Merge p15-w2-controls-fixes into dev

Phase 15 follow-up: fix seven control-panel + knob defects from Daniel's smoke
test — greyer panel ground, drag scrollbar + body-scroll lock, light caption
icons, centered WAVE slider, milder scrim, overlay above header/footer, and
real RadialKnob pointer capture (site-wide stuck-knob fix).

DeepDrftPublic/wwwroot/styles/deepdrft-styles.css

@@ -399,8 +399,9 @@ h2, h3, h4, h5, h6,
    section labels are LIGHT (static). The slider track/thumb and the lamp toggles are green.
    ============================================================================= */
 .waveform-visualizer-control-panel.mix-visualizer-controls-bar {
-    /* Lighter-navy elevated panel ground (§5: navy-mid). */
+    /* Greyed panel ground — desaturated charcoal so the blue slider reads against it (defect #1).
-    background: var(--deepdrft-navy-mid);
+       Token is tunable in deepdrft-tokens.css without touching this rule. */
+    background: var(--deepdrft-panel-ground);
     /* Square corners + thin light border — NowPlayingCard chrome (§5). */
     border: 1px solid var(--deepdrft-border-light);
     border-radius: 0;
@@ -424,11 +425,12 @@ h2, h3, h4, h5, h6,
 
 /* ── Row layout (§3). Each row is a horizontal band. Row 1 (MODE) and row 3 (WAVE) use
    space-between so the right-pinned control (color / width) hugs the far edge. Row 2 (LAVA) uses
-   flex-start so its label + four knobs group left rather than spreading edge-to-edge. ── */
+   flex-start so its label + four knobs group left rather than spreading edge-to-edge.
+   align-items: center so the WAVE slider and section label vertically center with each other (defect #4). ── */
 .waveform-visualizer-control-panel .wvc-row {
     display: flex;
     flex-direction: row;
-    align-items: flex-start;
+    align-items: center;
     gap: 0.85rem 1rem;
 }
 
@@ -454,7 +456,7 @@ h2, h3, h4, h5, h6,
 .waveform-visualizer-control-panel .wvc-row-left {
     display: flex;
     flex-direction: row;
-    align-items: flex-start;
+    align-items: center;
     gap: 0.85rem 1rem;
 }
 
@@ -496,29 +498,52 @@ h2, h3, h4, h5, h6,
     width: 100%;
 }
 
-/* Caption icons + section labels render LIGHT (§5/§9 colour principle: static/decorative = light). MudIcon
+/* Caption icons render LIGHT (§5/§9: static/decorative = light). !important beats the scoped
-   is portaled here too, so this is a plain global descendant selector — no ::deep, no scope attribute (CSS
+   .mix-visualizer-control ::deep .mix-visualizer-control-icon rule (which sets green for the legacy
-   isolation does not reach inside the overlay). The knob arcs/pointers + slider stay green (interactive). */
+   inline mount) when the icon also carries mix-visualizer-control-icon. Lamp toggles are MudIconButton
+   not MudIcon so they are unaffected — they stay green (interactive, Color.Primary). (defect #3) */
 .waveform-visualizer-control-panel .waveform-visualizer-control-icon {
-    color: var(--deepdrft-white);
+    color: var(--deepdrft-white) !important;
     opacity: 0.85;
 }
 
 /* ── The modal overlay (Phase 15 §4). MudOverlay is already a full-viewport flex scrim that centers its
    content (.mud-overlay { display:flex; align-items:center; justify-content:center }), which gives the
-   screen-centered panel on every host for free — we do NOT fight that positioning. We only (a) set the
+   screen-centered panel on every host for free — we do NOT fight that positioning. We:
-   mild modal tint from the SINGLE --deepdrft-modal-scrim-alpha token (§10.5, one point of change) and
+   (a) Raise the overlay z-index above the header (100) and the player-dock footer (1200/1300) so the
-   (b) cap the centered content's height so a tall both-on deck scrolls inside the modal rather than
+       scrim tints the ENTIRE viewport uniformly — header and footer included (defect #7). The panel
-   overflowing the viewport. The overlay portals to the body, so these are plain global rules (no scope
+       content needs z-index: auto (inherits from stacking context) so it sits above the scrim naturally;
-   attribute). The doubled .mud-overlay-scrim.mud-overlay-dark selector (0,2,0) outranks MudBlazor's own
+       the RadialKnob capture div at 9999 remains above everything.
-   .mud-overlay-dark (0,1,0), so the tint wins regardless of stylesheet load order. ── */
+   (b) Set the mild tint from the SINGLE --deepdrft-modal-scrim-alpha token (§10.5, defect #6).
+   (c) Remove overflow-y:auto on the content wrapper — it was the source of the drag scrollbar (defect #2).
+       The panel's max-width/flex-column already contain its size; the outer overlay clips at 100vh.
+   (d) Suppress body scroll while the overlay is present so no page-scroll occurs during a drag (defect #2).
+   The overlay portals to the body, so these are plain global rules (no scope attribute). The doubled
+   .mud-overlay-scrim.mud-overlay-dark selector (0,2,0) outranks MudBlazor's own .mud-overlay-dark (0,1,0),
+   so the tint wins regardless of stylesheet load order. ── */
+
+/* Raise the overlay itself above the sticky header (z-index:100) and the fixed player dock (z-index:1200).
+   Use 1400 so it sits above the minimized-dock FAB (1300) too. The panel content inherits this context
+   and stacks above the scrim; the RadialKnob capture div (z-index:9999) stays highest. */
+.waveform-visualizer-control-overlay {
+    z-index: 1400 !important;
+}
+
 .waveform-visualizer-control-overlay .mud-overlay-scrim.mud-overlay-dark {
     background-color: rgba(var(--deepdrft-scrim-rgb), var(--deepdrft-modal-scrim-alpha));
 }
 
