/* ══════════════════════════════════════════════════════════════
   KEYBOARD STAGE (.kb-*)
   Scroll driven hero for keyboard.html: the exploded model assembles
   as you scroll, then the layout explorer sits on the real keycaps.
   Uses the site tokens from style.css.
   ══════════════════════════════════════════════════════════════ */

#kb-stage {
  --kb-title: 1;
  --kb-build: 0;
  --kb-layout: 0;
  position: relative;
  height: 380vh;
  padding: 0;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

.kb-sticky {
  position: sticky;
  top: 0;
  height: 100vh;
  height: 100svh;
  overflow: hidden;
  isolation: isolate;
  background:
    radial-gradient(ellipse 60% 45% at 50% 58%, rgba(255,255,255,0.075), rgba(255,255,255,0) 70%),
    var(--bg);
}

.kb-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  z-index: 0;
}

/* ── hero copy, floats above the exploded stack ── */
.kb-hero-copy {
  position: absolute;
  left: 0; right: 0;
  top: calc(60px + 9vh);
  z-index: 2;
  text-align: center;
  padding-inline: max(16px, env(safe-area-inset-left, 0px)) max(16px, env(safe-area-inset-right, 0px));
  opacity: var(--kb-title);
  transform: translateY(calc((1 - var(--kb-title)) * -40px));
  pointer-events: none;
}

.kb-hero-copy .section-label { margin-bottom: 0.9rem; color: var(--muted); }

.kb-hero-title {
  font-family: 'Rajdhani', sans-serif;
  font-size: clamp(2.8rem, 9vw, 6.5rem);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  line-height: 0.95;
  text-wrap: balance;
}

.kb-hero-spec {
  margin-top: 1.1rem;
  font-family: 'Rajdhani', sans-serif;
  font-size: clamp(0.78rem, 1.6vw, 0.95rem);
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
}

.kb-hero-spec span { white-space: nowrap; margin-inline: 0.4em; }

.kb-scroll-hint {
  opacity: calc(var(--kb-title) * 0.7);
  bottom: calc(1.8rem + env(safe-area-inset-bottom, 0px));
}

/* ── build order, lights up as each layer lands ── */
.kb-build {
  position: absolute;
  left: max(2.5rem, env(safe-area-inset-left, 0px));
  bottom: calc(2.5rem + env(safe-area-inset-bottom, 0px));
  z-index: 2;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  opacity: var(--kb-build);
  pointer-events: none;
}

.kb-build li {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  font-family: 'Rajdhani', sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted-2);
  transition: color 0.3s;
}

.kb-build li span {
  font-size: 0.68rem;
  letter-spacing: 0.25em;
  width: 1.6rem;
}

.kb-build li.is-set { color: var(--text); }

/* ── explorer chrome ── */
.kb-explorer {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding-top: calc(60px + 1.6rem);
  padding-bottom: calc(1.6rem + env(safe-area-inset-bottom, 0px));
  padding-left: max(2.5rem, env(safe-area-inset-left, 0px));
  padding-right: max(2.5rem, env(safe-area-inset-right, 0px));
  opacity: var(--kb-layout);
  transform: translateY(calc((1 - var(--kb-layout)) * 16px));
  pointer-events: none;
}

.kb-explore .kb-explorer > * { pointer-events: auto; }

.kb-explorer-head {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  max-width: 1060px;
  width: 100%;
  margin: 0 auto;
}

.kb-explorer-head .section-label { margin-bottom: 0; }

.kb-count {
  font-family: 'Rajdhani', sans-serif;
  font-size: clamp(1.5rem, 3.4vw, 2.3rem);
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1;
}

.kb-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  max-width: 100%;
}

.kb-tabs::-webkit-scrollbar { display: none; }

.kb-tab {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: baseline;
  gap: 0.45rem;
  padding: 0.4rem 0.75rem;
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: 2px;
  color: var(--muted);
  font-family: 'Rajdhani', sans-serif;
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
}

