/* AURORA 極光 — controls & keyboard (src/ui/components.js, src/ui/keyboard.js)
   Class prefix: ac-   Tokens come from css/style.css; the zero-specificity block below only
   provides fallbacks so components also render standalone (any real :root token wins). */

:where(:root) {
  --bg-0: #07080d; --bg-1: #0c0f18; --bg-2: #121726;
  --panel: rgba(22, 28, 46, .72); --panel-hi: rgba(38, 48, 78, .6);
  --line: rgba(140, 160, 220, .14); --text: #e8ecff; --text-dim: #8e97b8; --text-faint: #7a83a6;
  --a-cyan: #5cf2ff; --a-teal: #3ef0b0; --a-violet: #a78bfa; --a-pink: #ff6bd6; --a-amber: #ffc46b; --a-red: #ff6b81;
  --grad-aurora: linear-gradient(120deg, #3ef0b0, #5cf2ff 30%, #a78bfa 65%, #ff6bd6);
  --radius: 14px; --radius-sm: 8px; --shadow: 0 10px 40px rgba(0, 0, 0, .45);
  --font-ui: "Inter", "Noto Sans TC", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
}

/* ───────────────────────── shared ───────────────────────── */
.ac-knob, .ac-slider, .ac-toggle, .ac-select, .ac-env, .ac-xy, .ac-kb {
  --k-accent: var(--a-cyan);
  --k-glow: color-mix(in oklab, var(--k-accent) 65%, transparent);
  font-family: var(--font-ui);
  -webkit-user-select: none;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  box-sizing: border-box;
}
.ac-lbl { display: flex; flex-direction: column; align-items: center; line-height: 1.12; min-width: 0; }
.ac-zh { font-size: 12px; font-weight: 500; color: var(--text); letter-spacing: .02em; white-space: nowrap; }
.ac-en {
  font-size: var(--fs-cap, 11px); font-weight: 600; color: var(--text-faint); letter-spacing: var(--ls-cap, .07em);
  text-transform: uppercase; white-space: nowrap; margin-top: 1px; line-height: 1.15;
}
.ac-sr-only {
  position: absolute !important; width: 1px; height: 1px; margin: -1px; padding: 0; border: 0;
  overflow: hidden; clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap;
}
.ac-bubble-base, .ac-knob__bubble, .ac-slider__bubble, .ac-env__bubble {
  position: absolute; pointer-events: none; z-index: 30; white-space: nowrap;
  font: 600 11px/1 var(--font-mono); font-variant-numeric: tabular-nums; color: var(--text);
  padding: 5px 8px 5px; border-radius: 7px;
  background: linear-gradient(180deg, rgba(30, 37, 60, .96), rgba(14, 18, 30, .96));
  border: 1px solid color-mix(in oklab, var(--k-accent) 45%, transparent);
  box-shadow: 0 6px 22px rgba(0, 0, 0, .55), 0 0 16px color-mix(in oklab, var(--k-accent) 22%, transparent);
  opacity: 0;
  transition: opacity .16s ease, transform .2s cubic-bezier(.2, .8, .2, 1.2);
}

/* ───────────────────────── knob ───────────────────────── */
.ac-knob {
  --k-size: 50px;
  --k-mod: var(--a-amber);
  --k-g0: color-mix(in oklab, var(--k-accent) 62%, #3b3fd8);
  --k-g1: var(--k-accent);
  --k-g2: color-mix(in oklab, var(--k-accent) 70%, #ffffff);
  --k-ptr: color-mix(in oklab, var(--k-accent) 55%, #ffffff);
  position: relative;
  display: inline-flex; flex-direction: column; align-items: center; gap: 4px;
  min-width: calc(var(--k-size) + 10px);
  vertical-align: top;
}
@supports (color: oklch(from red l c h)) {
  .ac-knob {
    --k-g0: oklch(from var(--k-accent) calc(l - .1) c calc(h - 38));
    --k-g2: oklch(from var(--k-accent) calc(l + .07) calc(c * .85) calc(h + 14));
  }
}
.ac-knob.is-aurora {
  --k-accent: var(--a-violet);
  --k-g0: var(--a-teal); --k-g1: var(--a-cyan); --k-g2: var(--a-pink);
  --k-ptr: #ffffff;
}
.ac-knob--sm { --k-size: 34px; gap: 3px; }
.ac-knob--md { --k-size: 50px; }
.ac-knob--lg { --k-size: 68px; gap: 5px; }
.ac-knob--xl { --k-size: 104px; gap: 7px; }