+/* No overflow-y:auto — removing it eliminates the spurious scrollbar that appeared while dragging a
+   knob (defect #2). The panel's flex-column layout is self-contained and never overflows the overlay. */
 .waveform-visualizer-control-overlay .mud-overlay-content {
     max-height: 90vh;
-    overflow-y: auto;
+    overflow: visible;
+}
+
+/* Lock body scroll while the controls overlay is open so the page cannot be scrolled during a
+   knob drag (defect #2). :has() degrades gracefully in older browsers (no lock, no crash). */
+body:has(.waveform-visualizer-control-overlay) {
+    overflow: hidden;
 }
 
 @media (max-width: 419.98px) {

DeepDrftShared.Client/Components/RadialKnob.razor

@@ -1,15 +1,29 @@
 @using System.Globalization
+@inject IJSRuntime JS
+@implements IAsyncDisposable
 
-<!-- Global mouse capture container when dragging -->
+<!-- Drag-shield: full-viewport overlay while dragging.
+     position:fixed; inset:0; z-index:9999 so it sits above all overlays (the controls modal is z-index:1400).
+     Provides the cursor hint and blocks stray clicks on underlying content during a drag.
+     Event delivery is NOT via this div — setPointerCapture on the knob element routes
+     pointermove/pointerup/pointercancel directly to the knob regardless of where the cursor is,
+     even outside the browser window. This overlay is a belt-and-suspenders UX guard only. -->
 @if (_isDragging)
 {
-    <div style="position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; z-index: 9999; cursor: ns-resize;"
+    <div style="position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; z-index: 9999; cursor: ns-resize;">
-         @onmousemove="@OnGlobalMouseMove" @onmouseup="@OnGlobalMouseUp">
     </div>
 }
 
+<!-- Knob element owns pointer capture during drag.
+     @onpointerdown initiates drag and calls setPointerCapture via knob.js.
+     @onpointermove / @onpointerup / @onpointercancel are delivered here (not to the overlay)
+     for the captured pointer, even when the cursor has left the browser window. -->
 <div class="radial-knob" style="width: @(Size)px; height: @(Size)px; display: inline-block; position: relative;"
-     @onmousedown="@OnMouseDown">
+     @ref="_knobRef"
+     @onpointerdown="@OnPointerDown"
+     @onpointermove="@OnPointerMove"
+     @onpointerup="@OnPointerUp"
+     @onpointercancel="@OnPointerCancel">
 
     <!-- SVG Knob -->
     <svg width="@Size" height="@Size" viewBox="0 0 100 100">
@@ -78,6 +92,9 @@
     [Parameter] public MudBlazor.Color Color { get; set; } = MudBlazor.Color.Primary;
     [Parameter] public bool HoldValue { get; set; } = false;
 
+    private ElementReference _knobRef;
+    private IJSObjectReference? _knobModule;
+
     private bool _isDragging = false;
     private double _lastMouseY = 0;
     private double _dragValue = 0;
@@ -150,25 +167,36 @@
         return y.ToString("F1", CultureInfo.InvariantCulture);
     }
 
-    private async Task OnMouseDown(MouseEventArgs e)
+    private async Task OnPointerDown(PointerEventArgs e)
     {
         _isDragging = true;
         _lastMouseY = e.ClientY;
         _dragValue = Value; // Initialize drag value with current value
 
