/* ============================================================================
   SOUND DIFFUSER HUB — tool identity override
   ----------------------------------------------------------------------------
   Diffusers are the *finishing* tool in the treatment family — the last
   thing a treated room needs, after panels and traps have already done the
   heavy lifting. The colour system reflects that: a warm walnut-brown
   accent rather than the site's bright cyan. Walnut reads as furniture /
   craft / wood-grain — the visual grammar of finished mastering rooms,
   high-end listening spaces, and the diffuser's dominant material (solid
   hardwood or QRD plywood). It distances the hub from panels (cyan), foam
   (zinc), and bass traps (amber) while keeping the tool-family feel
   coherent.

   Load order:
     tokens.css                base design tokens
     treatment-hub.css         hub shell chrome (chips, rail, chapter heading)
     category-hub.css          editorial content cards (stage-entry, spec-grid,
                               placement-stack, pick-row, library)
     chapter-hub.css           shared chapter mechanics (directive-path,
                               priority reorder, install-block, rhythm)
     diffuser-hub.css          <- this file — sound-diffuser colour identity

   Scope: everything scoped to the .diffuser-hub class on <body> so nothing
   bleeds into the rest of the site (e.g. the site header's cyan accent on
   the "Acoustic Treatment" nav item stays cyan, not walnut).
   ============================================================================ */


/* ═══════════════════════════════════════════════════════════════════════════
   1. TOKENS — sound-diffuser colour identity swap
   ---------------------------------------------------------------------------
   Re-point the site's --color-accent* tokens to the walnut family when the
   page body carries the .diffuser-hub class. Every downstream rule that
   uses var(--color-accent) (chapter heading eyebrows, directive-path step
   numbers, CTAs, spec tags, etc.) picks up the new tone automatically —
   zero per-component rewrites needed.

   Accent scale (custom walnut palette — not a Tailwind standard so values
   are inlined rather than token-aliased; hue ~25deg, lower saturation than
   the amber-700 bass-hub palette so the two read as distinct families):
     --color-accent          walnut-700 (#7C4A2A) → the main brand moment
     --color-accent-hover    walnut-900 (#5C3817) → hover / focus darker
     --color-accent-soft     walnut-100 (#F5E8D9) → soft surface tints
     --color-accent-subtle   walnut-200 (#E8D3B8) → card-edge hover borders

   Also adds --color-accent-on-dark (walnut-300 / tan) for the hero and
   planner-cta aside contexts where the darker walnut-700 would collapse
   into the near-black backdrop (same pattern foam-hub.css and bass-hub.css
   established for their respective dark-background tones).
   ═══════════════════════════════════════════════════════════════════════════ */

.diffuser-hub {
  --color-accent:          var(--tool-diffuser-accent, #7C4A2A);
  --color-accent-hover:    #5C3817;
  --color-accent-soft:     #F5E8D9;
  --color-accent-subtle:   #E8D3B8;

  /* Hero "on-dark" emphasis tone. Walnut-700 has enough saturation to read
     on white body surfaces but loses contrast against the near-black hero
     background. Walnut-300 (tan) keeps the warmth of the palette while
     giving italics, step numbers, and link text enough luminance to
     register clearly. Slightly brighter than a pure mid-walnut to survive
     the dark backdrop without turning gold (which would conflict with the
     bass-hub amber identity). */
  --color-accent-on-dark:  #D4A574;  /* walnut-300 / tan */
}

/* ── Hero <em> readability fix ───────────────────────────────────────────────
   Base .mission__statement em uses color: var(--color-accent). With walnut-
   700 on the near-black hero the italic still reads but with less punch
   than the brighter walnut-300 the rest of the on-dark content uses. Bump
   it to the on-dark tone for consistency with directive-path step numbers,
   etc. */
.diffuser-hub .mission__statement em {
  color: var(--color-accent-on-dark, #D4A574);
}