.ac-knob__dial {
  position: relative; width: var(--k-size); height: var(--k-size);
  border-radius: 50%; cursor: ns-resize; touch-action: none; outline: none;
  transition: box-shadow .25s ease;
}
.ac-knob__dial svg { position: relative; display: block; width: 100%; height: 100%; overflow: visible; transition: transform .25s cubic-bezier(.3, 1.4, .5, 1); }
.ac-knob__dial:hover svg { transform: scale(1.035); }
.ac-knob.is-dragging .ac-knob__dial { box-shadow: 0 0 calc(var(--k-size) * .35) color-mix(in oklab, var(--k-accent) 22%, transparent); }
.ac-knob.is-dragging .ac-knob__dial svg { transform: scale(1.05); }
.ac-knob.has-mod .ac-knob__mod { opacity: 1; filter: drop-shadow(0 0 2.5px var(--k-mod)); }
.ac-knob__dial:focus-visible {
  box-shadow: 0 0 0 2px var(--bg-0), 0 0 0 3.5px color-mix(in oklab, var(--k-accent) 80%, transparent);
}
.ac-knob__aura {
  position: absolute; inset: -22%; border-radius: 50%; pointer-events: none; opacity: 0;
  background: radial-gradient(closest-side, color-mix(in oklab, var(--k-accent) 38%, transparent), transparent 75%);
  display: none;
}
.ac-knob--lg .ac-knob__aura, .ac-knob--xl .ac-knob__aura { display: block; }
.ac-knob.is-aurora .ac-knob__aura {
  background:
    radial-gradient(closest-side at 30% 60%, color-mix(in oklab, var(--a-teal) 30%, transparent), transparent 80%),
    radial-gradient(closest-side at 70% 40%, color-mix(in oklab, var(--a-pink) 26%, transparent), transparent 80%),
    radial-gradient(closest-side, color-mix(in oklab, var(--a-violet) 30%, transparent), transparent 80%);
}

.ac-knob__well { fill: rgba(4, 6, 12, .55); stroke: rgba(255, 255, 255, .035); stroke-width: 1; }
.ac-knob__ticks circle { fill: rgba(160, 175, 230, .28); transition: fill .25s ease; }
.ac-knob.has-scale .ac-knob__ticks circle { fill: rgba(160, 175, 230, .2); }
.ac-knob.has-scale .ac-knob__ticks circle.is-major { fill: rgba(170, 185, 235, .38); }
.ac-knob__ticks circle.is-lit, .ac-knob.has-scale .ac-knob__ticks circle.is-lit { fill: var(--k-g2); transition-duration: .08s; }
.ac-knob__track {
  fill: none; stroke: rgba(140, 160, 220, .15); stroke-width: 6.5; stroke-linecap: round;
  transition: stroke .2s ease;
}
.ac-knob__origin { fill: rgba(200, 210, 245, .45); }
.ac-knob__arc { fill: none; stroke-width: 6.5; stroke-linecap: round; }
.ac-knob__halo {
  fill: none; stroke: var(--k-accent); stroke-width: 9; stroke-linecap: round; opacity: .55;
  transition: opacity .2s ease;
}
.ac-knob.is-aurora .ac-knob__halo { stroke: var(--a-violet); }
.ac-knob__s0 { stop-color: var(--k-g0); }
.ac-knob__s1 { stop-color: var(--k-g1); }
.ac-knob__s2 { stop-color: var(--k-g2); }
.ac-knob__mod {
  fill: none; stroke: var(--k-mod); stroke-width: 3; stroke-linecap: round; opacity: .9;
  filter: drop-shadow(0 0 1.5px var(--k-mod));
}
.ac-knob__shadow { fill: #000; opacity: .55; }
.ac-knob__c0 { stop-color: #3d4766; }
.ac-knob__c1 { stop-color: #1b2135; }
.ac-knob__c2 { stop-color: #0c0f1a; }
.ac-knob__rim { fill: none; stroke-width: 1.3; }
.ac-knob__gloss { fill: #fff; opacity: 0; transition: opacity .2s ease; }
.ac-knob__ptr line { stroke: var(--k-ptr); stroke-width: 3.6; stroke-linecap: round; }
.ac-knob__ptr { filter: drop-shadow(0 0 1.6px var(--k-accent)); }

.ac-knob__dial:hover .ac-knob__track { stroke: rgba(150, 170, 235, .24); }
.ac-knob__dial:hover .ac-knob__gloss { opacity: .045; }
.ac-knob__dial:hover .ac-knob__halo, .ac-knob.is-dragging .ac-knob__halo { opacity: .85; }
.ac-knob.is-dragging .ac-knob__gloss { opacity: .07; }

.ac-knob__label { max-width: calc(var(--k-size) + 34px); }
.ac-knob__label .ac-zh, .ac-knob__label .ac-en { overflow: hidden; text-overflow: ellipsis; max-width: 100%; }
.ac-knob--sm .ac-zh { font-size: 11px; }
.ac-knob--sm .ac-en { display: none; }
.ac-knob--lg .ac-zh { font-size: 12.5px; }
.ac-knob--xl .ac-zh { font-size: 14px; font-weight: 600; letter-spacing: .04em; }
.ac-knob--xl .ac-en { font-size: var(--fs-cap, 11px); letter-spacing: .1em; }
.ac-knob__value {
  font: 500 11px/1.1 var(--font-mono); font-variant-numeric: tabular-nums;
  color: var(--text-dim); white-space: nowrap; transition: color .2s ease, text-shadow .2s ease;
}
.ac-knob--xl .ac-knob__value { font-size: 12px; }
.ac-knob.is-dragging .ac-knob__value, .ac-knob.is-bubble .ac-knob__value {
  color: var(--k-g2); text-shadow: 0 0 8px var(--k-glow);
}
.ac-knob__bubble { left: 50%; top: -6px; transform: translate(-50%, -85%) scale(.9); }
.ac-knob.is-dragging .ac-knob__bubble, .ac-knob.is-bubble .ac-knob__bubble {
  opacity: 1; transform: translate(-50%, -100%) scale(1);
}