.kb-tab-ix {
  font-size: 0.66rem;
  letter-spacing: 0.12em;
  color: var(--muted-2);
}

.kb-tab:hover { color: var(--text); background: #161616; }
.kb-tab[aria-pressed="true"] { background: var(--text); color: var(--bg); border-color: var(--text); }
.kb-tab[aria-pressed="true"] .kb-tab-ix { color: var(--muted); }

.kb-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.5fr) minmax(0, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  max-width: 1060px;
  width: 100%;
  margin: 0 auto;
  max-height: 26vh;
}

.kb-panel > * {
  background: rgba(10, 10, 10, 0.88);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  padding: 1rem 1.2rem;
  min-width: 0;
  overflow-y: auto;
}

.kb-panel-label {
  font-family: 'Rajdhani', sans-serif;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--muted-2);
  margin-bottom: 0.5rem;
}

.kb-reach-title {
  font-family: 'Rajdhani', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 0.3rem;
}

.kb-reach-how, .kb-reach-note, .kb-detail-hint {
  color: var(--muted);
  font-size: 0.85rem;
  line-height: 1.6;
}

.kb-reach-note { margin-top: 0.5rem; }

.kb-combos {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.kb-combo {
  display: inline-flex;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.25rem 0.55rem;
  background: transparent;
  border: 1px solid var(--border-hi);
  border-radius: 2px;
  color: var(--muted);
  font-family: 'Rajdhani', sans-serif;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  cursor: default;
  transition: border-color 0.2s, color 0.2s;
}

.kb-combo:hover, .kb-combo:focus-visible { border-color: var(--text); color: var(--text); }
.kb-combo-out { color: var(--text); }
.kb-combo-out::before { content: '→ '; color: var(--muted-2); }

.kb-detail-pos {
  font-family: 'Rajdhani', sans-serif;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--muted-2);
  margin-bottom: 0.4rem;
}

.kb-detail-row {
  display: grid;
  grid-template-columns: 3.2rem minmax(0, 1fr);
  font-size: 0.9rem;
  line-height: 1.55;
}

.kb-detail-row span {
  font-family: 'Rajdhani', sans-serif;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted-2);
  padding-top: 0.15rem;
}

.kb-detail-code {
  display: inline-block;
  margin-top: 0.6rem;
  padding: 0.2rem 0.5rem;
  border: 1px solid var(--border-hi);
  font-family: ui-monospace, 'SFMono-Regular', Menlo, Consolas, monospace;
  font-size: 0.78rem;
  color: var(--text);
  overflow-wrap: anywhere;
}

/* ── legends laid over the 3D keycaps ── */
.kb-keys {
  position: absolute;
  inset: 0;
  z-index: 2;
  opacity: var(--kb-layout);
  pointer-events: none;
}

.kb-explore .kb-key { pointer-events: auto; }

.kb-key {
  position: absolute;
  left: 0; top: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.04em;
  padding: 0;
  background: transparent;
  border: none;
  border-radius: 0.09em;
  color: var(--text);
  font-family: 'Rajdhani', sans-serif;
  line-height: 1;
  cursor: pointer;
  will-change: transform;
  transition: box-shadow 0.15s, background 0.15s, opacity 0.2s;
}

.kb-tap {
  font-size: 0.3em;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  white-space: nowrap;
}

.kb-key.is-long .kb-tap { font-size: 0.19em; }

.kb-hold {
  font-size: 0.14em;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  white-space: nowrap;
}

.kb-hold:empty { display: none; }
.kb-key.is-through { opacity: 0.3; }
.kb-key.is-empty { opacity: 0; }

.kb-key:hover, .kb-key:focus-visible {
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.55);
  outline: none;
  opacity: 1;
}

.kb-key.is-activator {
  opacity: 1;
  box-shadow: inset 0 0 0 1.5px var(--text), 0 0 18px rgba(255, 255, 255, 0.25);
}