/* ═══════════════════════════════════════════════════════════════════════════
   2. HERO BACKDROP — diffuser-specific motif
   ---------------------------------------------------------------------------
   The mission backdrop SVG is page-specific (see the HTML head — each hub
   paints its own waveform / scatter motif there). At the CSS layer we only
   nudge the opacity: walnut-on-dark is more muted than cyan, so we let the
   backdrop show through a touch more than the panels default to keep the
   hero from feeling empty. Matches the bass-hub opacity so both warm-tone
   hubs feel visually parallel.
   ═══════════════════════════════════════════════════════════════════════════ */

.diffuser-hub .mission--hub .mission__backdrop {
  opacity: 0.22;
}


/* ═══════════════════════════════════════════════════════════════════════════
   3. SHAPE GRID — not used on sound-diffuser
   ---------------------------------------------------------------------------
   Sound-diffuser Ch 2 covers materials and scattering geometry in a
   .spec-grid (inherited from category-hub.css), not the .shape-list
   component that lives on the foam hub. Nothing to do here; kept as a
   comment for symmetry with foam-hub.css / bass-hub.css so the section
   numbering lines up across per-hub stylesheets.
   ═══════════════════════════════════════════════════════════════════════════ */


/* ═══════════════════════════════════════════════════════════════════════════
   4. CHIP ACTIVE STATE — no override needed
   ---------------------------------------------------------------------------
   treatment-hub.css's .reader-chip active state uses neutral white-alpha
   (not --color-accent), so the walnut swap doesn't affect it. Chips still
   read white-on-darker-white when selected. No override required.
   ═══════════════════════════════════════════════════════════════════════════ */


/* ═══════════════════════════════════════════════════════════════════════════
   5. DIRECTIVE-PATH ON-DARK READABILITY
   ---------------------------------------------------------------------------
   Same pattern as foam-hub.css / bass-hub.css Section 5. The directive-path
   (chapter-hub.css) uses var(--color-accent) for its step numbers, intro
   <strong>, CTA links, and the "Show step N of 4" button. Walnut-700 on
   the near-black hero is legible but low-energy; walnut-300 (tan) gives
   the numbered steps the visual weight they need to scan as a clear 4-step
   path.
   ═══════════════════════════════════════════════════════════════════════════ */

.diffuser-hub .directive-path__num,
.diffuser-hub .directive-path__intro strong,
.diffuser-hub .directive-path__link {
  color: var(--color-accent-on-dark);
}

.diffuser-hub .directive-path__link {
  border-bottom-color: color-mix(in srgb, var(--color-accent-on-dark) 55%, transparent);
}

.diffuser-hub .directive-path__link:hover,
.diffuser-hub .directive-path__link:focus-visible {
  border-bottom-color: var(--color-accent-on-dark);
  color: var(--color-accent-soft);  /* walnut-100 — brightens further on hover */
}

.diffuser-hub .directive-path__more {
  color: var(--color-accent-on-dark);
  border-color: color-mix(in srgb, var(--color-accent-on-dark) 40%, transparent);
}

.diffuser-hub .directive-path__more:hover,
.diffuser-hub .directive-path__more:focus-visible {
  border-color: var(--color-accent-on-dark);
  color: var(--color-accent-soft);
  background: color-mix(in srgb, var(--color-accent-on-dark) 8%, transparent);
}


/* ═══════════════════════════════════════════════════════════════════════════
   6. PLANNER-CTA ON-DARK READABILITY (Ch 3 aside)
   ---------------------------------------------------------------------------
   Same fix as foam-hub.css / bass-hub.css Section 6 — the planner-cta
   aside has a dark near-black background; category-hub.css points the
   eyebrow at var(--color-accent) and the note-variant launch button at
   var(--color-accent-hover). Both collapse into the dark bg on sound-
   diffuser because walnut-700 / walnut-900 are darker than cyan.
   ═══════════════════════════════════════════════════════════════════════════ */

.diffuser-hub .planner-cta__eyebrow {
  color: var(--color-accent-on-dark);
}

.diffuser-hub .planner-cta--note .planner-cta__launch {
  color: var(--color-accent-on-dark);
}

.diffuser-hub .planner-cta--note .planner-cta__launch:hover,
.diffuser-hub .planner-cta--note .planner-cta__launch:focus-visible {
  background: var(--color-accent-on-dark);
  color: var(--color-ink);  /* invert on hover: dark text on tan pill */
}