/* ───────────────────────── slider ───────────────────────── */
.ac-slider {
  --k-g2: color-mix(in oklab, var(--k-accent) 70%, #ffffff);
  --pos: 0; --from: 0; --to: 0;
  position: relative; display: flex; gap: 6px; min-width: 0;
}
.ac-slider.is-aurora { --k-accent: var(--a-violet); }
.ac-slider--h { flex-direction: column; width: 100%; min-width: 120px; }
.ac-slider--v { flex-direction: column; align-items: center; height: 150px; width: 52px; }
.ac-slider__head { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; }
.ac-slider--h .ac-slider__head .ac-lbl { flex-direction: row; align-items: baseline; gap: 6px; }
.ac-slider--v .ac-slider__head { flex-direction: column; align-items: center; gap: 2px; }
.ac-slider__value {
  font: 500 11px/1 var(--font-mono); font-variant-numeric: tabular-nums; color: var(--text-dim);
  white-space: nowrap; transition: color .2s ease;
}
.ac-slider.is-dragging .ac-slider__value { color: var(--k-g2); }
.ac-slider__track { position: relative; outline: none; cursor: pointer; touch-action: none; border-radius: 99px; }
.ac-slider--h .ac-slider__track { height: 22px; padding: 0 9px; }
.ac-slider--v .ac-slider__track { flex: 1; width: 22px; padding: 9px 0; }
.ac-slider__track:focus-visible {
  box-shadow: 0 0 0 2px var(--bg-0), 0 0 0 3.5px color-mix(in oklab, var(--k-accent) 80%, transparent);
}
.ac-slider__rail {
  position: relative; border-radius: 99px;
  background: linear-gradient(180deg, rgba(0, 0, 0, .45), rgba(255, 255, 255, .03));
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, .6), 0 0 0 1px rgba(140, 160, 220, .1);
}
.ac-slider--h .ac-slider__rail { top: 8px; height: 6px; }
.ac-slider--v .ac-slider__rail { left: 8px; width: 6px; height: 100%; }
.ac-slider__fill {
  position: absolute; border-radius: 99px;
  box-shadow: 0 0 10px var(--k-glow);
}
.ac-slider--h .ac-slider__fill {
  top: 0; bottom: 0; left: calc(var(--from) * 100%); right: calc((1 - var(--to)) * 100%);
  background: linear-gradient(90deg, color-mix(in oklab, var(--k-accent) 55%, #3b3fd8), var(--k-accent) 70%, var(--k-g2));
}
.ac-slider--v .ac-slider__fill {
  left: 0; right: 0; bottom: calc(var(--from) * 100%); top: calc((1 - var(--to)) * 100%);
  background: linear-gradient(0deg, color-mix(in oklab, var(--k-accent) 55%, #3b3fd8), var(--k-accent) 70%, var(--k-g2));
}
.ac-slider.is-aurora .ac-slider__fill { background: var(--grad-aurora); }
.ac-slider__thumb {
  position: absolute; width: 16px; height: 16px; border-radius: 50%;
  background: radial-gradient(circle at 38% 30%, #4a5476, #1a2034 60%, #0d111c);
  box-shadow: 0 0 0 1.5px var(--k-accent), 0 0 12px var(--k-glow), 0 3px 6px rgba(0, 0, 0, .6);
  transition: transform .15s ease, box-shadow .2s ease;
}
.ac-slider__thumb::after {
  content: ""; position: absolute; inset: 5px; border-radius: 50%; background: var(--k-g2);
  box-shadow: 0 0 6px var(--k-accent);
}
.ac-slider--h .ac-slider__thumb { top: 50%; left: calc(var(--pos) * 100%); transform: translate(-50%, -50%); }
.ac-slider--v .ac-slider__thumb { left: 50%; bottom: calc(var(--pos) * 100%); transform: translate(-50%, 50%); }
.ac-slider:not(.is-dragging) .ac-slider__fill { transition: left .2s ease, right .2s ease, top .2s ease, bottom .2s ease; }
.ac-slider:not(.is-dragging) .ac-slider__thumb { transition: left .2s ease, bottom .2s ease, transform .15s ease, box-shadow .2s ease; }
.ac-slider__track:hover .ac-slider__thumb, .ac-slider.is-dragging .ac-slider__thumb {
  box-shadow: 0 0 0 2px var(--k-accent), 0 0 18px var(--k-accent), 0 3px 6px rgba(0, 0, 0, .6);
}
.ac-slider--h.is-dragging .ac-slider__thumb { transform: translate(-50%, -50%) scale(1.12); }
.ac-slider--v.is-dragging .ac-slider__thumb { transform: translate(-50%, 50%) scale(1.12); }
.ac-slider__origin { position: absolute; background: rgba(200, 210, 245, .45); border-radius: 2px; }
.ac-slider--h .ac-slider__origin { left: calc(var(--o) * 100%); top: -3px; bottom: -3px; width: 2px; margin-left: -1px; }
.ac-slider--v .ac-slider__origin { bottom: calc(var(--o) * 100%); left: -3px; right: -3px; height: 2px; margin-bottom: -1px; }
.ac-slider__bubble { left: 50%; bottom: calc(100% + 8px); transform: translate(-50%, 4px) scale(.9); }
.ac-slider--v .ac-slider__bubble { bottom: auto; left: calc(100% + 10px); top: 50%; transform: translate(-4px, -50%) scale(.9); }
.ac-slider.is-dragging .ac-slider__bubble, .ac-slider.is-bubble .ac-slider__bubble { opacity: 1; transform: translate(-50%, 0) scale(1); }
.ac-slider--v.is-dragging .ac-slider__bubble, .ac-slider--v.is-bubble .ac-slider__bubble { transform: translate(0, -50%) scale(1); }

