid var(--line-strong); border-radius: var(--radius-lg); background: var(--bg-2); min-width: 0; }
.rag-panel--docs { grid-column: 1 / -1; }
.rag-panel__head { display: flex; justify-content: space-between; gap: 10px; align-items: center; flex-wrap: wrap; }
.rag-meta { font-family: var(--font-mono); font-size: 10.5px; color: var(--fg-faint); }

.rag-docs { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 6px 14px; }
.rag-doc { display: grid; grid-template-columns: 16px minmax(0, 1fr); gap: 8px; align-items: center; }
.rag-doc__mark { font-family: var(--font-mono); font-size: 10px; color: var(--fg-dim); text-align: center; }
.rag-doc__bar { position: relative; height: 10px; border-radius: 3px; background: var(--bg-3); overflow: hidden; }
.rag-doc__bar i {
  position: absolute;
  top: 0;
  bottom: 0;
  left: var(--l);
  width: var(--w);
  background: var(--line-strong);
  border-right: 1px solid var(--bg-2);
  mix-blend-mode: normal;
}
.rag-doc__bar i.is-chunk { background: color-mix(in srgb, var(--accent-soft) 70%, transparent); border: 1px solid var(--accent-line); border-radius: 2px; }
.rag-doc__bar i.is-cut { animation: rag-cut 0.5s var(--ease-out) both; animation-delay: calc(var(--i) * 70ms); }
@keyframes rag-cut { from { transform: scaleX(0.2); transform-origin: left; opacity: 0; } }

.rag-panel--map { position: relative; }
.rag-panel--map.is-off .rag-map-wrap { opacity: 0.35; }
.rag-map-wrap { position: relative; aspect-ratio: 1 / 1; max-height: 340px; width: 100%; margin: 0 auto; border-radius: var(--radius); background:
    radial-gradient(circle at 1px 1px, var(--line) 1px, transparent 0) 0 0 / 16px 16px, var(--bg); transition: opacity 0.4s var(--ease); }
.rag-map { width: 100%; height: 100%; display: block; overflow: visible; }
.rag-point { transition: transform 0.7s cubic-bezier(0.34, 1.2, 0.5, 1), opacity 0.4s var(--ease); }
.rag-point circle { fill: var(--bg-2); stroke: var(--fg-faint); stroke-width: 0.3; transition: fill 0.4s var(--ease), stroke 0.4s var(--ease); }
.rag-point text { font-family: var(--font-mono); font-size: 1.9px; fill: var(--fg-dim); pointer-events: none; }
.rag-point.is-hit circle { fill: var(--accent); stroke: var(--accent); }
.rag-point.is-hit text { fill: var(--accent-ink); }
.rag-point.is-new { animation: rag-appear 0.6s cubic-bezier(0.34, 1.4, 0.5, 1) both; animation-delay: var(--d); }
@keyframes rag-appear { from { opacity: 0; } }
.rag-link { stroke: var(--accent); stroke-width: 0.35; stroke-dasharray: 1; stroke-dashoffset: 0; opacity: 0.8; animation: rr-draw 0.6s var(--ease-out) both; animation-delay: calc(0.35s + var(--i) * 0.12s); }
.rag-query circle { fill: var(--fg); }
.rag-query .rag-query__halo { fill: none; stroke: var(--fg); stroke-width: 0.3; opacity: 0.5; }
.rag-query.is-new { animation: rag-drop 0.7s cubic-bezier(0.34, 1.5, 0.5, 1) both; }
@keyframes rag-drop { from { opacity: 0; } 40% { opacity: 1; } }
.rag-legend { display: flex; flex-wrap: wrap; gap: 4px 12px; font-size: 10.5px; color: var(--fg-faint); }
.rag-legend b { font-family: var(--font-mono); color: var(--fg-dim); margin-right: 4px; }

.rag-results { display: grid; gap: 6px; align-content: start; }
.rag-result {
  display: grid;
  grid-template-columns: 24px 16px minmax(0, 1fr) 44px;
  gap: 8px;
  align-items: start;
  padding: 7px 9px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg);
  font-size: 12px;
  line-height: 1.45;
  color: var(--fg-faint);
  transition: border-color 0.4s var(--ease), color 0.4s var(--ease), opacity 0.4s var(--ease);
}
.rag-result.is-in { color: var(--fg-dim); border-color: var(--accent-line); }
.rag-result.is-cited { border-color: var(--accent); background: var(--accent-soft); color: var(--fg); }
.rag-result.is-refused { opacity: 0.45; text-decoration: line-through; }
.rag-result__rank { font-family: var(--font-mono); font-size: 11px; color: var(--accent); }
.rag-result__doc { font-family: var(--font-mono); font-size: 10.5px; color: var(--fg-dim); }
.rag-result__text { display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.rag-result__score { font-family: var(--font-mono); font-size: 10.5px; text-align: right; }
.rag-refusal { padding: 8px 10px; border: 1px dashed var(--fg-faint); border-radius: var(--radius); font-size: 12.5px; color: var(--fg); }
@media (max-width: 760px) {
  .rag { grid-template-columns: 1fr; height: auto; max-height: none; }
  .rag-map-wrap { max-height: 280px; }
}
@media (prefers-reduced-motion: reduce) {
  .rag-point { transition: none; }
}