/* ═══════════════════════════════════════════════════════════════════════════
   7. HERO VISUAL — diffuser-specific SVG elements
   ═══════════════════════════════════════════════════════════════════════════ */

.diffuser-hub .diffuser-hero-visual {
  display: block;
  width: 100%;
  height: 100%;
}

.diffuser-hub .diffuser-hero-visual__wall {
  fill: currentColor;
  opacity: 0.08;
  stroke: currentColor;
  stroke-width: 1.4;
  stroke-opacity: 0.25;
}

.diffuser-hub .diffuser-hero-visual__panel {
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-opacity: 0.45;
}

.diffuser-hub .diffuser-hero-visual__scatter {
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  fill: none;
  opacity: 0.3;
  stroke-dasharray: 6 4;
}

.diffuser-hub .diffuser-hero-visual__listener,
.diffuser-hub .diffuser-hero-visual__chair {
  fill: currentColor;
  opacity: 0.55;
}


/* ═══════════════════════════════════════════════════════════════════════════
   8. HERO CTA BUTTONS
   ═══════════════════════════════════════════════════════════════════════════ */

.diffuser-hub .diffuser-hero-ctas {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4);
  margin-top: var(--space-6);
}

.diffuser-hub .diffuser-hero-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  text-decoration: none;
  font-family: var(--font-mono);
  line-height: 1;
  transition: background var(--duration-fast) var(--ease-out),
              color var(--duration-fast) var(--ease-out),
              border-color var(--duration-fast) var(--ease-out),
              transform var(--duration-fast) var(--ease-out);
}

.diffuser-hub .diffuser-hero-cta--primary {
  padding: var(--space-3) var(--space-5);
  border: 1px solid color-mix(in srgb, var(--color-accent-on-dark) 58%, transparent);
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  color: var(--color-surface);
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.diffuser-hub .diffuser-hero-cta--secondary {
  color: color-mix(in srgb, var(--color-surface) 88%, transparent);
  font-family: var(--font-serif);
  font-size: var(--fs-md);
  font-style: italic;
  border-bottom: 1px solid color-mix(in srgb, var(--color-accent-on-dark) 42%, transparent);
}

.diffuser-hub .diffuser-hero-cta:hover,
.diffuser-hub .diffuser-hero-cta:focus-visible {
  outline: none;
  transform: translateY(-1px);
}

.diffuser-hub .diffuser-hero-cta--primary:hover,
.diffuser-hub .diffuser-hero-cta--primary:focus-visible {
  background: var(--color-accent-soft);
  border-color: var(--color-accent-soft);
  color: var(--color-ink);
}

.diffuser-hub .diffuser-hero-cta--secondary:hover,
.diffuser-hub .diffuser-hero-cta--secondary:focus-visible {
  color: var(--color-accent-on-dark);
  border-bottom-color: var(--color-accent-on-dark);
}

.diffuser-hub .diffuser-hero-cta__icon {
  flex: 0 0 auto;
}


/* ═══════════════════════════════════════════════════════════════════════════
   9. CHAPTER CONTENT BLOCKS
   ═══════════════════════════════════════════════════════════════════════════ */

/* -- Ch 1: Readiness check -- */

.diffuser-check {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
}

@media (min-width: 768px) {
  .diffuser-check {
    grid-template-columns: 1.2fr 1fr;
  }
}

/* ── Reads: primary column (stacked rows, dominant) ── */

.diffuser-check__reads {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.diffuser-check__entry {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-4);
  padding: var(--space-4);
  border-bottom: 1px solid var(--color-line);
  text-decoration: none;
  color: var(--color-ink);
  transition: background var(--duration-fast) var(--ease-out);
}

.diffuser-check__entry:first-child {
  border-top: 2px solid var(--color-ink);
}

.diffuser-check__entry:hover,
.diffuser-check__entry:focus-visible {
  background: color-mix(in srgb, var(--color-accent) 6%, transparent);
}

.diffuser-check__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1.7;
}

.diffuser-check__body {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.diffuser-check__body strong {
  font-family: var(--font-serif);
  font-size: var(--fs-md);
  font-weight: 600;
  letter-spacing: var(--tracking-snug);
}