/* ───────────────────────── toggle ───────────────────────── */
.ac-toggle {
  --t-w: 34px; --t-h: 19px;
  position: relative; display: inline-flex; align-items: center; gap: 8px;
  padding: 3px 4px; margin: 0; border: 0; border-radius: 99px; background: none;
  color: var(--text); cursor: pointer; outline: none; font: inherit; text-align: left;
}
.ac-toggle--sm { --t-w: 28px; --t-h: 16px; gap: 6px; }
.ac-toggle.is-aurora { --k-accent: var(--a-violet); }
.ac-toggle__track {
  position: relative; flex: none; width: var(--t-w); height: var(--t-h); border-radius: 99px;
  background: linear-gradient(180deg, rgba(0, 0, 0, .5), rgba(255, 255, 255, .04));
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, .7), 0 0 0 1px rgba(140, 160, 220, .16);
  transition: background .25s ease, box-shadow .25s ease;
}
.ac-toggle__thumb {
  position: absolute; top: 2px; left: 2px;
  width: calc(var(--t-h) - 4px); height: calc(var(--t-h) - 4px); border-radius: 50%;
  background: radial-gradient(circle at 38% 30%, #9aa3c4, #5b6488 60%, #3a4262);
  box-shadow: 0 1px 3px rgba(0, 0, 0, .6);
  transition: transform .25s cubic-bezier(.3, 1.4, .5, 1), background .25s ease, box-shadow .25s ease;
}
.ac-toggle.is-on .ac-toggle__track {
  background: linear-gradient(90deg, color-mix(in oklab, var(--k-accent) 50%, #3b3fd8), var(--k-accent));
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, .35), 0 0 0 1px color-mix(in oklab, var(--k-accent) 60%, transparent),
    0 0 14px color-mix(in oklab, var(--k-accent) 55%, transparent);
}
.ac-toggle.is-aurora.is-on .ac-toggle__track { background: var(--grad-aurora); }
.ac-toggle.is-on .ac-toggle__thumb {
  transform: translateX(calc(var(--t-w) - var(--t-h)));
  background: radial-gradient(circle at 38% 30%, #ffffff, #eef2ff 55%, #cfd6f2);
  box-shadow: 0 1px 3px rgba(0, 0, 0, .4), 0 0 8px rgba(255, 255, 255, .7);
}
.ac-toggle:hover .ac-toggle__track { box-shadow: inset 0 1px 3px rgba(0, 0, 0, .7), 0 0 0 1px rgba(160, 180, 240, .3); }
.ac-toggle.is-on:hover .ac-toggle__track {
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, .35), 0 0 0 1px var(--k-accent), 0 0 18px color-mix(in oklab, var(--k-accent) 65%, transparent);
}
.ac-toggle:focus-visible { box-shadow: 0 0 0 2px color-mix(in oklab, var(--k-accent) 80%, transparent); }
/* press: the thumb squishes toward its travel direction */
.ac-toggle:active .ac-toggle__thumb { width: calc(var(--t-h) + 1px); }
.ac-toggle.is-on:active .ac-toggle__thumb { margin-left: -5px; }
.ac-toggle.is-on .ac-toggle__track::after { /* a soft pulse the moment it switches on */
  content: ""; position: absolute; inset: -3px; border-radius: inherit; pointer-events: none;
  box-shadow: 0 0 0 1px color-mix(in oklab, var(--k-accent) 70%, transparent);
  animation: ac-toggle-on .5s ease-out both;
}
@keyframes ac-toggle-on { from { opacity: 1; transform: scale(.9); } to { opacity: 0; transform: scale(1.25); } }
.ac-toggle__label { align-items: flex-start; }
.ac-toggle:not(.is-on) .ac-toggle__label .ac-zh { color: var(--text-dim); }
.ac-toggle__label .ac-zh { transition: color .2s ease; }

/* ───────────────────────── select: shared ───────────────────────── */
.ac-select { display: flex; flex-direction: column; gap: 5px; min-width: 0; }
.ac-select__label { flex-direction: row; align-items: baseline; gap: 6px; }

