/* ==========================================================================
   jb-playbook — components.css
   Single stylesheet for the Phase 1 design system.

   ARCHITECTURE NOTE — no cascade layers, on purpose.
   This CSS must win inside Thinkific, whose theme CSS is unlayered. Unlayered
   author styles beat layered ones at any specificity, so putting our rules in
   @layer would let the host theme silently override them. Instead: every rule
   is scoped under a `jb-` class, selectors stay flat, and we rely on class
   specificity. (Decision recorded in DESIGN_NOTES.md, 2026-07-05.)

   Contents:
     1.  Scoped reset + base
     2.  Page chrome (glow, theme toggle, footer)
     3.  Lesson layout grid + header
     4.  Prose (editorial typography, vertical-bar accents)
     5.  Cards: callouts, takeaways, prereq, link panels
     6.  Dividers
     7.  Code Display (frame, lines, pointers, clickables, popup, footnotes)
     8.  Syntax token colors
     9.  Code Stepper
     10. Shared states: skeleton, error, unsupported fallback
     11. Debug overlay
     12. Utilities, focus, selection, reduced motion
   Regenerated 2026-07-05.
   ========================================================================== */


/* ==========================================================================
   1. Scoped reset + base
   ========================================================================== */

.jb-page, .jb-lesson, .jb-component,
.jb-page *, .jb-lesson *, .jb-component * {
  box-sizing: border-box;
}

.jb-page {
  margin: 0;
  min-height: 100vh;
  background: var(--jb-page-glow), var(--jb-surface-page);
  background-attachment: scroll;
  color: var(--jb-text-primary);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-base);
  line-height: var(--jb-leading-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* A lesson embedded in a host page (Thinkific) carries its own base. */
.jb-lesson {
  color: var(--jb-text-primary);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-base);
  line-height: var(--jb-leading-body);
  -webkit-font-smoothing: antialiased;
}

.jb-page img, .jb-lesson img { max-width: 100%; }


/* ==========================================================================
   2. Page chrome
   ========================================================================== */

.jb-theme-toggle {
  position: fixed;
  top: var(--jb-space-4);
  right: var(--jb-space-4);
  z-index: var(--jb-z-toggle);
  display: inline-flex;
  gap: 2px;
  padding: 3px;
  border: 1px solid var(--jb-border-default);
  border-radius: var(--jb-radius-pill);
  background: var(--jb-surface-raised);
  box-shadow: var(--jb-elevation-sm);
}

.jb-theme-toggle__btn {
  appearance: none;
  border: 0;
  margin: 0;
  width: 30px;
  height: 30px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--jb-radius-pill);
  background: transparent;
  color: var(--jb-text-muted);
  cursor: pointer;
  transition: background var(--jb-dur-fast) var(--jb-ease-out),
              color var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-theme-toggle__btn:hover { color: var(--jb-text-primary); }
.jb-theme-toggle__btn.is-active {
  background: var(--jb-color-accent-soft);
  color: var(--jb-color-accent);
}
.jb-theme-toggle__btn svg { width: 15px; height: 15px; }

.jb-lesson__footer {
  margin-top: var(--jb-space-16);
  padding: var(--jb-space-8) 0 var(--jb-space-12);
  border-top: 1px solid var(--jb-border-subtle);
  font-size: var(--jb-text-sm);
  color: var(--jb-text-muted);
  text-align: center;
}


/* ==========================================================================
   3. Lesson layout grid + header
   Magazine layout: prose at ~68ch reading measure, code components may break
   out to the full lesson width (max 1080px) via .jb-component--wide.
   ========================================================================== */

.jb-lesson__inner {
  display: grid;
  grid-template-columns:
    [full-start] minmax(var(--jb-space-5), 1fr)
    [content-start] min(100% - 2 * var(--jb-space-5), 68ch) [content-end]
    minmax(var(--jb-space-5), 1fr) [full-end];
  row-gap: 0;
  padding-top: var(--jb-space-16);
}

.jb-lesson__inner > * {
  grid-column: content;
  min-width: 0;
}

/* Code components are full-bleed by default: prose needs a reading measure,
   code doesn't — long lines, stepper panels, and annotation gutters use every
   pixel available. Only a small side margin (the grid's rail minimum) remains.
   `.jb-component--wide` opts any other element into the full column;
   `.jb-component--narrow` keeps a code component at reading measure. */
.jb-lesson__inner > [data-component="code-display"],
.jb-lesson__inner > [data-component="code-stepper"],
.jb-lesson__inner > .jb-component--wide {
  grid-column: full;
  width: 100%;
  padding-left: var(--jb-space-5);
  padding-right: var(--jb-space-5);
}
.jb-lesson__inner > .jb-component--narrow {
  grid-column: content;
  width: auto;
  padding-left: 0;
  padding-right: 0;
}