-        // Add global mouse event handlers using Blazor's event handling
+        // Load the JS module on first drag (lazy — avoids import cost until the user interacts).
+        _knobModule ??= await JS.InvokeAsync<IJSObjectReference>(
+            "import", "./_content/DeepDrftShared.Client/js/knob/knob.js");
+
+        // Capture the pointer on the knob element so pointermove/pointerup are delivered
+        // even when the cursor leaves the browser window mid-drag.
+        await _knobModule.InvokeVoidAsync("capturePointer", _knobRef, e.PointerId);
+
+        // The full-viewport capture div (rendered when _isDragging) is a belt-and-suspenders
+        // guard that blocks stray clicks on underlying content while dragging.
         StateHasChanged();
     }
 
-    private async Task OnGlobalMouseMove(MouseEventArgs e)
+    // Delivered to the knob element because setPointerCapture routes the captured pointer here.
+    private async Task OnPointerMove(PointerEventArgs e)
     {
         if (_isDragging)
         {
-            await UpdateValueFromMouse(e);
+            await UpdateValueFromPointer(e);
         }
     }
 
-    private async Task OnGlobalMouseUp(MouseEventArgs e)
+    // pointerup implicitly releases pointer capture — no explicit releasePointerCapture needed.
+    private async Task OnPointerUp(PointerEventArgs e)
     {
         if (_isDragging && HoldValue)
         {
@@ -183,9 +211,35 @@
         StateHasChanged();
     }
 
-    private async Task UpdateValueFromMouse(MouseEventArgs e)
+    // Pointer capture cancelled by OS (e.g. Alt+Tab, system gesture) — end drag cleanly.
+    // Delivered to the knob element (the capturing element). Release capture explicitly since
+    // the implicit release on pointerup does not apply to pointercancel.
+    private async Task OnPointerCancel(PointerEventArgs e)
     {
-        // Calculate vertical delta from last mouse position
+        if (_knobModule != null)
+        {
+            try { await _knobModule.InvokeVoidAsync("releasePointer", _knobRef, e.PointerId); }
+            catch (JSException) { /* element may already be gone */ }
+        }
+
+        _isDragging = false;
+        StateHasChanged();
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_knobModule != null)
+        {
+            try { await _knobModule.DisposeAsync(); }
+            catch (JSDisconnectedException) { /* circuit torn down */ }
+        }
+
+        GC.SuppressFinalize(this);
+    }
+
+    private async Task UpdateValueFromPointer(PointerEventArgs e)
+    {
+        // Calculate vertical delta from last pointer position
         double deltaY = _lastMouseY - e.ClientY; // Inverted: up = positive, down = negative
         _lastMouseY = e.ClientY;
 

DeepDrftShared.Client/Interop/knob/knob.ts

@@ -0,0 +1,20 @@
+/**
+ * knob - pointer capture helpers for RadialKnob.
+ *
+ * setPointerCapture / releasePointerCapture are not exposed via Blazor's
+ * ElementReference, so the component delegates here via JS interop.
+ * Both functions are no-ops when the element reference is stale (e.g. the
+ * component was disposed between the JS call and the microtask).
+ */
+
+/** Capture the pointer on the given element so pointermove/pointerup are
+ *  delivered even when the cursor leaves the browser window. */
+export function capturePointer(el: Element, pointerId: number): void {
+    (el as HTMLElement).setPointerCapture(pointerId);
+}
+
+/** Release a previously captured pointer.  Called on pointercancel.
+ *  pointerup releases capture implicitly, but we call this on cancel too. */
+export function releasePointer(el: Element, pointerId: number): void {
+    (el as HTMLElement).releasePointerCapture(pointerId);
+}

DeepDrftShared.Client/wwwroot/styles/deepdrft-tokens.css

@@ -26,7 +26,10 @@
     --deepdrft-scrim-rgb: 13, 27, 42;
     /* Modal scrim opacity — the SINGLE point of truth for the visualizer-controls overlay tint
        (Phase 15 §4/§10.5). Mild so the panel reads as modal without a blackout. Change here once. */
-    --deepdrft-modal-scrim-alpha: 0.3;
+    --deepdrft-modal-scrim-alpha: 0.15;
+    /* Panel ground — desaturated from navy-mid toward charcoal so the blue slider stands out.
+       Tunable: increase blue channel (e.g. #1e2235) to recover warmth, lower (e.g. #1a1d22) to go darker. */
+    --deepdrft-panel-ground: #1e2028;
 
     /* Wireframe font stack */
     --deepdrft-font-display: "Cormorant Garamond", Georgia, serif;