/* segmented */
.ac-seg__track {
  --i: 0; --n: 2;
  position: relative; display: grid; grid-template-columns: repeat(var(--n), minmax(0, 1fr));
  padding: 3px; border-radius: 10px;
  background: linear-gradient(180deg, rgba(0, 0, 0, .42), rgba(255, 255, 255, .025));
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, .6), 0 0 0 1px rgba(140, 160, 220, .12);
}
.ac-seg__ind {
  position: absolute; top: 3px; bottom: 3px; left: 3px;
  width: calc((100% - 6px) / var(--n));
  transform: translateX(calc(var(--i) * 100%));
  border-radius: 7px;
  background: linear-gradient(180deg, color-mix(in oklab, var(--k-accent) 30%, #262e4a), color-mix(in oklab, var(--k-accent) 14%, #161b2c));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .12), 0 0 0 1px color-mix(in oklab, var(--k-accent) 55%, transparent),
    0 0 14px color-mix(in oklab, var(--k-accent) 28%, transparent);
  transition: transform .26s cubic-bezier(.3, 1.25, .5, 1);
}
.ac-seg__opt {
  position: relative; z-index: 1; min-width: 0; padding: 5px 6px; margin: 0; border: 0; background: none;
  border-radius: 7px; cursor: pointer; outline: none;
  font: 500 11px/1.2 var(--font-ui); color: var(--text-dim); letter-spacing: .02em;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis; transition: color .2s ease, text-shadow .2s ease;
}
.ac-seg__opt:hover { color: var(--text); background: rgba(255, 255, 255, .035); }
.ac-seg__opt:active { transform: scale(.96); }
.ac-seg__opt { transition: color .2s ease, text-shadow .2s ease, background .2s ease, transform .12s ease; }
.ac-seg__opt.is-on { color: #fff; text-shadow: 0 0 10px color-mix(in oklab, var(--k-accent) 80%, transparent); }
.ac-seg__opt:focus-visible { box-shadow: 0 0 0 1.5px color-mix(in oklab, var(--k-accent) 90%, transparent); }

/* dropdown */
.ac-dd__btn {
  display: flex; align-items: center; justify-content: space-between; gap: 8px; width: 100%; min-width: 0;
  padding: 6px 8px 6px 11px; margin: 0; border: 0; border-radius: 9px; cursor: pointer; outline: none;
  font: 500 12px/1.2 var(--font-ui); color: var(--text); text-align: left;
  background: linear-gradient(180deg, rgba(40, 48, 76, .75), rgba(20, 25, 40, .85));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .07), 0 0 0 1px rgba(140, 160, 220, .16), 0 2px 8px rgba(0, 0, 0, .3);
  transition: box-shadow .2s ease, background .2s ease, transform .12s ease;
}
.ac-dd__btn:active { transform: scale(.985); }
.ac-dd__btn:hover {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .09), 0 0 0 1px color-mix(in oklab, var(--k-accent) 45%, transparent), 0 2px 10px rgba(0, 0, 0, .35);
}
.ac-dd__btn:focus-visible, .ac-dd.is-open .ac-dd__btn {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .09), 0 0 0 1.5px var(--k-accent), 0 0 16px color-mix(in oklab, var(--k-accent) 30%, transparent);
}
.ac-dd__text { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.ac-dd__chev { flex: none; width: 14px; height: 14px; color: var(--text-dim); transition: transform .22s ease, color .2s ease; }
.ac-dd__chev svg { width: 100%; height: 100%; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.ac-dd.is-open .ac-dd__chev { transform: rotate(180deg); color: var(--k-accent); }
.ac-dd__pop {
  --k-accent: var(--a-cyan);
  position: fixed; z-index: 10000; overflow-y: auto; overscroll-behavior: contain; outline: none;
  padding: 5px; border-radius: 12px; box-sizing: border-box; max-width: min(420px, calc(100vw - 16px));
  font-family: var(--font-ui);
  background: linear-gradient(180deg, rgba(26, 32, 52, .97), rgba(12, 15, 25, .98));
  -webkit-backdrop-filter: blur(18px) saturate(1.3); backdrop-filter: blur(18px) saturate(1.3);
  box-shadow: 0 0 0 1px rgba(140, 160, 220, .18), 0 18px 50px rgba(0, 0, 0, .6), 0 0 30px color-mix(in oklab, var(--k-accent) 10%, transparent);
  opacity: 0; transform: translateY(-4px) scale(.98); transform-origin: top center;
  transition: opacity .14s ease, transform .18s cubic-bezier(.2, .9, .3, 1.1);
  scrollbar-width: thin; scrollbar-color: rgba(140, 160, 220, .3) transparent;
}
.ac-dd__pop.is-up { transform: translateY(4px) scale(.98); transform-origin: bottom center; }
.ac-dd__pop.is-shown { opacity: 1; transform: none; }
.ac-dd__group {
  padding: 8px 9px 4px; font-size: 11px; font-weight: 600; letter-spacing: .1em; text-transform: uppercase;
  color: var(--text-faint); position: sticky; top: -5px; background: rgba(16, 20, 33, .96); z-index: 1;
}
.ac-dd__opt {
  display: flex; align-items: baseline; gap: 8px; padding: 6px 10px 6px 6px; border-radius: 7px;
  cursor: pointer; font-size: 12.5px; color: var(--text-dim); white-space: nowrap;
  transition: background .12s ease;
}
.ac-dd__check {
  flex: none; width: 6px; height: 6px; border-radius: 50%; align-self: center; margin: 0 2px;
  background: transparent; transition: background .15s ease;
}
.ac-dd__olabel { color: var(--text); }
.ac-dd__osub { margin-left: auto; padding-left: 12px; font-size: var(--fs-cap, 11px); letter-spacing: .06em; text-transform: uppercase; color: var(--text-faint); }
.ac-dd__opt.is-active { background: color-mix(in oklab, var(--k-accent) 14%, rgba(60, 72, 110, .35)); }
.ac-dd__opt.is-selected .ac-dd__check { background: var(--k-accent); box-shadow: 0 0 8px var(--k-accent); }
.ac-dd__opt.is-selected .ac-dd__olabel { color: #fff; }