.jb-lesson__header { margin-bottom: var(--jb-space-10); }

.jb-lesson__title {
  margin: var(--jb-space-4) 0 var(--jb-space-4);
  font-family: var(--jb-font-serif);
  font-size: var(--jb-text-3xl);
  font-weight: 560;
  font-variation-settings: "opsz" 72, "SOFT" 40;
  line-height: var(--jb-leading-tight);
  letter-spacing: var(--jb-tracking-tight);
  color: var(--jb-text-primary);
}

.jb-dek {
  margin: 0 0 var(--jb-space-4);
  font-size: var(--jb-text-md);
  line-height: 1.55;
  color: var(--jb-text-secondary);
}

.jb-lesson__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--jb-space-2) var(--jb-space-4);
  font-size: var(--jb-text-xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--jb-text-muted);
  text-transform: uppercase;
}
.jb-lesson__meta span + span::before {
  content: "·";
  margin-right: var(--jb-space-4);
  color: var(--jb-text-faint);
}


/* ==========================================================================
   4. Prose — editorial typography
   Fraunces serif for H1–H3; Nunito for body; H4 is the only sans heading
   (uppercase minor-section label). Vertical accent bars anchor H2 + eyebrows.
   ========================================================================== */

.jb-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  margin: 0;
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-xs);
  font-weight: 800;
  letter-spacing: var(--jb-tracking-wide);
  text-transform: uppercase;
  color: var(--jb-text-secondary);
}
.jb-eyebrow::before {
  content: "";
  width: 3px;
  height: 0.95em;
  border-radius: 2px;
  background: var(--jb-color-accent);
  flex: none;
}

.jb-prose p {
  margin: 0 0 var(--jb-space-5);
  font-size: var(--jb-text-base);
  line-height: var(--jb-leading-body);
  color: var(--jb-text-primary);
}

.jb-prose h2 {
  position: relative;
  margin: var(--jb-space-12) 0 var(--jb-space-5);
  padding-left: 0.85em;
  font-family: var(--jb-font-serif);
  font-size: var(--jb-text-xl);
  font-weight: 580;
  font-variation-settings: "opsz" 40, "SOFT" 30;
  line-height: var(--jb-leading-snug);
  letter-spacing: var(--jb-tracking-tight);
  color: var(--jb-text-primary);
}
.jb-prose h2::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.16em;
  bottom: 0.12em;
  width: 3px;
  border-radius: 2px;
  background: var(--jb-color-accent);
}

.jb-prose h3 {
  margin: var(--jb-space-10) 0 var(--jb-space-4);
  font-family: var(--jb-font-serif);
  font-size: var(--jb-text-lg);
  font-weight: 560;
  font-variation-settings: "opsz" 28, "SOFT" 30;
  line-height: var(--jb-leading-snug);
  color: var(--jb-text-primary);
}

/* H4: the only sans heading — uppercase minor-section label. */
.jb-prose h4 {
  margin: var(--jb-space-8) 0 var(--jb-space-3);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-xs);
  font-weight: 800;
  letter-spacing: var(--jb-tracking-wide);
  text-transform: uppercase;
  color: var(--jb-text-secondary);
}

.jb-prose ul, .jb-prose ol {
  margin: 0 0 var(--jb-space-5);
  padding-left: 1.4em;
}
.jb-prose li { margin-bottom: var(--jb-space-2); }
.jb-prose li::marker { color: var(--jb-color-accent); }

.jb-prose a {
  color: var(--jb-link);
  text-decoration: underline;
  text-decoration-color: var(--jb-link-underline);
  text-decoration-thickness: 1.5px;
  text-underline-offset: 3px;
  transition: text-decoration-color var(--jb-dur-fast) var(--jb-ease-out),
              color var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-prose a:hover {
  color: var(--jb-link-hover);
  text-decoration-color: currentColor;
}

.jb-prose code {
  font-family: var(--jb-font-mono);
  font-size: 0.85em;
  padding: 0.1em 0.35em;
  border-radius: var(--jb-radius-xs);
  background: var(--jb-surface-sunken);
  color: var(--jb-text-primary);
}

.jb-prose strong { font-weight: 800; }
.jb-prose em { font-style: italic; }

/* <hr>: thematic break — thin centered 25% rule. */
.jb-prose hr {
  width: 25%;
  margin: var(--jb-space-12) auto;
  border: 0;
  border-top: 1px solid var(--jb-border-strong);
}

/* Compact prose (annotation bubbles, popups, stepper text panel) */
.jb-prose--sm p, .jb-prose--sm ul, .jb-prose--sm ol { font-size: var(--jb-text-sm); }
.jb-prose--sm p { margin-bottom: var(--jb-space-3); }
.jb-prose--sm p:last-child, .jb-prose--sm ul:last-child, .jb-prose--sm ol:last-child { margin-bottom: 0; }


