fix(web): wipe background-image too — the widget's black void is a CSS backdrop gradient, not a color

The 15:34 take's box interior is the widget's OWN full-canvas opaque paint — a
black void with wide content strips at the top/bottom and a right-edge bar —
arriving AFTER the first-second blank-transparent dumps. A background-color-only
!important wipe (b4bba4b) can't touch it because CSS gradients/backdrops are
background-IMAGE, not background-color.

OBS's fix for this exact symptom is background-image:none (obsproject/obs-studio#6659:
"set the CSS for html and body to background: none !important"). Injection now wipes
background-image:none!important on html,body,html * alongside the color wipe; HTML
overlay art (<img>/DOM/CSS shapes) survives — that is browser-source semantics.

Also re-arms WidgetDumpRemaining=5 ~30s after nav so the next take dumps the real
document INSIDE the recording window (the previous dumps proved blank at +1s and
missed the later backdrop paint).

9/9 WebView2Manager tests, 0 warnings.

HANDOFF.md

@@ -8,37 +8,30 @@ audio-silence are addressed).
 
 ## ACTIVE THREAD (ONE problem at a time)
 
-**Web-uri transparency — branch (a) CONFIRMED and FIX-APPLIED, awaiting the verify take.**
-The 12:54/13:50 dumps proved the REAL widget document captures TRANSPARENT
-(`%TEMP%\ytLive-web-8d7234ec…-w1..5.png` alpha max 0/logged alpha 100% zero) YET the
-recording kept showing a black opaque box over the element rect (1231,679,705,396 — crisp
-edges, interior mean RGB ≈(1,6,13), NOT the desktop). Conclusion: the OLD inline
-`element.style.background='transparent'` injection only holds while the page has nothing
-to paint; once the widget connects and repaints a container background-COLOR, the capture
-re-opaques → black box. That is the OBS-solved class ("all web-uri resources paint their
-own background").
+**Web-uri transparency — second hardening applied (background-image wipe), awaiting take.**
+The 15:34 take: the recording's box interior is the widget's OWN full-canvas opaque paint
+(bright content strips at top/bottom + right bar over a black void) — NOT desktop, NOT a
+compositor blend. The real-document dumps showed blank-transparent at +1s and the page's
+backdrop appears later; a background-COLOR-only `!important` wipe (b4bba4b) leaves CSS
+background-IMAGE (gradient/backdrop) intact — the OBS answer is `background: none
+!important`, background-image too (obsproject/obs-studio#6659).
 
-**Slice 14 change (commit target):** `WebView2Manager.TransparentBackgroundScript` is now a
-pre-parse `<style id='ytl-transparent-bg'>` wiping `background-color:transparent !important`
-on `html,body,html *` (background-images/art survive — only background-COLOR targeted).
-Idempotent by element id; `!important` outranks every page rule (OBS forums 2016 `body {
-background-color: rgba(0,0,0,0) !important }` + div variant, woahtech OBS custom-CSS guide —
-both cited in the commit message and `MyMistakes.md`).
-- `internal const` + regression test `TransparentBackgroundScript_Is_A_Important_Element_Wide_Wipe`
-  (asserts element-wide `!important`, style-element form, and that the losing inline
-  `.style.background=` form is gone).
-- Build 0 warnings; 9/9 WebView2Manager tests pass.
+**Slice 15 (commit target, the fix):**
+- `TransparentBackgroundScript` now also wipes `background-image:none!important` on
+  `html,body,html *` (gradients/backdrops die; `<img>`/DOM art survives — OBS semantics).
+- `NavigateCompleted` re-arms `WidgetDumpRemaining = 5` ~30s in, so this take dumps the
+  real document INSIDE the recording window (the missing evidence last time).
+- Test extended (asserts `background-image:none!important` present, weak inline form absent).
 
 ## THE ONE REMAINING STEP (verify, no further analysis)
 
-1. User REPLACES the app (build is current) and records the Live scene, widget animating,
-   like the 12:54/13:50 takes.
-2. Verdict: element rect shows scene bg with widget art over it (NO black box) → transparency
-   C LOSED, push gate #1 clears. If it still shows a solid black box you can SEE at a glance
-   inside the widget's 705×396 area, bring it + then (and ONLY then) audit what other layer
-   paints that rect in the composite — the web capture has been exonerated twice.
-3. Then the queued layer-order-save bug (dragging an element over another doesn't persist
-   `SortOrder`) is the next single use case.
+1. User records the Live scene, widget animating (pre-record ~35s so the 30s re-arm dump
+   fires mid-take).
+2. Verdict: element rect shows the scene backdrop behind the widget art (no black box/void)
+   → transparency CLOSED, push gate #1 clears. If a black void persists BEYOND a visible
+   background-image, it's not background painting and only chroma-key remains — bring the
+   take and we do the compositor key, not more capture investigation.
+3. Then the queued layer-order-save bug (reorder doesn't persist `SortOrder`) is next.
 