/* ───────────────────────── envelope editor ───────────────────────── */
.ac-env {
  --e-accent: var(--a-amber);
  --k-accent: var(--e-accent);
  position: relative; width: 100%; height: var(--env-h, 150px); min-width: 180px;
  border-radius: var(--radius-sm);
  background:
    radial-gradient(120% 90% at 20% 0%, color-mix(in oklab, var(--e-accent) 7%, transparent), transparent 60%),
    linear-gradient(180deg, rgba(6, 8, 15, .6), rgba(6, 8, 15, .32));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .04), 0 0 0 1px var(--line);
  transition: box-shadow .2s ease;
}
.ac-env:focus-within {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .04), 0 0 0 1.5px color-mix(in oklab, var(--e-accent) 70%, transparent);
}
.ac-env__canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; touch-action: none; border-radius: inherit; }
.ac-env__bubble { left: 0; top: 0; transform: translate(0, 0); }
.ac-env.is-bubble .ac-env__bubble { opacity: 1; }
.ac-env:not(.is-bubble) .ac-env__bubble { transition: opacity .16s ease; }

/* ───────────────────────── XY pad ───────────────────────── */
.ac-xy {
  --xy-accent: var(--a-cyan);
  --k-accent: var(--xy-accent);
  position: relative; width: 100%; aspect-ratio: 4 / 3; min-height: 120px; overflow: hidden;
  border-radius: var(--radius); cursor: crosshair; touch-action: none; outline: none;
  background:
    radial-gradient(120% 100% at 50% 110%, color-mix(in oklab, var(--a-violet) 12%, transparent), transparent 60%),
    linear-gradient(180deg, rgba(8, 10, 18, .72), rgba(5, 6, 12, .82));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .05), inset 0 0 40px rgba(0, 0, 0, .55), 0 0 0 1px var(--line);
  transition: box-shadow .2s ease;
}
.ac-xy.is-focus {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .05), inset 0 0 40px rgba(0, 0, 0, .55),
    0 0 0 1.5px color-mix(in oklab, var(--xy-accent) 75%, transparent);
}
.ac-xy__canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
.ac-xy__puck {
  position: absolute; left: 0; top: 0; width: 22px; height: 22px; margin: -11px 0 0 -11px;
  border-radius: 50%; pointer-events: none; will-change: transform;
  background: radial-gradient(circle at 36% 30%, #ffffff 0%, color-mix(in oklab, var(--xy-accent) 55%, #fff) 30%, var(--xy-accent) 62%, color-mix(in oklab, var(--xy-accent) 60%, #1a1f40) 100%);
  box-shadow: 0 0 0 1.5px rgba(255, 255, 255, .35), 0 0 16px 3px color-mix(in oklab, var(--xy-accent) 75%, transparent),
    0 0 44px 12px color-mix(in oklab, var(--xy-accent) 28%, transparent);
}
.ac-xy.is-aurora .ac-xy__puck {
  background: radial-gradient(circle at 36% 30%, #ffffff 0%, #d9fbff 22%, var(--a-cyan) 50%, var(--a-violet) 78%, var(--a-pink) 100%);
  box-shadow: 0 0 0 1.5px rgba(255, 255, 255, .35), 0 0 16px 3px color-mix(in oklab, var(--a-cyan) 70%, transparent),
    0 0 46px 14px color-mix(in oklab, var(--a-violet) 30%, transparent);
}
.ac-xy__puck::before, .ac-xy__puck::after {
  content: ""; position: absolute; inset: -9px; border-radius: 50%;
  border: 1px solid color-mix(in oklab, var(--xy-accent) 60%, transparent);
  opacity: .0; animation: ac-xy-breathe 3.2s ease-in-out infinite;
}
.ac-xy__puck::after { animation-delay: -1.6s; }
@keyframes ac-xy-breathe {
  0% { transform: scale(.55); opacity: .0; }
  30% { opacity: .55; }
  100% { transform: scale(1.45); opacity: 0; }
}
.ac-xy.is-dragging .ac-xy__puck { width: 26px; height: 26px; margin: -13px 0 0 -13px; }
.ac-xy.is-dragging .ac-xy__puck::before, .ac-xy.is-dragging .ac-xy__puck::after { animation-duration: 1.1s; }
.ac-xy__axis {
  position: absolute; display: flex; align-items: baseline; gap: 6px; pointer-events: none; z-index: 1;
  padding: 2px 7px; border-radius: 6px; background: rgba(6, 8, 15, .45);
}
.ac-xy__axis .ac-lbl { flex-direction: row; align-items: baseline; gap: 5px; }
.ac-xy__axis .ac-zh { font-size: 11.5px; color: var(--text-dim); }
.ac-xy__axis .ac-en { font-size: var(--fs-cap, 11px); }
.ac-xy__v { font: 600 11px/1 var(--font-mono); font-variant-numeric: tabular-nums; color: var(--xy-accent); font-weight: 600; }
.ac-xy.is-aurora .ac-xy__v { color: var(--a-cyan); }
.ac-xy__axis--x { left: 50%; bottom: 7px; transform: translateX(-50%); }
.ac-xy__axis--y { left: 7px; top: 50%; transform: translate(-50%, -50%) rotate(-90deg) translateY(50%); transform-origin: center; }
.ac-xy.is-dragging .ac-xy__axis .ac-zh { color: var(--text); }
.ac-xy__axis { transition: opacity .25s ease; }
.ac-xy.is-near-x .ac-xy__axis--x, .ac-xy.is-near-y .ac-xy__axis--y { opacity: .28; }