/* ==========================================================================
   5. Cards
   ========================================================================== */

/* ---- Callouts — five variants: note, tip, info, warn, danger ------------- */
.jb-callout {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--jb-space-3);
  margin: var(--jb-space-6) 0;
  padding: var(--jb-space-4) var(--jb-space-5);
  border: 1px solid var(--jb-callout-note-border);
  border-left: 3px solid var(--jb-callout-note-accent);
  border-radius: var(--jb-radius-md);
  background: var(--jb-callout-note-bg);
}
.jb-callout__icon {
  width: 20px;
  height: 20px;
  margin-top: 0.15em;
  color: var(--jb-callout-note-accent);
  flex: none;
}
.jb-callout__icon svg { width: 100%; height: 100%; display: block; }
.jb-callout__title {
  margin: 0 0 var(--jb-space-1);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-xs);
  font-weight: 800;
  letter-spacing: var(--jb-tracking-wide);
  text-transform: uppercase;
  color: var(--jb-callout-note-accent);
}
.jb-callout__body p { font-size: var(--jb-text-sm); margin-bottom: var(--jb-space-2); }
.jb-callout__body p:last-child { margin-bottom: 0; }

.jb-callout--tip {
  border-color: var(--jb-callout-tip-border);
  border-left-color: var(--jb-callout-tip-accent);
  background: var(--jb-callout-tip-bg);
}
.jb-callout--tip .jb-callout__icon, .jb-callout--tip .jb-callout__title { color: var(--jb-callout-tip-accent); }

.jb-callout--info {
  border-color: var(--jb-callout-info-border);
  border-left-color: var(--jb-callout-info-accent);
  background: var(--jb-callout-info-bg);
}
.jb-callout--info .jb-callout__icon, .jb-callout--info .jb-callout__title { color: var(--jb-callout-info-accent); }

.jb-callout--warn {
  border-color: var(--jb-callout-warn-border);
  border-left-color: var(--jb-callout-warn-accent);
  background: var(--jb-callout-warn-bg);
}
.jb-callout--warn .jb-callout__icon, .jb-callout--warn .jb-callout__title { color: var(--jb-callout-warn-accent); }

.jb-callout--danger {
  border-color: var(--jb-callout-danger-border);
  border-left-color: var(--jb-callout-danger-accent);
  background: var(--jb-callout-danger-bg);
}
.jb-callout--danger .jb-callout__icon, .jb-callout--danger .jb-callout__title { color: var(--jb-callout-danger-accent); }

/* ---- Key takeaways — raised card, brand-red left border ------------------ */
.jb-takeaways {
  margin: var(--jb-space-10) 0;
  padding: var(--jb-space-6) var(--jb-space-6);
  border: 1px solid var(--jb-border-subtle);
  border-left: 3px solid var(--jb-color-accent);
  border-radius: var(--jb-radius-md);
  background: var(--jb-surface-raised);
  box-shadow: var(--jb-elevation-sm);
}
.jb-takeaways__label {
  margin: 0 0 var(--jb-space-4);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-xs);
  font-weight: 800;
  letter-spacing: var(--jb-tracking-wide);
  text-transform: uppercase;
  color: var(--jb-color-accent);
}
/* Card already carries the red border — suppress heading bars inside. */
.jb-takeaways h2::before { display: none; }
.jb-takeaways h2 { padding-left: 0; }
.jb-takeaways ul {
  margin: 0;
  padding: 0;
  list-style: none;
}
.jb-takeaways li {
  position: relative;
  margin-bottom: var(--jb-space-3);
  padding-left: var(--jb-space-5);
  font-size: var(--jb-text-sm);
  line-height: 1.6;
  color: var(--jb-text-primary);
}
.jb-takeaways li:last-child { margin-bottom: 0; }
.jb-takeaways li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.55em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--jb-color-accent);
}

/* ---- Prerequisites ------------------------------------------------------- */
.jb-prereq {
  margin: var(--jb-space-6) 0;
  padding: var(--jb-space-4) var(--jb-space-5);
  border: 1px solid var(--jb-border-subtle);
  border-radius: var(--jb-radius-md);
  background: var(--jb-surface-sunken);
}
.jb-prereq__label {
  margin: 0 0 var(--jb-space-2);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-xs);
  font-weight: 800;
  letter-spacing: var(--jb-tracking-wide);
  text-transform: uppercase;
  color: var(--jb-text-muted);
}
.jb-prereq__items {
  margin: 0;
  font-size: var(--jb-text-sm);
  color: var(--jb-text-secondary);
}