.diffuser-check__body > span:last-child {
  font-size: var(--fs-sm);
  color: var(--color-ink-muted);
  line-height: 1.5;
}

/* ── Choices: supporting aside (recessed) ── */

.diffuser-check__choices {
  display: flex;
  flex-direction: column;
  gap: 0;
  padding: var(--space-5);
  background: var(--color-surface-2, var(--color-bg));
  border-radius: var(--radius-lg);
  align-self: start;
}

.diffuser-check__gate {
  padding: 0 0 var(--space-3);
}

.diffuser-check__gate-title {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent);
  margin: 0 0 var(--space-1);
}

.diffuser-check__gate-desc {
  font-size: var(--fs-sm);
  color: var(--color-ink-muted);
  margin: 0;
  line-height: 1.5;
}

.diffuser-check__choice {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-3) 0;
  border-top: 1px solid var(--color-line);
  text-decoration: none;
  color: var(--color-ink);
  transition: color var(--duration-fast) var(--ease-out);
}

.diffuser-check__choice:hover,
.diffuser-check__choice:focus-visible {
  color: var(--color-accent);
}

.diffuser-check__symptom {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: var(--fs-sm);
  color: var(--color-ink-muted);
}

.diffuser-check__verdict {
  font-size: var(--fs-sm);
  font-weight: 600;
  letter-spacing: var(--tracking-snug);
}


/* -- Ch 2: Diffuser types (visual shelf) -- */

.diffuser-types {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

@media (min-width: 640px) {
  .diffuser-types {
    grid-template-columns: repeat(3, 1fr);
    gap: 0 var(--space-6);
  }

  .diffuser-type:nth-child(n) {
    border-top: 2px solid var(--color-ink);
  }
}

.diffuser-type {
  display: grid;
  grid-template-columns: 5rem 1fr;
  grid-template-rows: auto auto;
  gap: var(--space-2) var(--space-4);
  padding: var(--space-4) 0;
  border-top: 1px solid var(--color-line);
  text-decoration: none;
  color: var(--color-ink);
}

.diffuser-type:first-child {
  border-top: 2px solid var(--color-ink);
}

@media (min-width: 640px) {
  .diffuser-type {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: auto;
    gap: var(--space-3);
    padding: var(--space-5) 0;
  }
}

.diffuser-type__visual {
  display: block;
  box-sizing: border-box;
  width: 100%;
  aspect-ratio: 1;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-line);
  background: var(--color-bg);
  color: var(--color-accent);
  overflow: hidden;
  grid-row: 1 / -1;
}

@media (min-width: 640px) {
  .diffuser-type__visual {
    width: min(100%, 10rem);
    grid-row: auto;
  }
}

.diffuser-type__visual svg {
  display: block;
  width: 100%;
  height: 100%;
}

.diffuser-type__label {
  font-family: var(--font-serif);
  font-size: var(--fs-xl);
  font-weight: 600;
  color: var(--color-ink);
  margin: 0;
}

.diffuser-type__desc {
  font-size: var(--fs-sm);
  color: var(--color-ink-muted);
  line-height: 1.55;
}


/* -- Ch 3: Materials -- */

.diffuser-materials {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.diffuser-material {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  text-decoration: none;
  color: var(--color-ink);
  position: relative;
  transition: background var(--duration-fast) var(--ease-out);
}

.diffuser-material:hover,
.diffuser-material:focus-visible {
  background: color-mix(in srgb, var(--color-accent) 6%, transparent);
}

.diffuser-material__num {
  flex: 0 0 auto;
  width: 1.75rem;
  text-align: center;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1.7;
}


.diffuser-material__body {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.diffuser-material__body strong {
  font-family: var(--font-serif);
  font-size: var(--fs-md);
  font-weight: 600;
  letter-spacing: var(--tracking-snug);
}

.diffuser-material__body > span:last-child {
  font-size: var(--fs-sm);
  color: var(--color-ink-muted);
  line-height: 1.5;
}


/* -- Ch 4: Placement -- */

.diffuser-placement {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
}

@media (min-width: 768px) {
  .diffuser-placement {
    grid-template-columns: 1.3fr 1fr;
  }
}