/* ───────────────────────── keyboard ───────────────────────── */
.ac-kb {
  --kb-h: 128px; --kb-bh: 62%; --nw: 36;
  position: relative; width: 100%; height: var(--kb-h); touch-action: none; isolation: isolate;
  overflow-x: clip; overflow-y: visible; /* bloom may rise above the keys but never widens the page */
  padding-top: 5px; border-radius: 0 0 12px 12px;
  background: linear-gradient(180deg, #05060b, #0b0e18);
  box-shadow: inset 0 0 0 1px rgba(140, 160, 220, .08), 0 14px 40px rgba(0, 0, 0, .5);
}
.ac-kb::before { /* aurora key-bed line */
  content: ""; position: absolute; left: 0; right: 0; top: 0; height: 2px; z-index: 3; pointer-events: none;
  background: var(--grad-aurora); opacity: .75;
  box-shadow: 0 0 10px rgba(92, 242, 255, .45), 0 0 22px rgba(167, 139, 250, .3);
}
.ac-kb__keys { position: absolute; left: 3px; right: 3px; top: 5px; bottom: 3px; cursor: pointer; }
.ac-kb__key {
  position: absolute; top: 0; box-sizing: border-box;
  /* glow colour: the key's aurora hue, pushed toward white by velocity (harder = hotter) */
  --kg: color-mix(in oklab, var(--kc) calc(100% - var(--vel, .8) * 32%), #ffffff);
}
.ac-kb__key::before { /* bloom: rises a little above the key bed, never over the editor */
  content: ""; position: absolute; left: 50%; bottom: 50%; width: 280%; height: 84%;
  transform: translateX(-50%) scaleY(.7); transform-origin: 50% 100%; pointer-events: none; opacity: 0; z-index: -1;
  background: radial-gradient(closest-side, color-mix(in oklab, var(--kg) 60%, transparent), transparent);
  transition: opacity .6s ease-out, transform .7s cubic-bezier(.2, .8, .2, 1);
}
.ac-kb__key--w {
  left: calc(var(--i) * 100% / var(--nw) + 1px); width: calc(100% / var(--nw) - 2px); height: 100%;
  border-radius: 0 0 5px 5px;
  background: linear-gradient(180deg, #aeb6cc 0%, #e7ebf6 9%, #f3f5fb 62%, #dde2ef 92%, #c9d0e2 100%);
  box-shadow: inset 0 -4px 0 rgba(30, 38, 64, .16), inset 0 1px 0 rgba(255, 255, 255, .9), 0 1px 2px rgba(0, 0, 0, .5);
  transition: background .5s ease-out, box-shadow .5s ease-out, top .08s ease;
}
.ac-kb__key--b { /* no transform / z-index: keys must not form stacking contexts (bloom sits behind) */
  left: calc((var(--c) - .3) * 100% / var(--nw)); width: calc(100% / var(--nw) * .6); height: var(--kb-bh);
  border-radius: 0 0 4px 4px;
  background: linear-gradient(180deg, #0a0c14 0%, #1d2334 12%, #151a28 78%, #262d42 88%, #10131d 100%);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .06), inset 1px 0 0 rgba(255, 255, 255, .05), inset -1px 0 0 rgba(0, 0, 0, .5),
    0 3px 4px rgba(0, 0, 0, .55);
  transition: background .5s ease-out, box-shadow .5s ease-out;
}
.ac-kb__key--w:hover { background: linear-gradient(180deg, #aeb6cc 0%, #eef1fa 9%, #fafbfe 62%, #e6eaf5 92%, #d2d8e8 100%); }
.ac-kb__key--b:hover { background: linear-gradient(180deg, #0a0c14 0%, #262d42 12%, #1d2334 78%, #2f3750 88%, #151925 100%); }