/* ---- Link panels ---------------------------------------------------------- */
.jb-linkpanel {
  display: block;
  margin: var(--jb-space-4) 0;
  padding: var(--jb-space-4) var(--jb-space-5);
  border: 1px solid var(--jb-border-default);
  border-radius: var(--jb-radius-md);
  background: var(--jb-surface-raised);
  text-decoration: none;
  transition: border-color var(--jb-dur-fast) var(--jb-ease-out),
              transform var(--jb-dur-fast) var(--jb-ease-out),
              box-shadow var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-linkpanel:hover {
  border-color: var(--jb-color-accent);
  transform: translateY(-1px);
  box-shadow: var(--jb-elevation-sm);
}
.jb-linkpanel__title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--jb-space-3);
  font-family: var(--jb-font-serif);
  font-size: var(--jb-text-md);
  font-weight: 580;
  color: var(--jb-text-primary);
}
.jb-linkpanel__arrow {
  color: var(--jb-text-faint);
  transition: color var(--jb-dur-fast) var(--jb-ease-out),
              transform var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-linkpanel:hover .jb-linkpanel__arrow {
  color: var(--jb-color-accent);
  transform: translateX(3px);
}
.jb-linkpanel__desc {
  margin-top: var(--jb-space-1);
  font-size: var(--jb-text-sm);
  color: var(--jb-text-muted);
}


/* ==========================================================================
   6. Dividers — centered tri-dot (the Medium move)
   ========================================================================== */

.jb-divider {
  margin: var(--jb-space-12) 0;
  border: 0;
  text-align: center;
}
.jb-divider::before {
  content: "· · ·";
  display: block;
  font-family: var(--jb-font-serif);
  font-size: var(--jb-text-lg);
  letter-spacing: 0.6em;
  padding-left: 0.6em; /* recenters against trailing letter-spacing */
  color: var(--jb-text-faint);
}


/* ==========================================================================
   7. Code Display
   ========================================================================== */

.jb-code-display { margin: var(--jb-space-6) 0; }

.jb-code-display__stage { position: relative; }

/* Inline-pointer mode: right gutter reserved for bubbles */
.jb-code-display--inline .jb-code-display__stage {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  column-gap: var(--jb-space-4);
}

.jb-code-display__frame {
  border: 1px solid var(--jb-code-display-border);
  border-radius: var(--jb-radius-lg);
  background: var(--jb-code-display-bg);
  min-width: 0;
}

.jb-code-display__scroll {
  overflow-x: auto;
  padding: var(--jb-space-4) 0;
  border-radius: var(--jb-radius-lg);
}

.jb-code-display__code {
  font-family: var(--jb-font-mono);
  font-size: var(--jb-text-sm);
  line-height: var(--jb-leading-code);
  color: var(--jb-code-text);
  tab-size: 4;
}

.jb-cd-line {
  display: flex;
  min-width: 100%;
  width: max-content;
  padding: 0 var(--jb-space-5) 0 0;
}
.jb-cd-line.is-pointer-line { background: var(--jb-code-line-highlight); }

.jb-cd-ln {
  flex: none;
  min-width: 3.2ch;
  padding: 0 var(--jb-space-3) 0 var(--jb-space-4);
  text-align: right;
  color: var(--jb-code-ln);
  border-right: 1px solid var(--jb-code-gutter-border);
  margin-right: var(--jb-space-4);
  user-select: none;
  -webkit-user-select: none;
}
.jb-code-display--no-ln .jb-cd-ln { display: none; }
.jb-code-display--no-ln .jb-cd-line { padding-left: var(--jb-space-5); }

.jb-cd-lc { white-space: pre; }
.jb-cd-lc:empty::before { content: "\200B"; }
.jb-code-display--wrap .jb-cd-lc { white-space: pre-wrap; overflow-wrap: anywhere; }
.jb-code-display--wrap .jb-cd-line { width: auto; }

/* ---- Pointer targets ------------------------------------------------------
   .is-hot states are the two-way hover pairing: hovering annotated code
   highlights its bubble/footnote and vice versa. */
.jb-pointer-target {
  border-bottom: 2px solid color-mix(in oklab, var(--jb-color-accent) 35%, transparent);
  background: color-mix(in oklab, var(--jb-color-accent) 5%, transparent);
  border-radius: 2px 2px 0 0;
  transition: background var(--jb-dur-fast) var(--jb-ease-out),
              border-color var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-pointer-target.is-hot {
  background: color-mix(in oklab, var(--jb-color-accent) 16%, transparent);
  border-bottom-color: var(--jb-color-accent);
}
.jb-cd-line.is-pointer-line.is-hot {
  background: color-mix(in oklab, var(--jb-color-accent) 12%, transparent);
}