.diffuser-placement__reads {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.diffuser-placement__entry {
  display: flex;
  gap: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--color-ink);
  border: 1px solid var(--color-line);
  transition: border-color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out);
}

.diffuser-placement__entry:hover {
  border-color: var(--color-accent);
  box-shadow: 0 2px 8px color-mix(in srgb, var(--color-accent) 10%, transparent);
}

.diffuser-placement__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1.7;
}

.diffuser-placement__body {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.diffuser-placement__body strong {
  font-family: var(--font-serif);
  font-size: var(--fs-md);
  font-weight: 600;
}

.diffuser-placement__body > span:last-child {
  font-size: var(--fs-sm);
  color: var(--color-ink-muted);
  line-height: 1.5;
}

.diffuser-placement__rule {
  padding: var(--space-6);
  background: var(--color-accent-soft);
  border: 1px solid var(--color-accent-subtle);
  border-radius: var(--radius-lg);
  align-self: start;
  position: sticky;
  top: calc(var(--header-height, 80px) + var(--space-5));
}

.diffuser-placement__rule-title {
  font-family: var(--font-serif);
  font-size: var(--fs-xl);
  font-weight: 700;
  margin: 0 0 var(--space-3);
  color: var(--color-accent);
}

.diffuser-placement__rule-body {
  font-size: var(--fs-sm);
  line-height: 1.6;
  color: var(--color-ink);
  margin: 0 0 var(--space-5);
}

.diffuser-placement__rule-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  font-size: var(--fs-sm);
  font-family: var(--font-mono);
  color: var(--color-ink-muted);
}

.diffuser-placement__rule-list li::before {
  content: "→ ";
  color: var(--color-accent);
}


/* -- Ch 5: Buy lanes (visual product cards) -- */

.diffuser-buy-lanes {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-5);
}

@media (min-width: 480px) and (max-width: 767px) {
  .diffuser-buy-lanes {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 768px) {
  .diffuser-buy-lanes {
    grid-template-columns: repeat(3, 1fr);
  }
}

.diffuser-buy-lane {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-5);
  text-decoration: none;
  color: var(--color-ink);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  transition: border-color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out);
}

.diffuser-buy-lane:hover,
.diffuser-buy-lane:focus-visible {
  border-color: var(--color-accent);
  box-shadow: 0 4px 20px color-mix(in srgb, var(--color-accent) 12%, transparent);
}

.diffuser-buy-lane__visual {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-md);
  background: var(--color-accent-soft);
  color: var(--color-accent);
  overflow: hidden;
}

.diffuser-buy-lane__visual svg {
  display: block;
  width: 100%;
  height: 100%;
}

.diffuser-buy-lane__tag {
  display: inline-flex;
  align-self: flex-start;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-pill);
  background: var(--color-accent-soft);
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: var(--fs-2xs, 0.6875rem);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.diffuser-buy-lane strong {
  font-family: var(--font-serif);
  font-size: var(--fs-lg);
  font-weight: 600;
  letter-spacing: var(--tracking-snug);
}

.diffuser-buy-lane__desc {
  font-size: var(--fs-sm);
  color: var(--color-ink-muted);
  line-height: 1.55;
  flex: 1;
}

.diffuser-buy-lane__cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin-top: auto;
  padding: var(--space-2) 0;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.04em;
  transition: color var(--duration-fast) var(--ease-out);
}

.diffuser-buy-lane:hover .diffuser-buy-lane__cta {
  color: var(--color-accent-hover);
}


/* ═══════════════════════════════════════════════════════════════════════════
   10. LIBRARY — featured hero cards
   ═══════════════════════════════════════════════════════════════════════════ */

.diffuser-hub .library__featured {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

@media (min-width: 480px) and (max-width: 767px) {
  .diffuser-hub .library__featured {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 768px) {
  .diffuser-hub .library__featured {
    grid-template-columns: repeat(3, 1fr);
  }
}

.diffuser-hub .library__hero {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-5);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: var(--color-ink);
  min-height: 14rem;
  overflow: hidden;
  transition: border-color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out),
              transform var(--duration-fast) var(--ease-out);
}