.ac-kb__key.is-active, .ac-kb__key.is-pressed { transition-duration: .05s; }
.ac-kb__key.is-active::before, .ac-kb__key.is-pressed::before {
  opacity: calc(.5 + var(--vel, .8) * .5); transform: translateX(-50%) scaleY(calc(.78 + var(--vel, .8) * .3)); transition-duration: .06s, .12s;
}
.ac-kb__key--w.is-active, .ac-kb__key--w.is-pressed {
  background: linear-gradient(180deg,
    color-mix(in oklab, var(--kc) 35%, #9aa5c4) 0%,
    color-mix(in oklab, var(--kc) 22%, #f4f6fc) 22%,
    color-mix(in oklab, var(--kc) 62%, #ffffff) 70%,
    var(--kc) 100%);
  box-shadow: inset 0 -2px 0 rgba(0, 0, 0, .12), inset 0 0 12px color-mix(in oklab, var(--kc) 45%, transparent),
    0 0 calc(8px + var(--vel, .8) * 10px) color-mix(in oklab, var(--kg) 70%, transparent),
    0 0 calc(18px + var(--vel, .8) * 24px) color-mix(in oklab, var(--kg) 34%, transparent);
  top: 1px;
  animation: ac-key-hit-w .42s cubic-bezier(.2, .8, .2, 1);
}
@keyframes ac-key-hit-w {
  0% { top: 2px; box-shadow: inset 0 -1px 0 rgba(0, 0, 0, .1), inset 0 0 22px rgba(255, 255, 255, .9), 0 0 16px var(--kg), 0 0 46px color-mix(in oklab, var(--kg) 60%, transparent); }
}
@keyframes ac-key-hit-b {
  0% { box-shadow: inset 0 1px 0 rgba(255, 255, 255, .3), 0 0 16px var(--kg), 0 0 40px color-mix(in oklab, var(--kg) 60%, transparent); }
}
.ac-kb__key--b.is-active, .ac-kb__key--b.is-pressed {
  background: linear-gradient(180deg, #0a0c14 0%, color-mix(in oklab, var(--kc) 35%, #1a2033) 18%, color-mix(in oklab, var(--kc) 85%, #ffffff) 100%);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .15), 0 0 calc(7px + var(--vel, .8) * 8px) color-mix(in oklab, var(--kg) 80%, transparent),
    0 0 calc(16px + var(--vel, .8) * 22px) color-mix(in oklab, var(--kg) 40%, transparent);
  animation: ac-key-hit-b .42s cubic-bezier(.2, .8, .2, 1);
}

/* note names on C keys, qwerty hints, scale marks */
.ac-kb__name {
  position: absolute; left: 0; right: 0; bottom: 6px; text-align: center; pointer-events: none;
  font: 600 10px/1 var(--font-mono); color: rgba(30, 38, 64, .55); letter-spacing: .02em;
}
.ac-kb__key.is-active .ac-kb__name, .ac-kb__key.is-pressed .ac-kb__name { color: rgba(10, 14, 30, .7); }
.ac-kb__hint {
  position: absolute; left: 0; right: 0; bottom: 20px; text-align: center; pointer-events: none;
  font: 600 10px/1 var(--font-ui); color: rgba(30, 38, 64, .4); text-transform: uppercase;
}
.ac-kb__key--b .ac-kb__hint { bottom: 8px; color: rgba(210, 220, 255, .38); }
.ac-kb__key--w:not(.is-c) .ac-kb__hint { bottom: 8px; }
.ac-kb.has-scale .ac-kb__key.in-scale::after {
  content: ""; position: absolute; left: 50%; width: 6px; height: 6px; margin-left: -3px; border-radius: 50%;
  pointer-events: none; background: var(--a-teal); box-shadow: 0 0 6px var(--a-teal);
}
.ac-kb.has-scale .ac-kb__key--w.in-scale::after { top: 12px; opacity: .8; }
.ac-kb.has-scale .ac-kb__key--b.in-scale::after { top: 8px; }
.ac-kb.has-scale .ac-kb__key.is-root::after { background: var(--a-amber); box-shadow: 0 0 8px var(--a-amber); width: 7px; height: 7px; margin-left: -3.5px; opacity: 1; }
.ac-kb.has-scale .ac-kb__key--w.out-scale:not(.is-active):not(.is-pressed) {
  background: linear-gradient(180deg, #8a93aa 0%, #b5bccd 9%, #bec4d4 62%, #aeb5c8 92%, #9fa7bb 100%);
}
.ac-kb.has-scale .ac-kb__key--b.out-scale:not(.is-active):not(.is-pressed) {
  background: linear-gradient(180deg, #06070c 0%, #0f121c 50%, #0c0e16 100%);
}

/* narrow keys (phones / wide ranges): thin out labels */
.ac-kb.is-narrow .ac-kb__name { font-size: 7.5px; bottom: 4px; letter-spacing: 0; }
.ac-kb.is-narrow .ac-kb__hint { font-size: 8px; }
.ac-kb.is-tiny .ac-kb__hint { display: none; }
.ac-kb.is-tiny .ac-kb__name { font-size: 0; }
.ac-kb.is-tiny:not(.has-scale) .ac-kb__key.is-c::after { /* tiny C marker instead of the name */
  content: ""; position: absolute; left: 50%; bottom: 5px; width: 3px; height: 3px; margin-left: -1.5px;
  border-radius: 50%; background: rgba(30, 38, 64, .45);
}
.ac-kb.is-narrow.has-scale .ac-kb__key.in-scale::after { width: 4px; height: 4px; margin-left: -2px; }

@media (prefers-reduced-motion: reduce) {
  .ac-knob *, .ac-slider *, .ac-toggle *, .ac-select *, .ac-dd__pop, .ac-kb__key, .ac-kb__key::before, .ac-xy__puck {
    transition-duration: 0s !important;
  }
  .ac-kb__key { animation: none !important; }
  .ac-xy__puck::before, .ac-xy__puck::after { animation: none; }
}