/* ---- Footnote markers ------------------------------------------------------
   Circled numbers, deliberately quiet (muted text, faint accent ring) so they
   can't be misread as code. They light up on hover — and when their footnote
   is hovered (two-way pairing). Mirrors the footnote list's circle markers. */
.jb-fn-marker {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 0.95rem;
  height: 0.95rem;
  margin-left: 4px;
  vertical-align: super;
  font-family: var(--jb-font-sans);
  font-size: 0.58rem;
  font-weight: 800;
  line-height: 1;
  border-radius: 50%;
  border: 1px solid color-mix(in oklab, var(--jb-color-accent) 30%, transparent);
  color: var(--jb-text-muted);
  cursor: default;
  user-select: none;
  -webkit-user-select: none;
  transition: background var(--jb-dur-fast) var(--jb-ease-out),
              color var(--jb-dur-fast) var(--jb-ease-out),
              border-color var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-fn-marker.is-hot {
  background: var(--jb-color-accent);
  border-color: var(--jb-color-accent);
  color: var(--jb-text-on-accent);
}
/* Markers only make sense in footnote mode */
.jb-code-display--inline .jb-fn-marker { display: none; }

/* ---- Footnote list ---------------------------------------------------------- */
.jb-code-display__footnotes {
  border-top: 1px solid var(--jb-code-display-border);
  padding: var(--jb-space-4) var(--jb-space-5);
}
.jb-code-display--inline .jb-code-display__footnotes { display: none; }
.jb-code-display__footnotes ol {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: jb-fn;
}
.jb-footnote {
  counter-increment: jb-fn;
  position: relative;
  margin-bottom: var(--jb-space-2);
  padding: var(--jb-space-1) var(--jb-space-2) var(--jb-space-1) var(--jb-space-8);
  border-radius: var(--jb-radius-sm);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-sm);
  line-height: 1.55;
  color: var(--jb-text-secondary);
  transition: background var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-footnote:last-child { margin-bottom: 0; }
.jb-footnote::before {
  content: counter(jb-fn);
  position: absolute;
  left: var(--jb-space-2);
  top: 0.45em;
  width: 1.15rem;
  height: 1.15rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-size: 0.63rem;
  font-weight: 800;
  color: var(--jb-color-accent);
  border: 1px solid color-mix(in oklab, var(--jb-color-accent) 45%, transparent);
}
.jb-footnote:hover, .jb-footnote:focus-visible, .jb-footnote.is-hot {
  background: color-mix(in oklab, var(--jb-color-accent) 6%, transparent);
}
.jb-footnote .jb-prose--sm p { display: inline; }

/* ---- Inline pointer bubbles -------------------------------------------------- */
.jb-code-display__gutter { position: relative; min-height: 100%; }

.jb-pointer-bubble {
  position: absolute;
  left: 8px;
  right: 0;
  z-index: var(--jb-z-bubble);
  padding: var(--jb-space-3) var(--jb-space-4);
  border: 1px solid var(--jb-code-display-pointer-border);
  border-radius: var(--jb-radius-md);
  background: var(--jb-code-display-pointer-bg);
  box-shadow: var(--jb-elevation-sm);
  font-family: var(--jb-font-sans);
  font-size: 0.74rem;
  line-height: 1.5;
  color: var(--jb-text-secondary);
  transition: border-color var(--jb-dur-fast) var(--jb-ease-out),
              box-shadow var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-pointer-bubble.is-hot {
  border-color: var(--jb-color-accent);
  box-shadow: var(--jb-elevation-md);
  color: var(--jb-text-primary);
}

.jb-pointer-svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: var(--jb-z-pointer-svg);
  pointer-events: none;
  overflow: visible;
}
.jb-pointer-path {
  fill: none;
  stroke: var(--jb-code-display-pointer-arrow);
  stroke-width: 1.5;
  stroke-linecap: round;
}
.jb-pointer-dot { fill: var(--jb-code-display-pointer-arrow); }
.jb-pointer-path.is-hot { stroke: var(--jb-color-accent); stroke-width: 2; }
.jb-pointer-dot.is-hot { fill: var(--jb-color-accent); }

/* ---- Clickable regions --------------------------------------------------------- */
.jb-clickable {
  appearance: none;
  display: inline;
  margin: 0;
  padding: 0.1em 0;
  border: 0;
  font: inherit;
  color: inherit;
  white-space: inherit;
  background: var(--jb-code-display-clickable-bg);
  border-bottom: 1.5px dotted var(--jb-code-display-clickable-underline);
  border-radius: 3px 3px 0 0;
  cursor: pointer;
  transition: background var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-clickable:hover, .jb-clickable.is-open {
  background: var(--jb-code-display-clickable-hover-bg);
  border-bottom-color: var(--jb-color-accent);
}
/* Touch devices can't hover: resting state = desktop hover state */
@media (hover: none) {
  .jb-clickable {
    background: var(--jb-code-display-clickable-hover-bg);
    border-bottom-color: var(--jb-color-accent);
  }
}

