/* Full-viewport fixed backdrop. Sits behind the detail content (.mix-detail-foreground is z-index:1)
   and never intercepts pointer events — except the zoom slider, which re-enables them on itself.

   Footer clip (Phase 10 W1, spec §2c): the backdrop must stop cleanly ABOVE the audio player bar so
   no lava/waveform pixel paints over or under it. `overflow: hidden` clips the canvas to this box, and
   `bottom` is inset by the player bar's LIVE height — `--player-height`, the custom property the player
   already publishes on :root via its ResizeObserver (AudioPlayerBar + Interop/layout/spacer.ts). That
   var tracks the expanded bar's border-box height across breakpoints/error-banner reflow, and resets to
   0 when the bar is minimized — so the clip line follows the bar's actual current height with no extra
   coupling: when minimized the var is 0 and the backdrop reaches the viewport bottom (the floating FAB,
   z-index 1300, simply sits over it — there is no full-width bar to clip to), matching spec §2c. The
   0px fallback keeps the backdrop full-height on any page that doesn't host the player. */
.mix-waveform-bg {
    position: fixed;
    inset: 0;
    bottom: var(--player-height, 0px);
    z-index: 0;
    pointer-events: none;
    overflow: hidden;
}

/* The canvas fills the viewport. All ribbon shading (luminous depth, soft edges) is drawn inside the
   canvas by the WebGL2 fragment shader. NO CSS backdrop-filter: it was a confirmed per-frame perf killer
   on the Canvas predecessor and is exactly the cost the GPU move exists to eliminate (spec §2, §5.2);
   the glass treatment returns in-shader in Wave 3. */
.mix-waveform-canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: block;
}