.kb-key.is-combo {
  opacity: 1;
  background: rgba(255, 255, 255, 0.16);
  box-shadow: inset 0 0 0 1px var(--text);
}

.kb-fallback {
  display: none;
  position: absolute;
  inset: 0;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.kb-no-webgl .kb-fallback { display: flex; }

/* ── responsive ── */
@media (max-width: 900px) {
  .kb-panel { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); max-height: 36vh; }
  .kb-panel .kb-panel-combos { grid-column: 1 / -1; order: 3; }
}

@media (max-width: 640px) {
  #kb-stage { height: 320vh; }
  .kb-explorer { padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); padding-top: calc(60px + 1rem); }
  .kb-build { left: max(16px, env(safe-area-inset-left, 0px)); bottom: calc(1.4rem + env(safe-area-inset-bottom, 0px)); }
  .kb-build li { font-size: 0.72rem; }
  .kb-panel > * { padding: 0.8rem 0.9rem; }
  .kb-tabs { flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; }
  .kb-combos { flex-wrap: nowrap; overflow-x: auto; }
  .kb-combo { flex: 0 0 auto; }
}

@media (prefers-reduced-motion: reduce) {
  .kb-build li, .kb-key { transition: none; }
}

/* the case study intro follows the stage instead of opening the page */
#kb-stage + #cs-hero { padding-top: 5rem; }

/* ── diagrams in the process steps (wiring, keymap layers) ── */
.cs-step-media.cs-step-media--diagram {
  aspect-ratio: auto;
  cursor: default;
  background: #0a0a0a;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.cs-step-media--diagram svg { display: block; width: 100%; height: auto; }
.kbw-board { font: 700 20px 'Rajdhani', sans-serif; letter-spacing: 0.12em; fill: #ffffff; text-transform: uppercase; }
.kbw-sub   { font: 600 11px 'Rajdhani', sans-serif; letter-spacing: 0.22em; fill: #7d8187; text-transform: uppercase; }
.kbw-tiny  { font: 600 8px 'Rajdhani', sans-serif; letter-spacing: 0.18em; fill: #7d8187; }
.kbw-pin   { font: 500 11px ui-monospace, 'SFMono-Regular', Menlo, Consolas, monospace; fill: #5d6167; }
.kbw-pin-on{ font: 700 12px ui-monospace, 'SFMono-Regular', Menlo, Consolas, monospace; fill: #ffffff; }
.kbw-map   { font: 500 12px ui-monospace, 'SFMono-Regular', Menlo, Consolas, monospace; fill: #9aa0a6; }
.kbw-map-a { fill: #ffffff; font-weight: 700; }
.kbw-note  { font: 600 11px 'Rajdhani', sans-serif; letter-spacing: 0.14em; fill: #6b6f75; text-transform: uppercase; }
.kbw-chain { font: 600 12.5px 'Rajdhani', sans-serif; letter-spacing: 0.08em; fill: #c9ccd0; }

.kb-layers { display: flex; flex-direction: column; gap: 1.6rem; padding: 1.6rem 1.4rem; }
.kb-layer-fig { margin: 0; display: flex; flex-direction: column; gap: 0.55rem; }
.kb-layer-fig figcaption {
  font-family: 'Rajdhani', sans-serif;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--muted);
  line-height: 1.45;
}
.kb-layer-fig figcaption span {
  display: block;
  color: var(--text);
  font-size: 0.95rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}
.kbl-tap  { font-family: 'Rajdhani', sans-serif; font-weight: 700; fill: #ffffff; }
.kbl-hold { font-family: 'Rajdhani', sans-serif; font-weight: 600; letter-spacing: 0.08em; fill: #8a8e94; }
.kbl-dim  { font-family: 'Rajdhani', sans-serif; font-weight: 600; fill: #4a4d52; }
.kbl-act  { font-family: 'Rajdhani', sans-serif; font-weight: 700; letter-spacing: 0.2em; fill: #a6ff6a; }