.diffuser-hub .library__hero::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: var(--color-accent);
  opacity: 0.7;
}

@media (hover: hover) and (pointer: fine) {
  .diffuser-hub .library__hero:hover {
    border-color: var(--color-accent);
    box-shadow: 0 8px 24px -8px color-mix(in srgb, var(--color-accent) 20%, transparent);
    transform: translateY(-2px);
  }
}

.diffuser-hub .library__hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
}

.diffuser-hub .library__hero-title {
  font-family: var(--font-sans);
  font-size: var(--fs-lg, 18px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.25;
}

.diffuser-hub .library__hero-desc {
  font-family: var(--font-serif);
  font-size: var(--fs-sm, 14px);
  line-height: 1.55;
  color: var(--color-ink-muted);
  flex: 1;
}

.diffuser-hub .library__hero-cta {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--color-accent);
  margin-top: var(--space-2);
}


/* ── Filter dots (color-coded by stage) ──────────────────────────────── */

.diffuser-hub .library__filter-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--stage-color, var(--color-accent));
}

.diffuser-hub [data-filter="all"] .library__filter-dot { background: var(--color-accent); }
.diffuser-hub [data-filter="orient"] .library__filter-dot { background: #2563EB; }
.diffuser-hub [data-filter="material"] .library__filter-dot { background: #7C3AED; }
.diffuser-hub [data-filter="placement"] .library__filter-dot { background: #059669; }
.diffuser-hub [data-filter="picks"] .library__filter-dot { background: #D97706; }

/* ── Library items (color-coded left border) ─────────────────────────── */

.diffuser-hub .library__item {
  --stage-color: var(--color-accent);
  border-top: 0;
  border-left: 3px solid var(--stage-color);
  padding-left: var(--space-4);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  transition: background var(--duration-fast) var(--ease-out),
              border-color var(--duration-fast) var(--ease-out);
}

.diffuser-hub .library__item[data-stage="orient"] { --stage-color: #2563EB; }
.diffuser-hub .library__item[data-stage="material"] { --stage-color: #7C3AED; }
.diffuser-hub .library__item[data-stage="placement"] { --stage-color: #059669; }
.diffuser-hub .library__item[data-stage="picks"] { --stage-color: #D97706; }

.diffuser-hub .adj-card[data-hub="acoustic"] { --hub-accent: #0891B2; }
.diffuser-hub .adj-card[data-hub="panels"] { --hub-accent: #0284C7; }
.diffuser-hub .adj-card[data-hub="bass-traps"] { --hub-accent: #0D9488; }
.diffuser-hub .adj-card[data-hub="diffusers"] { --hub-accent: #7C3AED; }
.diffuser-hub .adj-card[data-hub="soundproofing"] { --hub-accent: #B45309; }

.diffuser-hub .adj-reads {
  display: flex;
  flex-direction: row;
  gap: var(--space-5);
  overflow-x: auto;
  overflow-y: visible;
  scroll-snap-type: x mandatory;
  scroll-padding-left: var(--space-1);
  padding: var(--space-2) var(--space-1) var(--space-4);
  margin: 0 calc(var(--space-1) * -1);
  scrollbar-width: thin;
  scrollbar-color: color-mix(in srgb, var(--color-accent) 25%, transparent) transparent;
  -webkit-overflow-scrolling: touch;
  -webkit-mask-image: linear-gradient(to right, black 0, black calc(100% - 32px), transparent 100%);
  mask-image: linear-gradient(to right, black 0, black calc(100% - 32px), transparent 100%);
}

.diffuser-hub .adj-reads::-webkit-scrollbar {
  height: 6px;
}

.diffuser-hub .adj-reads::-webkit-scrollbar-track {
  background: transparent;
}

.diffuser-hub .adj-reads::-webkit-scrollbar-thumb {
  background: color-mix(in srgb, var(--color-accent) 22%, transparent);
  border-radius: 4px;
}

.diffuser-hub .adj-reads::-webkit-scrollbar-thumb:hover {
  background: color-mix(in srgb, var(--color-accent) 40%, transparent);
}