/* ---- Popup (singleton) ------------------------------------------------------------ */
.jb-popup {
  position: absolute;
  z-index: var(--jb-z-popup);
  width: min(340px, 86vw);
  padding: var(--jb-space-4) var(--jb-space-5) var(--jb-space-4) var(--jb-space-4);
  border: 1px solid var(--jb-code-display-popup-border);
  border-radius: var(--jb-radius-md);
  background: var(--jb-code-display-popup-bg);
  box-shadow: var(--jb-elevation-lg);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-sm);
  line-height: 1.55;
  color: var(--jb-text-primary);
  animation: jb-popup-in var(--jb-dur-base) var(--jb-ease-out);
}
@keyframes jb-popup-in {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}
.jb-popup__arrow {
  position: absolute;
  width: 10px;
  height: 10px;
  background: var(--jb-code-display-popup-bg);
  border-left: 1px solid var(--jb-code-display-popup-border);
  border-top: 1px solid var(--jb-code-display-popup-border);
}
.jb-popup--below .jb-popup__arrow { top: -6px; transform: rotate(45deg); }
.jb-popup--above .jb-popup__arrow { bottom: -6px; transform: rotate(225deg); }
.jb-popup__close {
  appearance: none;
  position: absolute;
  top: 6px;
  right: 6px;
  width: 26px;
  height: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 0;
  border-radius: var(--jb-radius-sm);
  background: transparent;
  color: var(--jb-text-muted);
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
}
.jb-popup__close:hover { background: var(--jb-surface-sunken); color: var(--jb-text-primary); }
.jb-popup__body { padding-right: var(--jb-space-4); }


/* ==========================================================================
   8. Syntax token colors (Prism output, styled by our tokens — no Prism theme)
   ========================================================================== */

.jb-code-display .token.keyword,
.jb-code-display .token.boolean     { color: var(--jb-syntax-keyword); }
.jb-code-display .token.string,
.jb-code-display .token.char        { color: var(--jb-syntax-string); }
.jb-code-display .token.number      { color: var(--jb-syntax-number); }
.jb-code-display .token.comment     { color: var(--jb-syntax-comment); font-style: italic; }
.jb-code-display .token.class-name,
.jb-code-display .token.tag,
.jb-code-display .token.builtin     { color: var(--jb-syntax-type); }
.jb-code-display .token.function,
.jb-code-display .token.attr-name,
.jb-code-display .token.property    { color: var(--jb-syntax-function); }
.jb-code-display .token.operator    { color: var(--jb-syntax-operator); background: none; }
.jb-code-display .token.punctuation { color: var(--jb-syntax-punctuation); }
.jb-code-display .token.annotation,
.jb-code-display .token.atrule      { color: var(--jb-syntax-annotation); }
.jb-code-display .token.generics    { color: var(--jb-syntax-punctuation); }


/* ==========================================================================
   9. Code Stepper
   ========================================================================== */

.jb-stepper {
  margin: var(--jb-space-6) 0;
  border: 1px solid var(--jb-stepper-border);
  border-radius: var(--jb-radius-lg);
  background: var(--jb-stepper-bg);
  outline: none;
}

.jb-stepper__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--jb-space-4);
  padding: var(--jb-space-3) var(--jb-space-4);
  border-bottom: 1px solid var(--jb-stepper-border);
}

/* ---- Indicator ---- */
.jb-stepper__indicator {
  display: flex;
  align-items: center;
  gap: var(--jb-space-2);
  min-width: 0;
  flex-wrap: wrap;
  font-family: var(--jb-font-sans);
}
.jb-stepper__indicator-text {
  font-size: var(--jb-text-sm);
  font-weight: 700;
  color: var(--jb-text-secondary);
}
.jb-stepper__indicator-text strong { color: var(--jb-stepper-indicator-active); }

.jb-stepper__dot {
  appearance: none;
  padding: 0;
  margin: 0;
  border: 0;
  width: 22px;
  height: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  cursor: pointer;
}
.jb-stepper__dot::after {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--jb-stepper-indicator-inactive);
  transition: transform var(--jb-dur-fast) var(--jb-ease-out),
              background var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-stepper__dot:hover::after { transform: scale(1.3); }
.jb-stepper__dot.is-current::after {
  background: var(--jb-stepper-indicator-active);
  transform: scale(1.35);
}
.jb-stepper__dot[disabled] { cursor: default; }