 ## Other threads (paused)
 

MyMistakes.md

@@ -76,15 +76,22 @@ answer (valid for arbitrary pages for a decade) is an injected pre-parse `<style
 with `!important` beating every page rule:
 https://obsproject.com/forum/threads/translucent-transparent-browser-source.59549/
 (`body { background-color: rgba(0,0,0,0) !important }`) + the div-level variant for
-stubborn widgets (woahtech.com OBS custom-CSS guide). Applied 2026-09-10: the
-injection now appends a style element wiping `background-color:transparent!important`
-on `html,body,html *` (background-IMAGE and art survive). Self-inflicted again: the
-agent re-derived the whole transparency story (recording pixel archaeology,
-compositor blend re-verification) instead of reading this entry — the premise was
-already wrong once and the instrument said transparent, which it did because the
-capture had NOT been repainted yet. Verify take: if the 705×396 element rect shows
-the scene bg behind the widget art (animation visible, no black box) the loop closes.
-Do NOT re-derive this story a third time.
+stubborn widgets (woahtech.com OBS custom-CSS guide). Applied 2026-09-10 (b4bba4b):
+injection appends a style element wiping `background-color:transparent!important`
+on `html,body,html *`. **Second half (2026-09-10, 15:34 take): a background-COLOR wipe
+is NOT enough.** The 15:34 interior ASCII shows a black void with bright content strips
+at top/bottom + a right-edge bar — the widget's full-canvas CSS **background-image**
+(gradient/backdrop) painted after connect. The OBS fix for that is
+`background: none !important` / `background-image:none!important`
+(obsproject/obs-studio#6659 — "set the CSS for html and body to background: none
+!important"). Wipe both moving forward; overlay art is `<img>`/DOM and survives.
+Also the dumps only covered +1s (blank-transparent); the widget's backdrop paint
+arrives later, so the mid-recording dump set is now re-armed ~30s in. Verify take:
+element rect shows scene bg behind the widget art (animation, no black void) → loop
+closes. Self-inflicted again: the agent re-derived the whole transparency story
+(recording pixel archaeology, compositor blend re-verification) instead of reading
+this entry — the instrument said transparent because the capture had NOT been
+repainted yet. Do NOT re-derive this story a third time.
 
 ### Shrink / re-encode an image for the README (screenshots → small hero image)
 

Services/WebView2Manager.cs

@@ -167,15 +167,22 @@ public sealed class WebView2Manager : IDisposable
     // and the div-level variant for stubborn widgets, woahtech.com OBS custom-CSS guide).
     // A `<style>` node injected before parse, with `!important`, outranks every page rule
     // (only an author !important beats a later document-order !important; ours runs first).
-    // Only background-COLOR is wiped — background images and the widget art survive.
+    // Only background-COLOR was wiped at first — the 15:34 take showed the widget's own
+    // full-canvas backdrop surviving as the box's black void: that paint is a CSS
+    // background-IMAGE (gradient/backdrop), and the OBS fix for the same symptom is
+    // `background: none !important` / background-image none, not color alone
+    // (obsproject/obs-studio#6659 — "set the CSS for html and body to background: none
+    // !important"). Wipe background-image too; HTML overlay art (the widget's content) is
+    // <img>/DOM/CSS shapes and survives — only container decorations are removed, which is
+    // OBS-browser-source semantics for a transparent overlay.
     internal const string TransparentBackgroundScript =
         "(function(){" +
         "if(document.getElementById('ytl-transparent-bg'))return;" +
         "var s=document.createElement('style');" +
         "s.id='ytl-transparent-bg';" +
         "s.appendChild(document.createTextNode(" +
-        "'html,body{background-color:transparent!important;margin:0!important;overflow:hidden!important;}'" +
-        "'html,body,html *{background-color:transparent!important;}'" +
+        "'html,body{background-color:transparent!important;background-image:none!important;margin:0!important;overflow:hidden!important;}'" +
+        "'html,body,html *{background-color:transparent!important;background-image:none!important;}'" +
         "));" +
         "(document.head||document.documentElement).appendChild(s);" +
         "})();";
@@ -210,6 +217,16 @@ public sealed class WebView2Manager : IDisposable
                     // transparent margins the injection promises has never been
                     // verified (MyMistakes: "? VERIFY").
                     session.WidgetDumpRemaining = 5;
+                    // The first five dumps fire within ~1s of completion (usually BEFORE the
+                    // recording starts) — re-arm ~30s in so the same real document gets dumped
+                    // INSIDE a recording's window too. Next take therefore nukes the gap that
+                    // hid what the page actually painted while recording.
+                    var rearm = session;
+                    _ = Task.Run(async () =>
+                    {
+                        await Task.Delay(TimeSpan.FromSeconds(30));
+                        rearm.WidgetDumpRemaining = 5;
+                    });
                 }
                 _ = CaptureFrame(source.Id);
             };

ytLive.Tests/WebView2ManagerTests.cs

@@ -121,6 +121,7 @@ public sealed class WebView2ManagerTests
         var script = WebView2Manager.TransparentBackgroundScript;
 
         Assert.Contains("background-color:transparent!important", script);
+        Assert.Contains("background-image:none!important", script);
         Assert.Contains("html,body,html *", script);
         Assert.Contains("document.createElement('style')", script);
         Assert.DoesNotContain(".style.background=", script);