.diffuser-hub .adj-reads .adj-card {
  flex: 0 0 320px;
  scroll-snap-align: start;
}

.diffuser-hub .adj-card {
  position: relative;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  color: inherit;
  text-decoration: none;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  transition: border-color var(--duration-base) var(--ease-out),
              box-shadow var(--duration-base) var(--ease-out),
              transform var(--duration-base) var(--ease-out);
}

.diffuser-hub .adj-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 3px;
  background: var(--hub-accent, var(--color-accent));
  opacity: 0.6;
  transition: opacity var(--duration-fast) var(--ease-out);
}

.diffuser-hub .adj-card__visual {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-6) var(--space-5) var(--space-3);
  background: color-mix(in srgb, var(--hub-accent, var(--color-accent)) 4%, transparent);
}

.diffuser-hub .adj-card__svg {
  display: block;
  width: 100%;
  max-width: 160px;
  height: auto;
  color: var(--hub-accent, var(--color-accent));
  opacity: 0.72;
  transition: opacity var(--duration-base) var(--ease-out);
}

.diffuser-hub .adj-card__body {
  display: flex;
  flex: 1;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-5);
}

.diffuser-hub .adj-card__role {
  color: var(--hub-accent, var(--color-accent));
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: var(--fw-bold);
  letter-spacing: 0.08em;
  line-height: 1.3;
  text-transform: uppercase;
}

.diffuser-hub .adj-card__name {
  margin: 0;
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  letter-spacing: 0;
  line-height: 1.15;
  transition: color var(--duration-fast) var(--ease-out);
}

.diffuser-hub .adj-card__hook {
  flex: 1;
  margin: 0;
  color: var(--color-ink-muted);
  font-family: var(--font-serif);
  font-size: var(--fs-sm);
  line-height: 1.6;
}

.diffuser-hub .adj-card__cta {
  margin-top: var(--space-2);
  color: var(--hub-accent, var(--color-accent));
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: var(--fw-bold);
  letter-spacing: 0.04em;
  transition: letter-spacing var(--duration-fast) var(--ease-out);
}

.diffuser-hub #next-topics {
  scroll-margin-top: var(--space-20);
}

@media (hover: hover) and (pointer: fine) {
  .diffuser-hub .adj-card:hover,
  .diffuser-hub .adj-card:focus-visible {
    outline: none;
    border-color: var(--hub-accent, var(--color-accent));
    box-shadow: 0 12px 32px -8px color-mix(in srgb, var(--hub-accent, var(--color-accent)) 20%, transparent);
    transform: translateY(-3px);
  }

  .diffuser-hub .adj-card:hover::before,
  .diffuser-hub .adj-card:focus-visible::before {
    opacity: 1;
  }

  .diffuser-hub .adj-card:hover .adj-card__svg,
  .diffuser-hub .adj-card:focus-visible .adj-card__svg {
    opacity: 0.88;
  }

  .diffuser-hub .adj-card:hover .adj-card__name,
  .diffuser-hub .adj-card:focus-visible .adj-card__name {
    color: var(--hub-accent, var(--color-accent));
  }

  .diffuser-hub .adj-card:hover .adj-card__cta,
  .diffuser-hub .adj-card:focus-visible .adj-card__cta {
    letter-spacing: 0.06em;
  }
}

@media (min-width: 780px) {
  .diffuser-hub .adj-reads .adj-card {
    flex-basis: 340px;
  }
}

@media (max-width: 520px) {
  .diffuser-hub .adj-reads .adj-card {
    flex-basis: 280px;
  }

  .diffuser-hub .adj-card__visual {
    padding: var(--space-4) var(--space-4) var(--space-2);
  }

  .diffuser-hub .adj-card__svg {
    max-width: 120px;
  }
}


/* ═══════════════════════════════════════════════════════════════════════════
   11. MOBILE OVERRIDES
   ═══════════════════════════════════════════════════════════════════════════ */

@media (max-width: 639px) {
  .diffuser-hub .diffuser-hero-ctas {
    align-items: stretch;
  }

  .diffuser-hub .diffuser-hero-cta--primary {
    width: 100%;
  }
}