.jb-stepper__num {
  appearance: none;
  margin: 0;
  padding: 0;
  width: 1.7rem;
  height: 1.7rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--jb-stepper-btn-border);
  border-radius: 50%;
  background: transparent;
  font-family: var(--jb-font-sans);
  font-size: 0.74rem;
  font-weight: 800;
  color: var(--jb-text-muted);
  cursor: pointer;
  transition: border-color var(--jb-dur-fast) var(--jb-ease-out),
              color var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-stepper__num:hover { border-color: var(--jb-stepper-indicator-active); color: var(--jb-stepper-indicator-active); }
.jb-stepper__num.is-current {
  background: var(--jb-stepper-indicator-active);
  border-color: var(--jb-stepper-indicator-active);
  color: var(--jb-text-on-accent);
}
.jb-stepper__num[disabled] { cursor: default; }

.jb-stepper__progress {
  flex: 1;
  min-width: 80px;
  max-width: 260px;
  height: 4px;
  border-radius: var(--jb-radius-pill);
  background: var(--jb-stepper-indicator-inactive);
  overflow: hidden;
}
.jb-stepper__progress-fill {
  height: 100%;
  border-radius: var(--jb-radius-pill);
  background: var(--jb-stepper-indicator-active);
  transition: width var(--jb-dur-slow) var(--jb-ease-out);
}
.jb-stepper__progress-label {
  font-size: var(--jb-text-xs);
  font-weight: 800;
  color: var(--jb-text-muted);
}

/* ---- Nav buttons ---- */
.jb-stepper__nav { display: flex; gap: var(--jb-space-2); flex: none; }

.jb-stepper__btn {
  appearance: none;
  display: inline-flex;
  align-items: center;
  gap: var(--jb-space-2);
  min-height: 44px;
  padding: var(--jb-space-2) var(--jb-space-4);
  border: 1px solid var(--jb-stepper-btn-border);
  border-radius: var(--jb-radius-sm);
  background: var(--jb-stepper-btn-bg);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-sm);
  font-weight: 700;
  color: var(--jb-stepper-btn-text);
  cursor: pointer;
  transition: background var(--jb-dur-fast) var(--jb-ease-out),
              border-color var(--jb-dur-fast) var(--jb-ease-out);
}
.jb-stepper__btn:hover:not([disabled]) {
  background: var(--jb-stepper-btn-hover-bg);
  border-color: var(--jb-border-strong);
}
.jb-stepper__btn[disabled] { opacity: 0.4; cursor: default; }
.jb-stepper__btn svg { width: 14px; height: 14px; }

/* ---- Panels ---- */
.jb-stepper__panels {
  display: grid;
  grid-template-columns: 3fr 2fr;
  gap: var(--jb-space-5);
  padding: var(--jb-space-5);
  transition: opacity 160ms var(--jb-ease-out);
}
.jb-stepper__panels.is-fading { opacity: 0; }
.jb-stepper--code-right .jb-stepper__code { order: 2; }
.jb-stepper--code-right .jb-stepper__text { order: 1; }

.jb-stepper__code { min-width: 0; }
.jb-stepper__code .jb-code-display { margin: 0; }

.jb-stepper__text { min-width: 0; }
.jb-stepper__steplabel {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  margin: 0 0 var(--jb-space-2);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-xs);
  font-weight: 800;
  letter-spacing: var(--jb-tracking-wide);
  text-transform: uppercase;
  color: var(--jb-color-accent);
}
.jb-stepper__steplabel::before {
  content: "";
  width: 3px;
  height: 0.95em;
  border-radius: 2px;
  background: var(--jb-color-accent);
}
.jb-stepper__title {
  margin: 0 0 var(--jb-space-3);
  font-family: var(--jb-font-serif);
  font-size: var(--jb-text-lg);
  font-weight: 560;
  font-variation-settings: "opsz" 24, "SOFT" 30;
  line-height: var(--jb-leading-snug);
  color: var(--jb-text-primary);
}

@media (min-width: 1024px) {
  .jb-stepper__text {
    max-height: 480px;
    overflow-y: auto;
    padding-right: var(--jb-space-2);
  }
}
@media (max-width: 1023px) {
  .jb-stepper__panels { grid-template-columns: 1fr; }
  .jb-stepper--code-right .jb-stepper__code { order: 0; }
  .jb-stepper--code-right .jb-stepper__text { order: 0; }
}
@media (max-width: 640px) {
  .jb-stepper__bar { flex-wrap: wrap; }
  .jb-stepper__btn span { display: none; }        /* icon-only on tiny screens */
  .jb-stepper__btn { padding: var(--jb-space-2) var(--jb-space-3); }
}


/* ==========================================================================
   10. Shared states
   ========================================================================== */

/* ---- Loading skeleton ---- */
.jb-skeleton {
  border: 1px solid var(--jb-border-subtle);
  border-radius: var(--jb-radius-lg);
  padding: var(--jb-space-5);
  background: var(--jb-surface-raised);
}
.jb-skeleton__line {
  height: 0.85rem;
  margin-bottom: var(--jb-space-3);
  border-radius: var(--jb-radius-xs);
  background: linear-gradient(90deg,
      var(--jb-skeleton-base) 25%,
      var(--jb-skeleton-sheen) 40%,
      var(--jb-skeleton-base) 55%);
  background-size: 300% 100%;
  animation: jb-shimmer 1.4s linear infinite;
}
.jb-skeleton__line:last-child { margin-bottom: 0; }
@keyframes jb-shimmer {
  from { background-position: 100% 0; }
  to   { background-position: -100% 0; }
}

/* ---- Error placeholder ---- */
.jb-component-error {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: var(--jb-space-4);
  margin: var(--jb-space-6) 0;
  padding: var(--jb-space-4) var(--jb-space-5);
  border: 1px solid var(--jb-callout-danger-border);
  border-radius: var(--jb-radius-md);
  background: var(--jb-callout-danger-bg);
}
.jb-component-error__icon { width: 22px; height: 22px; color: var(--jb-callout-danger-accent); }
.jb-component-error__icon svg { width: 100%; height: 100%; display: block; }
.jb-component-error__title {
  margin: 0 0 2px;
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-sm);
  font-weight: 800;
  color: var(--jb-text-primary);
}
.jb-component-error__msg {
  margin: 0;
  font-size: var(--jb-text-sm);
  color: var(--jb-text-secondary);
}
.jb-component-error__retry {
  appearance: none;
  min-height: 44px;
  padding: var(--jb-space-2) var(--jb-space-4);
  border: 1px solid var(--jb-border-strong);
  border-radius: var(--jb-radius-sm);
  background: var(--jb-surface-raised);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-sm);
  font-weight: 700;
  color: var(--jb-text-primary);
  cursor: pointer;
}
.jb-component-error__retry:hover { border-color: var(--jb-color-accent); color: var(--jb-color-accent); }
@media (max-width: 640px) {
  .jb-component-error { grid-template-columns: auto 1fr; }
  .jb-component-error__retry { grid-column: 1 / -1; justify-self: start; }
}

/* ---- Unsupported-environment fallback ----
   Authors put this INSIDE the marker. If the library never runs (mobile app,
   blocked script), the learner sees this instead of an empty box. Hydration
   replaces it. */
.jb-unsupported {
  margin: var(--jb-space-6) 0;
  padding: var(--jb-space-4) var(--jb-space-5);
  border: 1px dashed var(--jb-border-strong);
  border-radius: var(--jb-radius-md);
  font-family: var(--jb-font-sans);
  font-size: var(--jb-text-sm);
  color: var(--jb-text-muted);
}


/* ==========================================================================
   11. Debug overlay (?jb-debug=1) — deliberately out-of-palette magenta
   ========================================================================== */

.jb-debug-outline { outline: 2px dashed #D619B9 !important; outline-offset: 1px; }
.jb-cd-line.jb-debug-outline { outline-offset: -2px; }

.jb-debug-badges {
  padding: var(--jb-space-2) var(--jb-space-5) var(--jb-space-3);
  display: flex;
  flex-wrap: wrap;
  gap: var(--jb-space-2);
}
.jb-debug-badge {
  font-family: var(--jb-font-mono);
  font-size: 0.63rem;
  padding: 2px 8px;
  border-radius: var(--jb-radius-pill);
  background: #D619B9;
  color: #fff;
}

.jb-debug-tag {
  display: inline-block;
  margin-bottom: 4px;
  font-family: var(--jb-font-mono);
  font-size: 0.6rem;
  padding: 1px 8px;
  border-radius: var(--jb-radius-pill);
  background: #fff;
  border: 1.5px solid #D619B9;
  color: #D619B9;
}


/* ==========================================================================
   12. Utilities, focus, selection, motion
   ========================================================================== */

.jb-visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* Focus: visible ring on everything interactive, never suppressed */
.jb-clickable:focus-visible,
.jb-popup__close:focus-visible,
.jb-stepper__btn:focus-visible,
.jb-stepper__dot:focus-visible,
.jb-stepper__num:focus-visible,
.jb-stepper:focus-visible,
.jb-footnote:focus-visible,
.jb-theme-toggle__btn:focus-visible,
.jb-component-error__retry:focus-visible,
.jb-linkpanel:focus-visible {
  outline: 2px solid var(--jb-focus-ring);
  outline-offset: 2px;
}

.jb-page ::selection, .jb-lesson ::selection, .jb-component ::selection {
  background: var(--jb-selection-bg);
}

@media (prefers-reduced-motion: reduce) {
  .jb-page *, .jb-lesson *, .jb-component *,
  .jb-page *::before, .jb-lesson *::before, .jb-component *::before,
  .jb-page *::after, .jb-lesson *::after, .jb-component *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}